feat(rust): discover providers at shared SDK dispatch boundaries

litellm-rust/crates/ai-gateway/src/io/ocr.rs

@@ -1 +1 @@
-pub use crate::ocr::{OcrRequest, ocr};
+pub use crate::ocr::{OcrRequest, ocr, ocr_provider_supported};

litellm-rust/crates/ai-gateway/src/io/responses_ws.rs

@@ -40,6 +40,14 @@ impl ResponsesWebSocketConnection {
         options: &RequestOptions,
         _context: &LiteLlmRequestContext,
     ) -> Result<Self, Error> {
+        if !litellm_core::responses::websocket::native_websocket_supported(
+            options
+                .custom_llm_provider
+                .as_deref()
+                .unwrap_or("openai"),
+        ) {
+            return Err(Error::Unsupported("unsupported native WebSocket provider"));
+        }
         let headers = string_headers("Responses WebSocket", options.extra_headers.clone())?;
         let mut request = input
             .url

litellm-rust/crates/ai-gateway/src/ocr/mod.rs

@@ -35,6 +35,10 @@ pub async fn ocr(
         .await
 }
 
+pub fn ocr_provider_supported(model: &str, provider: &str) -> bool {
+    common_utils::ocr_provider_config(provider, model).is_some()
+}
+
 #[cfg(test)]
 mod tests {
     use crate::integrations::types::RequestHooks;

litellm-rust/crates/core/src/audio_transcription/mod.rs

@@ -26,5 +26,9 @@ pub async fn audio_transcription(
     .await
 }
 
+pub fn transcription_provider_supported(provider: &str) -> bool {
+    prepare::provider_config(provider).is_some()
+}
+
 #[cfg(test)]
 mod tests;

litellm-rust/crates/core/src/audio_transcription/prepare.rs

@@ -9,7 +9,9 @@ use super::transformation::{AudioTranscriptionAuth, AudioTranscriptionProviderCo
 use super::types::{AudioTranscriptionRequest, ProviderAudioTranscriptionRequest};
 
 #[tracing::instrument(target = "litellm::function_trace", level = "trace", skip_all)]
-fn provider_config(provider: &str) -> Option<&'static dyn AudioTranscriptionProviderConfig> {
+pub(super) fn provider_config(
+    provider: &str,
+) -> Option<&'static dyn AudioTranscriptionProviderConfig> {
     #[cfg(feature = "bedrock-auth")]
     if provider == "bedrock" {
         return Some(&BEDROCK_AUDIO_TRANSCRIPTION_CONFIG);

litellm-rust/crates/core/src/messages/mod.rs

@@ -37,5 +37,9 @@ pub async fn messages_stream(
     execute_messages_provider_stream(request, options.clone()).await
 }
 
+pub fn messages_provider_supported(provider: &str) -> bool {
+    common_utils::messages_provider_config(provider).is_some()
+}
+
 #[cfg(test)]
 mod tests;

litellm-rust/crates/core/src/responses/websocket.rs

@@ -2,6 +2,14 @@ use crate::Error;
 use crate::constants::{OPENAI_RESPONSES_DEFAULT_API_BASE, OPENAI_RESPONSES_PATH};
 use crate::responses::types::{ResponsesWsEvent, ResponsesWsEventType, ResponsesWsTransformResult};
 
+pub fn native_websocket_supported(provider: &str) -> bool {
+    match provider {
+        "openai" => crate::providers::openai::responses::transformation::OPENAI_RESPONSES_WS_CONFIG
+            .supports_native_websocket(),
+        _ => false,
+    }
+}
+
 pub trait ResponsesWebSocketProviderConfig: Sync {
     fn supports_native_websocket(&self) -> bool {
         false

litellm-rust/crates/python-bridge/src/lib.rs

@@ -35,6 +35,16 @@ impl ResponsesWebSocketConnection {
         options: NativeRequestOptions,
         context: NativeRequestContext,
     ) -> PyResult<Bound<'py, PyAny>> {
+        if let Some(reason) = responses_websocket_decline(
+            "responses websocket",
+            options.provider("openai"),
+            false,
+            false,
+            false,
+            None,
+        ) {
+            return Err(crate::errors::RustBridgeDeclined::new_err(reason));
+        }
         let options: litellm_core::request_options::RequestOptions = options.into();
         let context: litellm_core::request_context::LiteLlmRequestContext = context.into();
         let request = ResponsesWebSocketRequest { url: request.url };
@@ -68,6 +78,25 @@ impl ResponsesWebSocketConnection {
     }
 }
 
+#[pyfunction]
+#[pyo3(signature = (_model, custom_llm_provider, *, stream=false, has_agentic_hook=false, has_custom_client=false, request_format=None))]
+fn responses_websocket_decline(
+    _model: &str,
+    custom_llm_provider: &str,
+    stream: bool,
+    has_agentic_hook: bool,
+    has_custom_client: bool,
+    request_format: Option<&str>,
+) -> Option<String> {
+    routes::definition::request_decline(
+        litellm_core::responses::websocket::native_websocket_supported(custom_llm_provider),
+        stream,
+        has_agentic_hook,
+        has_custom_client,
+        request_format,
+    )
+}
+
 #[pymodule(gil_used = false)]
 mod _native {
     use pyo3::prelude::*;
@@ -77,6 +106,10 @@ mod _native {
         super::errors::register(module)?;
         super::routes::register(module)?;
         module.add_class::<super::ResponsesWebSocketConnection>()?;
+        module.add_function(wrap_pyfunction!(
+            super::responses_websocket_decline,
+            module
+        )?)?;
         super::diagnostics::register(module)
     }
 }
@@ -101,16 +134,20 @@ mod tests {
             let expected = [
                 "RustBridgeDeclined",
                 "RustUpstreamError",
+                "ocr_decline",
                 "ocr",
                 "aocr",
+                "transcription_decline",
                 "transcription",
                 "atranscription",
+                "messages_decline",
                 "messages",
                 "amessages",
                 "chat_completions_decline",
                 "chat_completions",
                 "achat_completions",
                 "ResponsesWebSocketConnection",
+                "responses_websocket_decline",
                 "gil_stats",
             ];
 

litellm-rust/crates/python-bridge/src/marshal.rs

@@ -84,6 +84,12 @@ pub(crate) struct NativeRequestOptions {
     vertex: Option<NativeVertexOptions>,
 }
 
+impl NativeRequestOptions {
+    pub(crate) fn provider(&self, default: &'static str) -> &str {
+        self.custom_llm_provider.as_deref().unwrap_or(default)
+    }
+}
+
 impl From<NativeRequestOptions> for litellm_core::request_options::RequestOptions {
     fn from(input: NativeRequestOptions) -> Self {
         Self {

litellm-rust/crates/python-bridge/src/routes/audio_transcription.rs

@@ -22,6 +22,23 @@ fn prepare_transcription(
     options: NativeRequestOptions,
     context: NativeRequestContext,
 ) -> PyResult<impl Future<Output = Result<Value, Error>> + Send + 'static> {
+    if let Some(reason) = transcription_decline(
+        &input.model,
+        input.options.provider("bedrock"),
+        input
+            .optional_params
+            .get("stream")
+            .and_then(Value::as_bool)
+            .unwrap_or(false),
+        false,
+        false,
+        input
+            .optional_params
+            .get("response_format")
+            .and_then(Value::as_str),
+    ) {
+        return Err(crate::errors::RustBridgeDeclined::new_err(reason));
+    }
     let context: LiteLlmRequestContext = context.into();
     let audio = input.audio;
     Ok(async move {
@@ -38,10 +55,30 @@ fn prepare_transcription(
     })
 }
 
+#[pyfunction]
+#[pyo3(signature = (_model, custom_llm_provider, *, stream=false, has_agentic_hook=false, has_custom_client=false, request_format=None))]
+fn transcription_decline(
+    _model: &str,
+    custom_llm_provider: &str,
+    stream: bool,
+    has_agentic_hook: bool,
+    has_custom_client: bool,
+    request_format: Option<&str>,
+) -> Option<String> {
+    super::definition::request_decline(
+        litellm_core::audio_transcription::transcription_provider_supported(custom_llm_provider),
+        stream,
+        has_agentic_hook,
+        has_custom_client,
+        request_format,
+    )
+}
+
 bridge_route! {
     sync = transcription,
     asynchronous = atranscription,
     request = AudioTranscriptionInputs,
     prepare = prepare_transcription,
     errors = core_error_to_pyerr,
+    extra = [transcription_decline],
 }

litellm-rust/crates/python-bridge/src/routes/chat_completions.rs

@@ -5,7 +5,6 @@ use litellm_core::chat_completions::chat_completions as run_route;
 use litellm_core::chat_completions::chat_completions_decline_reason;
 use litellm_core::chat_completions::types::{ChatCompletionsRequest, ChatCompletionsResponse};
 use litellm_core::request_context::LiteLlmRequestContext;
-use litellm_core::request_options::RequestOptions;
 use pyo3::prelude::*;
 use serde_json::{Map, Value};
 use std::future::Future;
@@ -40,26 +39,52 @@ fn prepare_chat_completions(
     })
 }
 
+fn preflight_context(context: &Bound<'_, PyAny>) -> PyResult<LiteLlmRequestContext> {
+    let metadata = context.getattr("metadata")?;
+    let user_id = if metadata.is_none() {
+        None
+    } else {
+        match metadata.get_item("user_id") {
+            Ok(value) => Some(if value.is_none() {
+                Value::Null
+            } else {
+                Value::Bool(true)
+            }),
+            Err(error) if error.is_instance_of::<pyo3::exceptions::PyKeyError>(context.py()) => {
+                None
+            }
+            Err(error) => return Err(error),
+        }
+    };
+    Ok(LiteLlmRequestContext {
+        metadata: user_id.map(|value| Map::from_iter([("user_id".into(), value)])),
+        request_metadata_fields: context.getattr("request_metadata_fields")?.extract()?,
+        ..Default::default()
+    })
+}
+
 #[pyfunction]
-#[pyo3(signature = (model, messages, optional_params=None, custom_llm_provider=None, *, options, context))]
+#[pyo3(signature = (model, messages, optional_params=None, custom_llm_provider=None, *, context, stream=false, has_custom_client=false, has_agentic_hook=false))]
+#[allow(
+    clippy::too_many_arguments,
+    reason = "PyO3 preserves chat preflight arguments alongside request features"
+)]
 fn chat_completions_decline(
     model: String,
     #[pyo3(from_py_with = litellm_python_interop::from_py)] messages: Value,
     #[pyo3(from_py_with = litellm_python_interop::from_py)] optional_params: Option<Value>,
     custom_llm_provider: Option<String>,
-    options: NativeRequestOptions,
-    context: NativeRequestContext,
+    context: &Bound<'_, PyAny>,
+    stream: bool,
+    has_custom_client: bool,
+    has_agentic_hook: bool,
 ) -> PyResult<Option<String>> {
-    if !matches!(
-        custom_llm_provider.as_deref(),
-        Some("anthropic" | "bedrock")
-    ) {
-        return Ok(Some(
-            "provider is not on the rust chat completions path".into(),
-        ));
+    if let Some(reason) =
+        super::definition::request_decline(true, stream, has_agentic_hook, has_custom_client, None)
+    {
+        return Ok(Some(reason));
     }
-    let context: LiteLlmRequestContext = context.into();
-    let options: RequestOptions = options.into();
+    let context = preflight_context(context)?;
     let optional_params = match optional_params {
         None | Some(Value::Null) => Map::new(),
         Some(Value::Object(params)) => params,
@@ -74,7 +99,6 @@ fn chat_completions_decline(
         custom_llm_provider.as_deref(),
         messages,
         &optional_params,
-        &options,
         &context,
     )
     .map(str::to_string))

litellm-rust/crates/python-bridge/src/routes/definition.rs

@@ -98,6 +98,29 @@ pub(super) fn add_function(
     module.add_function(function)
 }
 
+pub(crate) fn request_decline(
+    provider_supported: bool,
+    stream: bool,
+    has_agentic_hook: bool,
+    has_custom_client: bool,
+    request_format: Option<&str>,
+) -> Option<String> {
+    let reason = if !provider_supported {
+        Some("unsupported native provider")
+    } else if stream {
+        Some("native streaming is unavailable")
+    } else if has_agentic_hook {
+        Some("native agentic hooks are unavailable")
+    } else if has_custom_client {
+        Some("native custom clients are unavailable")
+    } else if request_format == Some("native") {
+        Some("native OCR response format is unavailable")
+    } else {
+        None
+    };
+    reason.map(str::to_string)
+}
+
 #[cfg(test)]
 mod tests {
     use std::ffi::CString;
@@ -262,6 +285,64 @@ for field in ('litellm_call_id', 'trace_id', 'request_model'):
         });
     }
 
+    #[test]
+    fn acceptance_and_execution_decline_unsupported_requests_before_io() {
+        Python::initialize();
+        Python::attach(|py| {
+            let module = PyModule::new(py, "routes").expect("module should be created");
+            crate::routes::register(&module).expect("routes should register");
+            module
+                .add_class::<crate::ResponsesWebSocketConnection>()
+                .unwrap();
+            module
+                .add_function(
+                    wrap_pyfunction!(crate::responses_websocket_decline, &module).unwrap(),
+                )
+                .unwrap();
+            let locals = crate::marshal::request_fixtures(py);
+            locals.set_item("routes", module).unwrap();
+            py.run(
+                c"
+for route, provider in (
+    ('messages', 'anthropic'),
+    ('transcription', 'bedrock'),
+    ('ocr', 'mistral'),
+    ('responses_websocket', 'openai'),
+):
+    decline = getattr(routes, route + '_decline')
+    assert decline('model', provider) is None, route
+    for flag in ('stream', 'has_agentic_hook', 'has_custom_client'):
+        assert decline('model', provider, **{flag: True}) is not None, (route, flag)
+    reason = decline('model', 'unsupported-native-provider')
+    assert reason is not None, route
+    request = Request(
+        messages=[], body={}, audio={}, document={}, optional_params={},
+        url='invalid-url-must-not-be-used',
+        options=Options(custom_llm_provider='unsupported-native-provider'),
+    )
+    functions = (
+        (routes.ResponsesWebSocketConnection.connect,)
+        if route == 'responses_websocket'
+        else (getattr(routes, route), getattr(routes, 'a' + route))
+    )
+    for execute in functions:
+        try:
+            execute(request, context=context)
+        except Exception as error:
+            assert type(error).__name__ == 'RustBridgeDeclined', (route, error)
+            assert str(error) == reason, (route, reason, error)
+        else:
+            raise AssertionError('unsupported request reached provider execution')
+assert routes.ocr_decline('model', 'mistral', request_format='native') is not None
+assert routes.ocr_decline('model', 'mistral', request_format='litellm') is None
+",
+                Some(&locals),
+                Some(&locals),
+            )
+            .expect("acceptance must match execution eligibility without I/O");
+        });
+    }
+
     #[test]
     fn generated_routes_execute_sync_and_async_contracts() {
         Python::initialize();

litellm-rust/crates/python-bridge/src/routes/messages.rs

@@ -20,6 +20,20 @@ fn prepare_messages(
     options: NativeRequestOptions,
     context: NativeRequestContext,
 ) -> PyResult<impl Future<Output = Result<AnthropicMessagesResponse, Error>> + Send + 'static> {
+    if let Some(reason) = messages_decline(
+        &input.model,
+        input.options.provider("anthropic"),
+        input
+            .body
+            .get("stream")
+            .and_then(Value::as_bool)
+            .unwrap_or(false),
+        false,
+        false,
+        input.body.get("response_format").and_then(Value::as_str),
+    ) {
+        return Err(crate::errors::RustBridgeDeclined::new_err(reason));
+    }
     let context: LiteLlmRequestContext = context.into();
     let body = required_value("body", input.body, Value::is_object, "dict")?;
     Ok(async move {
@@ -35,10 +49,30 @@ fn prepare_messages(
     })
 }
 
+#[pyfunction]
+#[pyo3(signature = (_model, custom_llm_provider, *, stream=false, has_agentic_hook=false, has_custom_client=false, request_format=None))]
+fn messages_decline(
+    _model: &str,
+    custom_llm_provider: &str,
+    stream: bool,
+    has_agentic_hook: bool,
+    has_custom_client: bool,
+    request_format: Option<&str>,
+) -> Option<String> {
+    super::definition::request_decline(
+        litellm_core::messages::messages_provider_supported(custom_llm_provider),
+        stream,
+        has_agentic_hook,
+        has_custom_client,
+        request_format,
+    )
+}
+
 bridge_route! {
     sync = messages,
     asynchronous = amessages,
     request = MessagesInputs,
     prepare = prepare_messages,
     errors = core_error_to_pyerr,
+    extra = [messages_decline],
 }

litellm-rust/crates/python-bridge/src/routes/mod.rs

@@ -1,7 +1,7 @@
 use pyo3::prelude::*;
 
 #[macro_use]
-mod definition;
+pub(crate) mod definition;
 
 #[cfg(feature = "trace-parity")]
 mod gateway_messages;

litellm-rust/crates/python-bridge/src/routes/ocr.rs

@@ -23,6 +23,23 @@ fn prepare_ocr(
     options: NativeRequestOptions,
     context: NativeRequestContext,
 ) -> PyResult<impl Future<Output = Result<Value, Error>> + Send + 'static> {
+    if let Some(reason) = ocr_decline(
+        &input.model,
+        input.options.provider("mistral"),
+        input
+            .optional_params
+            .get("stream")
+            .and_then(Value::as_bool)
+            .unwrap_or(false),
+        false,
+        false,
+        input
+            .optional_params
+            .get("req_format")
+            .and_then(Value::as_str),
+    ) {
+        return Err(crate::errors::RustBridgeDeclined::new_err(reason));
+    }
     let context: LiteLlmRequestContext = context.into();
     let document = input.document;
     Ok(async move {
@@ -43,10 +60,30 @@ fn prepare_ocr(
     })
 }
 
+#[pyfunction]
+#[pyo3(signature = (model, custom_llm_provider, *, stream=false, has_agentic_hook=false, has_custom_client=false, request_format=None))]
+fn ocr_decline(
+    model: &str,
+    custom_llm_provider: &str,
+    stream: bool,
+    has_agentic_hook: bool,
+    has_custom_client: bool,
+    request_format: Option<&str>,
+) -> Option<String> {
+    super::definition::request_decline(
+        litellm_ai_gateway::io::ocr::ocr_provider_supported(model, custom_llm_provider),
+        stream,
+        has_agentic_hook,
+        has_custom_client,
+        request_format,
+    )
+}
+
 bridge_route! {
     sync = ocr,
     asynchronous = aocr,
     request = OcrInputs,
     prepare = prepare_ocr,
     errors = ocr_error_to_pyerr,
+    extra = [ocr_decline],
 }

litellm/litellm_core_utils/litellm_logging.py

@@ -10,7 +10,8 @@ import subprocess
 import sys
 import time
 import traceback
-from collections.abc import Awaitable, Callable, Iterator, Mapping, Sequence
+from collections.abc import Awaitable, Callable, Generator, Iterator, Mapping, Sequence
+from contextlib import contextmanager
 from datetime import datetime as dt_object
 from functools import lru_cache
 from types import MappingProxyType, TracebackType
@@ -459,6 +460,7 @@ class Logging(LiteLLMLoggingBaseClass):
         log_raw_request_response: bool = False,
         supports_correlation_logging: bool = True,
     ):
+        self._suppress_next_pre_call: bool = False
         _input: Final[str | None] = messages  # save original value of messages
         if messages is not None:
             if isinstance(messages, str):
@@ -1188,7 +1190,19 @@ class Logging(LiteLLMLoggingBaseClass):
             additional_args.get("api_base", "")
         )
 
+    @contextmanager
+    def suppress_next_pre_call(self) -> Generator[None]:
+        previous: Final = self._suppress_next_pre_call
+        self._suppress_next_pre_call = True
+        try:
+            yield
+        finally:
+            self._suppress_next_pre_call = previous
+
     def pre_call(self, input, api_key, model=None, additional_args={}):
+        if self._suppress_next_pre_call:
+            self._suppress_next_pre_call = False
+            return
         # Log the exact input to the LLM API
         try:
             self._pre_call(

litellm/llms/anthropic/chat/handler.py

@@ -25,11 +25,6 @@ from litellm.llms.custom_httpx.http_handler import (
     _get_httpx_client,
     get_async_httpx_client,
 )
-from litellm.rust_bridge import chat_completions as rust_chat_completions_bridge
-from litellm.rust_bridge.chat_completions import rust_chat_completions_accepts
-from litellm.rust_bridge.dispatch import anative_first, native_first, provider_errors
-from litellm.rust_bridge.request import anthropic_options, request_context
-from litellm.rust_bridge.runtime import DispatchResult
 from litellm.types.llms.anthropic import (
     ContentBlockDelta,
     ContentBlockStart,
@@ -371,7 +366,12 @@ class AnthropicChatCompletion(BaseLLM):
         if config is None:
             raise ValueError(f"Provider config not found for model: {model} and provider: {custom_llm_provider}")
 
-        def prepare_python() -> tuple[dict[str, str], dict[str, object]]:  # mutable-ok: stream mutates data
+        def build_request() -> tuple[dict, dict]:  # mutable-ok: rewritten in place downstream
+            """Translate the request the Python way, returning `(headers, data)`.
+
+            The pair stays mutable because the streaming path rewrites it in
+            place (`data["stream"] = True`) before sending.
+            """
             request_data: Final = config.transform_request(
                 model=model,
                 messages=messages,
@@ -379,119 +379,32 @@ class AnthropicChatCompletion(BaseLLM):
                 litellm_params=litellm_params,
                 headers=headers,
             )
-            python_headers, data = update_request_with_filtered_beta(
+            return update_request_with_filtered_beta(
                 headers=headers,
                 request_data=request_data,
                 provider=custom_llm_provider,
             )
 
-            ## LOGGING
-            # Reaching here with `serves_via_rust` set means the Rust attempt
-            # declined at call time, before the provider was called, and already
-            # logged this request. That is the same attempt continuing.
-            if not serves_via_rust:
-                logging_obj.pre_call(
-                    input=messages,
-                    api_key=api_key,
-                    additional_args={
-                        "complete_input_dict": data,
-                        "api_base": api_base,
-                        "headers": python_headers,
-                    },
-                )
-            print_verbose(f"_is_function_call: {_is_function_call}")
-            return python_headers, data
+        headers, data = build_request()
 
-        # The Rust core owns the whole call for the subset it accepts, so ask
-        # before transforming: whichever path runs emits pre_call exactly once.
-        # `get_config` merges the class-level defaults (Anthropic's required
-        # `max_tokens` among them) that `transform_request` would have applied.
-        rust_optional_params: Final = {  # mutable-ok: json.dumps in the bridge rejects a mappingproxy
-            **AnthropicConfig.get_config(model=model),
-            **optional_params,
-        }
-        serves_via_rust: Final = rust_chat_completions_accepts(
-            model=model,
-            messages=messages,
-            optional_params=rust_optional_params,
-            custom_llm_provider=custom_llm_provider,
-            litellm_params=litellm_params,
-            stream=stream,
-        )
-        rust_logging_args: Final = {  # mutable-ok: logging callbacks read additional_args as a plain dict
-            "complete_input_dict": {  # mutable-ok: same, and it is serialized alongside its parent
-                "model": model,
-                "messages": messages,
-                **rust_optional_params,
-            },
-            "api_base": api_base,
-            "headers": headers,
-        }
-        if serves_via_rust:
-            logging_obj.pre_call(input=messages, api_key=api_key, additional_args=rust_logging_args)
-        log_rust_post_call: Final = rust_chat_completions_bridge.response_logger(
-            logging_obj=logging_obj,
-            messages=messages,
+        ## LOGGING
+        logging_obj.pre_call(
+            input=messages,
             api_key=api_key,
-            additional_args=rust_logging_args,
+            additional_args={
+                "complete_input_dict": data,
+                "api_base": api_base,
+                "headers": headers,
+            },
         )
-        rust_context: Final = request_context(
-            logging_obj=logging_obj,
-            request_model=logging_obj.model,
-            litellm_params=litellm_params,
-        )
-
-        def native_completion() -> DispatchResult[ModelResponse]:
-            return rust_chat_completions_bridge.chat_completions(
-                model=model,
-                messages=messages,
-                optional_params=rust_optional_params,
-                model_response=model_response,
-                api_key=api_key,
-                api_base=api_base,
-                custom_llm_provider=custom_llm_provider,
-                extra_headers=headers,
-                timeout=timeout,
-                on_response=log_rust_post_call,
-                anthropic=anthropic_options(litellm_params),
-                stream=bool(stream),
-                has_custom_client=client is not None,
-                eligible=serves_via_rust,
-                context=rust_context,
-            )
-
-        async def native_acompletion() -> DispatchResult[ModelResponse]:
-            return await rust_chat_completions_bridge.achat_completions(
-                model=model,
-                messages=messages,
-                optional_params=rust_optional_params,
-                model_response=model_response,
-                api_key=api_key,
-                api_base=api_base,
-                custom_llm_provider=custom_llm_provider,
-                extra_headers=headers,
-                timeout=timeout,
-                on_response=log_rust_post_call,
-                anthropic=anthropic_options(litellm_params),
-                stream=bool(stream),
-                has_custom_client=client is not None,
-                eligible=serves_via_rust,
-                context=rust_context,
-            )
-
-        @anative_first(
-            native=native_acompletion,
-            route="chat_completions",
-            errors=lambda: provider_errors(custom_llm_provider or "", model),
-        )
-        async def execute_async() -> ModelResponse | CustomStreamWrapper:
-            headers, data = prepare_python()
+        print_verbose(f"_is_function_call: {_is_function_call}")
+        if acompletion is True:
             if (
                 stream is True
             ):  # if function call - fake the streaming (need complete blocks for output parsing in openai format)
                 print_verbose("makes async anthropic streaming POST request")
                 data["stream"] = stream
-                return await self.acompletion_stream_function(
+                return self.acompletion_stream_function(
                     model=model,
                     messages=messages,
                     data=data,
@@ -513,7 +426,7 @@ class AnthropicChatCompletion(BaseLLM):
                     client=(client if client is not None and isinstance(client, AsyncHTTPHandler) else None),
                 )
             else:
-                return await self.acompletion_function(
+                return self.acompletion_function(
                     model=model,
                     messages=messages,
                     data=data,
@@ -535,14 +448,7 @@ class AnthropicChatCompletion(BaseLLM):
                     json_mode=json_mode,
                     timeout=timeout,
                 )
-
-        @native_first(
-            native=native_completion,
-            route="chat_completions",
-            errors=lambda: provider_errors(custom_llm_provider or "", model),
-        )
-        def execute_sync() -> ModelResponse | CustomStreamWrapper:
-            headers, data = prepare_python()
+        else:
             ## COMPLETION CALL
             if (
                 stream is True
@@ -574,12 +480,13 @@ class AnthropicChatCompletion(BaseLLM):
                 )
 
             else:
-                python_client: Final = (
-                    client if isinstance(client, HTTPHandler) else _get_httpx_client(params={"timeout": timeout})
-                )
+                if client is None or not isinstance(client, HTTPHandler):
+                    client = _get_httpx_client(params={"timeout": timeout})
+                else:
+                    client = client
 
                 try:
-                    response: Final = python_client.post(
+                    response: Final = client.post(
                         api_base,
                         headers=headers,
                         data=json.dumps(data),
@@ -600,21 +507,20 @@ class AnthropicChatCompletion(BaseLLM):
                         status_code=status_code,
                         headers=error_headers,
                     )
-            return config.transform_response(
-                model=model,
-                raw_response=response,
-                model_response=model_response,
-                logging_obj=logging_obj,
-                api_key=api_key,
-                request_data=data,
-                messages=messages,
-                optional_params=optional_params,
-                litellm_params=litellm_params,
-                encoding=encoding,
-                json_mode=json_mode,
-            )
 
-        return execute_async() if acompletion else execute_sync()
+        return config.transform_response(
+            model=model,
+            raw_response=response,
+            model_response=model_response,
+            logging_obj=logging_obj,
+            api_key=api_key,
+            request_data=data,
+            messages=messages,
+            optional_params=optional_params,
+            litellm_params=litellm_params,
+            encoding=encoding,
+            json_mode=json_mode,
+        )
 
     def embedding(self):
         # logic for parsing in - calling - parsing out model embedding calls

litellm/llms/anthropic/chat/transformation.py

@@ -315,6 +315,12 @@ class AnthropicConfig(AnthropicModelInfo, BaseConfig):
     def _resolved_provider(self) -> str:
         return self.custom_llm_provider or "anthropic"
 
+    @classmethod
+    def get_config_for_model(cls, model: str) -> dict[str, object]:
+        from pydantic import TypeAdapter
+
+        return TypeAdapter(dict[str, object]).validate_python(cls.get_config(model=model))
+
     @classmethod
     def get_config(cls, *, model: str | None = None):
         config: Final = super().get_config()

litellm/llms/anthropic/experimental_pass_through/messages/handler.py

@@ -559,27 +559,54 @@ def anthropic_messages_handler(
                 **kwargs,
             )
 
-    anthropic_messages_provider_config: BaseAnthropicMessagesConfig | None = None
+    def python_fallback():
+        anthropic_messages_provider_config: BaseAnthropicMessagesConfig | None = None
 
-    if custom_llm_provider is not None and custom_llm_provider in [provider.value for provider in LlmProviders]:
-        anthropic_messages_provider_config = ProviderConfigManager.get_provider_anthropic_messages_config(
-            model=model,
-            provider=litellm.LlmProviders(custom_llm_provider),
-        )
-    if anthropic_messages_provider_config is None and _deployment_passes_through_anthropic_messages(
-        kwargs.get("model_info")
-    ):
-        from litellm.llms.openai_like.messages.transformation import (
-            OpenAILikeAnthropicMessagesConfig,
-        )
+        if custom_llm_provider is not None and custom_llm_provider in [provider.value for provider in LlmProviders]:
+            anthropic_messages_provider_config = ProviderConfigManager.get_provider_anthropic_messages_config(
+                model=model,
+                provider=litellm.LlmProviders(custom_llm_provider),
+            )
+        if anthropic_messages_provider_config is None and _deployment_passes_through_anthropic_messages(
+            kwargs.get("model_info")
+        ):
+            from litellm.llms.openai_like.messages.transformation import (
+                OpenAILikeAnthropicMessagesConfig,
+            )
 
-        anthropic_messages_provider_config = OpenAILikeAnthropicMessagesConfig(
-            cache_control_ttl=_deployment_supports_cache_control_ttl(kwargs.get("model_info")),
-        )
-    if anthropic_messages_provider_config is None:
-        # Route to Responses API for OpenAI / Azure, chat/completions for everything else.
-        if _should_route_to_responses_api(custom_llm_provider, original_model, model):
-            return LiteLLMMessagesToResponsesAPIHandler.anthropic_messages_handler(
+            anthropic_messages_provider_config = OpenAILikeAnthropicMessagesConfig(
+                cache_control_ttl=_deployment_supports_cache_control_ttl(kwargs.get("model_info")),
+            )
+        if anthropic_messages_provider_config is None:
+            # Route to Responses API for OpenAI / Azure, chat/completions for everything else.
+            if _should_route_to_responses_api(custom_llm_provider, original_model, model):
+                return LiteLLMMessagesToResponsesAPIHandler.anthropic_messages_handler(
+                    max_tokens=max_tokens,
+                    messages=messages,
+                    model=original_model,
+                    metadata=metadata,
+                    stop_sequences=stop_sequences,
+                    stream=stream,
+                    system=system,
+                    temperature=temperature,
+                    thinking=thinking,
+                    tool_choice=tool_choice,
+                    tools=tools,
+                    top_k=top_k,
+                    top_p=top_p,
+                    _is_async=is_async,
+                    api_key=api_key,
+                    api_base=api_base,
+                    client=client,
+                    custom_llm_provider=custom_llm_provider,
+                    **kwargs,
+                )
+
+            # The in-gateway context_management polyfill runs inside
+            # ``async_anthropic_messages_handler`` so it can ``await`` the
+            # summarization model for ``compact_20260112``. ``context_management``
+            # is passed through as a regular kwarg.
+            return LiteLLMMessagesToCompletionTransformationHandler.anthropic_messages_handler(
                 max_tokens=max_tokens,
                 messages=messages,
                 model=original_model,
@@ -601,66 +628,87 @@ def anthropic_messages_handler(
                 **kwargs,
             )
 
-        # The in-gateway context_management polyfill runs inside
-        # ``async_anthropic_messages_handler`` so it can ``await`` the
-        # summarization model for ``compact_20260112``. ``context_management``
-        # is passed through as a regular kwarg.
-        return LiteLLMMessagesToCompletionTransformationHandler.anthropic_messages_handler(
-            max_tokens=max_tokens,
-            messages=messages,
-            model=original_model,
-            metadata=metadata,
-            stop_sequences=stop_sequences,
-            stream=stream,
-            system=system,
-            temperature=temperature,
-            thinking=thinking,
-            tool_choice=tool_choice,
-            tools=tools,
-            top_k=top_k,
-            top_p=top_p,
+        if custom_llm_provider is None:
+            raise ValueError(
+                f"custom_llm_provider is required for Anthropic messages, passed in model={model}, custom_llm_provider={custom_llm_provider}"
+            )
+
+        local_vars.update(kwargs)
+        anthropic_messages_optional_request_params: Final = (
+            AnthropicMessagesRequestUtils.get_requested_anthropic_messages_optional_param(
+                params=local_vars,
+                model=model,
+                drop_params=litellm_params.get("drop_params") is True,
+                custom_llm_provider=custom_llm_provider,
+            )
+        )
+        if is_reasoning_auto_summary_enabled():
+            thinking_param: Final = anthropic_messages_optional_request_params.get("thinking")
+            if isinstance(thinking_param, dict) and thinking_param.get("type") != "disabled":
+                anthropic_messages_optional_request_params["thinking"] = {
+                    **thinking_param,
+                    "display": "summarized",
+                }
+
+        return base_llm_http_handler.anthropic_messages_handler(
+            model=model,
+            messages=strip_provider_specific_fields_from_anthropic_messages(messages),
+            anthropic_messages_provider_config=anthropic_messages_provider_config,
+            anthropic_messages_optional_request_params=dict(anthropic_messages_optional_request_params),
             _is_async=is_async,
-            api_key=api_key,
-            api_base=api_base,
             client=client,
             custom_llm_provider=custom_llm_provider,
-            **kwargs,
+            litellm_params=litellm_params,
+            logging_obj=litellm_logging_obj,
+            api_key=api_key,
+            api_base=api_base,
+            stream=stream,
+            kwargs=kwargs,
         )
 
-    if custom_llm_provider is None:
-        raise ValueError(
-            f"custom_llm_provider is required for Anthropic messages, passed in model={model}, custom_llm_provider={custom_llm_provider}"
-        )
+    from pydantic import TypeAdapter
 
-    local_vars.update(kwargs)
-    anthropic_messages_optional_request_params: Final = (
-        AnthropicMessagesRequestUtils.get_requested_anthropic_messages_optional_param(
-            params=local_vars,
+    from litellm.rust_bridge.messages import dispatch_messages
+
+    return dispatch_messages(
+        model=model,
+        provider=custom_llm_provider,
+        messages=TypeAdapter(list[dict[str, object]]).validate_python(
+            strip_provider_specific_fields_from_anthropic_messages(messages)
+        ),
+        body=lambda: _native_messages_body(
+            params={**local_vars, **kwargs},
             model=model,
             drop_params=litellm_params.get("drop_params") is True,
-            custom_llm_provider=custom_llm_provider,
+            provider=custom_llm_provider,
+        ),
+        params=litellm_params,
+        logging=litellm_logging_obj,
+        api_key=api_key or dynamic_api_key,
+        api_base=api_base or dynamic_api_base,
+        stream=bool(stream),
+        asynchronous=bool(is_async),
+        has_custom_client=client is not None,
+        fallback=python_fallback,
+    )
+
+
+def _native_messages_body(params: dict[str, object], model: str, drop_params: bool, provider: str) -> dict[str, object]:
+    from pydantic import TypeAdapter
+
+    requested: Final = TypeAdapter(dict[str, object]).validate_python(
+        AnthropicMessagesRequestUtils.get_requested_anthropic_messages_optional_param(
+            params=params,
+            model=model,
+            drop_params=drop_params,
+            custom_llm_provider=provider,
         )
     )
-    if is_reasoning_auto_summary_enabled():
-        thinking_param: Final = anthropic_messages_optional_request_params.get("thinking")
-        if isinstance(thinking_param, dict) and thinking_param.get("type") != "disabled":
-            anthropic_messages_optional_request_params["thinking"] = {
-                **thinking_param,
-                "display": "summarized",
-            }
-
-    return base_llm_http_handler.anthropic_messages_handler(
-        model=model,
-        messages=strip_provider_specific_fields_from_anthropic_messages(messages),
-        anthropic_messages_provider_config=anthropic_messages_provider_config,
-        anthropic_messages_optional_request_params=dict(anthropic_messages_optional_request_params),
-        _is_async=is_async,
-        client=client,
-        custom_llm_provider=custom_llm_provider,
-        litellm_params=litellm_params,
-        logging_obj=litellm_logging_obj,
-        api_key=api_key,
-        api_base=api_base,
-        stream=stream,
-        kwargs=kwargs,
-    )
+    thinking_param: Final = requested.get("thinking")
+    if (
+        is_reasoning_auto_summary_enabled()
+        and isinstance(thinking_param, dict)
+        and thinking_param.get("type") != "disabled"
+    ):
+        return {**requested, "thinking": {**thinking_param, "display": "summarized"}}
+    return requested

litellm/llms/base_llm/chat/transformation.py

@@ -8,7 +8,7 @@ from collections.abc import AsyncIterator, Iterator
 from typing import TYPE_CHECKING, Any, Final, Union
 
 import httpx
-from pydantic import BaseModel
+from pydantic import BaseModel, TypeAdapter
 
 from litellm.constants import DEFAULT_MAX_TOKENS, RESPONSE_FORMAT_TOOL_NAME
 from litellm.llms.custom_httpx.http_handler import AsyncHTTPHandler, HTTPHandler
@@ -70,6 +70,10 @@ class BaseConfig(ABC):
     def __init__(self):
         pass
 
+    @classmethod
+    def get_config_for_model(cls, model: str) -> dict[str, object]:
+        return TypeAdapter(dict[str, object]).validate_python(cls.get_config())
+
     @classmethod
     def get_config(cls):
         return {

litellm/llms/bedrock/chat/converse_handler.py

@@ -1,6 +1,4 @@
 import json
-from collections.abc import Mapping
-from types import MappingProxyType
 from typing import Any, Final
 
 import httpx
@@ -16,11 +14,6 @@ from litellm.llms.custom_httpx.http_handler import (
     _get_httpx_client,
     get_async_httpx_client,
 )
-from litellm.rust_bridge import chat_completions as rust_chat_completions_bridge
-from litellm.rust_bridge.chat_completions import rust_chat_completions_accepts
-from litellm.rust_bridge.dispatch import anative_first, native_first, provider_errors
-from litellm.rust_bridge.request import bedrock_options, request_context
-from litellm.rust_bridge.runtime import DispatchResult
 from litellm.types.utils import ModelResponse
 from litellm.utils import CustomStreamWrapper
 
@@ -29,22 +22,6 @@ from ..common_utils import BedrockError, _get_all_bedrock_regions
 from .invoke_handler import AWSEventStreamDecoder, MockResponseIterator, make_call
 
 
-def _sigv4_principal(credentials: Credentials | None) -> Mapping[str, str]:
-    if credentials is None:
-        return MappingProxyType({})
-    return MappingProxyType(
-        {
-            key: value
-            for key, value in (
-                ("aws_access_key_id", credentials.access_key),
-                ("aws_secret_access_key", credentials.secret_key),
-                ("aws_session_token", credentials.token),
-            )
-            if value is not None
-        }
-    )
-
-
 def make_sync_call(
     client: HTTPHandler | None,
     api_base: str,
@@ -215,9 +192,6 @@ class BedrockConverseLLM(BaseAWSLLM):
         )
 
         ## LOGGING
-        # The Rust path already logged this request's pre_call before handing
-        # it here, and it only declines before the provider is called, so this
-        # is the same attempt continuing rather than a second one.
         if not skip_pre_call_logging:
             logging_obj.pre_call(
                 input=messages,
@@ -390,94 +364,12 @@ class BedrockConverseLLM(BaseAWSLLM):
         # Filter beta headers in HTTP headers before making the request
         headers = update_headers_with_filtered_beta(headers=headers, provider="bedrock_converse")
 
-        # The Rust core owns the whole call for the subset it accepts. Ask
-        # before transforming so whichever path runs emits pre_call once, and
-        # hand down the credentials, region and endpoint this handler already
-        # resolved so both paths sign as the same principal. Bearer-token auth
-        # resolves no SigV4 principal at all, and each path reads that token
-        # itself.
-        rust_optional_params: Final = {  # mutable-ok: json.dumps in the bridge rejects a mappingproxy
-            **optional_params,
-            **_sigv4_principal(credentials),
-            "aws_region_name": aws_region_name,
-        }
-        serves_via_rust: Final = rust_chat_completions_accepts(
-            model=model,
-            messages=messages,
-            optional_params=rust_optional_params,
-            custom_llm_provider="bedrock",
-            litellm_params=litellm_params,
-            stream=stream,
-        )
-        rust_logging_args: Final = {  # mutable-ok: logging callbacks read additional_args as a plain dict
-            "complete_input_dict": {  # mutable-ok: same, and it is serialized alongside its parent
-                "messages": messages,
-                **optional_params,
-            },
-            "api_base": proxy_endpoint_url,
-            "headers": headers,
-        }
-        if serves_via_rust:
-            logging_obj.pre_call(input=messages, api_key="", additional_args=rust_logging_args)
-        log_rust_post_call: Final = rust_chat_completions_bridge.response_logger(
-            logging_obj=logging_obj,
-            messages=messages,
-            api_key="",
-            additional_args=rust_logging_args,
-        )
-        rust_context: Final = request_context(
-            logging_obj=logging_obj,
-            request_model=logging_obj.model,
-            litellm_params=litellm_params,
-        )
-
-        def native_completion() -> DispatchResult[ModelResponse]:
-            return rust_chat_completions_bridge.chat_completions(
-                model=model,
-                messages=messages,
-                optional_params=rust_optional_params,
-                model_response=model_response,
-                api_key=api_key,
-                api_base=proxy_endpoint_url,
-                custom_llm_provider="bedrock",
-                extra_headers=headers,
-                timeout=timeout,
-                on_response=log_rust_post_call,
-                bedrock=bedrock_options(rust_optional_params),
-                stream=bool(stream),
-                has_custom_client=client is not None,
-                eligible=serves_via_rust,
-                context=rust_context,
-            )
-
-        async def native_acompletion() -> DispatchResult[ModelResponse]:
-            return await rust_chat_completions_bridge.achat_completions(
-                model=model,
-                messages=messages,
-                optional_params=rust_optional_params,
-                model_response=model_response,
-                api_key=api_key,
-                api_base=proxy_endpoint_url,
-                custom_llm_provider="bedrock",
-                extra_headers=headers,
-                timeout=timeout,
-                on_response=log_rust_post_call,
-                bedrock=bedrock_options(rust_optional_params),
-                stream=bool(stream),
-                has_custom_client=client is not None,
-                eligible=serves_via_rust,
-                context=rust_context,
-            )
-
-        @anative_first(
-            native=native_acompletion,
-            route="chat_completions",
-            errors=lambda: provider_errors("bedrock", model),
-        )
-        async def execute_async() -> ModelResponse | CustomStreamWrapper:
-            python_client: Final = None if isinstance(client, HTTPHandler) else client
+        ### ROUTING (ASYNC, STREAMING, SYNC)
+        if acompletion:
+            if isinstance(client, HTTPHandler):
+                client = None
             if stream is True:
-                return await self.async_streaming(
+                return self.async_streaming(
                     model=model,
                     messages=messages,
                     api_base=proxy_endpoint_url,
@@ -490,7 +382,7 @@ class BedrockConverseLLM(BaseAWSLLM):
                     logger_fn=logger_fn,
                     headers=headers,
                     timeout=timeout,
-                    client=python_client,
+                    client=client,
                     json_mode=json_mode,
                     fake_stream=fake_stream,
                     credentials=credentials,
@@ -498,7 +390,7 @@ class BedrockConverseLLM(BaseAWSLLM):
                     stream_chunk_size=stream_chunk_size,
                 )
             ### ASYNC COMPLETION
-            return await self.async_completion(
+            return self.async_completion(
                 model=model,
                 messages=messages,
                 api_base=proxy_endpoint_url,
@@ -511,112 +403,102 @@ class BedrockConverseLLM(BaseAWSLLM):
                 logger_fn=logger_fn,
                 headers=headers,
                 timeout=timeout,
-                client=python_client,
+                client=client,
                 credentials=credentials,
                 api_key=api_key,
-                skip_pre_call_logging=serves_via_rust,
             )
 
-        @native_first(
-            native=native_completion,
-            route="chat_completions",
-            errors=lambda: provider_errors("bedrock", model),
+        ## TRANSFORMATION ##
+
+        _data: Final = litellm.AmazonConverseConfig()._transform_request(
+            model=model,
+            messages=messages,
+            optional_params=optional_params,
+            litellm_params=litellm_params,
+            headers=extra_headers,
         )
-        def execute_sync() -> ModelResponse | CustomStreamWrapper:
-            ## TRANSFORMATION ##
+        data: Final = json.dumps(_data)
 
-            _data: Final = litellm.AmazonConverseConfig()._transform_request(
+        prepped: Final = self.get_request_headers(
+            credentials=credentials,
+            aws_region_name=aws_region_name,
+            extra_headers=extra_headers,
+            endpoint_url=proxy_endpoint_url,
+            data=data,
+            headers=headers,
+            api_key=api_key,
+        )
+
+        ## LOGGING
+        logging_obj.pre_call(
+            input=messages,
+            api_key="",
+            additional_args={
+                "complete_input_dict": data,
+                "api_base": proxy_endpoint_url,
+                "headers": prepped.headers,
+            },
+        )
+        if client is None or isinstance(client, AsyncHTTPHandler):
+            _params: Final = {}
+            if timeout is not None:
+                if isinstance(timeout, float) or isinstance(timeout, int):
+                    timeout = httpx.Timeout(timeout)
+                _params["timeout"] = timeout
+            client = _get_httpx_client(_params)
+        else:
+            client = client
+
+        if stream is not None and stream is True:
+            completion_stream, response_headers = make_sync_call(
+                client=(client if client is not None and isinstance(client, HTTPHandler) else None),
+                api_base=proxy_endpoint_url,
+                headers=prepped.headers,
+                data=data,
                 model=model,
                 messages=messages,
-                optional_params=optional_params,
-                litellm_params=litellm_params,
-                headers=extra_headers,
-            )
-            data: Final = json.dumps(_data)
-
-            prepped: Final = self.get_request_headers(
-                credentials=credentials,
-                aws_region_name=aws_region_name,
-                extra_headers=extra_headers,
-                endpoint_url=proxy_endpoint_url,
-                data=data,
-                headers=headers,
-                api_key=api_key,
-            )
-
-            ## LOGGING
-            # Reaching here with `serves_via_rust` set means the synchronous Rust
-            # attempt declined at call time, before the provider was called, and
-            # already logged this request. That is the same attempt continuing.
-            if not serves_via_rust:
-                logging_obj.pre_call(
-                    input=messages,
-                    api_key="",
-                    additional_args={
-                        "complete_input_dict": data,
-                        "api_base": proxy_endpoint_url,
-                        "headers": prepped.headers,
-                    },
-                )
-            resolved_timeout: Final = httpx.Timeout(timeout) if isinstance(timeout, (float, int)) else timeout
-            python_client: Final = (
-                _get_httpx_client({"timeout": resolved_timeout} if resolved_timeout is not None else None)
-                if client is None or isinstance(client, AsyncHTTPHandler)
-                else client
-            )
-
-            if stream is not None and stream is True:
-                completion_stream, response_headers = make_sync_call(
-                    client=python_client,
-                    api_base=proxy_endpoint_url,
-                    headers=prepped.headers,
-                    data=data,
-                    model=model,
-                    messages=messages,
-                    logging_obj=logging_obj,
-                    json_mode=json_mode,
-                    fake_stream=fake_stream,
-                    stream_chunk_size=stream_chunk_size,
-                )
-                streaming_response: Final = CustomStreamWrapper(
-                    completion_stream=completion_stream,
-                    model=model,
-                    custom_llm_provider="bedrock",
-                    logging_obj=logging_obj,
-                    _response_headers=response_headers,
-                )
-
-                return streaming_response
-
-            ### COMPLETION
-
-            try:
-                response: Final = python_client.post(
-                    url=proxy_endpoint_url,
-                    headers=prepped.headers,
-                    data=data,
-                    logging_obj=logging_obj,
-                )
-                response.raise_for_status()
-            except httpx.HTTPStatusError as err:
-                error_code: Final = err.response.status_code
-                raise BedrockError(status_code=error_code, message=err.response.text)
-            except httpx.TimeoutException:
-                raise BedrockError(status_code=408, message="Timeout error occurred.")
-
-            sync_transformed_response: Final = litellm.AmazonConverseConfig()._transform_response(
-                model=model,
-                response=response,
-                model_response=model_response,
-                stream=stream if isinstance(stream, bool) else False,
                 logging_obj=logging_obj,
-                api_key="",
-                data=data,
-                messages=messages,
-                optional_params=optional_params,
-                encoding=encoding,
+                json_mode=json_mode,
+                fake_stream=fake_stream,
+                stream_chunk_size=stream_chunk_size,
+            )
+            streaming_response: Final = CustomStreamWrapper(
+                completion_stream=completion_stream,
+                model=model,
+                custom_llm_provider="bedrock",
+                logging_obj=logging_obj,
+                _response_headers=response_headers,
             )
-            sync_transformed_response.set_provider_response_headers(response.headers)
-            return sync_transformed_response
 
-        return execute_async() if acompletion else execute_sync()
+            return streaming_response
+
+        ### COMPLETION
+
+        try:
+            response: Final = client.post(
+                url=proxy_endpoint_url,
+                headers=prepped.headers,
+                data=data,
+                logging_obj=logging_obj,
+            )
+            response.raise_for_status()
+        except httpx.HTTPStatusError as err:
+            error_code: Final = err.response.status_code
+            raise BedrockError(status_code=error_code, message=err.response.text)
+        except httpx.TimeoutException:
+            raise BedrockError(status_code=408, message="Timeout error occurred.")
+
+        sync_transformed_response: Final = litellm.AmazonConverseConfig()._transform_response(
+            model=model,
+            response=response,
+            model_response=model_response,
+            stream=stream if isinstance(stream, bool) else False,
+            logging_obj=logging_obj,
+            api_key="",
+            data=data,
+            messages=messages,
+            optional_params=optional_params,
+            encoding=encoding,
+        )
+        sync_transformed_response.set_provider_response_headers(response.headers)
+        return sync_transformed_response

litellm/llms/custom_httpx/llm_http_handler.py

@@ -1,8 +1,7 @@
 import asyncio
 import json
 import ssl
-from collections.abc import AsyncGenerator, AsyncIterator, Coroutine, Iterator, Mapping, Sequence
-from contextlib import AbstractAsyncContextManager, asynccontextmanager
+from collections.abc import AsyncIterator, Coroutine, Iterator, Mapping, Sequence
 from functools import lru_cache
 from types import MappingProxyType, ModuleType
 from typing import TYPE_CHECKING, Any, Final, Literal, Optional, TypedDict, TypeVar, Union, cast, get_type_hints
@@ -92,8 +91,6 @@ from litellm.responses.streaming_iterator import (
     ResponsesWebSocketStreaming,
     SyncResponsesAPIStreamingIterator,
 )
-from litellm.rust_bridge.dispatch import anative_context, anative_first, provider_errors
-from litellm.rust_bridge.runtime import DispatchResult, NativeSkipped, NativeSkipReason, adapt_result
 from litellm.types.containers.main import (
     ContainerFileListResponse,
     ContainerListResponse,
@@ -162,15 +159,6 @@ from litellm.utils import (
     async_pre_call_deployment_hook,
 )
 
-
-def _rust_responses_websocket_enabled(
-    custom_llm_provider: str | None,
-) -> bool:
-    from litellm.rust_bridge.configuration import rust_enabled
-
-    return custom_llm_provider == "openai" and rust_enabled()
-
-
 from .http_handler import get_shared_realtime_ssl_context
 
 if TYPE_CHECKING:
@@ -183,9 +171,6 @@ if TYPE_CHECKING:
     from litellm.llms.anthropic.experimental_pass_through.messages.fake_stream_iterator import (
         FakeAnthropicMessagesStreamIterator,
     )
-    from litellm.llms.anthropic.experimental_pass_through.messages.streaming_iterator import (
-        AnthropicMessagesStreamingResponse,
-    )
     from litellm.llms.base_llm.passthrough.transformation import BasePassthroughConfig
     from litellm.types.llms.openai_evals import (
         CancelEvalResponse,
@@ -245,7 +230,7 @@ def _responses_api_optional_request_param_names() -> frozenset[str]:
     return frozenset(get_type_hints(ResponsesAPIOptionalRequestParams).keys())
 
 
-def _custom_logger_callbacks(logging_obj: LiteLLMLoggingObj) -> list["CustomLogger"]:
+def _custom_logger_callbacks(logging_obj: LiteLLMLoggingObj | None) -> list["CustomLogger"]:
     from litellm.integrations.custom_logger import CustomLogger
     from litellm.litellm_core_utils.litellm_logging import (
         get_custom_logger_compatible_class,
@@ -2055,7 +2040,7 @@ class BaseLLMHTTPHandler:
         raise RuntimeError("unreachable: anthropic messages HTTP retry loop exited without return")
 
     @staticmethod
-    def _resolve_anthropic_messages_timeout(
+    def resolve_anthropic_messages_timeout(
         litellm_params: GenericLiteLLMParams,
         stream: bool,
         custom_llm_provider: str,
@@ -2227,116 +2212,86 @@ class BaseLLMHTTPHandler:
             },
         )
 
-        async def native_messages() -> DispatchResult[AnthropicMessagesResponse | AsyncIterator[object]]:
-            result: Final = await self._attempt_rust_anthropic_messages(
-                custom_llm_provider=custom_llm_provider,
+        response: Final = await self._async_post_anthropic_messages_with_http_error_retry(
+            async_httpx_client=async_httpx_client,
+            request_url=request_url,
+            headers=headers,
+            signed_json_body=(signed_json_body if signed_json_body is not None else request_body_json),
+            request_body=request_body,
+            stream=stream or False,
+            logging_obj=logging_obj,
+            provider_config=anthropic_messages_provider_config,
+            litellm_params=litellm_params,
+            api_key=api_key,
+            model=model,
+            timeout=self.resolve_anthropic_messages_timeout(
                 litellm_params=litellm_params,
-                has_agentic_hook=self._has_agentic_completion_hook(logging_obj),
-                stream=bool(stream),
-                has_custom_client=client is not None,
-                model=model,
-                api_key=api_key,
-                api_base=api_base,
-                headers=headers,
-                request_body=request_body,
-                timeout=self._resolve_anthropic_messages_timeout(
-                    litellm_params=litellm_params,
-                    stream=stream or False,
-                    custom_llm_provider=custom_llm_provider,
-                ),
-                logging_obj=logging_obj,
-            )
-            return adapt_result(result, self._rust_anthropic_messages_fake_stream) if stream else result
-
-        @anative_first(
-            native=native_messages, route="messages", errors=lambda: provider_errors(custom_llm_provider, model)
-        )
-        async def execute_messages() -> AnthropicMessagesResponse | AsyncIterator[object]:
-            response: Final = await self._async_post_anthropic_messages_with_http_error_retry(
-                async_httpx_client=async_httpx_client,
-                request_url=request_url,
-                headers=headers,
-                signed_json_body=(signed_json_body if signed_json_body is not None else request_body_json),
-                request_body=request_body,
                 stream=stream or False,
-                logging_obj=logging_obj,
-                provider_config=anthropic_messages_provider_config,
-                litellm_params=litellm_params,
-                api_key=api_key,
-                model=model,
-                timeout=self._resolve_anthropic_messages_timeout(
-                    litellm_params=litellm_params,
-                    stream=stream or False,
-                    custom_llm_provider=custom_llm_provider,
-                ),
+                custom_llm_provider=custom_llm_provider,
+            ),
+        )
+
+        # used for logging + cost tracking
+        logging_obj.model_call_details["httpx_response"] = response
+
+        initial_response: AsyncIterator | AnthropicMessagesResponse
+        if stream:
+            from litellm.llms.anthropic.experimental_pass_through.messages.streaming_iterator import (
+                AnthropicMessagesStreamingResponse,
+                anthropic_messages_stream_hidden_params,
             )
 
-            # used for logging + cost tracking
-            logging_obj.model_call_details["httpx_response"] = response
+            completion_stream: Final = anthropic_messages_provider_config.get_async_streaming_response_iterator(
+                model=model,
+                httpx_response=response,
+                request_body=request_body,
+                litellm_logging_obj=logging_obj,
+            )
+            stream_hidden_params: Final = anthropic_messages_stream_hidden_params(response.headers)
 
-            initial_response: AsyncIterator | AnthropicMessagesResponse
-            if stream:
-                from litellm.llms.anthropic.experimental_pass_through.messages.streaming_iterator import (
-                    AnthropicMessagesStreamingResponse,
-                    anthropic_messages_stream_hidden_params,
-                )
-
-                completion_stream: Final = anthropic_messages_provider_config.get_async_streaming_response_iterator(
-                    model=model,
-                    httpx_response=response,
-                    request_body=request_body,
-                    litellm_logging_obj=logging_obj,
-                )
-                stream_hidden_params: Final = anthropic_messages_stream_hidden_params(response.headers)
-
-                if not self._has_agentic_completion_hook(logging_obj):
-                    # No callback overrides async_should_run_agentic_loop, so the
-                    # agentic wrapper's only effect would be buffering every chunk
-                    # and rebuilding the response from SSE at end-of-stream to call
-                    # hooks that all return (False, {}). Stream through directly and
-                    # skip that per-chunk + end-of-stream overhead.
-                    return AnthropicMessagesStreamingResponse(
-                        completion_stream=completion_stream,
-                        hidden_params=stream_hidden_params,
-                    )
-
-                from litellm.llms.anthropic.experimental_pass_through.messages.agentic_streaming_iterator import (
-                    AgenticAnthropicStreamingIterator,
-                )
-
-                held_back_tool_names: Final = self._server_fulfilled_tools_in_request(
-                    logging_obj=logging_obj,
-                    tools=anthropic_messages_optional_request_params.get("tools"),
-                )
-                initial_response = AgenticAnthropicStreamingIterator(
-                    completion_stream=completion_stream,
-                    http_handler=self,
-                    model=model,
-                    messages=messages,
-                    anthropic_messages_provider_config=anthropic_messages_provider_config,
-                    anthropic_messages_optional_request_params=anthropic_messages_optional_request_params,
-                    logging_obj=logging_obj,
-                    custom_llm_provider=custom_llm_provider,
-                    kwargs={**kwargs, "api_key": api_key} if api_key else kwargs,
-                    hold_back=bool(held_back_tool_names),
-                    server_fulfilled_tool_names=held_back_tool_names,
-                )
+            if not self.has_agentic_completion_hook(logging_obj):
+                # No callback overrides async_should_run_agentic_loop, so the
+                # agentic wrapper's only effect would be buffering every chunk
+                # and rebuilding the response from SSE at end-of-stream to call
+                # hooks that all return (False, {}). Stream through directly and
+                # skip that per-chunk + end-of-stream overhead.
                 return AnthropicMessagesStreamingResponse(
-                    completion_stream=initial_response,
+                    completion_stream=completion_stream,
                     hidden_params=stream_hidden_params,
                 )
-            else:
-                initial_response = anthropic_messages_provider_config.transform_anthropic_messages_response(
-                    model=model,
-                    raw_response=response,
-                    logging_obj=logging_obj,
-                )
 
-            return initial_response
+            from litellm.llms.anthropic.experimental_pass_through.messages.agentic_streaming_iterator import (
+                AgenticAnthropicStreamingIterator,
+            )
+
+            held_back_tool_names: Final = self._server_fulfilled_tools_in_request(
+                logging_obj=logging_obj,
+                tools=anthropic_messages_optional_request_params.get("tools"),
+            )
+            initial_response = AgenticAnthropicStreamingIterator(
+                completion_stream=completion_stream,
+                http_handler=self,
+                model=model,
+                messages=messages,
+                anthropic_messages_provider_config=anthropic_messages_provider_config,
+                anthropic_messages_optional_request_params=anthropic_messages_optional_request_params,
+                logging_obj=logging_obj,
+                custom_llm_provider=custom_llm_provider,
+                kwargs={**kwargs, "api_key": api_key} if api_key else kwargs,
+                hold_back=bool(held_back_tool_names),
+                server_fulfilled_tool_names=held_back_tool_names,
+            )
+            return AnthropicMessagesStreamingResponse(
+                completion_stream=initial_response,
+                hidden_params=stream_hidden_params,
+            )
+        else:
+            initial_response = anthropic_messages_provider_config.transform_anthropic_messages_response(
+                model=model,
+                raw_response=response,
+                logging_obj=logging_obj,
+            )
 
-        initial_response: Final = await execute_messages()
-        if stream:
-            return initial_response
         return await self._finalize_anthropic_messages_response(
             initial_response=initial_response,
             model=model,
@@ -2385,80 +2340,6 @@ class BaseLLMHTTPHandler:
             "anthropic_messages",
         )
 
-    @staticmethod
-    async def _attempt_rust_anthropic_messages(
-        *,
-        custom_llm_provider: str,
-        litellm_params: GenericLiteLLMParams,
-        has_agentic_hook: bool,
-        stream: bool,
-        has_custom_client: bool,
-        model: str,
-        api_key: str | None,
-        api_base: str | None,
-        headers: dict,
-        request_body: dict,
-        timeout: float | httpx.Timeout | None,
-        logging_obj: LiteLLMLoggingObj | None = None,
-    ) -> DispatchResult[AnthropicMessagesResponse]:
-        if custom_llm_provider not in ("azure_ai", "anthropic"):
-            return NativeSkipped(NativeSkipReason.INELIGIBLE)
-        from litellm.rust_bridge.configuration import rust_enabled
-
-        if not rust_enabled():
-            return NativeSkipped(NativeSkipReason.DISABLED)
-        if has_agentic_hook:
-            return NativeSkipped(NativeSkipReason.INELIGIBLE)
-
-        from litellm.rust_bridge import messages as rust_messages_bridge
-        from litellm.rust_bridge.request import request_context
-
-        upstream_body: Final = {key: value for key, value in request_body.items() if key != "stream"}
-        result: Final = await rust_messages_bridge.amessages(
-            model=model,
-            body=upstream_body,
-            api_key=api_key,
-            api_base=api_base,
-            custom_llm_provider=custom_llm_provider,
-            extra_headers=headers,
-            timeout=timeout,
-            stream=stream,
-            has_custom_client=has_custom_client,
-            has_agentic_hook=has_agentic_hook,
-            context=request_context(
-                logging_obj=logging_obj,
-                request_model=logging_obj.model if logging_obj is not None else model,
-                litellm_params=litellm_params.model_dump(),
-            ),
-        )
-
-        def adapt(rust_response: dict[str, object]) -> AnthropicMessagesResponse:
-            return cast(
-                AnthropicMessagesResponse,
-                {**rust_response, "_hidden_params": {"additional_headers": {"x-litellm-rust": "true"}}},
-            )
-
-        return adapt_result(result, adapt)
-
-    @staticmethod
-    def _rust_anthropic_messages_fake_stream(
-        rust_response: AnthropicMessagesResponse,
-    ) -> "AnthropicMessagesStreamingResponse":
-        from litellm.llms.anthropic.experimental_pass_through.messages.fake_stream_iterator import (
-            FakeAnthropicMessagesStreamIterator,
-        )
-        from litellm.llms.anthropic.experimental_pass_through.messages.streaming_iterator import (
-            AnthropicMessagesStreamHiddenParams,
-            AnthropicMessagesStreamingResponse,
-        )
-
-        completion_stream = cast(AsyncIterator[bytes], FakeAnthropicMessagesStreamIterator(response=rust_response))
-        hidden_params: Final = AnthropicMessagesStreamHiddenParams(additional_headers={"x-litellm-rust": "true"})
-        return AnthropicMessagesStreamingResponse(
-            completion_stream=completion_stream,
-            hidden_params=hidden_params,
-        )
-
     def anthropic_messages_handler(
         self,
         model: str,
@@ -2767,7 +2648,7 @@ class BaseLLMHTTPHandler:
             logging_obj=logging_obj,
         )
 
-        if self._has_agentic_completion_hook(logging_obj):
+        if self.has_agentic_completion_hook(logging_obj):
             agentic_kwargs: Final = dict(litellm_params)  # mutable-ok: agentic hooks mutate kwargs in place
             final_response: Final = run_async_function(
                 self._call_agentic_completion_hooks,
@@ -5158,7 +5039,7 @@ class BaseLLMHTTPHandler:
         return depth, max_loops, fingerprints
 
     @staticmethod
-    def _has_agentic_completion_hook(logging_obj: LiteLLMLoggingObj) -> bool:
+    def has_agentic_completion_hook(logging_obj: LiteLLMLoggingObj | None) -> bool:
         """
         True if any registered callback actually overrides
         ``async_should_run_agentic_loop`` (the gate every agentic hook goes
@@ -6516,41 +6397,21 @@ class BaseLLMHTTPHandler:
                 },
             )
 
-            from litellm.rust_bridge import responses_websocket as rust_responses_websocket
-            from litellm.rust_bridge.request import request_context
+            from litellm.rust_bridge.responses_websocket import open_connection
 
-            async def attempt_connection() -> DispatchResult[
-                AbstractAsyncContextManager[rust_responses_websocket.ConnectionAdapter]
-            ]:
-                if not _rust_responses_websocket_enabled(custom_llm_provider):
-                    return NativeSkipped(NativeSkipReason.INELIGIBLE)
-                return await rust_responses_websocket.managed_connect(
-                    url=ws_url,
-                    headers={str(key): str(value) for key, value in headers.items()},
-                    timeout=timeout,
-                    context=request_context(
-                        logging_obj=logging_obj,
-                        request_model=logging_obj.model,
-                        litellm_params=litellm_params.model_dump(),
-                    ),
-                )
-
-            @anative_context(
-                native=attempt_connection,
-                route="responses_websocket",
-                errors=lambda: provider_errors("openai", "responses websocket"),
-            )
-            @asynccontextmanager
-            async def _backend_connection() -> AsyncGenerator[ClientConnection, None]:
-                async with websockets.connect(
+            async with open_connection(
+                url=ws_url,
+                headers={str(key): str(value) for key, value in headers.items()},
+                timeout=timeout,
+                model=model,
+                provider=custom_llm_provider,
+                fallback=lambda: websockets.connect(
                     ws_url,
                     additional_headers=headers,
                     max_size=REALTIME_WEBSOCKET_MAX_MESSAGE_SIZE_BYTES,
                     ssl=ssl_context,
-                ) as backend:
-                    yield backend
-
-            async with _backend_connection() as backend_ws:
+                ),
+            ) as backend_ws:
                 _request_data: Final[dict[str, object]] = {}
                 if litellm_metadata:
                     _request_data["litellm_metadata"] = litellm_metadata

litellm/main.py

@@ -19,7 +19,7 @@ import random
 import sys
 import time
 import traceback
-from collections.abc import AsyncIterator, Coroutine, Iterable, Mapping, Sequence
+from collections.abc import AsyncIterator, Callable, Coroutine, Iterable, Mapping, Sequence
 from concurrent import futures
 from concurrent.futures import FIRST_COMPLETED, ThreadPoolExecutor, wait
 from copy import deepcopy
@@ -4958,6 +4958,183 @@ def _complete_langflow(ctx: _CompletionDispatchContext) -> _CompletionDispatchRe
     )
 
 
+_PYTHON_PRIMARY_COMPLETION_HANDLERS: Final[
+    Mapping[str, Callable[[_CompletionDispatchContext], _CompletionDispatchResult]]
+] = MappingProxyType(
+    {
+        "azure": _complete_azure,
+        "azure_text": _complete_azure_text,
+        "deepseek": _complete_deepseek,
+        "azure_ai": _complete_azure_ai,
+    }
+)
+
+_PYTHON_COMPATIBLE_COMPLETION_HANDLERS: Final[
+    Mapping[str, Callable[[_CompletionDispatchContext], _CompletionDispatchResult]]
+] = MappingProxyType(
+    {
+        "fireworks_ai": _complete_fireworks_ai,
+        "together_ai": _complete_together_ai,
+        "heroku": _complete_heroku,
+        "ragflow": _complete_ragflow,
+        "xai": _complete_xai,
+        "groq": _complete_groq,
+        "bedrock_mantle": _complete_bedrock_mantle,
+        "a2a": _complete_a2a,
+        "gigachat": _complete_gigachat,
+        "sap": _complete_sap,
+        "aiohttp_openai": _complete_aiohttp_openai,
+        "cometapi": _complete_cometapi,
+        "minimax": _complete_minimax,
+        "hosted_vllm": _complete_hosted_vllm,
+    }
+)
+
+_PYTHON_LEGACY_COMPLETION_HANDLERS: Final[
+    Mapping[str, Callable[[_CompletionDispatchContext], _CompletionDispatchResult]]
+] = MappingProxyType(
+    {
+        "anthropic_text": _complete_anthropic_text,
+        "anthropic": _complete_anthropic,
+        "nlp_cloud": _complete_nlp_cloud,
+        "aleph_alpha": _complete_aleph_alpha,
+        "cohere_chat": _complete_cohere_chat,
+        "cohere": _complete_cohere_chat,
+        "maritalk": _complete_maritalk,
+        "amazon_nova": _complete_amazon_nova,
+        "huggingface": _complete_huggingface,
+        "oci": _complete_oci,
+        "compactifai": _complete_compactifai,
+        "oobabooga": _complete_oobabooga,
+        "databricks": _complete_databricks,
+        "datarobot": _complete_datarobot,
+        "openrouter": _complete_openrouter,
+        "vercel_ai_gateway": _complete_vercel_ai_gateway,
+    }
+)
+
+_PYTHON_EXTENDED_COMPLETION_HANDLERS: Final[
+    Mapping[str, Callable[[_CompletionDispatchContext], _CompletionDispatchResult]]
+] = MappingProxyType(
+    {
+        "vertex_ai_beta": _complete_vertex_ai_beta,
+        "gemini": _complete_vertex_ai_beta,
+        "vertex_ai": _complete_vertex_ai,
+        "predibase": _complete_predibase,
+        "text-completion-codestral": _complete_text_completion_codestral,
+        "text-completion-inception": _complete_text_completion_inception,
+        "sagemaker_chat": _complete_sagemaker_chat,
+        "sagemaker_nova": _complete_sagemaker_chat,
+        "sagemaker": _complete_sagemaker,
+        "bedrock": _complete_bedrock,
+        "watsonx": _complete_watsonx,
+        "watsonx_text": _complete_watsonx_text,
+        "vllm": _complete_vllm,
+        "ollama": _complete_ollama,
+        "ollama_chat": _complete_ollama_chat,
+        "triton": _complete_triton,
+        "cloudflare": _complete_cloudflare,
+    }
+)
+
+_PYTHON_ADDITIONAL_COMPLETION_HANDLERS: Final[
+    Mapping[str, Callable[[_CompletionDispatchContext], _CompletionDispatchResult]]
+] = MappingProxyType(
+    {
+        "gradient_ai": _complete_gradient_ai,
+        "gdc": _complete_gdc,
+        "bytez": _complete_bytez,
+        "lemonade": _complete_lemonade,
+    }
+)
+
+_PYTHON_CUSTOM_COMPLETION_HANDLERS: Final[
+    Mapping[str, Callable[[_CompletionDispatchContext], _CompletionDispatchResult]]
+] = MappingProxyType(
+    {
+        "langgraph": _complete_langgraph,
+        "langflow": _complete_langflow,
+    }
+)
+
+
+def _complete_python(_dispatch_ctx: _CompletionDispatchContext) -> _CompletionDispatchResult:
+    custom_llm_provider: Final = _dispatch_ctx.custom_llm_provider
+    model: Final = _dispatch_ctx.model
+    kwargs: Final = _dispatch_ctx.kwargs
+    if (primary_handler := _PYTHON_PRIMARY_COMPLETION_HANDLERS.get(custom_llm_provider)) is not None:
+        return primary_handler(_dispatch_ctx)
+    elif (
+        custom_llm_provider == "text-completion-openai"
+        or "ft:babbage-002" in model
+        or "ft:davinci-002" in model
+        or (
+            custom_llm_provider in litellm.openai_text_completion_compatible_providers
+            and kwargs.get("text_completion") is True
+        )
+    ):
+        return _complete_text_completion_openai(_dispatch_ctx)
+    elif (compatible_handler := _PYTHON_COMPATIBLE_COMPLETION_HANDLERS.get(custom_llm_provider)) is not None:
+        return compatible_handler(_dispatch_ctx)
+    elif (
+        model in litellm.open_ai_chat_completion_models
+        and custom_llm_provider in (None, "openai")
+        or custom_llm_provider == "custom_openai"
+        or custom_llm_provider == "deepinfra"
+        or (custom_llm_provider == "perplexity")
+        or (custom_llm_provider == "nvidia_nim")
+        or (custom_llm_provider == "cerebras")
+        or (custom_llm_provider == "baseten")
+        or (custom_llm_provider == "sambanova")
+        or (custom_llm_provider == "volcengine")
+        or (custom_llm_provider == "anyscale")
+        or (custom_llm_provider == "openai")
+        or (custom_llm_provider == "nebius")
+        or (custom_llm_provider == "wandb")
+        or (custom_llm_provider == "clarifai")
+        or (custom_llm_provider in litellm.openai_compatible_providers)
+        or JSONProviderRegistry.exists(custom_llm_provider)
+        or ("ft:gpt-3.5-turbo" in model)
+    ):
+        return _complete_custom_openai(_dispatch_ctx)
+    return _complete_python_provider(_dispatch_ctx)
+
+
+def _complete_python_provider(_dispatch_ctx: _CompletionDispatchContext) -> _CompletionDispatchResult:
+    custom_llm_provider: Final = _dispatch_ctx.custom_llm_provider
+    model: Final = _dispatch_ctx.model
+    if custom_llm_provider == "mistral":
+        return _complete_mistral(_dispatch_ctx)
+    elif "replicate" in model or custom_llm_provider == "replicate" or model in litellm.replicate_models:
+        return _complete_replicate(_dispatch_ctx)
+    elif "clarifai" in model or custom_llm_provider == "clarifai" or model in litellm.clarifai_models:
+        return _complete_custom_openai(_dispatch_ctx)
+    elif (legacy_handler := _PYTHON_LEGACY_COMPLETION_HANDLERS.get(custom_llm_provider)) is not None:
+        return legacy_handler(_dispatch_ctx)
+    elif custom_llm_provider == "palm":
+        raise ValueError(
+            "Palm was decommisioned on October 2024. Please use the `gemini/` route for Gemini Google AI Studio Models. Announcement: https://ai.google.dev/palm_docs/palm?hl=en"
+        )
+    elif (extended_handler := _PYTHON_EXTENDED_COMPLETION_HANDLERS.get(custom_llm_provider)) is not None:
+        return extended_handler(_dispatch_ctx)
+    elif custom_llm_provider == "petals" or model in litellm.petals_models:
+        return _complete_petals(_dispatch_ctx)
+    elif custom_llm_provider == "snowflake" or model in litellm.snowflake_models:
+        return _complete_snowflake(_dispatch_ctx)
+    elif (additional_handler := _PYTHON_ADDITIONAL_COMPLETION_HANDLERS.get(custom_llm_provider)) is not None:
+        return additional_handler(_dispatch_ctx)
+    elif custom_llm_provider == "ovhcloud" or model in litellm.ovhcloud_models:
+        return _complete_ovhcloud(_dispatch_ctx)
+    elif custom_llm_provider == "custom":
+        return _complete_custom(_dispatch_ctx)
+    elif custom_llm_provider in litellm._custom_providers:
+        return _complete_custom_providers(_dispatch_ctx)
+    elif (custom_handler := _PYTHON_CUSTOM_COMPLETION_HANDLERS.get(custom_llm_provider)) is not None:
+        return custom_handler(_dispatch_ctx)
+    else:
+        raise LiteLLMUnknownProvider(model=model, custom_llm_provider=custom_llm_provider)
+
+
 @tracer.wrap()
 @client
 def completion(
@@ -5640,209 +5817,9 @@ def completion(
             timeout=timeout,
             top_p=top_p,
         )
-        if custom_llm_provider == "azure":
-            # azure configs
-            ## check dynamic params ##
-            response = _complete_azure(_dispatch_ctx)
-        elif custom_llm_provider == "azure_text":
-            # azure configs
-            response = _complete_azure_text(_dispatch_ctx)
-        elif custom_llm_provider == "deepseek":
-            ## COMPLETION CALL
+        from litellm.rust_bridge.chat_completions import dispatch_completion
 
-            response = _complete_deepseek(_dispatch_ctx)
-
-        elif custom_llm_provider == "azure_ai":
-            response = _complete_azure_ai(_dispatch_ctx)
-        elif (
-            custom_llm_provider == "text-completion-openai"
-            or "ft:babbage-002" in model
-            or "ft:davinci-002" in model  # support for finetuned completion models
-            or custom_llm_provider in litellm.openai_text_completion_compatible_providers
-            and kwargs.get("text_completion") is True
-        ):
-            response = _complete_text_completion_openai(_dispatch_ctx)
-        elif custom_llm_provider == "fireworks_ai":
-            ## COMPLETION CALL
-            response = _complete_fireworks_ai(_dispatch_ctx)
-        elif custom_llm_provider == "together_ai":
-            response = _complete_together_ai(_dispatch_ctx)
-        elif custom_llm_provider == "heroku":
-            response = _complete_heroku(_dispatch_ctx)
-
-        elif custom_llm_provider == "ragflow":
-            ## COMPLETION CALL - RAGFlow uses HTTP handler to support custom URL paths
-            response = _complete_ragflow(_dispatch_ctx)
-        elif custom_llm_provider == "xai":
-            ## COMPLETION CALL
-            response = _complete_xai(_dispatch_ctx)
-        elif custom_llm_provider == "groq":
-            response = _complete_groq(_dispatch_ctx)
-        elif custom_llm_provider == "bedrock_mantle":
-            response = _complete_bedrock_mantle(_dispatch_ctx)
-        elif custom_llm_provider == "a2a":
-            # A2A (Agent-to-Agent) Protocol
-            # Resolve agent configuration from registry if model format is "a2a/<agent-name>"
-            response = _complete_a2a(_dispatch_ctx)
-        elif custom_llm_provider == "gigachat":
-            # GigaChat - Sber AI's LLM (Russia)
-            response = _complete_gigachat(_dispatch_ctx)
-
-        elif custom_llm_provider == "sap":
-            response = _complete_sap(_dispatch_ctx)
-        elif custom_llm_provider == "aiohttp_openai":
-            # NEW aiohttp provider for 10-100x higher RPS
-            response = _complete_aiohttp_openai(_dispatch_ctx)
-        elif custom_llm_provider == "cometapi":
-            response = _complete_cometapi(_dispatch_ctx)
-        elif custom_llm_provider == "minimax":
-            response = _complete_minimax(_dispatch_ctx)
-        elif custom_llm_provider == "hosted_vllm":
-            response = _complete_hosted_vllm(_dispatch_ctx)
-        elif (
-            # A known OpenAI model name only decides the route when nothing else
-            # resolved a provider. get_llm_provider() already maps these names to
-            # "openai", so a different value here was asked for explicitly (or came
-            # from a register_model entry), and the provider config built for it
-            # would be handed to the OpenAI handler.
-            (model in litellm.open_ai_chat_completion_models and custom_llm_provider in (None, "openai"))
-            or custom_llm_provider == "custom_openai"
-            or custom_llm_provider == "deepinfra"
-            or custom_llm_provider == "perplexity"
-            or custom_llm_provider == "nvidia_nim"
-            or custom_llm_provider == "cerebras"
-            or custom_llm_provider == "baseten"
-            or custom_llm_provider == "sambanova"
-            or custom_llm_provider == "volcengine"
-            or custom_llm_provider == "anyscale"
-            or custom_llm_provider == "openai"
-            or custom_llm_provider == "nebius"
-            or custom_llm_provider == "wandb"
-            or custom_llm_provider == "clarifai"
-            or custom_llm_provider in litellm.openai_compatible_providers
-            or JSONProviderRegistry.exists(custom_llm_provider)  # JSON-configured providers
-            or "ft:gpt-3.5-turbo" in model  # finetune gpt-3.5-turbo
-        ):  # allow user to make an openai call with a custom base
-            # note: if a user sets a custom base - we should ensure this works
-            # allow for the setting of dynamic and stateful api-bases
-            response = _complete_custom_openai(_dispatch_ctx)
-
-        elif custom_llm_provider == "mistral":
-            response = _complete_mistral(_dispatch_ctx)
-        elif "replicate" in model or custom_llm_provider == "replicate" or model in litellm.replicate_models:
-            # Setting the relevant API KEY for replicate, replicate defaults to using os.environ.get("REPLICATE_API_TOKEN")
-            response = _complete_replicate(_dispatch_ctx)
-        elif "clarifai" in model or custom_llm_provider == "clarifai" or model in litellm.clarifai_models:
-            pass  # Deprecated - handled in the openai compatible provider section above
-        elif custom_llm_provider == "anthropic_text":
-            response = _complete_anthropic_text(_dispatch_ctx)
-        elif custom_llm_provider == "anthropic":
-            response = _complete_anthropic(_dispatch_ctx)
-        elif custom_llm_provider == "nlp_cloud":
-            response = _complete_nlp_cloud(_dispatch_ctx)
-        elif custom_llm_provider == "aleph_alpha":
-            response = _complete_aleph_alpha(_dispatch_ctx)
-        elif custom_llm_provider == "cohere_chat" or custom_llm_provider == "cohere":
-            response = _complete_cohere_chat(_dispatch_ctx)
-        elif custom_llm_provider == "maritalk":
-            response = _complete_maritalk(_dispatch_ctx)
-        elif custom_llm_provider == "amazon_nova":
-            response = _complete_amazon_nova(_dispatch_ctx)
-        elif custom_llm_provider == "huggingface":
-            response = _complete_huggingface(_dispatch_ctx)
-        elif custom_llm_provider == "oci":
-            response = _complete_oci(_dispatch_ctx)
-        elif custom_llm_provider == "compactifai":
-            response = _complete_compactifai(_dispatch_ctx)
-        elif custom_llm_provider == "oobabooga":
-            response = _complete_oobabooga(_dispatch_ctx)
-        elif custom_llm_provider == "databricks":
-            response = _complete_databricks(_dispatch_ctx)
-
-        elif custom_llm_provider == "datarobot":
-            response = _complete_datarobot(_dispatch_ctx)
-        elif custom_llm_provider == "openrouter":
-            response = _complete_openrouter(_dispatch_ctx)
-        elif custom_llm_provider == "vercel_ai_gateway":
-            response = _complete_vercel_ai_gateway(_dispatch_ctx)
-        elif custom_llm_provider == "palm":
-            raise ValueError(
-                "Palm was decommisioned on October 2024. Please use the `gemini/` route for Gemini Google AI Studio Models. Announcement: https://ai.google.dev/palm_docs/palm?hl=en"
-            )
-        elif custom_llm_provider == "vertex_ai_beta" or custom_llm_provider == "gemini":
-            response = _complete_vertex_ai_beta(_dispatch_ctx)
-
-        elif custom_llm_provider == "vertex_ai":
-            response = _complete_vertex_ai(_dispatch_ctx)
-        elif custom_llm_provider == "predibase":
-            response = _complete_predibase(_dispatch_ctx)
-        elif custom_llm_provider == "text-completion-codestral":
-            response = _complete_text_completion_codestral(_dispatch_ctx)
-        elif custom_llm_provider == "text-completion-inception":
-            response = _complete_text_completion_inception(_dispatch_ctx)
-        elif custom_llm_provider in ("sagemaker_chat", "sagemaker_nova"):
-            # boto3 reads keys from .env
-            # sagemaker_chat: HF Messages API endpoints
-            # sagemaker_nova: Nova models on SageMaker (OpenAI-compatible)
-            response = _complete_sagemaker_chat(_dispatch_ctx)
-        elif custom_llm_provider == "sagemaker":
-            # boto3 reads keys from .env
-            response = _complete_sagemaker(_dispatch_ctx)
-        elif custom_llm_provider == "bedrock":
-            # boto3 reads keys from .env
-            response = _complete_bedrock(_dispatch_ctx)
-        elif custom_llm_provider == "watsonx":
-            response = _complete_watsonx(_dispatch_ctx)
-        elif custom_llm_provider == "watsonx_text":
-            response = _complete_watsonx_text(_dispatch_ctx)
-        elif custom_llm_provider == "vllm":
-            response = _complete_vllm(_dispatch_ctx)
-        elif custom_llm_provider == "ollama":
-            response = _complete_ollama(_dispatch_ctx)
-
-        elif custom_llm_provider == "ollama_chat":
-            response = _complete_ollama_chat(_dispatch_ctx)
-
-        elif custom_llm_provider == "triton":
-            response = _complete_triton(_dispatch_ctx)
-        elif custom_llm_provider == "cloudflare":
-            response = _complete_cloudflare(_dispatch_ctx)
-
-        elif custom_llm_provider == "petals" or model in litellm.petals_models:
-            response = _complete_petals(_dispatch_ctx)
-        elif custom_llm_provider == "snowflake" or model in litellm.snowflake_models:
-            response = _complete_snowflake(_dispatch_ctx)
-        elif custom_llm_provider == "gradient_ai":
-            response = _complete_gradient_ai(_dispatch_ctx)
-
-        elif custom_llm_provider == "gdc":
-            response = _complete_gdc(_dispatch_ctx)
-        elif custom_llm_provider == "bytez":
-            response = _complete_bytez(_dispatch_ctx)
-        elif custom_llm_provider == "lemonade":
-            response = _complete_lemonade(_dispatch_ctx)
-
-        elif custom_llm_provider == "ovhcloud" or model in litellm.ovhcloud_models:
-            response = _complete_ovhcloud(_dispatch_ctx)
-
-        elif custom_llm_provider == "custom":
-            response = _complete_custom(_dispatch_ctx)
-
-        elif custom_llm_provider in litellm._custom_providers:  # Assume custom LLM provider
-            # Get the Custom Handler
-            response = _complete_custom_providers(_dispatch_ctx)
-
-        elif custom_llm_provider == "langgraph":
-            # LangGraph - Agent Runtime Provider
-            response = _complete_langgraph(_dispatch_ctx)
-
-        elif custom_llm_provider == "langflow":
-            # LangFlow - Visual AI Agent Platform
-            response = _complete_langflow(_dispatch_ctx)
-
-        else:
-            raise LiteLLMUnknownProvider(model=model, custom_llm_provider=custom_llm_provider)
-        return response
+        return dispatch_completion(_dispatch_ctx, lambda: _complete_python(_dispatch_ctx))
     except Exception as e:
         ## Map to OpenAI Exception
         raise exception_type(
@@ -7771,179 +7748,176 @@ def transcription(
         custom_llm_provider=custom_llm_provider,
     )
 
-    response: TranscriptionResponse | Coroutine[object, object, TranscriptionResponse] | None = None
+    def python_fallback(
+        file: FileTypes,
+        api_key: str | None = api_key,
+        api_base: str | None = api_base,
+        api_version: str | None = api_version,
+    ) -> TranscriptionResponse | Coroutine[object, object, TranscriptionResponse]:
+        response: TranscriptionResponse | Coroutine[object, object, TranscriptionResponse] | None = None
 
-    provider_config: Final = ProviderConfigManager.get_provider_audio_transcription_config(
+        provider_config: Final = ProviderConfigManager.get_provider_audio_transcription_config(
+            model=model,
+            provider=LlmProviders(custom_llm_provider),
+        )
+
+        if custom_llm_provider in AZURE_OPENAI_AUDIO_PROVIDERS and provider_config is None:
+            # azure configs
+            api_base = api_base or litellm.api_base or get_secret_str("AZURE_API_BASE")
+
+            api_version = api_version or litellm.api_version or get_secret_str("AZURE_API_VERSION")
+
+            azure_ad_token: Final = kwargs.pop("azure_ad_token", None) or get_secret_str("AZURE_AD_TOKEN")
+
+            api_key = api_key or litellm.api_key or litellm.azure_key or get_secret_str("AZURE_API_KEY")
+
+            optional_params["extra_headers"] = extra_headers
+
+            response = azure_audio_transcriptions.audio_transcriptions(
+                model=model,
+                audio_file=file,
+                optional_params=optional_params,
+                model_response=model_response,
+                atranscription=atranscription,
+                client=client,
+                timeout=timeout,
+                logging_obj=litellm_logging_obj,
+                api_base=api_base,
+                api_key=api_key,
+                api_version=api_version,
+                azure_ad_token=azure_ad_token,
+                max_retries=max_retries,
+                litellm_params=litellm_params_dict,
+            )
+        elif custom_llm_provider == "openai" or (custom_llm_provider in litellm.openai_compatible_providers):
+            api_base = (
+                api_base
+                or litellm.api_base
+                or get_secret("OPENAI_BASE_URL")
+                or get_secret("OPENAI_API_BASE")
+                or "https://api.openai.com/v1"
+            )
+            openai.organization = (
+                litellm.organization
+                or get_secret("OPENAI_ORGANIZATION")
+                or None  # default - https://github.com/openai/openai-python/blob/284c1799070c723c6a553337134148a7ab088dd8/openai/util.py#L105
+            )
+            # set API KEY
+
+            api_key = api_key or litellm.api_key or litellm.openai_key or get_secret("OPENAI_API_KEY")
+            response = openai_audio_transcriptions.audio_transcriptions(
+                model=model,
+                audio_file=file,
+                optional_params=optional_params,
+                model_response=model_response,
+                atranscription=atranscription,
+                client=client,
+                timeout=timeout,
+                logging_obj=litellm_logging_obj,
+                max_retries=max_retries,
+                api_base=api_base,
+                api_key=api_key,
+                provider_config=provider_config,
+                litellm_params=litellm_params_dict,
+                shared_session=shared_session,
+            )
+        elif custom_llm_provider == "nvidia_riva":
+            # NVIDIA Riva is gRPC-based, not HTTP. It has its own dedicated handler
+            # rather than going through base_llm_http_handler.
+            response = nvidia_riva_audio_transcriptions.audio_transcriptions(
+                model=model,
+                audio_file=file,
+                optional_params=optional_params,
+                litellm_params=litellm_params_dict,
+                model_response=model_response,
+                atranscription=atranscription,
+                timeout=timeout,
+                logging_obj=litellm_logging_obj,
+                api_base=api_base,
+                api_key=api_key,
+                provider_config=(
+                    provider_config if isinstance(provider_config, NvidiaRivaAudioTranscriptionConfig) else None
+                ),
+            )
+        elif custom_llm_provider == "soniox":
+            from litellm.llms.soniox.audio_transcription.handler import (
+                SonioxAudioTranscriptionHandler,
+            )
+
+            response = SonioxAudioTranscriptionHandler().audio_transcriptions(
+                model=model,
+                audio_file=file,
+                optional_params=optional_params,
+                litellm_params=litellm_params_dict,
+                model_response=model_response,
+                atranscription=atranscription,
+                client=(
+                    client
+                    if client is not None and (isinstance(client, HTTPHandler) or isinstance(client, AsyncHTTPHandler))
+                    else None
+                ),
+                timeout=timeout,
+                max_retries=max_retries,
+                logging_obj=litellm_logging_obj,
+                api_base=api_base,
+                api_key=api_key,
+                headers=extra_headers,
+                provider_config=provider_config,
+            )
+        elif provider_config is not None:
+            response = base_llm_http_handler.audio_transcriptions(
+                model=model,
+                audio_file=file,
+                optional_params=optional_params,
+                litellm_params=litellm_params_dict,
+                model_response=model_response,
+                atranscription=atranscription,
+                client=(
+                    client
+                    if client is not None and (isinstance(client, HTTPHandler) or isinstance(client, AsyncHTTPHandler))
+                    else None
+                ),
+                timeout=timeout,
+                max_retries=max_retries,
+                logging_obj=litellm_logging_obj,
+                api_base=api_base,
+                api_key=api_key,
+                custom_llm_provider=custom_llm_provider,
+                headers={},
+                provider_config=provider_config,
+                shared_session=shared_session,
+            )
+
+        if response is None:
+            raise ValueError("Unmapped provider passed in. Unable to get the response.")
+        return response
+
+    from litellm.rust_bridge.transcription import dispatch_transcription
+
+    response: Final = dispatch_transcription(
         model=model,
-        provider=LlmProviders(custom_llm_provider),
+        provider=custom_llm_provider,
+        file=file,
+        api_key=api_key,
+        api_base=api_base,
+        headers=extra_headers,
+        optional_params=optional_params,
+        timeout=timeout,
+        logging=litellm_logging_obj,
+        asynchronous=bool(atranscription),
+        has_custom_client=client is not None or shared_session is not None,
+        fallback=python_fallback,
     )
 
-    if custom_llm_provider in AZURE_OPENAI_AUDIO_PROVIDERS and provider_config is None:
-        # azure configs
-        api_base = api_base or litellm.api_base or get_secret_str("AZURE_API_BASE")
-
-        api_version = api_version or litellm.api_version or get_secret_str("AZURE_API_VERSION")
-
-        azure_ad_token: Final = kwargs.pop("azure_ad_token", None) or get_secret_str("AZURE_AD_TOKEN")
-
-        api_key = api_key or litellm.api_key or litellm.azure_key or get_secret_str("AZURE_API_KEY")
-
-        optional_params["extra_headers"] = extra_headers
-
-        response = azure_audio_transcriptions.audio_transcriptions(
-            model=model,
-            audio_file=file,
-            optional_params=optional_params,
-            model_response=model_response,
-            atranscription=atranscription,
-            client=client,
-            timeout=timeout,
-            logging_obj=litellm_logging_obj,
-            api_base=api_base,
-            api_key=api_key,
-            api_version=api_version,
-            azure_ad_token=azure_ad_token,
-            max_retries=max_retries,
-            litellm_params=litellm_params_dict,
-        )
-    elif custom_llm_provider == "openai" or (custom_llm_provider in litellm.openai_compatible_providers):
-        api_base = (
-            api_base
-            or litellm.api_base
-            or get_secret("OPENAI_BASE_URL")
-            or get_secret("OPENAI_API_BASE")
-            or "https://api.openai.com/v1"
-        )
-        openai.organization = (
-            litellm.organization
-            or get_secret("OPENAI_ORGANIZATION")
-            or None  # default - https://github.com/openai/openai-python/blob/284c1799070c723c6a553337134148a7ab088dd8/openai/util.py#L105
-        )
-        # set API KEY
-
-        api_key = api_key or litellm.api_key or litellm.openai_key or get_secret("OPENAI_API_KEY")
-        response = openai_audio_transcriptions.audio_transcriptions(
-            model=model,
-            audio_file=file,
-            optional_params=optional_params,
-            model_response=model_response,
-            atranscription=atranscription,
-            client=client,
-            timeout=timeout,
-            logging_obj=litellm_logging_obj,
-            max_retries=max_retries,
-            api_base=api_base,
-            api_key=api_key,
-            provider_config=provider_config,
-            litellm_params=litellm_params_dict,
-            shared_session=shared_session,
-        )
-    elif custom_llm_provider == "nvidia_riva":
-        # NVIDIA Riva is gRPC-based, not HTTP. It has its own dedicated handler
-        # rather than going through base_llm_http_handler.
-        response = nvidia_riva_audio_transcriptions.audio_transcriptions(
-            model=model,
-            audio_file=file,
-            optional_params=optional_params,
-            litellm_params=litellm_params_dict,
-            model_response=model_response,
-            atranscription=atranscription,
-            timeout=timeout,
-            logging_obj=litellm_logging_obj,
-            api_base=api_base,
-            api_key=api_key,
-            provider_config=(
-                provider_config if isinstance(provider_config, NvidiaRivaAudioTranscriptionConfig) else None
-            ),
-        )
-    elif custom_llm_provider == "soniox":
-        from litellm.llms.soniox.audio_transcription.handler import (
-            SonioxAudioTranscriptionHandler,
-        )
-
-        response = SonioxAudioTranscriptionHandler().audio_transcriptions(
-            model=model,
-            audio_file=file,
-            optional_params=optional_params,
-            litellm_params=litellm_params_dict,
-            model_response=model_response,
-            atranscription=atranscription,
-            client=(
-                client
-                if client is not None and (isinstance(client, HTTPHandler) or isinstance(client, AsyncHTTPHandler))
-                else None
-            ),
-            timeout=timeout,
-            max_retries=max_retries,
-            logging_obj=litellm_logging_obj,
-            api_base=api_base,
-            api_key=api_key,
-            headers=extra_headers,
-            provider_config=provider_config,
-        )
-    elif custom_llm_provider == "bedrock":
-        from litellm.llms.bedrock.audio_transcription import BedrockAudioTranscriptionRustDispatch
-
-        dispatch: Final = BedrockAudioTranscriptionRustDispatch()
-        if atranscription:
-            response = dispatch.async_audio_transcriptions(
-                model=model,
-                audio_file=file,
-                api_key=api_key,
-                api_base=api_base,
-                custom_llm_provider=custom_llm_provider,
-                extra_headers=extra_headers,
-                optional_params=optional_params,
-                timeout=timeout,
-                logging_obj=litellm_logging_obj,
-            )
-        else:
-            response = dispatch.audio_transcriptions(
-                model=model,
-                audio_file=file,
-                api_key=api_key,
-                api_base=api_base,
-                custom_llm_provider=custom_llm_provider,
-                extra_headers=extra_headers,
-                optional_params=optional_params,
-                timeout=timeout,
-                logging_obj=litellm_logging_obj,
-            )
-    elif provider_config is not None:
-        response = base_llm_http_handler.audio_transcriptions(
-            model=model,
-            audio_file=file,
-            optional_params=optional_params,
-            litellm_params=litellm_params_dict,
-            model_response=model_response,
-            atranscription=atranscription,
-            client=(
-                client
-                if client is not None and (isinstance(client, HTTPHandler) or isinstance(client, AsyncHTTPHandler))
-                else None
-            ),
-            timeout=timeout,
-            max_retries=max_retries,
-            logging_obj=litellm_logging_obj,
-            api_base=api_base,
-            api_key=api_key,
-            custom_llm_provider=custom_llm_provider,
-            headers={},
-            provider_config=provider_config,
-            shared_session=shared_session,
-        )
-
     # Store duration in _hidden_params for cost calculation without
     # exposing it in the response body (see sync path comment above).
-    if response is not None and not isinstance(response, Coroutine):
+    if not isinstance(response, Coroutine):
         existing_duration: Final = getattr(response, "duration", None)
         if existing_duration is None:
             calculated_duration: Final = calculate_request_duration(file)
             if calculated_duration is not None:
                 response._hidden_params["audio_transcription_duration"] = calculated_duration
 
-    if response is None:
-        raise ValueError("Unmapped provider passed in. Unable to get the response.")
     return response
 
 

litellm/ocr/main.py

@@ -8,6 +8,8 @@ import mimetypes
 import os
 import re
 from collections.abc import Callable, Coroutine, Mapping
+from contextlib import nullcontext
+from dataclasses import dataclass
 from io import IOBase
 from typing import Any, Final, cast
 
@@ -17,16 +19,23 @@ import litellm
 from litellm._logging import verbose_logger
 from litellm.constants import request_timeout
 from litellm.litellm_core_utils.litellm_logging import Logging as LiteLLMLoggingObj
-from litellm.llms.azure_ai.ocr.common_utils import is_azure_document_intelligence_model
+from litellm.llms.azure_ai.ocr.common_utils import (
+    is_azure_document_intelligence_model,
+)
 from litellm.llms.base_llm.ocr.transformation import (
     OCR_REQUEST_FORMAT_PARAM,
+    BaseOCRConfig,
     OCRResponse,
     parse_ocr_request_format,
 )
 from litellm.llms.custom_httpx.llm_http_handler import BaseLLMHTTPHandler
 from litellm.rust_bridge import ocr as rust_ocr_bridge
-from litellm.rust_bridge.dispatch import anative_first, native_first, provider_errors
-from litellm.rust_bridge.runtime import DispatchResult
+from litellm.rust_bridge.request import (
+    NativeRequestOptions,
+    PreparedNativeCall,
+    vertex_options,
+)
+from litellm.rust_bridge.timeouts import timeout_to_seconds
 from litellm.types.router import GenericLiteLLMParams
 from litellm.utils import ProviderConfigManager, client
 
@@ -35,6 +44,21 @@ base_llm_http_handler = BaseLLMHTTPHandler()
 #################################################
 
 
+@dataclass
+class _PreparedOCRRequest:
+    model: str
+    document: dict[str, Any]
+    api_key: str | None
+    api_base: str | None
+    custom_llm_provider: str
+    extra_headers: dict[str, object] | None
+    provider_config: BaseOCRConfig
+    optional_params: dict[str, object]
+    litellm_params: dict[str, object]
+    effective_timeout: float | httpx.Timeout
+    litellm_logging_obj: LiteLLMLoggingObj
+
+
 def _prepare_ocr_request(
     model: str,
     document: Mapping[str, object],
@@ -44,7 +68,7 @@ def _prepare_ocr_request(
     custom_llm_provider: str | None,
     extra_headers: dict[str, object] | None,
     kwargs: dict[str, object],
-) -> rust_ocr_bridge.PreparedOCRRequest:
+) -> _PreparedOCRRequest:
     litellm_logging_obj: Final = cast(LiteLLMLoggingObj, kwargs.pop("litellm_logging_obj"))
     litellm_call_id: Final = cast(str | None, kwargs.get("litellm_call_id", None))
 
@@ -141,7 +165,7 @@ def _prepare_ocr_request(
         custom_llm_provider=custom_llm_provider,
     )
 
-    return rust_ocr_bridge.PreparedOCRRequest(
+    return _PreparedOCRRequest(
         model=model,
         document=document,
         api_key=api_key,
@@ -156,71 +180,157 @@ def _prepare_ocr_request(
     )
 
 
-@anative_first(
-    native=rust_ocr_bridge.aattempt_ocr,
-    route="ocr",
-    errors=lambda prepared_request, resolve_api_key: provider_errors(
-        prepared_request.custom_llm_provider, prepared_request.model
-    ),
-)
-async def _execute_aocr(
-    prepared_request: rust_ocr_bridge.PreparedOCRRequest,
+def _rust_bridge_optional_params(
+    prepared_request: _PreparedOCRRequest,
+    resolve_secret: Callable[[str], str | None],
+) -> dict[str, object]:
+    optional_params: Final = dict(prepared_request.optional_params)
+    if prepared_request.custom_llm_provider == "vertex_ai":
+        vertex_project: Final = (
+            prepared_request.litellm_params.get("vertex_project")
+            or prepared_request.litellm_params.get("vertex_ai_project")
+            or litellm.vertex_project
+            or resolve_secret("VERTEXAI_PROJECT")
+        )
+        vertex_location: Final = (
+            prepared_request.litellm_params.get("vertex_location")
+            or prepared_request.litellm_params.get("vertex_ai_location")
+            or litellm.vertex_location
+            or resolve_secret("VERTEXAI_LOCATION")
+            or resolve_secret("VERTEX_LOCATION")
+        )
+        if vertex_project is not None:
+            optional_params["vertex_project"] = vertex_project
+        if vertex_location is not None:
+            optional_params["vertex_location"] = vertex_location
+    return optional_params
+
+
+def _rust_bridge_api_base(
+    prepared_request: _PreparedOCRRequest,
+    resolve_secret: Callable[[str], str | None],
+) -> str | None:
+    if prepared_request.api_base is not None:
+        return prepared_request.api_base
+    if prepared_request.custom_llm_provider == "azure_ai":
+        if is_azure_document_intelligence_model(prepared_request.model):
+            return resolve_secret("AZURE_DOCUMENT_INTELLIGENCE_ENDPOINT")
+        return resolve_secret("AZURE_AI_API_BASE")
+    return None
+
+
+def _prepare_rust_ocr_call(
+    prepared_request: _PreparedOCRRequest,
     resolve_api_key: Callable[[str], str | None],
-) -> OCRResponse:
-    pending: Final = base_llm_http_handler.ocr(
+) -> PreparedNativeCall[rust_ocr_bridge.NativeOCRRequest]:
+    provider_config: Final = prepared_request.provider_config
+    api_key_env_var: Final = provider_config.get_api_key_env_var()
+    resolved_api_key: Final = prepared_request.api_key or (
+        resolve_api_key(api_key_env_var) if api_key_env_var is not None else None
+    )
+    resolved_headers: Final = provider_config.validate_environment(
+        headers=prepared_request.extra_headers or {},
         model=prepared_request.model,
-        document=prepared_request.document,
-        optional_params=prepared_request.optional_params,
-        timeout=prepared_request.effective_timeout,
-        logging_obj=prepared_request.litellm_logging_obj,
-        api_key=prepared_request.api_key,
+        api_key=resolved_api_key,
         api_base=prepared_request.api_base,
-        custom_llm_provider=prepared_request.custom_llm_provider,
-        aocr=True,
-        headers=prepared_request.extra_headers,
-        provider_config=prepared_request.provider_config,
         litellm_params=prepared_request.litellm_params,
     )
-    response: Final = await pending if asyncio.iscoroutine(pending) else pending
-    if response is None:
-        raise ValueError(f"Got an unexpected None response from the OCR API: {response}")
-    return response
-
-
-def _attempt_ocr(
-    prepared_request: rust_ocr_bridge.PreparedOCRRequest,
-    resolve_api_key: Callable[[str], str | None],
-    is_async: bool,
-) -> DispatchResult[OCRResponse]:
-    return rust_ocr_bridge.attempt_ocr(prepared_request=prepared_request, resolve_api_key=resolve_api_key)
-
-
-@native_first(
-    native=_attempt_ocr,
-    route="ocr",
-    errors=lambda prepared_request, resolve_api_key, is_async: provider_errors(
-        prepared_request.custom_llm_provider, prepared_request.model
-    ),
-)
-def _execute_ocr(
-    prepared_request: rust_ocr_bridge.PreparedOCRRequest,
-    resolve_api_key: Callable[[str], str | None],
-    is_async: bool,
-) -> OCRResponse | Coroutine[object, object, OCRResponse]:
-    return base_llm_http_handler.ocr(
-        model=prepared_request.model,
-        document=prepared_request.document,
-        optional_params=prepared_request.optional_params,
-        timeout=prepared_request.effective_timeout,
-        logging_obj=prepared_request.litellm_logging_obj,
-        api_key=prepared_request.api_key,
+    resolved_complete_url: Final = provider_config.get_complete_url(
         api_base=prepared_request.api_base,
-        custom_llm_provider=prepared_request.custom_llm_provider,
-        aocr=is_async,
-        headers=prepared_request.extra_headers,
-        provider_config=prepared_request.provider_config,
+        model=prepared_request.model,
+        optional_params=prepared_request.optional_params,
         litellm_params=prepared_request.litellm_params,
     )
+    rust_api_base: Final = _rust_bridge_api_base(prepared_request, resolve_api_key)
+    rust_optional_params: Final = _rust_bridge_optional_params(prepared_request, resolve_api_key)
+    prepared_request.litellm_logging_obj.pre_call(
+        input="OCR document processing",
+        api_key=resolved_api_key,
+        additional_args={
+            "complete_input_dict": {
+                "model": prepared_request.model,
+                "document": prepared_request.document,
+                **rust_optional_params,
+            },
+            "api_base": resolved_complete_url,
+            "headers": resolved_headers,
+        },
+    )
+    return PreparedNativeCall(
+        request=rust_ocr_bridge.NativeOCRRequest(
+            model=prepared_request.model,
+            document=prepared_request.document,
+            optional_params=prepared_request.optional_params,
+        ),
+        options=NativeRequestOptions(
+            vertex=vertex_options(rust_optional_params),
+            api_key=resolved_api_key,
+            api_base=rust_api_base,
+            custom_llm_provider=prepared_request.custom_llm_provider,
+            extra_headers=cast(  # cast-ok: provider header normalization returns string-object pairs
+                dict[str, object], resolved_headers
+            ),
+            timeout_seconds=timeout_to_seconds(prepared_request.effective_timeout),
+        ),
+    )
+
+
+@dataclass
+class _OCROperation:
+    request: _PreparedOCRRequest
+    resolve_api_key: Callable[[str], str | None]
+    python: Callable[[], OCRResponse | Coroutine[object, object, OCRResponse]]
+    logged: bool = False
+
+    def prepare(self) -> PreparedNativeCall[rust_ocr_bridge.NativeOCRRequest]:
+        prepared: Final = _prepare_rust_ocr_call(self.request, self.resolve_api_key)
+        self.logged = True
+        return prepared
+
+    def fallback(self) -> OCRResponse | Coroutine[object, object, OCRResponse]:
+        with self.request.litellm_logging_obj.suppress_next_pre_call() if self.logged else nullcontext():
+            return self.python()
+
+    async def afallback(self) -> OCRResponse:
+        with self.request.litellm_logging_obj.suppress_next_pre_call() if self.logged else nullcontext():
+            result: Final = self.python()
+            return await result if isinstance(result, Coroutine) else result
+
+
+def _run_rust_ocr(
+    prepared_request: _PreparedOCRRequest,
+    resolve_api_key: Callable[[str], str | None],
+    fallback: Callable[[], OCRResponse | Coroutine[object, object, OCRResponse]],
+) -> OCRResponse | Coroutine[object, object, OCRResponse]:
+    operation: Final = _OCROperation(prepared_request, resolve_api_key, fallback)
+    return rust_ocr_bridge.dispatch_ocr(
+        prepare=operation.prepare,
+        fallback=operation.fallback,
+        adapt=OCRResponse.model_validate,
+        model=prepared_request.model,
+        provider=prepared_request.custom_llm_provider,
+        request_format=(
+            "native" if prepared_request.optional_params.get(OCR_REQUEST_FORMAT_PARAM) == "native" else None
+        ),
+    )
+
+
+async def _run_rust_aocr(
+    prepared_request: _PreparedOCRRequest,
+    resolve_api_key: Callable[[str], str | None],
+    fallback: Callable[[], Coroutine[object, object, OCRResponse]],
+) -> OCRResponse:
+    operation: Final = _OCROperation(prepared_request, resolve_api_key, fallback)
+    return await rust_ocr_bridge.adispatch_ocr(
+        prepare=operation.prepare,
+        fallback=operation.afallback,
+        adapt=OCRResponse.model_validate,
+        model=prepared_request.model,
+        provider=prepared_request.custom_llm_provider,
+        request_format=(
+            "native" if prepared_request.optional_params.get(OCR_REQUEST_FORMAT_PARAM) == "native" else None
+        ),
+    )
 
 
 @client
@@ -319,7 +429,31 @@ async def aocr(
 
         from litellm.secret_managers.main import get_secret_str
 
-        return await _execute_aocr(prepared_request=prepared, resolve_api_key=get_secret_str)
+        async def python_fallback() -> OCRResponse:
+            pending: Final = base_llm_http_handler.ocr(
+                model=prepared.model,
+                document=prepared.document,
+                optional_params=prepared.optional_params,
+                timeout=prepared.effective_timeout,
+                logging_obj=prepared.litellm_logging_obj,
+                api_key=prepared.api_key,
+                api_base=prepared.api_base,
+                custom_llm_provider=prepared.custom_llm_provider,
+                aocr=True,
+                headers=prepared.extra_headers,
+                provider_config=prepared.provider_config,
+                litellm_params=prepared.litellm_params,
+            )
+            response: Final = await pending if asyncio.iscoroutine(pending) else pending
+            if response is None:
+                raise ValueError(f"Got an unexpected None response from the OCR API: {response}")
+            return response
+
+        return await _run_rust_aocr(
+            prepared_request=prepared,
+            resolve_api_key=get_secret_str,
+            fallback=python_fallback,
+        )
     except Exception as e:
         raise litellm.exception_type(
             model=model,
@@ -560,7 +694,27 @@ def ocr(
 
         from litellm.secret_managers.main import get_secret_str
 
-        return _execute_ocr(prepared_request=prepared, resolve_api_key=get_secret_str, is_async=_is_async)
+        def python_fallback() -> OCRResponse | Coroutine[object, object, OCRResponse]:
+            return base_llm_http_handler.ocr(
+                model=prepared.model,
+                document=prepared.document,
+                optional_params=prepared.optional_params,
+                timeout=prepared.effective_timeout,
+                logging_obj=prepared.litellm_logging_obj,
+                api_key=prepared.api_key,
+                api_base=prepared.api_base,
+                custom_llm_provider=prepared.custom_llm_provider,
+                aocr=_is_async,
+                headers=prepared.extra_headers,
+                provider_config=prepared.provider_config,
+                litellm_params=prepared.litellm_params,
+            )
+
+        return _run_rust_ocr(
+            prepared_request=prepared,
+            resolve_api_key=get_secret_str,
+            fallback=python_fallback,
+        )
     except Exception as e:
         raise litellm.exception_type(
             model=model,

litellm/rust_bridge/chat_completions.py

@@ -4,22 +4,31 @@ The Rust core owns the conversation translation, the provider call, and the
 response normalization for the subset of `/chat/completions` requests it
 accepts. This module only marshals inputs and hands the normalized result to
 LiteLLM's existing `ModelResponse` builder.
+
+``None`` means the provider was never called, so the caller is free to serve the
+request on the Python path. A failure after the call was issued raises instead:
+retrying it there would bill the customer for the same work twice.
 """
 
 from __future__ import annotations
 
 import json
-from collections.abc import Mapping, Sequence
-from dataclasses import replace
+from collections.abc import Awaitable, Callable, Coroutine, Mapping, Sequence
+from contextlib import nullcontext
+from dataclasses import dataclass
+from types import MappingProxyType
 from typing import TYPE_CHECKING, Final, Protocol
 
 import httpx
+from pydantic import TypeAdapter, ValidationError
 
+import litellm
 from litellm.litellm_core_utils.llm_response_utils.convert_dict_to_response import (
     convert_to_model_response_object,
 )
 from litellm.llms.bedrock.request_metadata import get_bedrock_request_metadata_fields
-from litellm.rust_bridge.bindings import UNCHANGED, NativeBinding, Unchanged
+from litellm.llms.custom_httpx.llm_http_handler import BaseLLMHTTPHandler
+from litellm.rust_bridge.bindings import UNCHANGED, Unchanged
 from litellm.rust_bridge.configuration import rust_enabled
 from litellm.rust_bridge.protocols import (
     RustAchatCompletions,
@@ -30,22 +39,32 @@ from litellm.rust_bridge.request import (
     NativeAnthropicOptions,
     NativeBedrockOptions,
     NativeChatCompletionsRequest,
-    NativeRequestCapabilities,
+    NativePreCallDetails,
     NativeRequestContext,
     NativeRequestOptions,
     PreparedNativeCall,
-    anthropic_options,
-    bedrock_options,
     call_native,
-    with_capabilities,
 )
-from litellm.rust_bridge.runtime import DispatchResult, aattempt, attempt
+from litellm.rust_bridge.runtime import (
+    BridgeErrorContext,
+    EndpointBinding,
+    EndpointDispatch,
+    PythonFallback,
+    async_none,
+)
 from litellm.rust_bridge.timeouts import timeout_to_seconds
+from litellm.secret_managers.main import get_secret_str
+from litellm.types.completion import (
+    _CompletionDispatchContext,  # pyright: ignore[reportPrivateUsage]  # shared internal SDK dispatch context
+    _CompletionDispatchResult,  # pyright: ignore[reportPrivateUsage]  # shared internal SDK dispatch result
+)
 from litellm.types.utils import ModelResponse
 
 if TYPE_CHECKING:
     from litellm.litellm_core_utils.litellm_logging import Logging as LiteLLMLoggingObj
 
+_LITELLM_METADATA_ADAPTER: Final = TypeAdapter(Mapping[str, object])
+
 RUST_RESPONSE_HEADER: Final = "x-litellm-rust"
 
 
@@ -89,10 +108,16 @@ def response_logger(
     return log
 
 
-_CHAT: Final[NativeBinding[RustChatCompletions]] = NativeBinding(lambda native: native.chat_completions)
-_ACHAT: Final[NativeBinding[RustAchatCompletions]] = NativeBinding(lambda native: native.achat_completions)
-_CHAT_PREFLIGHT: Final[NativeBinding[RustChatCompletionsDecline]] = NativeBinding(
-    lambda native: native.chat_completions_decline
+_CHAT: Final[EndpointDispatch[RustChatCompletions, RustAchatCompletions]] = EndpointDispatch.native(
+    route="chat_completions",
+    sync=lambda native: native.chat_completions,
+    asynchronous=lambda native: native.achat_completions,
+    enabled=rust_enabled,
+)
+_CHAT_PREFLIGHT: Final[EndpointBinding[RustChatCompletionsDecline]] = EndpointBinding.native(
+    route="chat_completions",
+    select=lambda native: native.chat_completions_decline,
+    enabled=rust_enabled,
 )
 
 
@@ -106,14 +131,14 @@ def set_rust_chat_completions(
     patching module attributes."""
     if not isinstance(chat_completions, Unchanged):
         if chat_completions is None:
-            _CHAT.reset()
+            _CHAT.sync.reset()
         else:
-            _CHAT.override(chat_completions)
+            _CHAT.sync.override(chat_completions)
     if not isinstance(achat_completions, Unchanged):
         if achat_completions is None:
-            _ACHAT.reset()
+            _CHAT.asynchronous.reset()
         else:
-            _ACHAT.override(achat_completions)
+            _CHAT.asynchronous.override(achat_completions)
     if not isinstance(decline, Unchanged):
         if decline is None:
             _CHAT_PREFLIGHT.reset()
@@ -121,21 +146,16 @@ def set_rust_chat_completions(
             _CHAT_PREFLIGHT.override(decline)
 
 
-def _provider_eligibility_options(
-    provider: str | None,
-    litellm_params: Mapping[str, object] | None,
-    optional_params: Mapping[str, object],
-) -> NativeRequestOptions:
-    bedrock: Final = (
-        replace(
-            bedrock_options(optional_params),
-            request_metadata_fields=get_bedrock_request_metadata_fields(),
-        )
-        if provider == "bedrock"
-        else None
+def _preflight_context(litellm_params: Mapping[str, object] | None) -> NativeRequestContext:
+    metadata: Final = litellm_params.get("metadata") if litellm_params is not None else None
+    try:
+        entries: Final = _LITELLM_METADATA_ADAPTER.validate_python(metadata)
+    except ValidationError:
+        return NativeRequestContext(request_metadata_fields=get_bedrock_request_metadata_fields())
+    return NativeRequestContext(
+        metadata=entries,
+        request_metadata_fields=get_bedrock_request_metadata_fields(),
     )
-    anthropic: Final = anthropic_options(litellm_params) if provider == "anthropic" else None
-    return NativeRequestOptions(custom_llm_provider=provider, bedrock=bedrock, anthropic=anthropic)
 
 
 def rust_chat_completions_accepts(
@@ -154,28 +174,16 @@ def rust_chat_completions_accepts(
     capability gate answers the second half; it resolves no credentials and
     performs no I/O.
     """
-    if not rust_enabled():
-        return False
-    decline: Final = _CHAT_PREFLIGHT.load()
-    if decline is None:
-        return False
-    try:
-        reason: Final = decline(
+    return _CHAT_PREFLIGHT.accepts(
+        check=lambda decline: decline(
             model=model,
             messages=messages,
             optional_params=optional_params,
             custom_llm_provider=custom_llm_provider,
-            options=_provider_eligibility_options(custom_llm_provider, litellm_params, optional_params),
-            context=NativeRequestContext(
-                capabilities=NativeRequestCapabilities(stream=bool(stream))
-            ),
-        )
-    except Exception as error:  # noqa: BLE001  # capability checks perform no provider I/O
-        verbose_logger.debug("Native chat acceptance check failed: %s", error)
-        return False
-    if reason is not None:
-        verbose_logger.debug("Native chat request is ineligible: %s", reason)
-    return reason is None
+            context=_preflight_context(litellm_params),
+            stream=bool(stream),
+        ),
+    )
 
 
 def _build_model_response(
@@ -206,26 +214,18 @@ def chat_completions(
     on_response: ResponseObserver,
     bedrock: NativeBedrockOptions | None = None,
     anthropic: NativeAnthropicOptions | None = None,
-    stream: bool = False,
-    has_custom_client: bool = False,
-    eligible: bool = True,
-    context: NativeRequestContext | None = None,
-) -> DispatchResult[ModelResponse]:
+) -> ModelResponse | None:
     def adapt(rust_response: Mapping[str, object]) -> ModelResponse:
         on_response(rust_response)
         return _build_model_response(rust_response, model_response)
 
-    def call(
-        native: RustChatCompletions, prepared: PreparedNativeCall[NativeChatCompletionsRequest]
-    ) -> Mapping[str, object]:
-        return call_native(native, prepared)
-
-    return attempt(
-        load=_CHAT.load,
-        enabled=rust_enabled(),
-        eligible=eligible,
+    return _CHAT.invoke(
         prepare=lambda: PreparedNativeCall(
-            request=NativeChatCompletionsRequest(model=model, messages=messages, optional_params=optional_params),
+            NativeChatCompletionsRequest(
+                model=model,
+                messages=messages,
+                optional_params=optional_params,
+            ),
             options=NativeRequestOptions(
                 api_key=api_key,
                 api_base=api_base,
@@ -235,17 +235,12 @@ def chat_completions(
                 bedrock=bedrock,
                 anthropic=anthropic,
             ),
-            context=with_capabilities(
-                context or NativeRequestContext(),
-                NativeRequestCapabilities(
-                    execution_mode="sync",
-                    stream=stream,
-                    has_custom_client=has_custom_client,
-                ),
-            ),
+            context=NativeRequestContext(),
         ),
-        call=call,
+        call=call_native,
+        fallback=lambda: None,
         adapt=adapt,
+        error_context=BridgeErrorContext(provider=custom_llm_provider or "", model=model),
     )
 
 
@@ -263,27 +258,18 @@ async def achat_completions(
     on_response: ResponseObserver,
     bedrock: NativeBedrockOptions | None = None,
     anthropic: NativeAnthropicOptions | None = None,
-    stream: bool = False,
-    has_custom_client: bool = False,
-    eligible: bool = True,
-    context: NativeRequestContext | None = None,
-) -> DispatchResult[ModelResponse]:
+) -> ModelResponse | None:
     def adapt(rust_response: Mapping[str, object]) -> ModelResponse:
         on_response(rust_response)
         return _build_model_response(rust_response, model_response)
 
-    async def call(
-        native: RustAchatCompletions,
-        prepared: PreparedNativeCall[NativeChatCompletionsRequest],
-    ) -> Mapping[str, object]:
-        return await call_native(native, prepared)
-
-    return await aattempt(
-        load=_ACHAT.load,
-        enabled=rust_enabled(),
-        eligible=eligible,
+    return await _CHAT.ainvoke(
         prepare=lambda: PreparedNativeCall(
-            request=NativeChatCompletionsRequest(model=model, messages=messages, optional_params=optional_params),
+            NativeChatCompletionsRequest(
+                model=model,
+                messages=messages,
+                optional_params=optional_params,
+            ),
             options=NativeRequestOptions(
                 api_key=api_key,
                 api_base=api_base,
@@ -293,15 +279,197 @@ async def achat_completions(
                 bedrock=bedrock,
                 anthropic=anthropic,
             ),
-            context=with_capabilities(
-                context or NativeRequestContext(),
-                NativeRequestCapabilities(
-                    execution_mode="async",
-                    stream=stream,
-                    has_custom_client=has_custom_client,
+            context=NativeRequestContext(),
+        ),
+        call=call_native,
+        fallback=async_none,
+        adapt=adapt,
+        error_context=BridgeErrorContext(provider=custom_llm_provider or "", model=model),
+    )
+
+
+async def achat_completions_or_fallback(
+    *,
+    model: str,
+    messages: Sequence[object],
+    optional_params: Mapping[str, object],
+    model_response: ModelResponse,
+    api_key: str | None,
+    api_base: str | None,
+    custom_llm_provider: str | None,
+    extra_headers: Mapping[str, object] | None,
+    timeout: float | httpx.Timeout | None,
+    on_response: ResponseObserver,
+    python_fallback: Callable[[], Awaitable[object]],
+    bedrock: NativeBedrockOptions | None = None,
+    anthropic: NativeAnthropicOptions | None = None,
+) -> object:
+    """Await the Rust path, falling back to the caller's own Python path when
+    the bridge is unavailable or the call fails.
+
+    The caller supplies the fallback, so the bridge stays free of provider
+    dispatch. This exists because a caller that dispatches asynchronously has
+    already returned a coroutine by the time a Rust failure surfaces, and so
+    cannot fall back on its own.
+    """
+
+    def adapt(rust_response: Mapping[str, object]) -> object:
+        on_response(rust_response)
+        return _build_model_response(rust_response, model_response)
+
+    return await _CHAT.ainvoke(
+        prepare=lambda: PreparedNativeCall(
+            NativeChatCompletionsRequest(
+                model=model,
+                messages=messages,
+                optional_params=optional_params,
+            ),
+            options=NativeRequestOptions(
+                api_key=api_key,
+                api_base=api_base,
+                custom_llm_provider=custom_llm_provider,
+                extra_headers=extra_headers,
+                timeout_seconds=timeout_to_seconds(timeout),
+                bedrock=bedrock,
+                anthropic=anthropic,
+            ),
+            context=NativeRequestContext(),
+        ),
+        call=call_native,
+        fallback=python_fallback,
+        adapt=adapt,
+        error_context=BridgeErrorContext(provider=custom_llm_provider or "", model=model),
+    )
+
+
+_PARAMS_ADAPTER: Final = TypeAdapter(dict[str, object])
+_STR_ADAPTER: Final = TypeAdapter(str | None)
+
+
+@dataclass
+class _ChatOperation:
+    context: _CompletionDispatchContext
+    python: Callable[[], _CompletionDispatchResult]
+    pre_call_logged: bool = False
+
+    def assess(self) -> PythonFallback | None:
+        ctx: Final = self.context
+        return _CHAT_PREFLIGHT.assess(
+            check=lambda decline: decline(
+                model=ctx.model,
+                messages=ctx.messages,
+                optional_params=ctx.optional_params,
+                custom_llm_provider=ctx.custom_llm_provider,
+                context=_preflight_context(ctx.litellm_params),
+                stream=bool(ctx.stream),
+                has_custom_client=ctx.client is not None or ctx.shared_session is not None,
+                has_agentic_hook=BaseLLMHTTPHandler.has_agentic_completion_hook(ctx.logging),
+            ),
+        )
+
+    def prepare(self) -> PreparedNativeCall[NativeChatCompletionsRequest]:
+        ctx: Final = self.context
+        config: Final = ctx.provider_config
+        defaults: Final = (
+            _PARAMS_ADAPTER.validate_python(config.get_config_for_model(ctx.model))
+            if config is not None
+            else MappingProxyType({})
+        )
+        params: Final = _PARAMS_ADAPTER.validate_python(MappingProxyType({**defaults, **ctx.optional_params}))
+        key: Final = (
+            ctx.api_key
+            or _STR_ADAPTER.validate_python(getattr(litellm, f"{ctx.custom_llm_provider}_key", None))
+            or litellm.api_key
+            or get_secret_str(f"{ctx.custom_llm_provider.upper()}_API_KEY")
+        )
+        base: Final = (
+            ctx.api_base
+            or litellm.api_base
+            or get_secret_str(f"{ctx.custom_llm_provider.upper()}_API_BASE")
+            or get_secret_str(f"{ctx.custom_llm_provider.upper()}_BASE_URL")
+        )
+        initial_headers: Final = _PARAMS_ADAPTER.validate_python(
+            MappingProxyType({**(ctx.headers or MappingProxyType({})), **(ctx.extra_headers or MappingProxyType({}))})
+        )
+        headers: Final = (
+            _PARAMS_ADAPTER.validate_python(
+                config.validate_environment(
+                    api_key=key,
+                    api_base=base,
+                    headers=initial_headers,
+                    model=ctx.model,
+                    messages=ctx.messages,
+                    optional_params=params,
+                    litellm_params=ctx.litellm_params,
+                )
+            )
+            if config is not None
+            else initial_headers
+        )
+        log_details: Final[NativePreCallDetails] = {
+            "complete_input_dict": {"model": ctx.model, "messages": ctx.messages, **params},
+            "api_base": base or "",
+            "headers": headers,
+        }
+        ctx.logging.pre_call(input=ctx.messages, api_key=key, additional_args=log_details)
+        self.pre_call_logged = True
+        return PreparedNativeCall(
+            NativeChatCompletionsRequest(
+                model=ctx.model,
+                messages=ctx.messages,
+                optional_params=provider_request_params(params),
+                options=NativeRequestOptions(
+                    api_key=key,
+                    api_base=base,
+                    custom_llm_provider=ctx.custom_llm_provider,
+                    extra_headers=headers,
+                    timeout_seconds=timeout_to_seconds(
+                        float(ctx.timeout) if isinstance(ctx.timeout, str) else ctx.timeout
+                    ),
+                    provider_connection=provider_connection_params(params),
                 ),
             ),
-        ),
-        call=call,
-        adapt=adapt,
+            context=_preflight_context(ctx.litellm_params),
+        )
+
+    def fallback(self) -> _CompletionDispatchResult:
+        with self.context.logging.suppress_next_pre_call() if self.pre_call_logged else nullcontext():
+            return self.python()
+
+    async def afallback(self) -> ModelResponse | litellm.CustomStreamWrapper:
+        with self.context.logging.suppress_next_pre_call() if self.pre_call_logged else nullcontext():
+            result: Final = self.python()
+            return await result if isinstance(result, Coroutine) else result
+
+    def adapt(self, response: Mapping[str, object]) -> ModelResponse:
+        self.context.logging.post_call(
+            input=self.context.messages,
+            api_key=self.context.api_key,
+            original_response=json.dumps(response),
+        )
+        return _build_model_response(response, self.context.model_response)
+
+
+def dispatch_completion(
+    context: _CompletionDispatchContext,
+    fallback: Callable[[], _CompletionDispatchResult],
+) -> _CompletionDispatchResult:
+    operation: Final = _ChatOperation(context, fallback)
+    error_context: Final = BridgeErrorContext(provider=context.custom_llm_provider, model=context.model)
+    if context.acompletion:
+        return _CHAT.ainvoke(
+            prepare=operation.prepare,
+            call=call_native,
+            fallback=operation.afallback,
+            adapt=operation.adapt,
+            error_context=error_context,
+            preflight=operation.assess,
+        )
+    return _CHAT.invoke(
+        prepare=operation.prepare,
+        call=call_native,
+        fallback=operation.fallback,
+        adapt=operation.adapt,
+        error_context=error_context,
+        preflight=operation.assess,
     )

litellm/rust_bridge/messages.py

@@ -2,51 +2,94 @@
 
 from __future__ import annotations
 
-from typing import Final
+import json
+from collections.abc import AsyncIterator, Callable, Coroutine, Iterator, Sequence
+from contextlib import nullcontext
+from dataclasses import dataclass
+from functools import reduce
+from types import MappingProxyType
+from typing import Final, Literal
 
 import httpx
+from pydantic import BaseModel, TypeAdapter
+from typing_extensions import ReadOnly
 
-from litellm.rust_bridge.bindings import UNCHANGED, NativeBinding, Unchanged
-from litellm.rust_bridge.protocols import RustAmessages, RustMessages
+from litellm.anthropic_beta_headers_manager import update_headers_with_filtered_beta
+from litellm.litellm_core_utils.dot_notation_indexing import delete_nested_value
+from litellm.litellm_core_utils.get_provider_specific_headers import ProviderSpecificHeaderUtils
+from litellm.litellm_core_utils.litellm_logging import Logging
+from litellm.llms.custom_httpx.llm_http_handler import BaseLLMHTTPHandler
+from litellm.rust_bridge.bindings import UNCHANGED, Unchanged
+from litellm.rust_bridge.configuration import rust_enabled
+from litellm.rust_bridge.protocols import RustAmessages, RustMessages, RustRouteDecline
 from litellm.rust_bridge.request import (
     NativeMessagesRequest,
-    NativeRequestCapabilities,
+    NativePreCallDetails,
     NativeRequestContext,
     NativeRequestOptions,
     PreparedNativeCall,
     call_native,
-    with_capabilities,
 )
-from litellm.rust_bridge.runtime import DispatchResult, aattempt, attempt, identity
+from litellm.rust_bridge.runtime import (
+    BridgeErrorContext,
+    EndpointBinding,
+    EndpointDispatch,
+    PythonFallback,
+    assess_route,
+    async_none,
+    identity,
+)
 from litellm.rust_bridge.timeouts import timeout_to_seconds
+from litellm.types.llms.anthropic_messages.anthropic_response import AnthropicMessagesResponse
+from litellm.types.llms.openai import ChatCompletionUserMessage
+from litellm.types.router import GenericLiteLLMParams
+from litellm.types.utils import LlmProviders, ProviderSpecificHeader
+from litellm.utils import ProviderConfigManager
 
-_MESSAGES: Final[NativeBinding[RustMessages]] = NativeBinding(lambda native: native.messages)
-_AMESSAGES: Final[NativeBinding[RustAmessages]] = NativeBinding(lambda native: native.amessages)
+_MESSAGES: Final[EndpointDispatch[RustMessages, RustAmessages]] = EndpointDispatch.native(
+    route="messages",
+    sync=lambda native: native.messages,
+    asynchronous=lambda native: native.amessages,
+    enabled=rust_enabled,
+)
+
+
+_PREFLIGHT: Final[EndpointBinding[RustRouteDecline]] = EndpointBinding.native(
+    route="messages",
+    select=lambda native: native.messages_decline,
+    enabled=rust_enabled,
+)
 
 
 def set_rust_messages(
     *,
     messages: RustMessages | None | Unchanged = UNCHANGED,
     amessages: RustAmessages | None | Unchanged = UNCHANGED,
+    decline: RustRouteDecline | None | Unchanged = UNCHANGED,
 ) -> None:
+    if not isinstance(decline, Unchanged):
+        if decline is None:
+            _PREFLIGHT.reset()
+        else:
+            _PREFLIGHT.override(decline)
     if not isinstance(messages, Unchanged):
         if messages is None:
-            _MESSAGES.reset()
+            _MESSAGES.sync.reset()
         else:
-            _MESSAGES.override(messages)
+            _MESSAGES.sync.override(messages)
     if not isinstance(amessages, Unchanged):
         if amessages is None:
-            _AMESSAGES.reset()
+            _MESSAGES.asynchronous.reset()
         else:
-            _AMESSAGES.override(amessages)
+            _MESSAGES.asynchronous.override(amessages)
 
 
 def load_rust_messages() -> RustMessages | None:
-    return _MESSAGES.load()
+    return _MESSAGES.sync.load()
 
 
 def load_rust_amessages() -> RustAmessages | None:
-    return _AMESSAGES.load()
+    return _MESSAGES.asynchronous.load()
 
 
 def messages(
@@ -58,17 +101,13 @@ def messages(
     custom_llm_provider: str | None,
     extra_headers: dict[str, object] | None,
     timeout: float | httpx.Timeout | None,
-    stream: bool = False,
-    has_custom_client: bool = False,
-    has_agentic_hook: bool = False,
-    context: NativeRequestContext | None = None,
-) -> DispatchResult[dict[str, object]]:
-    return attempt(
-        load=_MESSAGES.load,
-        enabled=True,
-        eligible=True,
+) -> dict[str, object] | None:
+    return _MESSAGES.invoke(
         prepare=lambda: PreparedNativeCall(
-            request=NativeMessagesRequest(model=model, body=body),
+            NativeMessagesRequest(
+                model=model,
+                body=body,
+            ),
             options=NativeRequestOptions(
                 api_key=api_key,
                 api_base=api_base,
@@ -76,18 +115,13 @@ def messages(
                 extra_headers=extra_headers,
                 timeout_seconds=timeout_to_seconds(timeout),
             ),
-            context=with_capabilities(
-                context or NativeRequestContext(),
-                NativeRequestCapabilities(
-                    execution_mode="sync",
-                    stream=stream,
-                    has_custom_client=has_custom_client,
-                    has_agentic_hook=has_agentic_hook,
-                ),
-            ),
+            context=NativeRequestContext(),
         ),
         call=call_native,
+        preflight=lambda: assess_route(_PREFLIGHT, model, custom_llm_provider or ""),
+        fallback=lambda: None,
         adapt=identity,
+        error_context=BridgeErrorContext(provider=custom_llm_provider or "", model=model),
     )
 
 
@@ -100,17 +134,13 @@ async def amessages(
     custom_llm_provider: str | None,
     extra_headers: dict[str, object] | None,
     timeout: float | httpx.Timeout | None,
-    stream: bool = False,
-    has_custom_client: bool = False,
-    has_agentic_hook: bool = False,
-    context: NativeRequestContext | None = None,
-) -> DispatchResult[dict[str, object]]:
-    return await aattempt(
-        load=_AMESSAGES.load,
-        enabled=True,
-        eligible=True,
+) -> dict[str, object] | None:
+    return await _MESSAGES.ainvoke(
         prepare=lambda: PreparedNativeCall(
-            request=NativeMessagesRequest(model=model, body=body),
+            NativeMessagesRequest(
+                model=model,
+                body=body,
+            ),
             options=NativeRequestOptions(
                 api_key=api_key,
                 api_base=api_base,
@@ -118,16 +148,197 @@ async def amessages(
                 extra_headers=extra_headers,
                 timeout_seconds=timeout_to_seconds(timeout),
             ),
-            context=with_capabilities(
-                context or NativeRequestContext(),
-                NativeRequestCapabilities(
-                    execution_mode="async",
-                    stream=stream,
-                    has_custom_client=has_custom_client,
-                    has_agentic_hook=has_agentic_hook,
-                ),
-            ),
+            context=NativeRequestContext(),
         ),
         call=call_native,
+        preflight=lambda: assess_route(_PREFLIGHT, model, custom_llm_provider or ""),
+        fallback=async_none,
         adapt=identity,
+        error_context=BridgeErrorContext(provider=custom_llm_provider or "", model=model),
+    )
+
+
+MessagesResponse = AnthropicMessagesResponse | Iterator[bytes] | AsyncIterator[object]
+MessagesResult = MessagesResponse | Coroutine[object, None, MessagesResponse]
+_BODY_ADAPTER: Final = TypeAdapter(dict[str, object])
+
+
+class _NativeMessagesResponse(BaseModel):
+    id: str
+    type: Literal["message"]
+    role: Literal["assistant"]
+    model: str
+    content: list[dict[str, object]]
+    usage: dict[str, object]
+
+
+class _BridgedMessagesResponse(AnthropicMessagesResponse):
+    _hidden_params: ReadOnly[dict[str, dict[str, str]]]
+
+
+_RESPONSE_ADAPTER: Final = TypeAdapter(AnthropicMessagesResponse)
+
+
+@dataclass
+class _MessagesOperation:
+    model: str
+    provider: str
+    messages: list[dict[str, object]]
+    body: Callable[[], dict[str, object]]
+    params: GenericLiteLLMParams
+    logging: Logging | None
+    api_key: str | None
+    api_base: str | None
+    python: Callable[[], MessagesResult]
+    logged: bool = False
+
+    def prepare(self) -> PreparedNativeCall[NativeMessagesRequest]:
+        requested: Final = self.body()
+        body: Final = _BODY_ADAPTER.validate_python(
+            reduce(
+                delete_nested_value,
+                TypeAdapter(tuple[str, ...]).validate_python(self.params.get("additional_drop_params") or ()),
+                requested,
+            )
+        )
+        provider_headers: Final = ProviderSpecificHeaderUtils.get_provider_specific_headers(
+            TypeAdapter(ProviderSpecificHeader | Sequence[ProviderSpecificHeader] | None).validate_python(
+                self.params.get("provider_specific_header")
+            ),
+            self.provider,
+        )
+        config: Final = ProviderConfigManager.get_provider_anthropic_messages_config(
+            model=self.model, provider=LlmProviders(self.provider)
+        )
+        initial_headers: Final = _BODY_ADAPTER.validate_python(
+            MappingProxyType(
+                {
+                    **(self.params.get("headers") or MappingProxyType({})),
+                    **(self.params.get("extra_headers") or MappingProxyType({})),
+                    **provider_headers,
+                }
+            )
+        )
+        validated_headers, base = (
+            config.validate_anthropic_messages_environment(
+                headers=initial_headers,
+                model=self.model,
+                messages=self.messages,
+                optional_params=body,
+                litellm_params=self.params.model_dump(),
+                api_key=self.api_key,
+                api_base=self.api_base,
+            )
+            if config is not None
+            else (initial_headers, self.api_base)
+        )
+        headers: Final = (
+            update_headers_with_filtered_beta(headers=validated_headers, provider=self.provider)
+            if config is not None and config.should_filter_anthropic_beta_headers()
+            else validated_headers
+        )
+        request_body: Final = _BODY_ADAPTER.validate_python(
+            MappingProxyType({**body, "model": self.model, "messages": self.messages})
+        )
+        if self.logging is not None:
+            self.logging.update_from_kwargs(
+                kwargs=self.params.model_dump(),
+                model=self.model,
+                optional_params=body,
+                litellm_params=self.params.model_dump(),
+                custom_llm_provider=self.provider,
+            )
+            self.logging.model_call_details.update(request_body)
+            log_details: Final[NativePreCallDetails] = {
+                "complete_input_dict": request_body,
+                "api_base": base or "",
+                "headers": headers,
+            }
+            log_input: Final[ChatCompletionUserMessage] = {"role": "user", "content": json.dumps(request_body)}
+            self.logging.pre_call(
+                input=[log_input],  # mutable-ok: logging callbacks expect a concrete message list
+                api_key=self.api_key,
+                additional_args=log_details,
+            )
+            self.logged = True
+        return PreparedNativeCall(
+            NativeMessagesRequest(
+                model=self.model,
+                body=request_body,
+                options=NativeRequestOptions(
+                    api_key=self.api_key,
+                    api_base=base,
+                    custom_llm_provider=self.provider,
+                    extra_headers=headers,
+                    timeout_seconds=timeout_to_seconds(
+                        BaseLLMHTTPHandler.resolve_anthropic_messages_timeout(self.params, False, self.provider)
+                    ),
+                ),
+            )
+        )
+
+    def fallback(self) -> MessagesResult:
+        with self.logging.suppress_next_pre_call() if self.logged and self.logging is not None else nullcontext():
+            return self.python()
+
+    async def afallback(self) -> MessagesResponse:
+        with self.logging.suppress_next_pre_call() if self.logged and self.logging is not None else nullcontext():
+            response: Final = self.python()
+            return await response if isinstance(response, Coroutine) else response
+
+    def adapt(self, response: dict[str, object]) -> AnthropicMessagesResponse:
+        _NativeMessagesResponse.model_validate(response)
+        parsed: Final[_BridgedMessagesResponse] = {
+            **_RESPONSE_ADAPTER.validate_python(response),
+            "_hidden_params": {"additional_headers": {"x-litellm-rust": "true"}},
+        }
+        if self.logging is not None:
+            self.logging.post_call(input=self.messages, api_key=self.api_key, original_response=json.dumps(response))
+        return parsed
+
+
+def dispatch_messages(
+    *,
+    model: str,
+    provider: str,
+    messages: list[dict[str, object]],
+    body: Callable[[], dict[str, object]],
+    params: GenericLiteLLMParams,
+    logging: Logging | None,
+    api_key: str | None,
+    api_base: str | None,
+    stream: bool,
+    asynchronous: bool,
+    has_custom_client: bool,
+    fallback: Callable[[], MessagesResult],
+) -> MessagesResult:
+    operation: Final = _MessagesOperation(model, provider, messages, body, params, logging, api_key, api_base, fallback)
+
+    def preflight() -> PythonFallback | None:
+        return assess_route(
+            _PREFLIGHT,
+            model,
+            provider,
+            stream=stream,
+            has_custom_client=has_custom_client,
+            has_agentic_hook=BaseLLMHTTPHandler.has_agentic_completion_hook(logging),
+        )
+
+    error_context: Final = BridgeErrorContext(provider=provider, model=model)
+    if asynchronous:
+        return _MESSAGES.ainvoke(
+            prepare=operation.prepare,
+            call=call_native,
+            adapt=operation.adapt,
+            fallback=operation.afallback,
+            preflight=preflight,
+            error_context=error_context,
+        )
+    return _MESSAGES.invoke(
+        prepare=operation.prepare,
+        call=call_native,
+        adapt=operation.adapt,
+        fallback=operation.fallback,
+        preflight=preflight,
+        error_context=error_context,
     )

litellm/rust_bridge/ocr.py

@@ -1,277 +1,109 @@
+"""Thin Python wrapper for the native Rust OCR bridge."""
+
 from __future__ import annotations
 
-from collections.abc import Callable
-from dataclasses import dataclass
-from typing import Final
+from collections.abc import Awaitable, Callable, Mapping
+from typing import Final, TypeVar
 
-import httpx
-from pydantic import TypeAdapter
-
-import litellm
-from litellm.litellm_core_utils.litellm_logging import Logging as LiteLLMLoggingObj
-from litellm.llms.azure_ai.ocr.common_utils import is_azure_document_intelligence_model
-from litellm.llms.base_llm.ocr.transformation import OCR_REQUEST_FORMAT_PARAM, BaseOCRConfig, OCRResponse
-from litellm.rust_bridge import configuration as _configuration
-from litellm.rust_bridge.bindings import NativeBinding
-from litellm.rust_bridge.protocols import RustAocr, RustOcr
-from litellm.rust_bridge.request import (
-    NativeOCRRequest,
-    NativeRequestCapabilities,
-    NativeRequestOptions,
-    PreparedNativeCall,
-    call_native,
-    request_context,
-    vertex_options,
+from . import configuration as _configuration
+from .bindings import UNCHANGED, Unchanged
+from .protocols import RustAocr, RustOcr, RustRouteDecline
+from .request import NativeOCRRequest, PreparedNativeCall, call_native
+from .runtime import (
+    BridgeErrorContext,
+    EndpointBinding,
+    EndpointDispatch,
+    assess_route,
 )
-from litellm.rust_bridge.runtime import DispatchResult, aattempt, attempt
-from litellm.rust_bridge.timeouts import timeout_to_seconds
 
-_OCR: Final[NativeBinding[RustOcr]] = NativeBinding(lambda native: native.ocr)
-_AOCR: Final[NativeBinding[RustAocr]] = NativeBinding(lambda native: native.aocr)
-_HEADERS: Final = TypeAdapter(dict[str, object])
+rust_ocr_enabled = _configuration.rust_ocr_enabled
+rust = _configuration.rust
+ResultT = TypeVar("ResultT")
 
 
-@dataclass(frozen=True, slots=True)
-class PreparedOCRRequest:
-    model: str
-    document: dict[str, object]
-    api_key: str | None
-    api_base: str | None
-    custom_llm_provider: str
-    extra_headers: dict[str, object] | None
-    provider_config: BaseOCRConfig
-    optional_params: dict[str, object]
-    litellm_params: dict[str, object]
-    effective_timeout: float | httpx.Timeout
-    litellm_logging_obj: LiteLLMLoggingObj
-
-
-@dataclass(frozen=True, slots=True)
-class _PreparedRustOCRCall:
-    api_key: str | None
-    api_base: str | None
-    headers: dict[str, object]
-    optional_params: dict[str, object]
-
-
-_RUST_OCR_PROVIDERS: Final = frozenset(
-    {
-        "mistral",
-        "azure_ai",
-        "vertex_ai",
-    }
+_OCR: Final[EndpointDispatch[RustOcr, RustAocr]] = EndpointDispatch.native(
+    route="ocr",
+    sync=lambda native: native.ocr,
+    asynchronous=lambda native: native.aocr,
+    enabled=_configuration.rust_ocr_enabled,
 )
 
 
+_PREFLIGHT: Final[EndpointBinding[RustRouteDecline]] = EndpointBinding.native(
+    route="ocr",
+    select=lambda native: native.ocr_decline,
+    enabled=_configuration.rust_ocr_enabled,
+)
+
+
+def set_rust_ocr(
+    *,
+    ocr: RustOcr | None | Unchanged = UNCHANGED,
+    aocr: RustAocr | None | Unchanged = UNCHANGED,
+    decline: RustRouteDecline | None | Unchanged = UNCHANGED,
+) -> None:
+    if not isinstance(decline, Unchanged):
+        if decline is None:
+            _PREFLIGHT.reset()
+        else:
+            _PREFLIGHT.override(decline)
+    if not isinstance(ocr, Unchanged):
+        if ocr is None:
+            _OCR.sync.reset()
+        else:
+            _OCR.sync.override(ocr)
+    if not isinstance(aocr, Unchanged):
+        if aocr is None:
+            _OCR.asynchronous.reset()
+        else:
+            _OCR.asynchronous.override(aocr)
+
+
 def load_rust_ocr() -> RustOcr | None:
-    return _OCR.load()
+    return _OCR.sync.load()
 
 
 def load_rust_aocr() -> RustAocr | None:
-    return _AOCR.load()
+    return _OCR.asynchronous.load()
 
 
-def _rust_ocr_supported(prepared_request: PreparedOCRRequest) -> bool:
-    if prepared_request.optional_params.get(OCR_REQUEST_FORMAT_PARAM) == "native":
-        return False
-    if not prepared_request.provider_config.supports_rust_bridge():
-        return False
-    return prepared_request.custom_llm_provider in _RUST_OCR_PROVIDERS
-
-
-def _ocr_input_source_kind(document: dict[str, object]) -> str:
-    if "document_url" in document:
-        return "document_url"
-    if "image_url" in document:
-        return "image_url"
-    if "file" in document:
-        return "file"
-    return "inline"
-
-
-def _ocr_request_format(optional_params: dict[str, object]) -> str | None:
-    value = optional_params.get(OCR_REQUEST_FORMAT_PARAM)
-    return value if isinstance(value, str) else None
-
-
-def _rust_bridge_optional_params(
-    prepared_request: PreparedOCRRequest,
-    resolve_secret: Callable[[str], str | None],
-) -> dict[str, object]:
-    if prepared_request.custom_llm_provider != "vertex_ai":
-        return prepared_request.optional_params
-    vertex_project: Final = (
-        prepared_request.litellm_params.get("vertex_project")
-        or prepared_request.litellm_params.get("vertex_ai_project")
-        or litellm.vertex_project
-        or resolve_secret("VERTEXAI_PROJECT")
-    )
-    vertex_location: Final = (
-        prepared_request.litellm_params.get("vertex_location")
-        or prepared_request.litellm_params.get("vertex_ai_location")
-        or litellm.vertex_location
-        or resolve_secret("VERTEXAI_LOCATION")
-        or resolve_secret("VERTEX_LOCATION")
-    )
-    return {
-        **prepared_request.optional_params,
-        **{
-            name: value
-            for name, value in (("vertex_project", vertex_project), ("vertex_location", vertex_location))
-            if value is not None
-        },
-    }
-
-
-def _rust_bridge_api_base(
-    prepared_request: PreparedOCRRequest,
-    resolve_secret: Callable[[str], str | None],
-) -> str | None:
-    if prepared_request.api_base is not None:
-        return prepared_request.api_base
-    if prepared_request.custom_llm_provider == "azure_ai":
-        if is_azure_document_intelligence_model(prepared_request.model):
-            return resolve_secret("AZURE_DOCUMENT_INTELLIGENCE_ENDPOINT")
-        return resolve_secret("AZURE_AI_API_BASE")
-    return None
-
-
-def _prepare_rust_ocr_call(
-    prepared_request: PreparedOCRRequest,
-    resolve_api_key: Callable[[str], str | None],
-) -> _PreparedRustOCRCall:
-    provider_config: Final = prepared_request.provider_config
-    api_key_env_var: Final = provider_config.get_api_key_env_var()
-    resolved_api_key: Final = prepared_request.api_key or (
-        resolve_api_key(api_key_env_var) if api_key_env_var is not None else None
-    )
-    resolved_headers: Final = _HEADERS.validate_python(
-        provider_config.validate_environment(
-            headers=prepared_request.extra_headers or {},
-            model=prepared_request.model,
-            api_key=resolved_api_key,
-            api_base=prepared_request.api_base,
-            litellm_params=prepared_request.litellm_params,
-        )
-    )
-    resolved_complete_url: Final = provider_config.get_complete_url(
-        api_base=prepared_request.api_base,
-        model=prepared_request.model,
-        optional_params=prepared_request.optional_params,
-        litellm_params=prepared_request.litellm_params,
-    )
-    rust_api_base: Final = _rust_bridge_api_base(prepared_request, resolve_api_key)
-    rust_optional_params: Final = _rust_bridge_optional_params(prepared_request, resolve_api_key)
-    prepared_request.litellm_logging_obj.pre_call(
-        input="OCR document processing",
-        api_key=resolved_api_key,
-        additional_args={
-            "complete_input_dict": {
-                "model": prepared_request.model,
-                "document": prepared_request.document,
-                **rust_optional_params,
-            },
-            "api_base": resolved_complete_url,
-            "headers": resolved_headers,
-        },
-    )
-    return _PreparedRustOCRCall(
-        api_key=resolved_api_key,
-        api_base=rust_api_base,
-        headers=resolved_headers,
-        optional_params=rust_optional_params,
+def dispatch_ocr(
+    *,
+    prepare: Callable[[], PreparedNativeCall[NativeOCRRequest]],
+    fallback: Callable[[], ResultT],
+    adapt: Callable[[Mapping[str, object]], ResultT],
+    model: str,
+    provider: str,
+    eligible: bool = True,
+    request_format: str | None = None,
+) -> ResultT:
+    return _OCR.invoke(
+        prepare=prepare,
+        call=call_native,
+        fallback=fallback,
+        adapt=adapt,
+        error_context=BridgeErrorContext(provider=provider, model=model),
+        eligible=eligible,
+        preflight=lambda: assess_route(_PREFLIGHT, model, provider, request_format=request_format),
     )
 
 
-def attempt_ocr(
-    prepared_request: PreparedOCRRequest,
-    resolve_api_key: Callable[[str], str | None],
-) -> DispatchResult[OCRResponse]:
-    return attempt(
-        load=_OCR.load,
-        enabled=_configuration.rust_enabled(),
-        prepare=lambda: _prepare_rust_ocr_call(
-            prepared_request=prepared_request,
-            resolve_api_key=resolve_api_key,
-        ),
-        call=lambda native, prepared: call_native(
-            native,
-            PreparedNativeCall(
-                request=NativeOCRRequest(
-                    model=prepared_request.model,
-                    document=prepared_request.document,
-                    optional_params=prepared.optional_params,
-                ),
-                options=NativeRequestOptions(
-                    api_key=prepared.api_key,
-                    api_base=prepared.api_base,
-                    custom_llm_provider=prepared_request.custom_llm_provider,
-                    extra_headers=prepared.headers,
-                    timeout_seconds=timeout_to_seconds(prepared_request.effective_timeout),
-                    vertex=vertex_options(prepared.optional_params),
-                ),
-                context=request_context(
-                    logging_obj=prepared_request.litellm_logging_obj,
-                    request_model=prepared_request.model,
-                    litellm_params=prepared_request.litellm_params,
-                    capabilities=NativeRequestCapabilities(
-                        execution_mode="sync",
-                        input_source_kind=_ocr_input_source_kind(prepared_request.document),
-                        request_format=_ocr_request_format(prepared_request.optional_params),
-                        native_response_format=(
-                            prepared_request.optional_params.get(OCR_REQUEST_FORMAT_PARAM) == "native"
-                        ),
-                    ),
-                ),
-            ),
-        ),
-        adapt=OCRResponse.model_validate,
-        eligible=_rust_ocr_supported(prepared_request),
-    )
-
-
-async def aattempt_ocr(
-    prepared_request: PreparedOCRRequest,
-    resolve_api_key: Callable[[str], str | None],
-) -> DispatchResult[OCRResponse]:
-    return await aattempt(
-        load=_AOCR.load,
-        enabled=_configuration.rust_enabled(),
-        prepare=lambda: _prepare_rust_ocr_call(
-            prepared_request=prepared_request,
-            resolve_api_key=resolve_api_key,
-        ),
-        call=lambda native, prepared: call_native(
-            native,
-            PreparedNativeCall(
-                request=NativeOCRRequest(
-                    model=prepared_request.model,
-                    document=prepared_request.document,
-                    optional_params=prepared.optional_params,
-                ),
-                options=NativeRequestOptions(
-                    api_key=prepared.api_key,
-                    api_base=prepared.api_base,
-                    custom_llm_provider=prepared_request.custom_llm_provider,
-                    extra_headers=prepared.headers,
-                    timeout_seconds=timeout_to_seconds(prepared_request.effective_timeout),
-                    vertex=vertex_options(prepared.optional_params),
-                ),
-                context=request_context(
-                    logging_obj=prepared_request.litellm_logging_obj,
-                    request_model=prepared_request.model,
-                    litellm_params=prepared_request.litellm_params,
-                    capabilities=NativeRequestCapabilities(
-                        execution_mode="async",
-                        input_source_kind=_ocr_input_source_kind(prepared_request.document),
-                        request_format=_ocr_request_format(prepared_request.optional_params),
-                        native_response_format=(
-                            prepared_request.optional_params.get(OCR_REQUEST_FORMAT_PARAM) == "native"
-                        ),
-                    ),
-                ),
-            ),
-        ),
-        adapt=OCRResponse.model_validate,
-        eligible=_rust_ocr_supported(prepared_request),
+async def adispatch_ocr(
+    *,
+    prepare: Callable[[], PreparedNativeCall[NativeOCRRequest]],
+    fallback: Callable[[], Awaitable[ResultT]],
+    adapt: Callable[[Mapping[str, object]], ResultT],
+    model: str,
+    provider: str,
+    eligible: bool = True,
+    request_format: str | None = None,
+) -> ResultT:
+    return await _OCR.ainvoke(
+        prepare=prepare,
+        call=call_native,
+        fallback=fallback,
+        adapt=adapt,
+        error_context=BridgeErrorContext(provider=provider, model=model),
+        eligible=eligible,
+        preflight=lambda: assess_route(_PREFLIGHT, model, provider, request_format=request_format),
     )

litellm/rust_bridge/protocols.py

@@ -32,8 +32,10 @@ class RustChatCompletionsDecline(Protocol):
         optional_params: Mapping[str, object] | None,
         custom_llm_provider: str | None,
         *,
-        options: NativeRequestOptions,
         context: NativeRequestContext,
+        stream: bool,
+        has_custom_client: bool = False,
+        has_agentic_hook: bool = False,
     ) -> str | None: ...
 
 
@@ -56,6 +58,19 @@ class RustResponsesWebSocketConnection(Protocol):
     ) -> RustResponsesWebSocket: ...
 
 
+class RustRouteDecline(Protocol):
+    def __call__(
+        self,
+        model: str,
+        custom_llm_provider: str,
+        *,
+        stream: bool = False,
+        has_agentic_hook: bool = False,
+        has_custom_client: bool = False,
+        request_format: str | None = None,
+    ) -> str | None: ...
+
+
 class NativeModule(Protocol):
     @property
     def chat_completions(self) -> RustChatCompletions: ...
@@ -92,3 +107,15 @@ class NativeModule(Protocol):
 
     @property
     def atranscription(self) -> RustAtranscription: ...
+
+    @property
+    def ocr_decline(self) -> RustRouteDecline: ...
+
+    @property
+    def messages_decline(self) -> RustRouteDecline: ...
+
+    @property
+    def transcription_decline(self) -> RustRouteDecline: ...
+
+    @property
+    def responses_websocket_decline(self) -> RustRouteDecline: ...

litellm/rust_bridge/request.py

@@ -68,6 +68,14 @@ def vertex_options(params: Mapping[str, object]) -> NativeVertexOptions:
         location=location if isinstance(location, str) else None,
     )
 
+from typing_extensions import ReadOnly, TypedDict
+
+
+class NativePreCallDetails(TypedDict):
+    complete_input_dict: ReadOnly[Mapping[str, object]]
+    api_base: ReadOnly[str]
+    headers: ReadOnly[Mapping[str, object] | None]
+
 
 @dataclass(frozen=True, slots=True)
 class NativeRequestOptions:

litellm/rust_bridge/responses_websocket.py

@@ -2,40 +2,59 @@
 
 from __future__ import annotations
 
-from collections.abc import AsyncGenerator
-from contextlib import AbstractAsyncContextManager, asynccontextmanager
-from typing import Final
+from collections.abc import AsyncGenerator, Awaitable, Callable
+from contextlib import AbstractAsyncContextManager, AsyncExitStack, asynccontextmanager
+from typing import Final, Protocol
 
 import httpx
 from websockets.exceptions import ConnectionClosedOK
 
-from litellm.rust_bridge.bindings import UNCHANGED, NativeBinding, Unchanged
+from litellm.rust_bridge.bindings import UNCHANGED, Unchanged
 from litellm.rust_bridge.configuration import rust_enabled
 from litellm.rust_bridge.protocols import (
     RustResponsesWebSocket,
     RustResponsesWebSocketConnection,
+    RustRouteDecline,
 )
 from litellm.rust_bridge.request import (
-    NativeRequestCapabilities,
     NativeRequestContext,
     NativeRequestOptions,
     NativeResponsesWebSocketRequest,
     PreparedNativeCall,
     call_native,
-    with_capabilities,
 )
-from litellm.rust_bridge.runtime import DispatchResult, aattempt, adapt_result
+from litellm.rust_bridge.runtime import (
+    BridgeErrorContext,
+    EndpointBinding,
+    assess_route,
+    async_none,
+)
 from litellm.rust_bridge.timeouts import timeout_to_seconds
 
-_RESPONSES_WEBSOCKET: Final[NativeBinding[RustResponsesWebSocketConnection]] = NativeBinding(
-    lambda native: native.ResponsesWebSocketConnection,
+_RESPONSES_WEBSOCKET: Final[EndpointBinding[RustResponsesWebSocketConnection]] = EndpointBinding.native(
+    route="responses_websocket",
+    select=lambda native: native.ResponsesWebSocketConnection,
+    enabled=rust_enabled,
+)
+
+
+_PREFLIGHT: Final[EndpointBinding[RustRouteDecline]] = EndpointBinding.native(
+    route="responses_websocket",
+    select=lambda native: native.responses_websocket_decline,
+    enabled=rust_enabled,
 )
 
 
 def set_rust_responses_websocket(
     *,
     connection: RustResponsesWebSocketConnection | None | Unchanged = UNCHANGED,
+    decline: RustRouteDecline | None | Unchanged = UNCHANGED,
 ) -> None:
+    if not isinstance(decline, Unchanged):
+        if decline is None:
+            _PREFLIGHT.reset()
+        else:
+            _PREFLIGHT.override(decline)
     if not isinstance(connection, Unchanged):
         if connection is None:
             _RESPONSES_WEBSOCKET.reset()
@@ -43,7 +62,13 @@ def set_rust_responses_websocket(
             _RESPONSES_WEBSOCKET.override(connection)
 
 
-class ConnectionAdapter:
+class Connection(Protocol):
+    async def send(self, text: str) -> None: ...
+    async def recv(self) -> str | bytes: ...
+    async def close(self) -> None: ...
+
+
+class _ConnectionAdapter:
     def __init__(self, connection: RustResponsesWebSocket):
         self._connection: Final[RustResponsesWebSocket] = connection
 
@@ -65,54 +90,55 @@ async def connect(
     url: str,
     headers: dict[str, str],
     timeout: float | httpx.Timeout | None,
-    websocket_mode: str = "native",
-    requires_connection: bool = True,
-    context: NativeRequestContext | None = None,
-) -> DispatchResult[ConnectionAdapter]:
-    return await aattempt(
-        load=_RESPONSES_WEBSOCKET.load,
-        enabled=rust_enabled(),
-        eligible=True,
+    model: str = "responses websocket",
+    provider: str = "openai",
+    fallback: Callable[[], Awaitable[Connection | None]] = async_none,
+) -> Connection | None:
+    return await _RESPONSES_WEBSOCKET.ainvoke(
         prepare=lambda: PreparedNativeCall(
-            request=NativeResponsesWebSocketRequest(url=url),
-            options=NativeRequestOptions(extra_headers=headers, timeout_seconds=timeout_to_seconds(timeout)),
-            context=with_capabilities(
-                context or NativeRequestContext(),
-                NativeRequestCapabilities(
-                    execution_mode="async",
-                    websocket_mode=websocket_mode,
-                    requires_connection=requires_connection,
-                ),
+            NativeResponsesWebSocketRequest(
+                url=url,
             ),
+            options=NativeRequestOptions(
+                extra_headers=headers,
+                timeout_seconds=timeout_to_seconds(timeout),
+                custom_llm_provider=provider,
+            ),
+            context=NativeRequestContext(),
         ),
-        call=lambda connection_type, prepared: call_native(connection_type.connect, prepared),
-        adapt=ConnectionAdapter,
+        call=lambda connection_type, request: call_native(connection_type.connect, request),
+        preflight=lambda: assess_route(_PREFLIGHT, model, provider),
+        fallback=fallback,
+        adapt=_ConnectionAdapter,
+        error_context=BridgeErrorContext(provider=provider, model=model),
     )
 
 
 @asynccontextmanager
-async def _connection_context(connection: ConnectionAdapter) -> AsyncGenerator[ConnectionAdapter, None]:
-    try:
-        yield connection
-    finally:
-        await connection.close()
-
-
-async def managed_connect(
+async def open_connection(
     *,
     url: str,
     headers: dict[str, str],
     timeout: float | httpx.Timeout | None,
-    websocket_mode: str = "managed",
-    requires_connection: bool = True,
-    context: NativeRequestContext | None = None,
-) -> DispatchResult[AbstractAsyncContextManager[ConnectionAdapter]]:
-    result: Final = await connect(
-        url=url,
-        headers=headers,
-        timeout=timeout,
-        websocket_mode=websocket_mode,
-        requires_connection=requires_connection,
-        context=context,
-    )
-    return adapt_result(result, _connection_context)
+    model: str,
+    provider: str,
+    fallback: Callable[[], AbstractAsyncContextManager[Connection]],
+) -> AsyncGenerator[Connection]:
+    async with AsyncExitStack() as stack:
+
+        async def python_connection() -> Connection:
+            return await stack.enter_async_context(fallback())
+
+        backend: Final = await connect(
+            url=url,
+            headers=headers,
+            timeout=timeout,
+            model=model,
+            provider=provider,
+            fallback=python_connection,
+        )
+        if backend is None:
+            raise RuntimeError("WebSocket connection returned no connection")
+        if isinstance(backend, _ConnectionAdapter):
+            stack.push_async_callback(backend.close)
+        yield backend

litellm/rust_bridge/runtime.py

@@ -1,22 +1,34 @@
 from __future__ import annotations
 
 from collections.abc import Awaitable, Callable
-from dataclasses import dataclass
+from dataclasses import dataclass, field
 from enum import Enum
-from typing import Final, Generic, TypeAlias, TypeVar
+from typing import Final, Generic, NoReturn, Protocol, TypeAlias, TypeVar
+
+from litellm.exceptions import APIError, AuthenticationError, InternalServerError, RateLimitError
+from litellm.rust_bridge.bindings import (
+    UNCHANGED,
+    NativeBinding,
+    Unchanged,
+    native_exception_types,
+)
+from litellm.rust_bridge.protocols import NativeModule, RustRouteDecline
 
 BindingT = TypeVar("BindingT")
+SelectedT = TypeVar("SelectedT")
+SelectedSyncT = TypeVar("SelectedSyncT")
+SelectedAsyncT = TypeVar("SelectedAsyncT")
 NativeT = TypeVar("NativeT")
 RequestT = TypeVar("RequestT")
 ResultT = TypeVar("ResultT")
+SyncBindingT = TypeVar("SyncBindingT")
+AsyncBindingT = TypeVar("AsyncBindingT")
 
 
-class NativeSkipReason(Enum):
-    DISABLED = "disabled"
-    INELIGIBLE = "ineligible"
-    UNAVAILABLE = "unavailable"
-    DECLINED = "declined"
-    FAILED = "failed"
+class PythonFallbackReason(Enum):
+    NATIVE_DISABLED = "native_disabled"
+    NATIVE_UNAVAILABLE = "native_unavailable"
+    NATIVE_DECLINED = "native_declined"
 
 
 @dataclass(frozen=True, slots=True)
@@ -25,71 +37,494 @@ class Handled(Generic[ResultT]):
 
 
 @dataclass(frozen=True, slots=True)
-class NativeSkipped:
-    reason: NativeSkipReason
+class PythonFallback:
+    reason: PythonFallbackReason
     detail: str | None = None
 
 
+DispatchResult: TypeAlias = Handled[ResultT] | PythonFallback
+
+
 @dataclass(frozen=True, slots=True)
-class NativeFailed:
-    error: Exception
+class BridgeErrorContext:
+    provider: str
+    model: str
 
 
-DispatchResult: TypeAlias = Handled[ResultT] | NativeSkipped | NativeFailed
+class RustEnablement(Protocol):
+    def __call__(self) -> bool: ...
 
 
-def _select(load: Callable[[], BindingT | None], enabled: bool, eligible: bool) -> BindingT | NativeSkipped:
-    if not enabled:
-        return NativeSkipped(NativeSkipReason.DISABLED)
-    if not eligible:
-        return NativeSkipped(NativeSkipReason.INELIGIBLE)
-    binding: Final = load()
-    return NativeSkipped(NativeSkipReason.UNAVAILABLE) if binding is None else binding
+@dataclass(frozen=True, slots=True)
+class EndpointBinding(Generic[BindingT]):
+    route: str
+    load: Callable[[], BindingT | None]
+    enabled: RustEnablement
+    _native_binding: NativeBinding[BindingT] | None = field(default=None, repr=False)
 
+    @staticmethod
+    def native(
+        *,
+        route: str,
+        select: Callable[[NativeModule], SelectedT],
+        enabled: RustEnablement,
+    ) -> EndpointBinding[SelectedT]:
+        binding: Final = NativeBinding(select)
+        return EndpointBinding(
+            route=route,
+            load=binding.load,
+            enabled=enabled,
+            _native_binding=binding,
+        )
 
-def attempt(
-    *,
-    load: Callable[[], BindingT | None],
-    enabled: bool,
-    eligible: bool,
-    prepare: Callable[[], RequestT],
-    call: Callable[[BindingT, RequestT], NativeT],
-    adapt: Callable[[NativeT], ResultT],
-) -> DispatchResult[ResultT]:
-    binding: Final = _select(load, enabled, eligible)
-    if isinstance(binding, NativeSkipped):
+    def override(self, value: BindingT | None) -> None:
+        if self._native_binding is None:
+            raise RuntimeError("only native Rust bridges support binding overrides")
+        self._native_binding.override(value)
+
+    def reset(self) -> None:
+        if self._native_binding is None:
+            raise RuntimeError("only native Rust bridges support binding resets")
+        self._native_binding.reset()
+
+    def _attempt(
+        self,
+        *,
+        prepare: Callable[[], RequestT],
+        call: Callable[[BindingT, RequestT], NativeT],
+        adapt: Callable[[NativeT], ResultT],
+        error_context: BridgeErrorContext,
+        eligible: bool = True,
+        preflight: Callable[[], PythonFallback | None] | None = None,
+    ) -> DispatchResult[ResultT]:
+        binding_or_fallback: Final = self._binding_or_python_fallback(
+            eligible=eligible,
+        )
+        if isinstance(binding_or_fallback, PythonFallback):
+            return binding_or_fallback
+        preflight_result: Final = preflight() if preflight is not None else None
+        if preflight_result is not None:
+            return preflight_result
+        return self._attempt_call(
+            call=lambda: call(binding_or_fallback, prepare()),
+            adapt=adapt,
+            error_context=error_context,
+        )
+
+    async def _aattempt(
+        self,
+        *,
+        prepare: Callable[[], RequestT],
+        call: Callable[[BindingT, RequestT], Awaitable[NativeT]],
+        adapt: Callable[[NativeT], ResultT],
+        error_context: BridgeErrorContext,
+        eligible: bool = True,
+        preflight: Callable[[], PythonFallback | None] | None = None,
+    ) -> DispatchResult[ResultT]:
+        binding_or_fallback: Final = self._binding_or_python_fallback(
+            eligible=eligible,
+        )
+        if isinstance(binding_or_fallback, PythonFallback):
+            return binding_or_fallback
+        preflight_result: Final = preflight() if preflight is not None else None
+        if preflight_result is not None:
+            return preflight_result
+        return await self._attempt_acall(
+            call=lambda: call(binding_or_fallback, prepare()),
+            adapt=adapt,
+            error_context=error_context,
+        )
+
+    def invoke(
+        self,
+        *,
+        prepare: Callable[[], RequestT],
+        call: Callable[[BindingT, RequestT], NativeT],
+        fallback: Callable[[], ResultT],
+        adapt: Callable[[NativeT], ResultT],
+        error_context: BridgeErrorContext,
+        eligible: bool = True,
+        preflight: Callable[[], PythonFallback | None] | None = None,
+    ) -> ResultT:
+        result: Final = self._attempt(
+            prepare=prepare,
+            call=call,
+            adapt=adapt,
+            error_context=error_context,
+            eligible=eligible,
+            preflight=preflight,
+        )
+        match result:
+            case Handled(value=value):
+                return value
+            case PythonFallback():
+                return fallback()
+
+    async def ainvoke(
+        self,
+        *,
+        prepare: Callable[[], RequestT],
+        call: Callable[[BindingT, RequestT], Awaitable[NativeT]],
+        fallback: Callable[[], Awaitable[ResultT]],
+        adapt: Callable[[NativeT], ResultT],
+        error_context: BridgeErrorContext,
+        eligible: bool = True,
+        preflight: Callable[[], PythonFallback | None] | None = None,
+    ) -> ResultT:
+        result: Final = await self._aattempt(
+            prepare=prepare,
+            call=call,
+            adapt=adapt,
+            error_context=error_context,
+            eligible=eligible,
+            preflight=preflight,
+        )
+        match result:
+            case Handled(value=value):
+                return value
+            case PythonFallback():
+                return await fallback()
+
+    def assess(
+        self,
+        *,
+        check: Callable[[BindingT], str | None],
+    ) -> PythonFallback | None:
+        binding: Final = self._binding_or_python_fallback(eligible=True)
+        if isinstance(binding, PythonFallback):
+            return binding
+        reason: Final = check(binding)
+        return PythonFallback(PythonFallbackReason.NATIVE_DECLINED, reason) if reason is not None else None
+
+    def accepts(
+        self,
+        *,
+        check: Callable[[BindingT], str | None],
+        eligible: bool = True,
+    ) -> bool:
+        binding_or_fallback: Final = self._binding_or_python_fallback(
+            eligible=eligible,
+        )
+        if isinstance(binding_or_fallback, PythonFallback):
+            return False
+        try:
+            reason: Final = check(binding_or_fallback)
+        except Exception:  # noqa: BLE001  # preflight performs no provider I/O, so Python handoff is safe
+            return False
+        return reason is None
+
+    def require(
+        self,
+        *,
+        prepare: Callable[[], RequestT],
+        call: Callable[[BindingT, RequestT], NativeT],
+        adapt: Callable[[NativeT], ResultT],
+        error_context: BridgeErrorContext,
+        eligible: bool = True,
+        preflight: Callable[[], PythonFallback | None] | None = None,
+    ) -> ResultT:
+        result: Final = self._attempt(
+            prepare=prepare,
+            call=call,
+            adapt=adapt,
+            error_context=error_context,
+            eligible=eligible,
+            preflight=preflight,
+        )
+        match result:
+            case Handled(value=value):
+                return value
+            case PythonFallback():
+                self._raise_required(result)
+
+    async def arequire(
+        self,
+        *,
+        prepare: Callable[[], RequestT],
+        call: Callable[[BindingT, RequestT], Awaitable[NativeT]],
+        adapt: Callable[[NativeT], ResultT],
+        error_context: BridgeErrorContext,
+        eligible: bool = True,
+        preflight: Callable[[], PythonFallback | None] | None = None,
+    ) -> ResultT:
+        result: Final = await self._aattempt(
+            prepare=prepare,
+            call=call,
+            adapt=adapt,
+            error_context=error_context,
+            eligible=eligible,
+            preflight=preflight,
+        )
+        match result:
+            case Handled(value=value):
+                return value
+            case PythonFallback():
+                self._raise_required(result)
+
+    def can_attempt(
+        self,
+        *,
+        eligible: bool = True,
+    ) -> bool:
+        return not isinstance(
+            self._binding_or_python_fallback(eligible=eligible),
+            PythonFallback,
+        )
+
+    def _raise_required(self, fallback: PythonFallback) -> NoReturn:
+        detail: Final = f": {fallback.detail}" if fallback.detail else ""
+        reason: Final = _required_reason(fallback.reason)
+        raise RuntimeError(f"native {self.route} endpoint {reason}{detail}")
+
+    def _binding_or_python_fallback(
+        self,
+        *,
+        eligible: bool,
+    ) -> BindingT | PythonFallback:
+        if not eligible or not self.enabled():
+            return PythonFallback(PythonFallbackReason.NATIVE_DISABLED)
+        binding: Final = self.load()
+        if binding is None:
+            return PythonFallback(PythonFallbackReason.NATIVE_UNAVAILABLE)
         return binding
-    try:
-        value: Final = call(binding, prepare())
-    except Exception as error:  # noqa: BLE001  # orchestration applies the endpoint's declared error policy
-        return NativeFailed(error)
-    return Handled(adapt(value))
+
+    def _attempt_call(
+        self,
+        *,
+        call: Callable[[], NativeT],
+        adapt: Callable[[NativeT], ResultT],
+        error_context: BridgeErrorContext,
+    ) -> DispatchResult[ResultT]:
+        exceptions: Final = native_exception_types()
+        if exceptions is None:
+            return Handled(adapt(call()))
+        declined, upstream = exceptions
+        try:
+            value: Final = call()
+        except declined as error:
+            return PythonFallback(PythonFallbackReason.NATIVE_DECLINED, _error_message(error))
+        except upstream as error:
+            self._raise_upstream(error, error_context)
+        return Handled(adapt(value))
+
+    async def _attempt_acall(
+        self,
+        *,
+        call: Callable[[], Awaitable[NativeT]],
+        adapt: Callable[[NativeT], ResultT],
+        error_context: BridgeErrorContext,
+    ) -> DispatchResult[ResultT]:
+        exceptions: Final = native_exception_types()
+        if exceptions is None:
+            return Handled(adapt(await call()))
+        declined, upstream = exceptions
+        try:
+            value: Final = await call()
+        except declined as error:
+            return PythonFallback(PythonFallbackReason.NATIVE_DECLINED, _error_message(error))
+        except upstream as error:
+            self._raise_upstream(error, error_context)
+        return Handled(adapt(value))
+
+    def _raise_upstream(self, error: BaseException, error_context: BridgeErrorContext) -> NoReturn:
+        args: Final[tuple[object, ...]] = error.args
+        attribute_status: Final = getattr(error, "status_code", None)
+        attribute_message: Final = getattr(error, "message", None)
+        status_value: Final = attribute_status if isinstance(attribute_status, int) else (args[0] if args else 0)
+        message_value: Final = (
+            attribute_message if isinstance(attribute_message, str) else (args[1] if len(args) > 1 else str(error))
+        )
+        status: Final = status_value if isinstance(status_value, int) else 0
+        message: Final = message_value if isinstance(message_value, str) else str(message_value)
+        error_message: Final = f"litellm rust {self.route}: {message}"
+        if status == 401:
+            raise AuthenticationError(
+                message=error_message,
+                llm_provider=error_context.provider,
+                model=error_context.model,
+            ) from error
+        if status == 429:
+            raise RateLimitError(
+                message=error_message,
+                llm_provider=error_context.provider,
+                model=error_context.model,
+            ) from error
+        if status == 500:
+            raise InternalServerError(
+                message=error_message,
+                llm_provider=error_context.provider,
+                model=error_context.model,
+            ) from error
+        raise APIError(
+            status_code=status or 500,
+            message=error_message,
+            llm_provider=error_context.provider,
+            model=error_context.model,
+        ) from error
 
 
-async def aattempt(
-    *,
-    load: Callable[[], BindingT | None],
-    enabled: bool,
-    eligible: bool,
-    prepare: Callable[[], RequestT],
-    call: Callable[[BindingT, RequestT], Awaitable[NativeT]],
-    adapt: Callable[[NativeT], ResultT],
-) -> DispatchResult[ResultT]:
-    binding: Final = _select(load, enabled, eligible)
-    if isinstance(binding, NativeSkipped):
-        return binding
-    try:
-        value: Final = await call(binding, prepare())
-    except Exception as error:  # noqa: BLE001  # orchestration applies the endpoint's declared error policy
-        return NativeFailed(error)
-    return Handled(adapt(value))
+@dataclass(frozen=True, slots=True)
+class EndpointDispatch(Generic[SyncBindingT, AsyncBindingT]):
+    sync: EndpointBinding[SyncBindingT]
+    asynchronous: EndpointBinding[AsyncBindingT]
+
+    @staticmethod
+    def native(
+        *,
+        route: str,
+        sync: Callable[[NativeModule], SelectedSyncT],
+        asynchronous: Callable[[NativeModule], SelectedAsyncT],
+        enabled: RustEnablement,
+    ) -> EndpointDispatch[SelectedSyncT, SelectedAsyncT]:
+        return EndpointDispatch(
+            sync=EndpointBinding.native(route=route, select=sync, enabled=enabled),
+            asynchronous=EndpointBinding.native(
+                route=route,
+                select=asynchronous,
+                enabled=enabled,
+            ),
+        )
+
+    def override(
+        self,
+        *,
+        sync: SyncBindingT | None | Unchanged = UNCHANGED,
+        asynchronous: AsyncBindingT | None | Unchanged = UNCHANGED,
+    ) -> None:
+        if not isinstance(sync, Unchanged):
+            self.sync.override(sync)
+        if not isinstance(asynchronous, Unchanged):
+            self.asynchronous.override(asynchronous)
+
+    def reset(self) -> None:
+        self.sync.reset()
+        self.asynchronous.reset()
+
+    def invoke(
+        self,
+        *,
+        prepare: Callable[[], RequestT],
+        call: Callable[[SyncBindingT, RequestT], NativeT],
+        fallback: Callable[[], ResultT],
+        adapt: Callable[[NativeT], ResultT],
+        error_context: BridgeErrorContext,
+        eligible: bool = True,
+        preflight: Callable[[], PythonFallback | None] | None = None,
+    ) -> ResultT:
+        return self.sync.invoke(
+            prepare=prepare,
+            call=call,
+            fallback=fallback,
+            adapt=adapt,
+            error_context=error_context,
+            eligible=eligible,
+            preflight=preflight,
+        )
+
+    async def ainvoke(
+        self,
+        *,
+        prepare: Callable[[], RequestT],
+        call: Callable[[AsyncBindingT, RequestT], Awaitable[NativeT]],
+        fallback: Callable[[], Awaitable[ResultT]],
+        adapt: Callable[[NativeT], ResultT],
+        error_context: BridgeErrorContext,
+        eligible: bool = True,
+        preflight: Callable[[], PythonFallback | None] | None = None,
+    ) -> ResultT:
+        return await self.asynchronous.ainvoke(
+            prepare=prepare,
+            call=call,
+            fallback=fallback,
+            adapt=adapt,
+            error_context=error_context,
+            eligible=eligible,
+            preflight=preflight,
+        )
+
+    def require(
+        self,
+        *,
+        prepare: Callable[[], RequestT],
+        call: Callable[[SyncBindingT, RequestT], NativeT],
+        adapt: Callable[[NativeT], ResultT],
+        error_context: BridgeErrorContext,
+        eligible: bool = True,
+        preflight: Callable[[], PythonFallback | None] | None = None,
+    ) -> ResultT:
+        return self.sync.require(
+            prepare=prepare,
+            call=call,
+            adapt=adapt,
+            error_context=error_context,
+            eligible=eligible,
+            preflight=preflight,
+        )
+
+    async def arequire(
+        self,
+        *,
+        prepare: Callable[[], RequestT],
+        call: Callable[[AsyncBindingT, RequestT], Awaitable[NativeT]],
+        adapt: Callable[[NativeT], ResultT],
+        error_context: BridgeErrorContext,
+        eligible: bool = True,
+        preflight: Callable[[], PythonFallback | None] | None = None,
+    ) -> ResultT:
+        return await self.asynchronous.arequire(
+            prepare=prepare,
+            call=call,
+            adapt=adapt,
+            error_context=error_context,
+            eligible=eligible,
+            preflight=preflight,
+        )
+
+
+def _error_message(error: BaseException) -> str:
+    reason: Final[object] = error.args[0] if error.args else str(error)
+    return reason if isinstance(reason, str) else str(reason)
+
+
+def _required_reason(reason: PythonFallbackReason) -> str:
+    match reason:
+        case PythonFallbackReason.NATIVE_DISABLED:
+            return "is disabled"
+        case PythonFallbackReason.NATIVE_UNAVAILABLE:
+            return "is unavailable"
+        case PythonFallbackReason.NATIVE_DECLINED:
+            return "declined the request"
+
+
+def always_enabled() -> bool:
+    return True
 
 
 def identity(value: ResultT) -> ResultT:
     return value
 
 
-def adapt_result(result: DispatchResult[NativeT], adapt: Callable[[NativeT], ResultT]) -> DispatchResult[ResultT]:
-    if isinstance(result, Handled):
-        return Handled(adapt(result.value))
-    return result
+async def async_none() -> None:
+    return None
+
+
+def assess_route(
+    binding: EndpointBinding[RustRouteDecline],
+    model: str,
+    provider: str,
+    *,
+    stream: bool = False,
+    has_agentic_hook: bool = False,
+    has_custom_client: bool = False,
+    request_format: str | None = None,
+) -> PythonFallback | None:
+    return binding.assess(
+        check=lambda decline: decline(
+            model,
+            provider,
+            stream=stream,
+            has_agentic_hook=has_agentic_hook,
+            has_custom_client=has_custom_client,
+            request_format=request_format,
+        ),
+    )

litellm/rust_bridge/transcription.py

@@ -1,74 +1,111 @@
 from __future__ import annotations
 
+import base64
+import json
+from collections.abc import Callable, Coroutine
+from contextlib import nullcontext
+from dataclasses import dataclass
+from io import IOBase
+from types import MappingProxyType
 from typing import Final
 
 import httpx
+from pydantic import TypeAdapter
 
-from litellm.rust_bridge.bindings import UNCHANGED, NativeBinding, Unchanged
-from litellm.rust_bridge.protocols import RustAtranscription, RustTranscription
+import litellm
+from litellm.litellm_core_utils.audio_utils.utils import process_audio_file
+from litellm.litellm_core_utils.litellm_logging import Logging
+from litellm.rust_bridge.bindings import UNCHANGED, Unchanged
+from litellm.rust_bridge.configuration import rust_enabled
+from litellm.rust_bridge.protocols import RustAtranscription, RustRouteDecline, RustTranscription
 from litellm.rust_bridge.request import (
-    NativeRequestCapabilities,
+    NativePreCallDetails,
     NativeRequestContext,
     NativeRequestOptions,
     NativeTranscriptionRequest,
     PreparedNativeCall,
     bedrock_options,
     call_native,
-    with_capabilities,
 )
-from litellm.rust_bridge.runtime import DispatchResult, aattempt, attempt, identity
+from litellm.rust_bridge.runtime import (
+    BridgeErrorContext,
+    EndpointBinding,
+    EndpointDispatch,
+    PythonFallback,
+    always_enabled,
+    assess_route,
+    async_none,
+    identity,
+)
 from litellm.rust_bridge.timeouts import timeout_to_seconds
+from litellm.secret_managers.main import get_secret_str
+from litellm.types.utils import FileTypes, TranscriptionResponse
 
-_TRANSCRIPTION: Final[NativeBinding[RustTranscription]] = NativeBinding(lambda native: native.transcription)
-_ATRANSCRIPTION: Final[NativeBinding[RustAtranscription]] = NativeBinding(lambda native: native.atranscription)
+_TRANSCRIPTION: Final[EndpointDispatch[RustTranscription, RustAtranscription]] = EndpointDispatch.native(
+    route="audio transcription",
+    sync=lambda native: native.transcription,
+    asynchronous=lambda native: native.atranscription,
+    enabled=always_enabled,
+)
+
+
+_PREFLIGHT: Final[EndpointBinding[RustRouteDecline]] = EndpointBinding.native(
+    route="transcription",
+    select=lambda native: native.transcription_decline,
+    enabled=always_enabled,
+)
 
 
 def configure_rust_transcription(
+    enabled: bool = True,
     *,
     transcription: RustTranscription | None | Unchanged = UNCHANGED,
     atranscription: RustAtranscription | None | Unchanged = UNCHANGED,
+    decline: RustRouteDecline | None | Unchanged = UNCHANGED,
 ) -> None:
+    if not isinstance(decline, Unchanged):
+        if decline is None:
+            _PREFLIGHT.reset()
+        else:
+            _PREFLIGHT.override(decline)
     if not isinstance(transcription, Unchanged):
         if transcription is None:
-            _TRANSCRIPTION.reset()
+            _TRANSCRIPTION.sync.reset()
         else:
-            _TRANSCRIPTION.override(transcription)
+            _TRANSCRIPTION.sync.override(transcription)
     if not isinstance(atranscription, Unchanged):
         if atranscription is None:
-            _ATRANSCRIPTION.reset()
+            _TRANSCRIPTION.asynchronous.reset()
         else:
-            _ATRANSCRIPTION.override(atranscription)
+            _TRANSCRIPTION.asynchronous.override(atranscription)
 
 
 def load_rust_transcription() -> RustTranscription | None:
-    return _TRANSCRIPTION.load()
+    return _TRANSCRIPTION.sync.load()
 
 
 def load_rust_atranscription() -> RustAtranscription | None:
-    return _ATRANSCRIPTION.load()
+    return _TRANSCRIPTION.asynchronous.load()
 
 
 def transcription(
     *,
     model: str,
-    audio: object,
+    audio: dict[str, object],
     api_key: str | None,
     api_base: str | None,
     custom_llm_provider: str | None,
     extra_headers: dict[str, object] | None,
     optional_params: dict[str, object],
     timeout: float | httpx.Timeout | None,
-    stream: bool = False,
-    has_custom_client: bool = False,
-    input_source_kind: str | None = None,
-    context: NativeRequestContext | None = None,
-) -> DispatchResult[dict[str, object]]:
-    return attempt(
-        load=_TRANSCRIPTION.load,
-        enabled=True,
-        eligible=True,
+) -> dict[str, object] | None:
+    return _TRANSCRIPTION.invoke(
         prepare=lambda: PreparedNativeCall(
-            request=NativeTranscriptionRequest(model=model, audio=audio, optional_params=optional_params),
+            NativeTranscriptionRequest(
+                model=model,
+                audio=audio,
+                optional_params=optional_params,
+            ),
             options=NativeRequestOptions(
                 api_key=api_key,
                 api_base=api_base,
@@ -77,42 +114,34 @@ def transcription(
                 timeout_seconds=timeout_to_seconds(timeout),
                 bedrock=bedrock_options(optional_params),
             ),
-            context=with_capabilities(
-                context or NativeRequestContext(),
-                NativeRequestCapabilities(
-                    execution_mode="sync",
-                    stream=stream,
-                    has_custom_client=has_custom_client,
-                    input_source_kind=input_source_kind,
-                ),
-            ),
+            context=NativeRequestContext(),
         ),
         call=call_native,
+        preflight=lambda: assess_route(_PREFLIGHT, model, custom_llm_provider or ""),
+        fallback=lambda: None,
         adapt=identity,
+        error_context=BridgeErrorContext(provider=custom_llm_provider or "", model=model),
     )
 
 
 async def atranscription(
     *,
     model: str,
-    audio: object,
+    audio: dict[str, object],
     api_key: str | None,
     api_base: str | None,
     custom_llm_provider: str | None,
     extra_headers: dict[str, object] | None,
     optional_params: dict[str, object],
     timeout: float | httpx.Timeout | None,
-    stream: bool = False,
-    has_custom_client: bool = False,
-    input_source_kind: str | None = None,
-    context: NativeRequestContext | None = None,
-) -> DispatchResult[dict[str, object]]:
-    return await aattempt(
-        load=_ATRANSCRIPTION.load,
-        enabled=True,
-        eligible=True,
+) -> dict[str, object] | None:
+    return await _TRANSCRIPTION.ainvoke(
         prepare=lambda: PreparedNativeCall(
-            request=NativeTranscriptionRequest(model=model, audio=audio, optional_params=optional_params),
+            NativeTranscriptionRequest(
+                model=model,
+                audio=audio,
+                optional_params=optional_params,
+            ),
             options=NativeRequestOptions(
                 api_key=api_key,
                 api_base=api_base,
@@ -121,16 +150,166 @@ async def atranscription(
                 timeout_seconds=timeout_to_seconds(timeout),
                 bedrock=bedrock_options(optional_params),
             ),
-            context=with_capabilities(
-                context or NativeRequestContext(),
-                NativeRequestCapabilities(
-                    execution_mode="async",
-                    stream=stream,
-                    has_custom_client=has_custom_client,
-                    input_source_kind=input_source_kind,
-                ),
-            ),
+            context=NativeRequestContext(),
         ),
         call=call_native,
+        preflight=lambda: assess_route(_PREFLIGHT, model, custom_llm_provider or ""),
+        fallback=async_none,
         adapt=identity,
+        error_context=BridgeErrorContext(provider=custom_llm_provider or "", model=model),
+    )
+
+
+TranscriptionResult = TranscriptionResponse | Coroutine[object, object, TranscriptionResponse]
+
+
+@dataclass
+class _TranscriptionOperation:
+    model: str
+    provider: str
+    file: FileTypes
+    api_key: str | None
+    api_base: str | None
+    headers: dict[str, object] | None
+    optional_params: dict[str, object]
+    timeout: float | httpx.Timeout | None
+    logging: Logging
+    python: Callable[[FileTypes], TranscriptionResult]
+    fallback_file: FileTypes | None = None
+    logged: bool = False
+
+    def prepare(self) -> PreparedNativeCall[NativeTranscriptionRequest]:
+        key: Final = (
+            self.api_key
+            or litellm.api_key
+            or TypeAdapter(str | None).validate_python(getattr(litellm, f"{self.provider}_key", None))
+            or get_secret_str(f"{self.provider.upper()}_API_KEY")
+        )
+        base: Final = (
+            self.api_base
+            or litellm.api_base
+            or get_secret_str(f"{self.provider.upper()}_BASE_URL")
+            or get_secret_str(f"{self.provider.upper()}_API_BASE")
+        )
+        content: Final = self.file[1] if isinstance(self.file, tuple) else self.file
+        position: Final = content.tell() if isinstance(content, IOBase) and content.seekable() else None
+        try:
+            processed: Final = process_audio_file(self.file)
+        finally:
+            if position is not None and isinstance(content, IOBase):
+                content.seek(position)
+        self.fallback_file = (processed.filename, processed.file_content, processed.content_type)
+        audio: Final = TypeAdapter(dict[str, object]).validate_python(
+            MappingProxyType(
+                {
+                    "data": base64.b64encode(processed.file_content).decode("ascii"),
+                    "format": processed.filename.rsplit(".", 1)[-1].lower() if "." in processed.filename else "wav",
+                    "filename": processed.filename,
+                }
+            )
+        )
+        log_details: Final[NativePreCallDetails] = {
+            "api_base": base or "",
+            "headers": self.headers,
+            "complete_input_dict": {"model": self.model, **self.optional_params},
+        }
+        self.logging.pre_call(input="audio transcription", api_key=key, additional_args=log_details)
+        self.logged = True
+        return PreparedNativeCall(
+            NativeTranscriptionRequest(
+                model=self.model,
+                audio=audio,
+                optional_params=provider_request_params(self.optional_params),
+                options=NativeRequestOptions(
+                    api_key=key,
+                    api_base=base,
+                    custom_llm_provider=self.provider,
+                    extra_headers=self.headers,
+                    timeout_seconds=timeout_to_seconds(self.timeout),
+                    provider_connection=provider_connection_params(self.optional_params),
+                ),
+            )
+        )
+
+    def fallback(self) -> TranscriptionResult:
+        with self.logging.suppress_next_pre_call() if self.logged else nullcontext():
+            return self.python(self.fallback_file if self.fallback_file is not None else self.file)
+
+    async def afallback(self) -> TranscriptionResponse:
+        with self.logging.suppress_next_pre_call() if self.logged else nullcontext():
+            result: Final = self.python(self.fallback_file if self.fallback_file is not None else self.file)
+            return await result if isinstance(result, Coroutine) else result
+
+    def adapt(self, response: dict[str, object]) -> TranscriptionResponse:
+        text: Final = TypeAdapter(str).validate_python(response["text"])
+        parsed: Final = TranscriptionResponse(text=text)
+        self.logging.post_call(
+            input="audio transcription", api_key=self.api_key, original_response=json.dumps(response)
+        )
+        return parsed
+
+
+def dispatch_transcription(
+    *,
+    model: str,
+    provider: str,
+    file: FileTypes,
+    api_key: str | None,
+    api_base: str | None,
+    headers: dict[str, object] | None,
+    optional_params: dict[str, object],
+    timeout: float | httpx.Timeout | None,
+    logging: Logging,
+    asynchronous: bool,
+    has_custom_client: bool,
+    fallback: Callable[[FileTypes], TranscriptionResult],
+) -> TranscriptionResult:
+    operation: Final = _TranscriptionOperation(
+        model, provider, file, api_key, api_base, headers, optional_params, timeout, logging, fallback
+    )
+
+    def preflight() -> PythonFallback | None:
+        return assess_route(
+            _PREFLIGHT,
+            model,
+            provider,
+            stream=optional_params.get("stream") is True,
+            has_custom_client=has_custom_client,
+        )
+
+    error_context: Final = BridgeErrorContext(provider=provider, model=model)
+    if provider == "bedrock":
+        if asynchronous:
+            return _TRANSCRIPTION.arequire(
+                prepare=operation.prepare,
+                call=call_native,
+                adapt=operation.adapt,
+                error_context=error_context,
+                preflight=preflight,
+            )
+        return _TRANSCRIPTION.require(
+            prepare=operation.prepare,
+            call=call_native,
+            adapt=operation.adapt,
+            error_context=error_context,
+            preflight=preflight,
+        )
+    if asynchronous:
+        return _TRANSCRIPTION.ainvoke(
+            prepare=operation.prepare,
+            call=call_native,
+            adapt=operation.adapt,
+            fallback=operation.afallback,
+            error_context=error_context,
+            eligible=rust_enabled(),
+            preflight=preflight,
+        )
+    return _TRANSCRIPTION.invoke(
+        prepare=operation.prepare,
+        call=call_native,
+        adapt=operation.adapt,
+        fallback=operation.fallback,
+        error_context=error_context,
+        eligible=rust_enabled(),
+        preflight=preflight,
     )

tests/test_litellm/anthropic_interface/test_rust_bridge_messages.py

@@ -1,20 +1,14 @@
 """Tests for the optional Rust-backed Anthropic Messages path."""
 
 import importlib
-from typing import cast
 
 import httpx
 import pytest
+from pydantic import ValidationError
 
 import litellm
-from litellm.llms.custom_httpx.llm_http_handler import BaseLLMHTTPHandler
 from litellm.rust_bridge import configuration
-from litellm.rust_bridge.request import NativeMessagesRequest, NativeRequestContext, NativeRequestOptions
-from litellm.rust_bridge.runtime import Handled, NativeFailed, NativeSkipped, NativeSkipReason
-from litellm.types.llms.anthropic_messages.anthropic_response import (
-    AnthropicMessagesResponse,
-)
-from litellm.types.router import GenericLiteLLMParams
+from litellm.rust_bridge.request import NativeMessagesRequest, NativeRequestContext
 
 rust_messages = importlib.import_module("litellm.rust_bridge.messages")
 rust_bridge_loader = importlib.import_module("litellm.rust_bridge.loader")
@@ -39,13 +33,12 @@ REQUEST_BODY: dict[str, object] = {
 class RecordingMessages:
     def __init__(self) -> None:
         self.calls: list[dict[str, object]] = []
-        self.contexts: list[NativeRequestContext] = []
 
     def __call__(
         self,
         request: NativeMessagesRequest,
         *,
-        options: NativeRequestOptions,
+        options: object,
         context: NativeRequestContext,
     ) -> dict[str, object]:
         self.calls.append(
@@ -59,20 +52,18 @@ class RecordingMessages:
                 "timeout_seconds": options.timeout_seconds,
             }
         )
-        self.contexts.append(context)
         return dict(FAKE_MESSAGES_RESPONSE)
 
 
 class RecordingAsyncMessages:
     def __init__(self) -> None:
         self.calls: list[dict[str, object]] = []
-        self.contexts: list[NativeRequestContext] = []
 
     async def __call__(
         self,
         request: NativeMessagesRequest,
         *,
-        options: NativeRequestOptions,
+        options: object,
         context: NativeRequestContext,
     ) -> dict[str, object]:
         self.calls.append(
@@ -86,7 +77,6 @@ class RecordingAsyncMessages:
                 "timeout_seconds": options.timeout_seconds,
             }
         )
-        self.contexts.append(context)
         return dict(FAKE_MESSAGES_RESPONSE)
 
 
@@ -94,7 +84,9 @@ class ExplodingAsyncMessages:
     def __init__(self) -> None:
         self.calls = 0
 
-    async def __call__(self, *args: object, **kwargs: object) -> dict[str, object]:
+    async def __call__(
+        self, request: NativeMessagesRequest, *, options: object, context: NativeRequestContext
+    ) -> dict[str, object]:
         self.calls += 1
         raise AssertionError("bridge must not be called")
 
@@ -103,18 +95,28 @@ class RaisingAsyncMessages:
     def __init__(self) -> None:
         self.calls = 0
 
-    async def __call__(self, *args: object, **kwargs: object) -> dict[str, object]:
+    async def __call__(
+        self, request: NativeMessagesRequest, *, options: object, context: NativeRequestContext
+    ) -> dict[str, object]:
         self.calls += 1
         raise RuntimeError("upstream request failed with status 400: bad request")
 
 
 @pytest.fixture(autouse=True)
 def _reset_rust_flag():
-    rust_messages.set_rust_messages(messages=None, amessages=None)
+    rust_messages.set_rust_messages(messages=None, amessages=None, decline=None)
     configuration.reset_rust_configuration()
     rust_bridge_loader._cached_bridge = rust_bridge_loader._BRIDGE_SENTINEL
+    rust_messages.set_rust_messages(
+        decline=lambda model, custom_llm_provider, **features: (
+            "unsupported feature"
+            if any(features.get(key) for key in ("stream", "has_agentic_hook", "has_custom_client"))
+            or features.get("request_format") == "native"
+            else None
+        )
+    )
     yield
-    rust_messages.set_rust_messages(messages=None, amessages=None)
+    rust_messages.set_rust_messages(messages=None, amessages=None, decline=None)
     configuration.reset_rust_configuration()
     rust_bridge_loader._cached_bridge = rust_bridge_loader._BRIDGE_SENTINEL
 
@@ -126,6 +128,16 @@ def test_load_rust_messages_returns_injected_impl():
     assert rust_messages.load_rust_messages() is bridge
 
 
+def test_bare_rust_still_toggles_ocr():
+    from litellm.rust_bridge.ocr import rust_ocr_enabled
+
+    litellm.rust(True)
+    assert rust_ocr_enabled() is True
+
+    litellm.rust(False)
+    assert rust_ocr_enabled() is False
+
+
 def test_load_rust_amessages_returns_injected_impl():
     bridge = RecordingAsyncMessages()
     litellm.rust(True)
@@ -133,7 +145,7 @@ def test_load_rust_amessages_returns_injected_impl():
     assert rust_messages.load_rust_amessages() is bridge
 
 
-def test_messages_wrapper_reports_unavailable(monkeypatch):
+def test_messages_wrapper_returns_none_when_bridge_absent(monkeypatch):
     monkeypatch.setattr(
         importlib.import_module("litellm.rust_bridge.bindings"),
         "get_native_bridge",
@@ -150,7 +162,7 @@ def test_messages_wrapper_reports_unavailable(monkeypatch):
         extra_headers={},
         timeout=30.0,
     )
-    assert result == NativeSkipped(NativeSkipReason.UNAVAILABLE)
+    assert result is None
 
 
 def test_messages_wrapper_forwards_args_and_converts_timeout():
@@ -168,7 +180,7 @@ def test_messages_wrapper_forwards_args_and_converts_timeout():
         timeout=httpx.Timeout(600.0, read=42.0),
     )
 
-    assert response == Handled(FAKE_MESSAGES_RESPONSE)
+    assert response == FAKE_MESSAGES_RESPONSE
     assert bridge.calls[0] == {
         "model": "claude-sonnet-4-5",
         "body": REQUEST_BODY,
@@ -196,331 +208,116 @@ async def test_amessages_wrapper_forwards_args():
         timeout=12.5,
     )
 
-    assert response == Handled(FAKE_MESSAGES_RESPONSE)
+    assert response == FAKE_MESSAGES_RESPONSE
     assert bridge.calls[0]["model"] == "claude-sonnet-4-5"
     assert bridge.calls[0]["timeout_seconds"] == 12.5
 
 
+class PythonMessages:
+    def __init__(self) -> None:
+        self.calls = 0
+
+    def anthropic_messages_handler(self, **kwargs: object) -> dict[str, object]:
+        self.calls += 1
+        return {**FAKE_MESSAGES_RESPONSE, "id": "python"}
+
+
+@pytest.mark.parametrize("asynchronous", [False, True])
+@pytest.mark.parametrize("provider", ["anthropic", "azure_ai", "openai"])
 @pytest.mark.asyncio
-async def test_amessages_wrapper_preserves_capability_facts():
-    bridge = RecordingAsyncMessages()
-    rust_messages.set_rust_messages(amessages=bridge)
-
-    await rust_messages.amessages(
-        model="claude-sonnet-4-5",
-        body=REQUEST_BODY,
-        api_key=None,
-        api_base=None,
-        custom_llm_provider="anthropic",
-        extra_headers=None,
-        timeout=None,
-        stream=True,
-        has_custom_client=True,
-        has_agentic_hook=True,
-    )
-
-    capabilities = bridge.contexts[0].capabilities
-    assert capabilities.execution_mode == "async"
-    assert capabilities.stream is True
-    assert capabilities.has_custom_client is True
-    assert capabilities.has_agentic_hook is True
-
-
-def _gate(**overrides):
-    kwargs = {
-        "custom_llm_provider": "azure_ai",
-        "litellm_params": GenericLiteLLMParams(api_key="sk-azure"),
-        "has_agentic_hook": False,
-        "stream": False,
-        "has_custom_client": False,
-        "model": "claude-sonnet-4-5",
-        "api_key": "sk-azure",
-        "api_base": "https://resource.services.ai.azure.com/anthropic",
-        "headers": {"x-api-key": "sk-azure", "anthropic-version": "2023-06-01"},
-        "request_body": dict(REQUEST_BODY),
-        "timeout": 30.0,
-    }
-    kwargs.update(overrides)
-    return BaseLLMHTTPHandler._attempt_rust_anthropic_messages(**kwargs)
-
-
-@pytest.mark.asyncio
-async def test_gate_invokes_rust_and_marks_response_header():
-    bridge = RecordingAsyncMessages()
+async def test_public_messages_routes_provider_acceptance(monkeypatch, asynchronous, provider):
+    bridge = RecordingMessages()
+    async_bridge = RecordingAsyncMessages()
     litellm.rust(True)
-    rust_messages.set_rust_messages(amessages=bridge)
-
-    response = await _gate()
-
-    assert isinstance(response, Handled)
-    response = response.value
+    rust_messages.set_rust_messages(messages=bridge, amessages=async_bridge)
+    if asynchronous:
+        response = await litellm.anthropic.messages.acreate(
+            model=f"{provider}/test-model",
+            max_tokens=64,
+            messages=[{"role": "user", "content": "hi"}],
+            api_key="key",
+            api_base="https://example.test",
+        )
+    else:
+        response = litellm.anthropic.messages.create(
+            model=f"{provider}/test-model",
+            max_tokens=64,
+            messages=[{"role": "user", "content": "hi"}],
+            api_key="key",
+            api_base="https://example.test",
+        )
     assert response["id"] == "msg_123"
-    assert response["_hidden_params"]["additional_headers"] == {"x-litellm-rust": "true"}
-    call = bridge.calls[0]
-    assert call["model"] == "claude-sonnet-4-5"
-    assert call["body"] == REQUEST_BODY
-    assert call["api_key"] == "sk-azure"
-    assert call["api_base"] == "https://resource.services.ai.azure.com/anthropic"
-    assert call["extra_headers"] == {"x-api-key": "sk-azure", "anthropic-version": "2023-06-01"}
-    assert call["timeout_seconds"] == 30.0
+    assert response["_hidden_params"]["additional_headers"]["x-litellm-rust"] == "true"
+    calls = async_bridge.calls if asynchronous else bridge.calls
+    assert len(calls) == 1
+    assert calls[0]["custom_llm_provider"] == provider
+    assert calls[0]["body"]["max_tokens"] == 64
 
 
-@pytest.mark.asyncio
-async def test_gate_reports_failure_to_harness():
-    bridge = RaisingAsyncMessages()
+@pytest.mark.parametrize("condition", ["disabled", "declined", "missing_binding", "missing_preflight", "stream"])
+def test_public_messages_fallback_once(monkeypatch, condition):
+    module = importlib.import_module("litellm.llms.anthropic.experimental_pass_through.messages.handler")
+    python = PythonMessages()
+    monkeypatch.setattr(module, "base_llm_http_handler", python)
+    bridge = RecordingMessages()
+    litellm.rust(condition != "disabled")
+    rust_messages.set_rust_messages(messages=bridge)
+    if condition == "declined":
+        rust_messages.set_rust_messages(decline=lambda model, custom_llm_provider, **features: "unsupported provider")
+    elif condition == "missing_binding":
+        rust_messages._MESSAGES.sync.override(None)
+    elif condition == "missing_preflight":
+        rust_messages._PREFLIGHT.override(None)
+    litellm.anthropic.messages.create(
+        model="anthropic/test-model",
+        max_tokens=64,
+        messages=[{"role": "user", "content": "hi"}],
+        api_key="key",
+        stream=condition == "stream",
+    )
+    assert python.calls == 1
+    assert bridge.calls == []
+
+
+@pytest.mark.parametrize("response", [{}, {"content": "invalid"}])
+def test_public_messages_invalid_response_does_not_fallback(monkeypatch, response):
+    module = importlib.import_module("litellm.llms.anthropic.experimental_pass_through.messages.handler")
+    python = PythonMessages()
+    monkeypatch.setattr(module, "base_llm_http_handler", python)
     litellm.rust(True)
-    rust_messages.set_rust_messages(amessages=bridge)
-
-    response = await _gate()
-    assert isinstance(response, NativeFailed)
-    assert bridge.calls == 1
+    rust_messages.set_rust_messages(messages=lambda request, *, context, callback_adapter=None: response)
+    with pytest.raises(ValidationError):
+        litellm.anthropic.messages.create(
+            model="anthropic/test-model",
+            max_tokens=64,
+            messages=[{"role": "user", "content": "hi"}],
+            api_key="key",
+        )
+    assert python.calls == 0
 
 
-@pytest.mark.asyncio
-async def test_gate_skips_rust_when_flag_absent():
-    bridge = ExplodingAsyncMessages()
-    rust_messages.set_rust_messages(amessages=bridge)
-
-    response = await _gate(litellm_params=GenericLiteLLMParams(api_key="sk-azure"))
-
-    assert isinstance(response, NativeSkipped)
-    assert bridge.calls == 0
-
-
-@pytest.mark.asyncio
-async def test_gate_uses_process_enable_without_request_override():
-    bridge = RecordingAsyncMessages()
-    rust_messages.set_rust_messages(amessages=bridge)
-    litellm.rust(True)
-
-    response = await _gate(litellm_params=GenericLiteLLMParams(api_key="sk-azure"))
-
-    assert isinstance(response, Handled)
-    response = response.value
-    assert bridge.calls[0]["custom_llm_provider"] == "azure_ai"
-
-
-@pytest.mark.asyncio
-async def test_gate_invokes_rust_for_native_anthropic_provider():
-    bridge = RecordingAsyncMessages()
-    litellm.rust(True)
-    rust_messages.set_rust_messages(amessages=bridge)
-
-    response = await _gate(
-        custom_llm_provider="anthropic",
-        litellm_params=GenericLiteLLMParams(api_key="sk-ant"),
-        api_key="sk-ant",
-        api_base="https://api.anthropic.com",
-        headers={"x-api-key": "sk-ant", "anthropic-version": "2023-06-01"},
+def test_public_messages_preserves_headers_and_optional_parameters(monkeypatch):
+    handler = importlib.import_module("litellm.llms.anthropic.experimental_pass_through.messages.handler")
+    monkeypatch.setattr(handler, "is_reasoning_auto_summary_enabled", lambda: True)
+    configuration.rust(True)
+    native = RecordingMessages()
+    rust_messages.set_rust_messages(messages=native)
+    response = litellm.anthropic.messages.create(
+        model="anthropic/claude-sonnet-4-5",
+        messages=[{"role": "user", "content": "hi"}],
+        max_tokens=2048,
+        thinking={"type": "enabled", "budget_tokens": 1024},
+        temperature=0.8,
+        additional_drop_params=["temperature"],
+        api_key="key",
+        headers={"x-source": "forwarded"},
+        extra_headers={"x-source": "extra"},
+        provider_specific_header={
+            "custom_llm_provider": "anthropic",
+            "extra_headers": {"x-source": "scoped"},
+        },
     )
-
-    assert isinstance(response, Handled)
-    response = response.value
-    assert response["_hidden_params"]["additional_headers"] == {"x-litellm-rust": "true"}
-    assert bridge.calls[0]["custom_llm_provider"] == "anthropic"
-    assert bridge.calls[0]["api_key"] == "sk-ant"
-
-
-@pytest.mark.asyncio
-async def test_gate_invokes_rust_when_env_var_set(monkeypatch):
-    bridge = RecordingAsyncMessages()
-    rust_messages.set_rust_messages(amessages=bridge)
-    monkeypatch.setenv("LITELLM_RUST", "1")
-
-    response = await _gate(
-        custom_llm_provider="anthropic",
-        litellm_params=GenericLiteLLMParams(api_key="sk-ant"),
-    )
-
-    assert isinstance(response, Handled)
-    response = response.value
-    assert bridge.calls[0]["custom_llm_provider"] == "anthropic"
-
-
-@pytest.mark.asyncio
-async def test_gate_env_var_falsey_does_not_enable(monkeypatch):
-    bridge = ExplodingAsyncMessages()
-    rust_messages.set_rust_messages(amessages=bridge)
-    monkeypatch.setenv("LITELLM_RUST", "0")
-
-    response = await _gate(
-        custom_llm_provider="anthropic",
-        litellm_params=GenericLiteLLMParams(api_key="sk-ant"),
-    )
-
-    assert isinstance(response, NativeSkipped)
-    assert bridge.calls == 0
-
-
-@pytest.mark.asyncio
-async def test_gate_skips_rust_for_unsupported_provider():
-    bridge = ExplodingAsyncMessages()
-    litellm.rust(True)
-    rust_messages.set_rust_messages(amessages=bridge)
-
-    response = await _gate(custom_llm_provider="openai")
-
-    assert isinstance(response, NativeSkipped)
-    assert bridge.calls == 0
-
-
-@pytest.mark.asyncio
-async def test_gate_skips_rust_for_agentic_hook():
-    bridge = ExplodingAsyncMessages()
-    litellm.rust(True)
-    rust_messages.set_rust_messages(amessages=bridge)
-
-    response = await _gate(has_agentic_hook=True)
-
-    assert isinstance(response, NativeSkipped)
-    assert bridge.calls == 0
-
-
-@pytest.mark.asyncio
-async def test_gate_streams_through_rust_when_eligible_and_strips_stream_flag():
-    bridge = RecordingAsyncMessages()
-    litellm.rust(True)
-    rust_messages.set_rust_messages(amessages=bridge)
-
-    streaming_body = {**REQUEST_BODY, "stream": True}
-    response = await _gate(
-        has_agentic_hook=False,
-        request_body=streaming_body,
-    )
-
-    assert isinstance(response, Handled)
-    response = response.value
-    assert response["_hidden_params"]["additional_headers"] == {"x-litellm-rust": "true"}
-    assert "stream" not in bridge.calls[0]["body"]
-    assert bridge.calls[0]["body"] == REQUEST_BODY
-
-
-@pytest.mark.asyncio
-async def test_fake_stream_wraps_rust_response_as_anthropic_sse():
-    response = cast(AnthropicMessagesResponse, dict(FAKE_MESSAGES_RESPONSE))
-    stream = BaseLLMHTTPHandler._rust_anthropic_messages_fake_stream(response)
-
-    assert stream._hidden_params["additional_headers"] == {"x-litellm-rust": "true"}
-
-    chunks = [chunk async for chunk in stream]
-    joined = b"".join(chunks)
-
-    assert b"event: message_start" in joined
-    assert b"event: content_block_delta" in joined
-    assert b"hello world" in joined
-    assert b"event: message_stop" in joined
-
-
-@pytest.mark.asyncio
-async def test_gate_falls_back_when_bridge_unavailable(monkeypatch):
-    monkeypatch.setattr(
-        importlib.import_module("litellm.rust_bridge.bindings"),
-        "get_native_bridge",
-        lambda: None,
-    )
-    litellm.rust(True)
-
-    response = await _gate()
-
-    assert isinstance(response, NativeSkipped)
-
-
-@pytest.mark.asyncio
-@pytest.mark.parametrize("selection", ("native", "disabled", "failed", "declined", "upstream"))
-async def test_messages_handler_runs_selected_backend_once(selection: str, monkeypatch: pytest.MonkeyPatch) -> None:
-    from datetime import datetime
-    from types import SimpleNamespace
-
-    import httpx
-
-    from litellm.exceptions import RateLimitError
-    from litellm.litellm_core_utils.litellm_logging import Logging
-    from litellm.llms.anthropic.experimental_pass_through.messages.transformation import AnthropicMessagesConfig
-    from litellm.llms.custom_httpx.http_handler import AsyncHTTPHandler
-    from litellm.rust_bridge import bindings
-
-    class Declined(Exception):
-        pass
-
-    class Upstream(Exception):
-        pass
-
-    error = (
-        Upstream(429, "rate limited")
-        if selection == "upstream"
-        else Declined("unsupported")
-        if selection == "declined"
-        else RuntimeError("native failed")
-        if selection == "failed"
-        else None
-    )
-
-    class Native:
-        def __init__(self) -> None:
-            self.calls = 0
-
-        async def __call__(self, *args: object, **kwargs: object) -> dict[str, object]:
-            self.calls += 1
-            if error is not None:
-                raise error
-            return dict(FAKE_MESSAGES_RESPONSE)
-
-    bridge = Native()
-    monkeypatch.setattr(
-        bindings,
-        "get_native_bridge",
-        lambda: SimpleNamespace(
-            RustBridgeDeclined=Declined,
-            RustUpstreamError=Upstream,
-        ),
-    )
-    rust_messages.set_rust_messages(amessages=bridge)
-    litellm.rust(selection != "disabled")
-    requests: list[httpx.Request] = []
-
-    def respond(request: httpx.Request) -> httpx.Response:
-        requests.append(request)
-        return httpx.Response(200, json=FAKE_MESSAGES_RESPONSE)
-
-    logging_obj = Logging(
-        model=FAKE_MESSAGES_RESPONSE["model"],
-        messages=[],
-        stream=False,
-        call_type="anthropic_messages",
-        start_time=datetime.now(),
-        litellm_call_id="harness-test",
-        function_id="harness-test",
-    )
-    client = AsyncHTTPHandler()
-    await client.client.aclose()
-    async with httpx.AsyncClient(transport=httpx.MockTransport(respond)) as transport:
-        client.client = transport
-
-        async def run():
-            return await BaseLLMHTTPHandler().async_anthropic_messages_handler(
-                model=FAKE_MESSAGES_RESPONSE["model"],
-                messages=[{"role": "user", "content": "hello"}],
-                anthropic_messages_provider_config=AnthropicMessagesConfig(),
-                anthropic_messages_optional_request_params={"max_tokens": 10},
-                custom_llm_provider="anthropic",
-                litellm_params=GenericLiteLLMParams(),
-                logging_obj=logging_obj,
-                api_key="sk-test",
-                api_base="https://example.test",
-                client=client,
-            )
-
-        if selection in ("failed", "upstream"):
-            with pytest.raises(RateLimitError if selection == "upstream" else RuntimeError) as caught:
-                await run()
-            if selection == "upstream":
-                assert caught.value.__cause__ is error
-                assert caught.value.llm_provider == "anthropic"
-                assert caught.value.model == FAKE_MESSAGES_RESPONSE["model"]
-            else:
-                assert caught.value is error
-        else:
-            response = await run()
-            assert response["id"] == FAKE_MESSAGES_RESPONSE["id"]
-    assert len(requests) == (1 if selection in ("disabled", "declined") else 0)
-    assert bridge.calls == (0 if selection == "disabled" else 1)
+    assert response["id"] == "msg_123"
+    assert native.calls[0]["extra_headers"]["x-source"] == "scoped"
+    assert native.calls[0]["body"]["thinking"]["display"] == "summarized"
+    assert "temperature" not in native.calls[0]["body"]

tests/test_litellm/llms/anthropic/chat/test_anthropic_chat_handler.py

@@ -2223,398 +2223,3 @@ def test_non_bash_tool_result_skipped():
     ), f"Expected 0 code_interpreter_results for text_editor result, got {len(code_results)}"
 
 
-class TestRustChatCompletionsHook:
-    """The `rust: true` opt-in on `/chat/completions` for the Anthropic provider.
-
-    The native callables are dependency-injected, so these run without the
-    compiled extension.
-    """
-
-    RUST_RESPONSE = {
-        "created": 1_700_000_000,
-        "model": "claude-sonnet-4-5-20260101",
-        "choices": [
-            {
-                "index": 0,
-                "message": {"role": "assistant", "content": "hello from rust"},
-                "finish_reason": "stop",
-            }
-        ],
-        "usage": {
-            "prompt_tokens": 11,
-            "completion_tokens": 4,
-            "total_tokens": 15,
-            "prompt_tokens_details": {
-                "cached_tokens": 0,
-                "cache_creation_tokens": 0,
-                "text_tokens": 11,
-            },
-        },
-    }
-
-    @pytest.fixture(autouse=True)
-    def _reset_bridge(self, monkeypatch):
-        from litellm.rust_bridge import chat_completions as bridge
-
-        monkeypatch.setenv("LITELLM_RUST", "1")
-        bridge.set_rust_chat_completions(
-            chat_completions=None, achat_completions=None, decline=None
-        )
-        yield
-        bridge.set_rust_chat_completions(
-            chat_completions=None, achat_completions=None, decline=None
-        )
-
-    @staticmethod
-    def _completion_kwargs(**overrides):
-        from litellm.types.utils import ModelResponse
-
-        kwargs = {
-            "model": "claude-sonnet-4-5",
-            "messages": [{"role": "user", "content": "hi"}],
-            "api_base": "https://api.anthropic.com/v1/messages",
-            "custom_llm_provider": "anthropic",
-            "custom_prompt_dict": {},
-            "model_response": ModelResponse(),
-            "print_verbose": lambda *_args, **_kwargs: None,
-            "encoding": None,
-            "api_key": "sk-ant-test",
-            "logging_obj": MagicMock(),
-            "optional_params": {"max_tokens": 16},
-            "timeout": 30.0,
-            "litellm_params": {},
-            "acompletion": False,
-            "headers": {},
-            "client": None,
-        }
-        kwargs.update(overrides)
-        return kwargs
-
-    @staticmethod
-    def _recording_logging_obj():
-        """A logging object that keeps each hook's payload in a real list, so a
-        test can assert which path logged and what it carried."""
-        calls = {"pre_call": [], "post_call": []}
-        logging_obj = MagicMock()
-        logging_obj.pre_call.side_effect = lambda **kwargs: calls["pre_call"].append(kwargs)
-        logging_obj.post_call.side_effect = lambda **kwargs: calls["post_call"].append(kwargs)
-        return logging_obj, calls
-
-    def _inject(self, *, decline_reason=None, sync_result=None, sync_error=None):
-        from litellm.rust_bridge import chat_completions as bridge
-
-        seen = {"gate": [], "call": []}
-
-        def gate(**kwargs):
-            seen["gate"].append(kwargs)
-            return decline_reason
-
-        def native(request, *, options, context):
-            seen["call"].append(
-                {
-                    "model": request.model,
-                    "messages": request.messages,
-                    "optional_params": request.optional_params,
-                    "api_key": options.api_key,
-                    "api_base": options.api_base,
-                    "context": context,
-                }
-            )
-            if sync_error is not None:
-                raise sync_error
-            return dict(sync_result if sync_result is not None else self.RUST_RESPONSE)
-
-        bridge.set_rust_chat_completions(decline=gate, chat_completions=native)
-        return seen
-
-    def test_rust_true_serves_the_call_and_stamps_the_header(self):
-        from litellm.llms.anthropic.chat.handler import AnthropicChatCompletion
-
-        seen = self._inject()
-        response = AnthropicChatCompletion().completion(**self._completion_kwargs())
-
-        assert response.choices[0].message.content == "hello from rust"
-        assert response._hidden_params["additional_headers"] == {"x-litellm-rust": "true"}
-        assert len(seen["call"]) == 1
-
-    def test_the_core_receives_the_untranslated_openai_messages(self):
-        """Rust owns the translation, so the handler must not pre-translate."""
-        from litellm.llms.anthropic.chat.handler import AnthropicChatCompletion
-
-        seen = self._inject()
-        AnthropicChatCompletion().completion(
-            **self._completion_kwargs(
-                messages=[
-                    {"role": "system", "content": "be terse"},
-                    {"role": "user", "content": "hi"},
-                ]
-            )
-        )
-        assert seen["call"][0]["messages"] == [
-            {"role": "system", "content": "be terse"},
-            {"role": "user", "content": "hi"},
-        ]
-
-    def test_the_anthropic_max_tokens_default_is_merged_in_before_the_gate(self):
-        """`transform_request` applies `AnthropicConfig.get_config`; the Rust
-        path skips it, so the handler has to merge it or Anthropic 400s on a
-        request that omits `max_tokens`."""
-        from litellm.llms.anthropic.chat.handler import AnthropicChatCompletion
-
-        seen = self._inject()
-        AnthropicChatCompletion().completion(**self._completion_kwargs(optional_params={}))
-        assert "max_tokens" in seen["gate"][0]["optional_params"]
-        assert seen["call"][0]["optional_params"]["max_tokens"] > 0
-
-    def test_a_caller_supplied_max_tokens_outranks_the_default(self):
-        from litellm.llms.anthropic.chat.handler import AnthropicChatCompletion
-
-        seen = self._inject()
-        AnthropicChatCompletion().completion(
-            **self._completion_kwargs(optional_params={"max_tokens": 7})
-        )
-        assert seen["call"][0]["optional_params"]["max_tokens"] == 7
-
-    def test_without_the_opt_in_the_core_is_never_consulted(self, monkeypatch):
-        monkeypatch.setenv("LITELLM_RUST", "0")
-        from litellm.llms.anthropic.chat.handler import AnthropicChatCompletion
-        from litellm.llms.anthropic.chat.transformation import AnthropicConfig
-
-        seen = self._inject()
-        with patch.object(
-            AnthropicConfig, "transform_request", return_value={"model": "m", "messages": []}
-        ) as transform, patch.object(
-            AnthropicChatCompletion, "acompletion_function"
-        ):
-            try:
-                AnthropicChatCompletion().completion(
-                    **self._completion_kwargs(litellm_params={})
-                )
-            except Exception:
-                # The Python path goes on to make an HTTP call; reaching it is
-                # the assertion, so the network failure below is expected.
-                pass
-        assert seen["gate"] == []
-        assert seen["call"] == []
-        assert transform.called
-
-    def test_a_declined_request_never_reaches_the_native_call(self):
-        from litellm.llms.anthropic.chat.handler import AnthropicChatCompletion
-        from litellm.llms.anthropic.chat.transformation import AnthropicConfig
-
-        seen = self._inject(decline_reason="unrecognized request parameter")
-        with patch.object(
-            AnthropicConfig, "transform_request", return_value={"model": "m", "messages": []}
-        ):
-            try:
-                AnthropicChatCompletion().completion(**self._completion_kwargs())
-            except Exception:
-                pass
-        assert len(seen["gate"]) == 1
-        assert seen["call"] == []
-
-    def test_streaming_stays_on_the_python_path(self):
-        from litellm.llms.anthropic.chat.handler import AnthropicChatCompletion
-        from litellm.llms.anthropic.chat.transformation import AnthropicConfig
-
-        seen = self._inject()
-        with patch.object(
-            AnthropicConfig, "transform_request", return_value={"model": "m", "messages": []}
-        ):
-            try:
-                AnthropicChatCompletion().completion(
-                    **self._completion_kwargs(optional_params={"max_tokens": 16, "stream": True})
-                )
-            except Exception:
-                pass
-        assert seen["call"] == []
-
-    def test_pre_call_logging_fires_exactly_once_on_the_rust_path(self):
-        from litellm.llms.anthropic.chat.handler import AnthropicChatCompletion
-
-        seen = self._inject()
-        logging_obj = MagicMock()
-        AnthropicChatCompletion().completion(
-            **self._completion_kwargs(logging_obj=logging_obj)
-        )
-        assert logging_obj.pre_call.call_count == 1
-        assert len(seen["call"]) == 1
-
-    def test_post_call_logging_fires_on_the_rust_path(self):
-        """The Rust core owns the provider call, so the Python transform that
-        normally raises `post_call` never runs. Without the bridge hook every
-        post_call callback goes silent and `original_response` stays unset."""
-        import json
-
-        from litellm.llms.anthropic.chat.handler import AnthropicChatCompletion
-
-        self._inject()
-        logging_obj = MagicMock()
-        AnthropicChatCompletion().completion(
-            **self._completion_kwargs(logging_obj=logging_obj)
-        )
-
-        assert logging_obj.post_call.call_count == 1
-        logged = logging_obj.post_call.call_args.kwargs["original_response"]
-        assert json.loads(logged)["choices"][0]["message"]["content"] == "hello from rust"
-
-    def test_post_call_is_not_logged_twice_when_the_sync_rust_call_declines(self, monkeypatch):
-        """A decline never reached the provider, so the Python path serves the
-        request and owns the only post_call. Firing the hook there too would
-        double every post_call callback for one request."""
-        from litellm.llms.anthropic.chat.handler import AnthropicChatCompletion
-        from litellm.llms.anthropic.chat.transformation import AnthropicConfig
-        from litellm.rust_bridge import chat_completions as bridge
-
-        class _Declined(Exception):
-            pass
-
-        class _FakeNative:
-            RustBridgeDeclined = _Declined
-            RustUpstreamError = type("_Upstream", (Exception,), {})
-
-        def declining_native(_request, *, options, context):
-            raise _Declined("blank message text")
-
-        monkeypatch.setattr("litellm.rust_bridge.bindings.get_native_bridge", lambda: _FakeNative())
-        bridge.set_rust_chat_completions(
-            decline=lambda **_kwargs: None, chat_completions=declining_native
-        )
-
-        logging_obj, calls = self._recording_logging_obj()
-        with patch.object(
-            AnthropicConfig, "transform_request", return_value={"model": "m", "messages": []}
-        ):
-            try:
-                AnthropicChatCompletion().completion(
-                    **self._completion_kwargs(logging_obj=logging_obj)
-                )
-            except Exception:
-                # The Python path goes on to make an HTTP call; the log count is
-                # the assertion, so a failure past this point is expected.
-                pass
-
-        assert calls["post_call"] == []
-
-    @pytest.mark.asyncio
-    async def test_the_async_path_falls_back_when_the_core_declines(self, monkeypatch):
-        from litellm.llms.anthropic.chat.handler import AnthropicChatCompletion
-        from litellm.rust_bridge import chat_completions as bridge
-
-        class _Declined(Exception):
-            pass
-
-        class _FakeNative:
-            RustBridgeDeclined = _Declined
-            RustUpstreamError = type("_Upstream", (Exception,), {})
-
-        monkeypatch.setattr("litellm.rust_bridge.bindings.get_native_bridge", lambda: _FakeNative())
-
-        async def declining_native(_request, *, options, context):
-            raise _Declined("blank message text")
-
-        bridge.set_rust_chat_completions(
-            decline=lambda **_kwargs: None, achat_completions=declining_native
-        )
-
-        sentinel = object()
-
-        async def python_path(**_kwargs):
-            return sentinel
-
-        with patch.object(
-            AnthropicChatCompletion, "acompletion_function", side_effect=python_path
-        ) as python_call:
-            result = await AnthropicChatCompletion().completion(
-                **self._completion_kwargs(acompletion=True)
-            )
-
-        assert result is sentinel
-        assert python_call.called, "a failing rust call must re-enter the python path"
-
-    @pytest.mark.asyncio
-    async def test_the_async_path_serves_the_rust_response_without_the_fallback(self):
-        from litellm.llms.anthropic.chat.handler import AnthropicChatCompletion
-        from litellm.rust_bridge import chat_completions as bridge
-
-        async def native(_request, *, options, context):
-            return dict(self.RUST_RESPONSE)
-
-        bridge.set_rust_chat_completions(
-            decline=lambda **_kwargs: None, achat_completions=native
-        )
-
-        with patch.object(AnthropicChatCompletion, "acompletion_function") as python_call:
-            result = await AnthropicChatCompletion().completion(
-                **self._completion_kwargs(acompletion=True)
-            )
-
-        assert result.choices[0].message.content == "hello from rust"
-        assert result._hidden_params["additional_headers"] == {"x-litellm-rust": "true"}
-        assert not python_call.called
-
-
-    def test_pre_call_logging_fires_once_when_the_sync_rust_call_declines(self, monkeypatch):
-        """One request, one pre_call, on the synchronous path too. Without the
-        suppression the Python path logs a second time for the same attempt."""
-        from litellm.llms.anthropic.chat.handler import AnthropicChatCompletion
-        from litellm.llms.anthropic.chat.transformation import AnthropicConfig
-        from litellm.rust_bridge import chat_completions as bridge
-
-        class _Declined(Exception):
-            pass
-
-        class _FakeNative:
-            RustBridgeDeclined = _Declined
-            RustUpstreamError = type("_Upstream", (Exception,), {})
-
-        monkeypatch.setattr("litellm.rust_bridge.bindings.get_native_bridge", lambda: _FakeNative())
-
-        def declining_native(_request, *, options, context):
-            raise _Declined("blank message text")
-
-        bridge.set_rust_chat_completions(
-            decline=lambda **_kwargs: None, chat_completions=declining_native
-        )
-
-        logging_obj, calls = self._recording_logging_obj()
-        with patch.object(
-            AnthropicConfig, "transform_request", return_value={"model": "m", "messages": []}
-        ):
-            try:
-                AnthropicChatCompletion().completion(
-                    **self._completion_kwargs(logging_obj=logging_obj)
-                )
-            except Exception:
-                # The Python path goes on to make an HTTP call; the log count is
-                # the assertion, so a failure past this point is expected.
-                pass
-
-        assert len(calls["pre_call"]) == 1
-        assert calls["pre_call"][0]["additional_args"]["complete_input_dict"]["model"] == (
-            "claude-sonnet-4-5"
-        )
-
-    def test_pre_call_logging_still_fires_when_rust_is_not_involved(self, monkeypatch):
-        """The suppression must not swallow the log on the ordinary path."""
-        monkeypatch.setenv("LITELLM_RUST", "0")
-        from litellm.llms.anthropic.chat.handler import AnthropicChatCompletion
-        from litellm.llms.anthropic.chat.transformation import AnthropicConfig
-
-        self._inject()
-        logging_obj, calls = self._recording_logging_obj()
-        with patch.object(
-            AnthropicConfig, "transform_request", return_value={"model": "m", "messages": []}
-        ):
-            try:
-                AnthropicChatCompletion().completion(
-                    **self._completion_kwargs(litellm_params={}, logging_obj=logging_obj)
-                )
-            except Exception:
-                pass
-
-        assert len(calls["pre_call"]) == 1
-        assert calls["pre_call"][0]["additional_args"]["complete_input_dict"] == {
-            "model": "m",
-            "messages": [],
-        }

tests/test_litellm/llms/bedrock/chat/test_bedrock_converse_handler.py

@@ -1,555 +1,69 @@
-"""Tests for `BedrockConverseLLM.completion`'s Rust chat completions hook.
-
-The native callables are dependency-injected, so these run without the compiled
-extension, and AWS credential resolution is stubbed so nothing reaches STS.
-"""
-
 from __future__ import annotations
 
-from unittest.mock import MagicMock, patch
-
-import httpx
 import pytest
 
-from botocore.credentials import Credentials
-from litellm.llms.bedrock.chat.converse_handler import BedrockConverseLLM
-from litellm.llms.custom_httpx.http_handler import AsyncHTTPHandler, HTTPHandler
+import litellm
 from litellm.rust_bridge import chat_completions as bridge
-from litellm.types.utils import ModelResponse
-
-RUST_RESPONSE = {
-    "created": 1_700_000_000,
-    "model": "anthropic.claude-sonnet-4-5-v1:0",
-    "choices": [
-        {
-            "index": 0,
-            "message": {"role": "assistant", "content": "hello from rust"},
-            "finish_reason": "stop",
-        }
-    ],
-    "usage": {
-        "prompt_tokens": 11,
-        "completion_tokens": 4,
-        "total_tokens": 15,
-        "prompt_tokens_details": {
-            "cached_tokens": 0,
-            "cache_creation_tokens": 0,
-            "text_tokens": 11,
-        },
-    },
-}
-
-RESOLVED_CREDENTIALS = Credentials(
-    access_key="AKIARESOLVED",
-    secret_key="resolved-secret",
-    token="resolved-token",
-)
+from litellm.rust_bridge.request import NativeChatCompletionsRequest, NativeRequestContext
 
 
 @pytest.fixture(autouse=True)
-def reset_bridge(monkeypatch):
+def native_bridge(monkeypatch):
     monkeypatch.setenv("LITELLM_RUST", "1")
-    bridge.set_rust_chat_completions(
-        chat_completions=None, achat_completions=None, decline=None
-    )
+    bridge.set_rust_chat_completions(decline=lambda **features: None)
     yield
-    bridge.set_rust_chat_completions(
-        chat_completions=None, achat_completions=None, decline=None
-    )
+    bridge.set_rust_chat_completions(chat_completions=None, achat_completions=None, decline=None)
 
 
-def _inject(*, decline_reason=None, error: Exception | None = None):
-    seen: dict[str, list[dict]] = {"gate": [], "call": []}
+def test_native_bedrock_receives_explicit_auth_and_endpoint():
+    requests = []
 
-    def gate(**kwargs):
-        seen["gate"].append(kwargs)
-        return decline_reason
+    def native(request: NativeChatCompletionsRequest, *, context: NativeRequestContext, callback_adapter=None):
+        requests.append(request)
+        return {
+            "choices": [{"index": 0, "message": {"role": "assistant", "content": "native"}, "finish_reason": "stop"}]
+        }
 
-    def native(request, *, options, context):
-        seen["call"].append(
-            {
-                "model": request.model,
-                "messages": request.messages,
-                "optional_params": request.optional_params,
-                "api_key": options.api_key,
-                "api_base": options.api_base,
-                "context": context,
-            }
-        )
-        if error is not None:
-            raise error
-        return dict(RUST_RESPONSE)
-
-    bridge.set_rust_chat_completions(decline=gate, chat_completions=native)
-    return seen
-
-
-def _completion_kwargs(**overrides):
-    kwargs = {
-        "model": "bedrock/us-east-1/anthropic.claude-sonnet-4-5-v1:0",
-        "messages": [{"role": "user", "content": "hi"}],
-        "api_base": None,
-        "custom_prompt_dict": {},
-        "model_response": ModelResponse(),
-        "encoding": None,
-        "logging_obj": MagicMock(),
-        "optional_params": {"maxTokens": 16},
-        "acompletion": False,
-        "timeout": 30.0,
-        "litellm_params": {},
-        "extra_headers": None,
-        "client": None,
-        "api_key": None,
-    }
-    kwargs.update(overrides)
-    return kwargs
-
-
-def _run(*, credentials: Credentials | None = RESOLVED_CREDENTIALS, **overrides):
-    with patch.object(BedrockConverseLLM, "get_credentials", return_value=credentials):
-        return BedrockConverseLLM().completion(**_completion_kwargs(**overrides))
-
-
-def _recording_logging_obj():
-    """A logging object that keeps each hook's payload in a real list, so a test
-    can assert which path logged and what it carried."""
-    calls = {"pre_call": [], "post_call": []}
-    logging_obj = MagicMock()
-    logging_obj.pre_call.side_effect = lambda **kwargs: calls["pre_call"].append(kwargs)
-    logging_obj.post_call.side_effect = lambda **kwargs: calls["post_call"].append(kwargs)
-    return logging_obj, calls
-
-
-def test_rust_true_serves_the_call_and_stamps_the_header():
-    seen = _inject()
-    response = _run()
-
-    assert response.choices[0].message.content == "hello from rust"
-    assert response._hidden_params["additional_headers"] == {"x-litellm-rust": "true"}
-    assert len(seen["call"]) == 1
-
-
-def test_the_core_receives_the_credentials_this_handler_already_resolved():
-    """Both paths must sign as the same principal, so the resolved credentials
-    are handed down rather than re-derived from ambient AWS state."""
-    seen = _inject()
-    _run()
-
-    params = seen["call"][0]["optional_params"]
-    assert params["aws_access_key_id"] == "AKIARESOLVED"
-    assert params["aws_secret_access_key"] == "resolved-secret"
-    assert params["aws_session_token"] == "resolved-token"
-    assert params["aws_region_name"] == "us-east-1"
-
-
-def test_the_core_receives_the_converse_url_this_handler_already_built():
-    seen = _inject()
-    _run()
-
-    assert seen["call"][0]["api_base"].endswith(
-        "/model/anthropic.claude-sonnet-4-5-v1%3A0/converse"
-    )
-    assert "bedrock-runtime.us-east-1.amazonaws.com" in seen["call"][0]["api_base"]
-
-
-def test_the_core_receives_the_untranslated_openai_messages():
-    seen = _inject()
-    _run(
-        messages=[
-            {"role": "system", "content": "be terse"},
-            {"role": "user", "content": "hi"},
-        ]
-    )
-    assert seen["call"][0]["messages"] == [
-        {"role": "system", "content": "be terse"},
-        {"role": "user", "content": "hi"},
-    ]
-
-
-def test_without_the_opt_in_the_core_is_never_consulted(monkeypatch):
-    monkeypatch.setenv("LITELLM_RUST", "0")
-    seen = _inject()
-    try:
-        _run(litellm_params={})
-    except Exception:
-        # The Python path goes on to make an HTTP call; not reaching the gate
-        # is the assertion, so a failure past this point is expected.
-        pass
-    assert seen["gate"] == []
-    assert seen["call"] == []
-
-
-def test_streaming_stays_on_the_python_path():
-    seen = _inject()
-    bridge.set_rust_chat_completions(
-        decline=pytest.importorskip("litellm.rust_bridge._native").chat_completions_decline
-    )
-    try:
-        _run(optional_params={"maxTokens": 16, "stream": True})
-    except Exception:
-        pass
-    assert seen["call"] == []
-
-
-def test_a_declined_request_never_reaches_the_native_call():
-    seen = _inject(decline_reason="unrecognized request parameter")
-    try:
-        _run()
-    except Exception:
-        pass
-    assert len(seen["gate"]) == 1
-    assert seen["call"] == []
-
-
-def test_pre_call_logging_fires_exactly_once_on_the_rust_path():
-    _inject()
-    logging_obj = MagicMock()
-    _run(logging_obj=logging_obj)
-    assert logging_obj.pre_call.call_count == 1
-
-
-@pytest.mark.asyncio
-async def test_the_async_path_falls_back_when_the_core_declines(monkeypatch):
-    class _Declined(Exception):
-        pass
-
-    class _FakeNative:
-        RustBridgeDeclined = _Declined
-        RustUpstreamError = type("_Upstream", (Exception,), {})
-
-    monkeypatch.setattr("litellm.rust_bridge.bindings.get_native_bridge", lambda: _FakeNative())
-
-    async def declining_native(_request, **_kwargs):
-        raise _Declined("blank message text")
-
-    bridge.set_rust_chat_completions(
-        decline=lambda **_kwargs: None, achat_completions=declining_native
-    )
-
-    sentinel = object()
-
-    async def python_path(**_kwargs):
-        return sentinel
-
-    with (
-        patch.object(
-            BedrockConverseLLM, "get_credentials", return_value=RESOLVED_CREDENTIALS
-        ),
-        patch.object(
-            BedrockConverseLLM, "async_completion", side_effect=python_path
-        ) as python_call,
-    ):
-        result = await BedrockConverseLLM().completion(
-            **_completion_kwargs(acompletion=True)
-        )
-
-    assert result is sentinel
-    assert python_call.called, "a failing rust call must re-enter the python path"
-
-
-@pytest.mark.asyncio
-async def test_the_async_path_serves_the_rust_response_without_the_fallback():
-    async def native(_request, **_kwargs):
-        return dict(RUST_RESPONSE)
-
-    bridge.set_rust_chat_completions(
-        decline=lambda **_kwargs: None, achat_completions=native
-    )
-
-    with (
-        patch.object(
-            BedrockConverseLLM, "get_credentials", return_value=RESOLVED_CREDENTIALS
-        ),
-        patch.object(BedrockConverseLLM, "async_completion") as python_call,
-    ):
-        result = await BedrockConverseLLM().completion(
-            **_completion_kwargs(acompletion=True)
-        )
-
-    assert result.choices[0].message.content == "hello from rust"
-    assert result._hidden_params["additional_headers"] == {"x-litellm-rust": "true"}
-    assert not python_call.called
-
-
-@pytest.mark.asyncio
-async def test_pre_call_logging_fires_once_even_when_the_rust_path_declines():
-    """One request, one pre_call. Without the suppression the Python fallback
-    logs a second one and non-idempotent callbacks run twice."""
-
-    class _Declined(Exception):
-        pass
-
-    class _FakeNative:
-        RustBridgeDeclined = _Declined
-        RustUpstreamError = type("_Upstream", (Exception,), {})
-
-    async def declining_native(_request, **_kwargs):
-        raise _Declined("blank message text")
-
-    logging_obj = MagicMock()
-    served = []
-
-    async def python_path(**kwargs):
-        served.append(kwargs)
-        return ModelResponse()
-
-    with (
-        patch("litellm.rust_bridge.bindings.get_native_bridge", lambda: _FakeNative()),
-        patch.object(
-            BedrockConverseLLM, "get_credentials", return_value=RESOLVED_CREDENTIALS
-        ),
-        patch.object(
-            BedrockConverseLLM, "async_completion", side_effect=python_path
-        ),
-    ):
-        bridge.set_rust_chat_completions(
-            decline=lambda **_kwargs: None, achat_completions=declining_native
-        )
-        await BedrockConverseLLM().completion(
-            **_completion_kwargs(acompletion=True, logging_obj=logging_obj)
-        )
-
-    assert logging_obj.pre_call.call_count == 1
-    assert served and served[0]["skip_pre_call_logging"] is True
-
-
-CONVERSE_RESPONSE = {
-    "output": {"message": {"role": "assistant", "content": [{"text": "hi"}]}},
-    "stopReason": "end_turn",
-    "usage": {"inputTokens": 5, "outputTokens": 2, "totalTokens": 7},
-}
-
-
-async def _drive_async_completion(*, skip_pre_call_logging: bool, logging_obj):
-    """Run the real `async_completion` with a stubbed transport."""
-    import httpx as _httpx
-
-    client = MagicMock()
-
-    async def post(**_kwargs):
-        return _httpx.Response(
-            200,
-            json=CONVERSE_RESPONSE,
-            request=_httpx.Request("POST", "https://bedrock-runtime.us-west-2.amazonaws.com"),
-        )
-
-    client.post = post
-    client.__class__ = AsyncHTTPHandler
-
-    return await BedrockConverseLLM().async_completion(
-        model="anthropic.claude-sonnet-4-5-v1:0",
+    bridge.set_rust_chat_completions(chat_completions=native)
+    response = litellm.completion(
+        model="bedrock/anthropic.claude-sonnet-4-5-v1:0",
         messages=[{"role": "user", "content": "hi"}],
-        api_base="https://bedrock-runtime.us-west-2.amazonaws.com/model/m/converse",
-        model_response=ModelResponse(),
-        timeout=30.0,
-        encoding=None,
-        logging_obj=logging_obj,
-        stream=None,
-        optional_params={"maxTokens": 16},
-        litellm_params={"aws_region_name": "us-west-2"},
-        credentials=RESOLVED_CREDENTIALS,
-        headers={},
-        client=client,
-        skip_pre_call_logging=skip_pre_call_logging,
+        aws_access_key_id="explicit-id",
+        aws_secret_access_key="explicit-secret",
+        aws_session_token="explicit-token",
+        aws_region_name="us-east-1",
+        api_base="https://example.test",
+        max_tokens=7,
     )
+    assert response.choices[0].message.content == "native"
+    assert len(requests) == 1
+    assert requests[0].options.provider_connection == {
+        "aws_access_key_id": "explicit-id",
+        "aws_secret_access_key": "explicit-secret",
+        "aws_session_token": "explicit-token",
+        "aws_region_name": "us-east-1",
+    }
+    assert requests[0].options.api_base == "https://example.test"
 
 
-@pytest.mark.asyncio
-async def test_async_completion_honors_the_pre_call_suppression():
-    logging_obj = MagicMock()
-    await _drive_async_completion(skip_pre_call_logging=True, logging_obj=logging_obj)
-    assert logging_obj.pre_call.call_count == 0
+@pytest.mark.parametrize("through_environment", [False, True])
+def test_native_bedrock_preserves_bearer_auth(monkeypatch, through_environment):
+    requests = []
 
+    def native(request, *, context, callback_adapter=None):
+        requests.append(request)
+        return {
+            "choices": [{"index": 0, "message": {"role": "assistant", "content": "native"}, "finish_reason": "stop"}]
+        }
 
-@pytest.mark.asyncio
-async def test_async_completion_logs_pre_call_by_default():
-    """The suppression must be opt-in, so every existing caller keeps its log."""
-    logging_obj = MagicMock()
-    await _drive_async_completion(skip_pre_call_logging=False, logging_obj=logging_obj)
-    assert logging_obj.pre_call.call_count == 1
-
-
-def _sync_client_returning_converse_response():
-    client = MagicMock()
-    client.post.side_effect = lambda **_kwargs: httpx.Response(
-        200,
-        json=CONVERSE_RESPONSE,
-        request=httpx.Request("POST", "https://bedrock-runtime.us-west-2.amazonaws.com"),
+    bridge.set_rust_chat_completions(chat_completions=native)
+    if through_environment:
+        monkeypatch.setenv("AWS_BEARER_TOKEN_BEDROCK", "bedrock-token")
+    litellm.completion(
+        model="bedrock/anthropic.claude-sonnet-4-5-v1:0",
+        messages=[{"role": "user", "content": "hi"}],
+        api_key=None if through_environment else "bedrock-token",
+        max_tokens=7,
     )
-    client.__class__ = HTTPHandler
-    return client
-
-
-def test_pre_call_logging_fires_once_when_the_sync_rust_path_declines():
-    """One request, one pre_call, on the synchronous path too.
-
-    The gate accepts and logs, then the native call declines before the
-    provider is reached, so execution continues into the Python path below.
-    That is the same attempt continuing; without the suppression it logs a
-    second pre_call and non-idempotent callbacks run twice for one request.
-    """
-
-    class _Declined(Exception):
-        pass
-
-    class _FakeNative:
-        RustBridgeDeclined = _Declined
-        RustUpstreamError = type("_Upstream", (Exception,), {})
-
-    def declining_native(_request, **_kwargs):
-        raise _Declined("blank message text")
-
-    logging_obj = MagicMock()
-
-    with patch("litellm.rust_bridge.bindings.get_native_bridge", lambda: _FakeNative()):
-        bridge.set_rust_chat_completions(
-            decline=lambda **_kwargs: None, chat_completions=declining_native
-        )
-        response = _run(
-            logging_obj=logging_obj,
-            client=_sync_client_returning_converse_response(),
-        )
-
-    assert response.choices[0].message.content == "hi"
-    assert logging_obj.pre_call.call_count == 1
-
-
-def test_the_sync_python_path_still_logs_pre_call_without_the_opt_in(monkeypatch):
-    """The suppression must not swallow the log on a request the gate declined,
-    so a deployment with no `rust` flag keeps exactly the log it always had."""
-    monkeypatch.setenv("LITELLM_RUST", "0")
-    logging_obj = MagicMock()
-    response = _run(
-        logging_obj=logging_obj,
-        litellm_params={},
-        client=_sync_client_returning_converse_response(),
-    )
-
-    assert response.choices[0].message.content == "hi"
-    assert logging_obj.pre_call.call_count == 1
-
-
-def test_post_call_logging_fires_on_the_sync_rust_path():
-    """The Rust core owns the provider call, so the Converse transform that
-    normally raises `post_call` never runs. Without the bridge hook every
-    post_call callback goes silent and `original_response` stays unset."""
-    import json
-
-    _inject()
-    logging_obj = MagicMock()
-    _run(logging_obj=logging_obj)
-
-    assert logging_obj.post_call.call_count == 1
-    logged = logging_obj.post_call.call_args.kwargs["original_response"]
-    assert json.loads(logged)["choices"][0]["message"]["content"] == "hello from rust"
-
-
-@pytest.mark.asyncio
-async def test_post_call_logging_fires_on_the_async_rust_path():
-    """The asynchronous path runs through the same hook, so the two paths
-    cannot drift apart the way the pre_call suppression once did."""
-    import json
-
-    async def native(_request, **_kwargs):
-        return dict(RUST_RESPONSE)
-
-    bridge.set_rust_chat_completions(
-        decline=lambda **_kwargs: None, achat_completions=native
-    )
-    logging_obj = MagicMock()
-
-    with patch.object(
-        BedrockConverseLLM, "get_credentials", return_value=RESOLVED_CREDENTIALS
-    ):
-        await BedrockConverseLLM().completion(
-            **_completion_kwargs(acompletion=True, logging_obj=logging_obj)
-        )
-
-    assert logging_obj.post_call.call_count == 1
-    logged = logging_obj.post_call.call_args.kwargs["original_response"]
-    assert json.loads(logged)["choices"][0]["message"]["content"] == "hello from rust"
-
-
-def test_post_call_is_not_logged_twice_when_the_sync_rust_call_declines():
-    """A decline never reached the provider, so the Python path serves the
-    request and owns the only post_call. Firing the hook there too would double
-    every post_call callback for one request."""
-
-    class _Declined(Exception):
-        pass
-
-    class _FakeNative:
-        RustBridgeDeclined = _Declined
-        RustUpstreamError = type("_Upstream", (Exception,), {})
-
-    def declining_native(_request, **_kwargs):
-        raise _Declined("blank message text")
-
-    logging_obj, calls = _recording_logging_obj()
-
-    with patch("litellm.rust_bridge.bindings.get_native_bridge", lambda: _FakeNative()):
-        bridge.set_rust_chat_completions(
-            decline=lambda **_kwargs: None, chat_completions=declining_native
-        )
-        response = _run(
-            logging_obj=logging_obj,
-            client=_sync_client_returning_converse_response(),
-        )
-
-    assert response.choices[0].message.content == "hi"
-    assert len(calls["post_call"]) == 1
-    assert "hi" in calls["post_call"][0]["original_response"]
-
-
-def test_bearer_token_auth_serves_when_boto3_resolves_no_sigv4_credentials(monkeypatch):
-    """With only `AWS_BEARER_TOKEN_BEDROCK` configured boto3 resolves no
-    credentials at all. Preparing the Rust handoff must not dereference that
-    None: the bearer token signs the request on its own."""
-    monkeypatch.setenv("LITELLM_RUST", "0")
-    monkeypatch.setenv("AWS_BEARER_TOKEN_BEDROCK", "bedrock-bearer-token")
-    client = _sync_client_returning_converse_response()
-
-    response = _run(credentials=None, litellm_params={}, client=client)
-
-    assert response.choices[0].message.content == "hi"
-    sent_headers = client.post.call_args.kwargs["headers"]
-    assert sent_headers["Authorization"] == "Bearer bedrock-bearer-token"
-
-
-def test_the_rust_opt_in_needs_no_sigv4_principal():
-    """The core resolves the bearer token itself, so a bearer-only deployment
-    keeps its opt-in and the gate sees no aws_* credential keys to sign with."""
-    seen = _inject()
-
-    response = _run(credentials=None, api_key="bedrock-bearer-token")
-
-    assert response.choices[0].message.content == "hello from rust"
-    params = seen["call"][0]["optional_params"]
-    assert not {"aws_access_key_id", "aws_secret_access_key", "aws_session_token"} & params.keys()
-    assert params["aws_region_name"] == "us-east-1"
-    assert seen["call"][0]["api_key"] == "bedrock-bearer-token"
-
-
-@pytest.mark.parametrize("configured_through", ["env_var", "api_key"])
-def test_bearer_token_auth_never_runs_the_sigv4_credential_chain(monkeypatch, configured_through):
-    """The deployment's AWS profile does not exist, so resolving SigV4 credentials
-    raises; a bearer-token deployment must still serve the request, since the
-    bearer token alone signs it."""
-    monkeypatch.setenv("LITELLM_RUST", "0")
-    if configured_through == "env_var":
-        monkeypatch.setenv("AWS_BEARER_TOKEN_BEDROCK", "bedrock-bearer-token")
-    else:
-        monkeypatch.delenv("AWS_BEARER_TOKEN_BEDROCK", raising=False)
-    client = _sync_client_returning_converse_response()
-
-    response = BedrockConverseLLM().completion(
-        **_completion_kwargs(
-            optional_params={"maxTokens": 16, "aws_profile_name": "litellm-no-such-aws-profile"},
-            litellm_params={},
-            client=client,
-            api_key="bedrock-bearer-token" if configured_through == "api_key" else None,
-        )
-    )
-
-    assert response.choices[0].message.content == "hi"
-    assert client.post.call_args.kwargs["headers"]["Authorization"] == "Bearer bedrock-bearer-token"
+    assert len(requests) == 1
+    assert requests[0].options.api_key == (None if through_environment else "bedrock-token")

tests/test_litellm/llms/custom_httpx/test_llm_http_handler.py

@@ -151,7 +151,7 @@ def test_response_api_handler_runs_agentic_hooks_in_sync_path(monkeypatch):
     )
     logging_obj = Mock()
 
-    monkeypatch.setattr(handler, "_has_agentic_completion_hook", Mock(return_value=True))
+    monkeypatch.setattr(handler, "has_agentic_completion_hook", Mock(return_value=True))
     hook_mock = AsyncMock(return_value=final_response)
     monkeypatch.setattr(handler, "_call_agentic_completion_hooks", hook_mock)
 
@@ -370,7 +370,7 @@ def test_get_agentic_loop_settings_defaults_and_overrides():
     assert fingerprints == ["fp-1", "fp-2"]
 
 
-def test_has_agentic_completion_hook_detection(monkeypatch):
+def testhas_agentic_completion_hook_detection(monkeypatch):
     """The streaming path skips the agentic wrapper only when no callback
     overrides async_should_run_agentic_loop. Verify both directions."""
     from litellm.integrations.custom_logger import CustomLogger
@@ -381,7 +381,7 @@ def test_has_agentic_completion_hook_detection(monkeypatch):
 
     # No callbacks at all -> no agentic hook.
     monkeypatch.setattr(litellm, "callbacks", [])
-    assert handler._has_agentic_completion_hook(logging_obj) is False
+    assert handler.has_agentic_completion_hook(logging_obj) is False
 
     # A plain CustomLogger that does NOT override the gate -> still no hook
     # (so the wrapper is safely skipped).
@@ -389,7 +389,7 @@ def test_has_agentic_completion_hook_detection(monkeypatch):
         pass
 
     monkeypatch.setattr(litellm, "callbacks", [_PlainLogger()])
-    assert handler._has_agentic_completion_hook(logging_obj) is False
+    assert handler.has_agentic_completion_hook(logging_obj) is False
 
     # A logger that overrides the gate (directly) -> hook present.
     class _AgenticLogger(CustomLogger):
@@ -399,7 +399,7 @@ def test_has_agentic_completion_hook_detection(monkeypatch):
             return True, {}
 
     monkeypatch.setattr(litellm, "callbacks", [_AgenticLogger()])
-    assert handler._has_agentic_completion_hook(logging_obj) is True
+    assert handler.has_agentic_completion_hook(logging_obj) is True
 
     # Override inherited through an intermediate class is still detected
     # (function-identity check, not a leaf __dict__ check).
@@ -407,12 +407,12 @@ def test_has_agentic_completion_hook_detection(monkeypatch):
         pass
 
     monkeypatch.setattr(litellm, "callbacks", [_DerivedAgenticLogger()])
-    assert handler._has_agentic_completion_hook(logging_obj) is True
+    assert handler.has_agentic_completion_hook(logging_obj) is True
 
     # Hook supplied via logging_obj.dynamic_success_callbacks is detected too.
     monkeypatch.setattr(litellm, "callbacks", [])
     logging_obj.dynamic_success_callbacks = [_AgenticLogger()]
-    assert handler._has_agentic_completion_hook(logging_obj) is True
+    assert handler.has_agentic_completion_hook(logging_obj) is True
 
     # String-named callback entry (e.g. "datadog") must be resolved to its
     # CustomLogger instance via get_custom_logger_compatible_class -- the same
@@ -426,7 +426,7 @@ def test_has_agentic_completion_hook_detection(monkeypatch):
         "litellm.litellm_core_utils.litellm_logging.get_custom_logger_compatible_class",
         lambda name: agentic_via_string if name == "fake_string_callback" else None,
     )
-    assert handler._has_agentic_completion_hook(logging_obj) is True
+    assert handler.has_agentic_completion_hook(logging_obj) is True
 
     # Unresolvable string (returns None) is skipped, no false positive.
     monkeypatch.setattr(litellm, "callbacks", ["unknown_callback"])
@@ -434,7 +434,7 @@ def test_has_agentic_completion_hook_detection(monkeypatch):
         "litellm.litellm_core_utils.litellm_logging.get_custom_logger_compatible_class",
         lambda name: None,
     )
-    assert handler._has_agentic_completion_hook(logging_obj) is False
+    assert handler.has_agentic_completion_hook(logging_obj) is False
 
 
 def test_fingerprint_agentic_tools_is_deterministic():
@@ -1181,7 +1181,7 @@ def test_sync_delete_responses_sets_json_content_type():
         ({}, True, None, None),
     ],
 )
-def test_resolve_anthropic_messages_timeout(
+def testresolve_anthropic_messages_timeout(
     monkeypatch, litellm_params_kwargs, stream, global_timeout, expected
 ):
     from litellm.constants import DEFAULT_REQUEST_TIMEOUT_SECONDS
@@ -1203,7 +1203,7 @@ def test_resolve_anthropic_messages_timeout(
             "litellm.request_timeout_explicitly_set", True, raising=False
         )
 
-    resolved = BaseLLMHTTPHandler._resolve_anthropic_messages_timeout(
+    resolved = BaseLLMHTTPHandler.resolve_anthropic_messages_timeout(
         litellm_params=GenericLiteLLMParams(**litellm_params_kwargs),
         stream=stream,
         custom_llm_provider="anthropic",

tests/test_litellm/ocr/test_rust_bridge.py

@@ -210,13 +210,12 @@ def build_prepared_request(
 @pytest.fixture(autouse=True)
 def _reset_rust_flag():
     """Keep the global toggle isolated between tests."""
-    rust_bridge._OCR.reset()
-    rust_bridge._AOCR.reset()
+    rust_bridge.set_rust_ocr(ocr=None, aocr=None, decline=None)
     configuration.reset_rust_configuration()
     rust_bridge_loader._cached_bridge = rust_bridge_loader._BRIDGE_SENTINEL
+    rust_bridge.set_rust_ocr(decline=lambda model, custom_llm_provider, **features: "unsupported feature" if any(features.get(key) for key in ("stream", "has_agentic_hook", "has_custom_client")) or features.get("request_format") == "native" else None)
     yield
-    rust_bridge._OCR.reset()
-    rust_bridge._AOCR.reset()
+    rust_bridge.set_rust_ocr(ocr=None, aocr=None, decline=None)
     configuration.reset_rust_configuration()
     rust_bridge_loader._cached_bridge = rust_bridge_loader._BRIDGE_SENTINEL
 
@@ -226,7 +225,7 @@ def fake_bridge():
     """Enable the Rust path with an injected recording bridge (no native wheel)."""
     bridge = RecordingBridge()
     litellm.rust(True)
-    rust_bridge._OCR.override(bridge)
+    rust_bridge.set_rust_ocr(ocr=bridge)
     return bridge
 
 
@@ -235,14 +234,27 @@ def fake_async_bridge():
     """Enable the async Rust path with an injected recording bridge."""
     bridge = RecordingAsyncBridge()
     litellm.rust(True)
-    rust_bridge._AOCR.override(bridge)
+    rust_bridge.set_rust_ocr(aocr=bridge)
     return bridge
 
 
+def test_rust_toggles_flag():
+    assert rust_bridge.rust_ocr_enabled() is False
+    litellm.rust(True)
+    assert rust_bridge.rust_ocr_enabled() is True
+    litellm.rust(False)
+    assert rust_bridge.rust_ocr_enabled() is False
+
+
+def test_env_var_enables_rust_ocr(monkeypatch):
+    monkeypatch.setenv("LITELLM_RUST", "1")
+    assert rust_bridge.rust_ocr_enabled() is True
+
+
 def test_load_rust_ocr_returns_injected_impl():
     bridge = RecordingBridge()
     litellm.rust(True)
-    rust_bridge._OCR.override(bridge)
+    rust_bridge.set_rust_ocr(ocr=bridge)
     assert rust_bridge.load_rust_ocr() is bridge
 
 
@@ -306,7 +318,7 @@ def test_native_bridge_available_reflects_loader(monkeypatch):
 def test_load_rust_aocr_returns_injected_impl():
     bridge = RecordingAsyncBridge()
     litellm.rust(True)
-    rust_bridge._AOCR.override(bridge)
+    rust_bridge.set_rust_ocr(aocr=bridge)
     assert rust_bridge.load_rust_aocr() is bridge
 
 
@@ -315,8 +327,7 @@ def test_toggle_without_ocr_arg_preserves_injected_impl():
     bridge = RecordingBridge()
     async_bridge = RecordingAsyncBridge()
     litellm.rust(True)
-    rust_bridge._OCR.override(bridge)
-    rust_bridge._AOCR.override(async_bridge)
+    rust_bridge.set_rust_ocr(ocr=bridge, aocr=async_bridge)
 
     litellm.rust(False)
     assert rust_bridge.load_rust_ocr() is bridge
@@ -335,11 +346,9 @@ def test_explicit_ocr_none_clears_injected_impl(monkeypatch):
     bridge = RecordingBridge()
     async_bridge = RecordingAsyncBridge()
     litellm.rust(True)
-    rust_bridge._OCR.override(bridge)
-    rust_bridge._AOCR.override(async_bridge)
+    rust_bridge.set_rust_ocr(ocr=bridge, aocr=async_bridge)
 
-    rust_bridge._OCR.override(None)
-    rust_bridge._AOCR.override(None)
+    rust_bridge.set_rust_ocr(ocr=None, aocr=None, decline=None)
     assert rust_bridge.load_rust_ocr() is None
     assert rust_bridge.load_rust_aocr() is None
 
@@ -385,7 +394,7 @@ def test_run_rust_ocr_prepares_request_and_wraps_response():
     bridge = RecordingBridge()
     logging_obj = RecordingLogging()
     litellm.rust(True)
-    rust_bridge._OCR.override(bridge)
+    rust_bridge.set_rust_ocr(ocr=bridge)
 
     response = rust_bridge.attempt_ocr(
         prepared_request=build_prepared_request(
@@ -423,7 +432,7 @@ def test_run_rust_ocr_prepares_request_and_wraps_response():
 def test_run_rust_ocr_resolves_key_via_secret_manager_when_missing():
     bridge = RecordingBridge()
     litellm.rust(True)
-    rust_bridge._OCR.override(bridge)
+    rust_bridge.set_rust_ocr(ocr=bridge)
 
     rust_bridge.attempt_ocr(
         prepared_request=build_prepared_request(api_key=None, timeout=None),
@@ -436,7 +445,7 @@ def test_run_rust_ocr_resolves_key_via_secret_manager_when_missing():
 def test_run_rust_ocr_prefers_explicit_key_over_resolver():
     bridge = RecordingBridge()
     litellm.rust(True)
-    rust_bridge._OCR.override(bridge)
+    rust_bridge.set_rust_ocr(ocr=bridge)
 
     def _resolver(name: str) -> str | None:
         raise AssertionError(f"resolver should not be called for {name}")
@@ -456,7 +465,7 @@ def test_run_rust_ocr_uses_provider_api_key_env_var():
     bridge = RecordingBridge()
     resolver_calls = []
     litellm.rust(True)
-    rust_bridge._OCR.override(bridge)
+    rust_bridge.set_rust_ocr(ocr=bridge)
 
     def _resolver(name):
         resolver_calls.append(name)
@@ -479,7 +488,7 @@ def test_run_rust_ocr_uses_provider_api_key_env_var():
 def test_prepare_rust_ocr_call_forwards_vertex_routing_metadata():
     bridge = RecordingBridge()
     litellm.rust(True)
-    rust_bridge._OCR.override(bridge)
+    rust_bridge.set_rust_ocr(ocr=bridge)
 
     rust_bridge.attempt_ocr(
         prepared_request=build_prepared_request(
@@ -506,7 +515,7 @@ def test_prepare_rust_ocr_call_forwards_vertex_routing_metadata():
 def test_prepare_rust_ocr_call_resolves_vertex_routing_metadata_from_secret_manager():
     bridge = RecordingBridge()
     litellm.rust(True)
-    rust_bridge._OCR.override(bridge)
+    rust_bridge.set_rust_ocr(ocr=bridge)
 
     def _resolver(name: str) -> str | None:
         return {
@@ -530,7 +539,7 @@ def test_prepare_rust_ocr_call_resolves_vertex_routing_metadata_from_secret_mana
 def test_prepare_rust_ocr_call_resolves_azure_ai_api_base_from_secret_manager():
     bridge = RecordingBridge()
     litellm.rust(True)
-    rust_bridge._OCR.override(bridge)
+    rust_bridge.set_rust_ocr(ocr=bridge)
 
     rust_bridge.attempt_ocr(
         prepared_request=build_prepared_request(
@@ -548,7 +557,7 @@ def test_prepare_rust_ocr_call_resolves_azure_ai_api_base_from_secret_manager():
 def test_prepare_rust_ocr_call_resolves_document_intelligence_endpoint():
     bridge = RecordingBridge()
     litellm.rust(True)
-    rust_bridge._OCR.override(bridge)
+    rust_bridge.set_rust_ocr(ocr=bridge)
 
     rust_bridge.attempt_ocr(
         prepared_request=build_prepared_request(
@@ -569,7 +578,7 @@ def test_run_rust_ocr_runs_pre_call_logging():
     logging_obj = RecordingLogging()
     bridge = RecordingBridge()
     litellm.rust(True)
-    rust_bridge._OCR.override(bridge)
+    rust_bridge.set_rust_ocr(ocr=bridge)
 
     rust_bridge.attempt_ocr(
         prepared_request=build_prepared_request(
@@ -633,7 +642,7 @@ def test_ocr_exception_type_uses_resolved_provider_context(
 
     monkeypatch.setattr(ocr_main.litellm, "exception_type", fake_exception_type)
     litellm.rust(True)
-    rust_bridge._OCR.override(RaisingBridge())
+    rust_bridge.set_rust_ocr(ocr=RaisingBridge())
 
     with pytest.raises(CapturedException):
         litellm.ocr(model=MODEL, document=DOCUMENT, api_key="sk-test")
@@ -679,7 +688,7 @@ async def test_aocr_exception_type_uses_resolved_provider_context(
 
     monkeypatch.setattr(ocr_main.litellm, "exception_type", fake_exception_type)
     litellm.rust(True)
-    rust_bridge._AOCR.override(RaisingAsyncBridge())
+    rust_bridge.set_rust_ocr(aocr=RaisingAsyncBridge())
 
     with pytest.raises(CapturedException):
         await litellm.aocr(model=MODEL, document=DOCUMENT, api_key="sk-test")

tests/test_litellm/responses/test_rust_bridge_websocket.py

@@ -2,14 +2,8 @@ from __future__ import annotations
 
 import pytest
 
-from litellm.llms.custom_httpx.llm_http_handler import _rust_responses_websocket_enabled
 from litellm.rust_bridge import configuration, responses_websocket
-from litellm.rust_bridge.request import (
-    NativeRequestContext,
-    NativeRequestOptions,
-    NativeResponsesWebSocketRequest,
-)
-from litellm.rust_bridge.runtime import Handled, NativeFailed, NativeSkipped, NativeSkipReason
+from litellm.rust_bridge.request import NativeRequestContext, NativeResponsesWebSocketRequest
 
 
 class _FakeNativeConnection:
@@ -33,55 +27,55 @@ class _ClosedNativeConnection:
 
 
 class _FakeNativeBridge:
-    contexts: list[NativeRequestContext] = []
-
     @classmethod
     async def connect(
         cls,
         request: NativeResponsesWebSocketRequest,
         *,
-        options: NativeRequestOptions,
+        options: object,
         context: NativeRequestContext,
     ) -> _FakeNativeConnection:
-        cls.contexts.append(context)
         return _FakeNativeConnection()
 
 
 @pytest.fixture(autouse=True)
 def reset_responses_websocket():
-    responses_websocket.set_rust_responses_websocket(connection=None)
+    responses_websocket.set_rust_responses_websocket(connection=None, decline=None)
     configuration.reset_rust_configuration()
+    responses_websocket.set_rust_responses_websocket(
+        decline=lambda model, custom_llm_provider, **features: (
+            "unsupported feature"
+            if any(features.get(key) for key in ("stream", "has_agentic_hook", "has_custom_client"))
+            or features.get("request_format") == "native"
+            else None
+        )
+    )
     yield
-    responses_websocket.set_rust_responses_websocket(connection=None)
+    responses_websocket.set_rust_responses_websocket(connection=None, decline=None)
     configuration.reset_rust_configuration()
 
 
-def test_rust_websocket_bridge_uses_process_enablement() -> None:
-    configuration.rust(False)
-    assert not _rust_responses_websocket_enabled("openai")
-    configuration.rust(True)
-    assert _rust_responses_websocket_enabled("openai")
-    assert not _rust_responses_websocket_enabled("anthropic")
-
-
 @pytest.mark.asyncio
 async def test_adapter_raises_clean_close_when_rust_connection_ends() -> None:
-    adapter = responses_websocket.ConnectionAdapter(_ClosedNativeConnection())
+    adapter = responses_websocket._ConnectionAdapter(_ClosedNativeConnection())
 
     with pytest.raises(responses_websocket.ConnectionClosedOK):
         await adapter.recv()
 
 
 @pytest.mark.asyncio
-async def test_bridge_reports_unavailable(monkeypatch: pytest.MonkeyPatch) -> None:
+async def test_bridge_unavailable_returns_none(monkeypatch: pytest.MonkeyPatch) -> None:
     configuration.rust(True)
     responses_websocket._RESPONSES_WEBSOCKET.override(None)
 
-    assert await responses_websocket.connect(
-        url="wss://example.test/responses",
-        headers={},
-        timeout=None,
-    ) == NativeSkipped(NativeSkipReason.UNAVAILABLE)
+    assert (
+        await responses_websocket.connect(
+            url="wss://example.test/responses",
+            headers={},
+            timeout=None,
+        )
+        is None
+    )
 
 
 @pytest.mark.asyncio
@@ -97,13 +91,10 @@ async def test_enabled_bridge_connects_and_adapts_socket(
         timeout=1.0,
     )
 
-    assert isinstance(connection, Handled)
-    connection = connection.value
+    assert connection is not None
     await connection.send("response.create")
     assert await connection.recv() == "response.completed"
     await connection.close()
-    assert _FakeNativeBridge.contexts[-1].capabilities.websocket_mode == "native"
-    assert _FakeNativeBridge.contexts[-1].capabilities.requires_connection is True
 
 
 class _FailingNativeBridge:
@@ -112,74 +103,96 @@ class _FailingNativeBridge:
         cls,
         request: NativeResponsesWebSocketRequest,
         *,
-        options: NativeRequestOptions,
+        options: object,
         context: NativeRequestContext,
     ) -> _FakeNativeConnection:
         raise RuntimeError("connection failed")
 
 
-@pytest.mark.asyncio
-async def test_connection_failure_is_reported_to_orchestration() -> None:
-    configuration.rust(True)
-    responses_websocket.set_rust_responses_websocket(connection=_FailingNativeBridge)
-    result = await responses_websocket.connect(url="wss://example.test/responses", headers={}, timeout=None)
-    assert isinstance(result, NativeFailed)
-    assert str(result.error) == "connection failed"
-
-
-@pytest.mark.asyncio
-async def test_managed_connection_closes_native_socket_on_consumer_failure() -> None:
-    configuration.rust(True)
-    socket = _FakeNativeConnection()
-
-    class Bridge:
-        @classmethod
-        async def connect(
-            cls,
-            request: NativeResponsesWebSocketRequest,
-            *,
-            options: NativeRequestOptions,
-            context: NativeRequestContext,
-        ) -> _FakeNativeConnection:
-            return socket
-
-    responses_websocket.set_rust_responses_websocket(connection=Bridge)
-    result = await responses_websocket.managed_connect(url="wss://example.test/responses", headers={}, timeout=1.0)
-    assert isinstance(result, Handled)
-
-    async def use_connection() -> None:
-        async with result.value as connection:
-            await connection.send("hello")
-            raise ValueError("consumer failed")
-
-    with pytest.raises(ValueError, match="consumer failed"):
-        await use_connection()
-    assert socket.sent == ["hello"]
-    assert socket.closed
-
-
 @pytest.mark.asyncio
 async def test_connection_failure_does_not_authorize_python_fallback() -> None:
-    from contextlib import AbstractAsyncContextManager
-
-    from litellm.rust_bridge.dispatch import anative_context, provider_errors
-
     configuration.rust(True)
     responses_websocket.set_rust_responses_websocket(connection=_FailingNativeBridge)
 
-    @anative_context(
-        native=lambda: responses_websocket.managed_connect(
-            url="wss://example.test/responses", headers={}, timeout=None
-        ),
-        route="responses_websocket",
-        errors=lambda: provider_errors("openai", "responses websocket"),
-    )
-    def execute() -> AbstractAsyncContextManager[object]:
-        pytest.fail("unknown native failures must not open a Python connection")
-
-    async def run() -> None:
-        async with execute():
-            pytest.fail("connection must fail before entering its body")
-
     with pytest.raises(RuntimeError, match="connection failed"):
+        await responses_websocket.connect(url="wss://example.test/responses", headers={}, timeout=None)
+
+
+@pytest.mark.parametrize("native", [False, True])
+@pytest.mark.parametrize("session_error", [False, True])
+@pytest.mark.asyncio
+async def test_connection_dispatch_cleans_up_without_reconnecting(native, session_error):
+    from contextlib import asynccontextmanager
+
+    configuration.rust(True)
+    native_socket = _FakeNativeConnection()
+    python_socket = _FakeNativeConnection()
+    connections = []
+
+    class Native:
+        @classmethod
+        async def connect(cls, request, *, context, callback_adapter=None):
+            connections.append("native")
+            assert request.options.custom_llm_provider == "azure"
+            return native_socket
+
+    @asynccontextmanager
+    async def python():
+        connections.append("python")
+        try:
+            yield python_socket
+        finally:
+            await python_socket.close()
+
+    responses_websocket.set_rust_responses_websocket(connection=Native)
+    if not native:
+        responses_websocket.set_rust_responses_websocket(
+            decline=lambda model, custom_llm_provider, **features: "declined"
+        )
+
+    async def run():
+        async with responses_websocket.open_connection(
+            url="wss://example.test",
+            headers={},
+            timeout=1,
+            model="test-model",
+            provider="azure",
+            fallback=python,
+        ):
+            if session_error:
+                raise RuntimeError("session failed")
+
+    if session_error:
+        with pytest.raises(RuntimeError, match="session failed"):
+            await run()
+    else:
         await run()
+    assert connections == ["native" if native else "python"]
+    assert native_socket.closed == native
+    assert python_socket.closed == (not native)
+
+
+@pytest.mark.asyncio
+async def test_missing_acceptance_export_uses_python_connection_once():
+    from contextlib import asynccontextmanager
+
+    calls = []
+    socket = _FakeNativeConnection()
+
+    @asynccontextmanager
+    async def python():
+        calls.append("python")
+        try:
+            yield socket
+        finally:
+            await socket.close()
+
+    configuration.rust(True)
+    responses_websocket.set_rust_responses_websocket(connection=_FailingNativeBridge)
+    responses_websocket._PREFLIGHT.override(None)
+    async with responses_websocket.open_connection(
+        url="wss://example.test", headers={}, timeout=1, model="model", provider="openai", fallback=python
+    ) as connection:
+        assert connection is socket
+    assert calls == ["python"]
+    assert socket.closed

tests/test_litellm/rust_bridge/test_chat_completions.py

@@ -12,8 +12,12 @@ import pytest
 import litellm
 from litellm.rust_bridge import bindings, configuration
 from litellm.rust_bridge import chat_completions as bridge
-from litellm.rust_bridge.request import NativeChatCompletionsRequest, NativeRequestContext, NativeRequestOptions
-from litellm.rust_bridge.runtime import Handled, NativeFailed, NativeSkipped
+from litellm.rust_bridge.request import (
+    NativeBedrockOptions,
+    NativeRequestCapabilities,
+    NativeRequestContext,
+    anthropic_options,
+)
 from litellm.types.utils import ModelResponse
 
 RUST_RESPONSE = {
@@ -96,40 +100,16 @@ class _RecordingCall:
         self.result = result if result is not None else dict(RUST_RESPONSE)
         self.error = error
         self.calls: list[dict] = []
-        self.contexts: list[NativeRequestContext] = []
 
-    def __call__(
-        self,
-        request: NativeChatCompletionsRequest,
-        *,
-        options: NativeRequestOptions,
-        context: NativeRequestContext,
-    ):
-        kwargs = {
-            "model": request.model,
-            "messages": request.messages,
-            "optional_params": request.optional_params,
-            "api_key": options.api_key,
-            "api_base": options.api_base,
-            "custom_llm_provider": options.custom_llm_provider,
-            "extra_headers": options.extra_headers,
-            "timeout_seconds": options.timeout_seconds,
-        }
-        self.calls.append(kwargs)
-        self.contexts.append(context)
+    def __call__(self, request, *, options, context):
+        self.calls.append({"request": request, "options": options, "context": context})
         if self.error is not None:
             raise self.error
         return self.result
 
 
 class _RecordingAsyncCall(_RecordingCall):
-    async def __call__(
-        self,
-        request: NativeChatCompletionsRequest,
-        *,
-        options: NativeRequestOptions,
-        context: NativeRequestContext,
-    ):
+    async def __call__(self, request, *, options, context):
         return _RecordingCall.__call__(self, request, options=options, context=context)
 
 
@@ -282,8 +262,7 @@ class TestSyncCall:
 
         result = bridge.chat_completions(**_call_kwargs(model_response))
 
-        assert isinstance(result, Handled)
-        result = result.value
+        assert result is not None
         assert result.choices[0].message.content == "hello from rust"
         assert result.choices[0].finish_reason == "stop"
         assert result.model == "claude-sonnet-4-5-20260101"
@@ -297,28 +276,16 @@ class TestSyncCall:
         native = _RecordingCall()
         bridge.set_rust_chat_completions(chat_completions=native)
         bridge.chat_completions(**_call_kwargs(ModelResponse()))
-        assert native.calls[0]["timeout_seconds"] == 30.0
+        assert native.calls[0]["options"].timeout_seconds == 30.0
 
-    def test_preserves_execution_and_client_capabilities(self):
-        native = _RecordingCall()
-        bridge.set_rust_chat_completions(chat_completions=native)
-        bridge.chat_completions(
-            **_call_kwargs(ModelResponse()),
-            stream=True,
-            has_custom_client=True,
-        )
-        assert native.contexts[0].capabilities.execution_mode == "sync"
-        assert native.contexts[0].capabilities.stream is True
-        assert native.contexts[0].capabilities.has_custom_client is True
-
-    def test_reports_unavailable_bridge(self, monkeypatch):
+    def test_falls_back_when_the_bridge_is_unavailable(self, monkeypatch):
         _hide_native_bridge(monkeypatch)
-        assert isinstance(bridge.chat_completions(**_call_kwargs(ModelResponse())), NativeSkipped)
+        assert bridge.chat_completions(**_call_kwargs(ModelResponse())) is None
 
-    def test_reports_native_decline_to_orchestration(self, monkeypatch):
+    def test_falls_back_when_the_core_declines_before_calling_the_provider(self, monkeypatch):
         _fake_native_bridge(monkeypatch)
         bridge.set_rust_chat_completions(chat_completions=_RecordingCall(error=_FakeDeclined("streaming")))
-        assert isinstance(bridge.chat_completions(**_call_kwargs(ModelResponse())), NativeFailed)
+        assert bridge.chat_completions(**_call_kwargs(ModelResponse())) is None
 
 
 class TestAsyncCall:
@@ -326,18 +293,286 @@ class TestAsyncCall:
     async def test_builds_a_model_response(self):
         bridge.set_rust_chat_completions(achat_completions=_RecordingAsyncCall())
         result = await bridge.achat_completions(**_call_kwargs(ModelResponse()))
-        assert isinstance(result, Handled)
-        result = result.value
+        assert result is not None
         assert result.choices[0].message.content == "hello from rust"
         assert result._hidden_params["additional_headers"] == {"x-litellm-rust": "true"}
 
     @pytest.mark.asyncio
-    async def test_reports_unavailable_bridge(self, monkeypatch):
+    async def test_falls_back_when_the_bridge_is_unavailable(self, monkeypatch):
         _hide_native_bridge(monkeypatch)
-        assert isinstance(await bridge.achat_completions(**_call_kwargs(ModelResponse())), NativeSkipped)
+        assert await bridge.achat_completions(**_call_kwargs(ModelResponse())) is None
 
     @pytest.mark.asyncio
-    async def test_reports_native_decline_to_orchestration(self, monkeypatch):
+    async def test_falls_back_when_the_core_declines_before_calling_the_provider(self, monkeypatch):
         _fake_native_bridge(monkeypatch)
         bridge.set_rust_chat_completions(achat_completions=_RecordingAsyncCall(error=_FakeDeclined("streaming")))
-        assert isinstance(await bridge.achat_completions(**_call_kwargs(ModelResponse())), NativeFailed)
+        assert await bridge.achat_completions(**_call_kwargs(ModelResponse())) is None
+
+
+class TestAsyncFallbackWrapper:
+    @pytest.mark.asyncio
+    async def test_returns_the_rust_response_without_running_the_fallback(self):
+        bridge.set_rust_chat_completions(achat_completions=_RecordingAsyncCall())
+        ran = []
+
+        async def fallback():
+            ran.append(True)
+            return "python"
+
+        result = await bridge.achat_completions_or_fallback(**_call_kwargs(ModelResponse()), python_fallback=fallback)
+        assert result.choices[0].message.content == "hello from rust"
+        assert ran == []
+
+    @pytest.mark.asyncio
+    async def test_runs_the_fallback_when_the_core_declines(self, monkeypatch):
+        _fake_native_bridge(monkeypatch)
+        bridge.set_rust_chat_completions(achat_completions=_RecordingAsyncCall(error=_FakeDeclined("streaming")))
+
+        async def fallback():
+            return "python"
+
+        result = await bridge.achat_completions_or_fallback(**_call_kwargs(ModelResponse()), python_fallback=fallback)
+        assert result == "python"
+
+    @pytest.mark.asyncio
+    async def test_runs_the_fallback_when_the_bridge_is_unavailable(self, monkeypatch):
+        _hide_native_bridge(monkeypatch)
+
+        async def fallback():
+            return "python"
+
+        result = await bridge.achat_completions_or_fallback(**_call_kwargs(ModelResponse()), python_fallback=fallback)
+        assert result == "python"
+
+
+class TestFailureClassification:
+    """A failure the provider already saw must not be retried on the Python
+    path: it would bill the customer for the same work twice."""
+
+    @pytest.fixture(autouse=True)
+    def _native_exceptions(self, monkeypatch):
+        _fake_native_bridge(monkeypatch)
+
+    def test_a_decline_falls_back_because_nothing_was_sent(self):
+        bridge.set_rust_chat_completions(chat_completions=_RecordingCall(error=_FakeDeclined("streaming")))
+        assert bridge.chat_completions(**_call_kwargs(ModelResponse())) is None
+
+    def test_an_upstream_failure_is_surfaced_with_its_status(self):
+        from litellm.exceptions import RateLimitError
+
+        bridge.set_rust_chat_completions(chat_completions=_RecordingCall(error=_FakeUpstream(429, "429: rate limited")))
+        with pytest.raises(RateLimitError) as raised:
+            bridge.chat_completions(**_call_kwargs(ModelResponse()))
+        assert raised.value.status_code == 429
+        assert "rate limited" in str(raised.value)
+
+    def test_a_transport_failure_with_no_response_surfaces_as_a_500(self):
+        from litellm.exceptions import APIError
+
+        bridge.set_rust_chat_completions(chat_completions=_RecordingCall(error=_FakeUpstream(0, "connection reset")))
+        with pytest.raises(APIError) as raised:
+            bridge.chat_completions(**_call_kwargs(ModelResponse()))
+        assert raised.value.status_code == 500
+
+    def test_an_unrecognized_error_is_not_swallowed(self):
+        bridge.set_rust_chat_completions(chat_completions=_RecordingCall(error=RuntimeError("something else")))
+        with pytest.raises(RuntimeError):
+            bridge.chat_completions(**_call_kwargs(ModelResponse()))
+
+    @pytest.mark.asyncio
+    async def test_the_async_wrapper_does_not_fall_back_on_an_upstream_failure(self):
+        from litellm.exceptions import InternalServerError
+
+        bridge.set_rust_chat_completions(achat_completions=_RecordingAsyncCall(error=_FakeUpstream(500, "500: boom")))
+        ran = []
+
+        async def fallback():
+            ran.append(True)
+            return "python"
+
+        with pytest.raises(InternalServerError):
+            await bridge.achat_completions_or_fallback(**_call_kwargs(ModelResponse()), python_fallback=fallback)
+        assert ran == [], "a request the provider already served must not be re-issued"
+
+    @pytest.mark.asyncio
+    async def test_the_async_wrapper_falls_back_on_a_decline(self):
+        bridge.set_rust_chat_completions(
+            achat_completions=_RecordingAsyncCall(error=_FakeDeclined("blank message text"))
+        )
+
+        async def fallback():
+            return "python"
+
+        result = await bridge.achat_completions_or_fallback(**_call_kwargs(ModelResponse()), python_fallback=fallback)
+        assert result == "python"
+
+
+@pytest.mark.asyncio
+async def test_missing_native_exception_types_does_not_authorize_python_fallback(monkeypatch):
+    _hide_native_bridge(monkeypatch)
+    bridge.set_rust_chat_completions(
+        chat_completions=_RecordingCall(error=RuntimeError("connection failed")),
+        achat_completions=_RecordingAsyncCall(error=RuntimeError("connection failed")),
+    )
+
+    with pytest.raises(RuntimeError, match="connection failed"):
+        bridge.chat_completions(**_call_kwargs(ModelResponse()))
+
+    async def fallback():
+        pytest.fail("unknown failure must not retry through Python")
+
+    with pytest.raises(RuntimeError, match="connection failed"):
+        await bridge.achat_completions_or_fallback(**_call_kwargs(ModelResponse()), python_fallback=fallback)
+
+
+def test_provider_credentials_are_separate_from_chat_body_params():
+    native = _RecordingCall()
+    bridge.set_rust_chat_completions(chat_completions=native)
+    configuration.rust(True)
+    kwargs = _call_kwargs(ModelResponse())
+    kwargs["optional_params"] = {
+        "max_tokens": 32,
+    }
+    kwargs["bedrock"] = NativeBedrockOptions(
+        aws_access_key_id="test-access-key",
+        aws_secret_access_key="test-secret-key",
+    )
+    bridge.chat_completions(**kwargs)
+    request = native.calls[0]["request"]
+    options = native.calls[0]["options"]
+    assert request.optional_params == {"max_tokens": 32}
+    assert options.bedrock.aws_access_key_id == "test-access-key"
+    assert options.bedrock.aws_secret_access_key == "test-secret-key"
+
+
+def test_provider_payload_extensions_cross_the_boundary_without_partitioning():
+    native = _RecordingCall()
+    bridge.set_rust_chat_completions(chat_completions=native)
+    configuration.rust(True)
+    extensions = {
+        "vendor_object": {"nested": None},
+        "vendor_array": [1, "two", False],
+        "vendor_scalar": 0.25,
+        "extra_body": {"temperature": 0.2, "config": {"replacement": True}},
+    }
+
+    kwargs = _call_kwargs(ModelResponse())
+    kwargs["optional_params"] = extensions
+    bridge.chat_completions(**kwargs)
+
+    assert native.calls[0]["request"].optional_params == extensions
+
+
+def test_typed_capability_and_provider_metadata_facts_are_isolated():
+    context = NativeRequestContext(
+        capabilities=NativeRequestCapabilities(
+            stream=True,
+            has_agentic_hook=True,
+            has_custom_client=True,
+            request_format="native",
+        )
+    )
+    anthropic = anthropic_options({"metadata": {"user_id": "user-123", "ignored": object()}})
+
+    assert context.capabilities.request_format == "native"
+    assert context.capabilities.has_agentic_hook is True
+    assert anthropic.user_id == "user-123"
+
+@pytest.mark.parametrize("provider", ["anthropic", "bedrock", "openai"])
+@pytest.mark.parametrize("asynchronous", [False, True])
+@pytest.mark.asyncio
+async def test_public_completion_discovers_any_provider(provider, asynchronous):
+    native = _RecordingCall()
+    anative = _RecordingAsyncCall()
+    gate = _RecordingDecline()
+    bridge.set_rust_chat_completions(chat_completions=native, achat_completions=anative, decline=gate)
+    kwargs = {
+        "model": f"{provider}/test-model",
+        "messages": MESSAGES,
+        "api_key": "key",
+        "max_tokens": 16,
+        "num_retries": 0,
+    }
+    response = await litellm.acompletion(**kwargs) if asynchronous else litellm.completion(**kwargs)
+    assert response.choices[0].message.content == "hello from rust"
+    calls = anative.calls if asynchronous else native.calls
+    assert len(calls) == 1
+    assert calls[0]["options"].custom_llm_provider == provider
+    assert calls[0]["request"].messages == MESSAGES
+    assert gate.calls[0]["custom_llm_provider"] == provider
+    assert len(native.calls) + len(anative.calls) == 1
+
+
+@pytest.mark.parametrize("asynchronous", [False, True])
+@pytest.mark.parametrize(
+    "failure", ["preflight", "missing_preflight", "decline", "unavailable", "error", "malformed", "cancelled"]
+)
+@pytest.mark.asyncio
+async def test_public_completion_fallback_contract(monkeypatch, asynchronous, failure):
+    import asyncio
+    import importlib
+
+    from litellm.integrations.custom_logger import CustomLogger
+
+    class Recorder(CustomLogger):
+        def __init__(self):
+            self.pre = 0
+            self.post = 0
+
+        def log_pre_api_call(self, model, messages, kwargs):
+            self.pre += 1
+
+        def log_post_api_call(self, kwargs, response_obj, start_time, end_time):
+            self.post += 1
+
+    recorder = Recorder()
+    monkeypatch.setattr(litellm, "input_callback", [recorder])
+    _fake_native_bridge(monkeypatch)
+    python_calls = []
+
+    def python(ctx):
+        python_calls.append(ctx)
+
+        def finish():
+            ctx.logging.pre_call(input=MESSAGES, api_key="key", additional_args={})
+            ctx.logging.post_call(input=MESSAGES, api_key="key", original_response="python")
+            return ModelResponse(choices=[{"message": {"role": "assistant", "content": "python"}}])
+
+        async def afinish():
+            return finish()
+
+        return afinish() if ctx.acompletion else finish()
+
+    monkeypatch.setattr(importlib.import_module("litellm.main"), "_complete_python", python)
+    native_error = {
+        "decline": _FakeDeclined("request unsupported"),
+        "error": RuntimeError("execution failed"),
+        "cancelled": asyncio.CancelledError(),
+    }.get(failure)
+    native = _RecordingCall(result={} if failure == "malformed" else None, error=native_error)
+    anative = _RecordingAsyncCall(result={} if failure == "malformed" else None, error=native_error)
+    bridge.set_rust_chat_completions(
+        chat_completions=native,
+        achat_completions=anative,
+        decline=_RecordingDecline("unsupported" if failure == "preflight" else None),
+    )
+    if failure == "missing_preflight":
+        bridge._CHAT_PREFLIGHT.override(None)
+    if failure == "unavailable":
+        bridge._CHAT.sync.override(None)
+        bridge._CHAT.asynchronous.override(None)
+
+    async def run():
+        kwargs = {"model": "openai/test-model", "messages": MESSAGES, "api_key": "key", "num_retries": 0}
+        return await litellm.acompletion(**kwargs) if asynchronous else litellm.completion(**kwargs)
+
+    if failure in {"error", "malformed", "cancelled"}:
+        with pytest.raises(asyncio.CancelledError if failure == "cancelled" else Exception):
+            await run()
+        assert python_calls == []
+    else:
+        result = await run()
+        assert result.choices[0].message.content == "python"
+        assert len(python_calls) == 1
+        assert recorder.pre == 1
+        assert recorder.post == 1