Merge pull request #42300 from BerriAI/litellm_python_interop_foundation

fix(rust): preserve Python settings semantics at the native boundary

.github/scripts/verify_linux_native_wheel.py

@@ -205,7 +205,7 @@ def main(
     native_module: Final = load_native_module(native_path)
     native_module_loads: Final = native_module is not None
     panic_test_hook_absent: Final = native_module is not None and not hasattr(native_module, "_panic_for_test")
-    native_size_limit: Final = 30_000_000
+    native_size_limit: Final = 40_000_000
     native_size_within_limit: Final = native_member.file_size <= native_size_limit
     validations: Final = (
         (f"Python tag is {EXPECTED_PYTHON_TAG}", python_tag == EXPECTED_PYTHON_TAG),
@@ -222,7 +222,7 @@ def main(
         ("Python extension entry point is present", extension_entry_point_present),
         ("Native module loads", native_module_loads),
         ("Production module omits the panic test hook", panic_test_hook_absent),
-        ("Native extension does not exceed 30 MB", native_size_within_limit),
+        (f"Native extension does not exceed {native_size_limit / 1_000_000:.0f} MB", native_size_within_limit),
         ("Wheel contents are valid", not unexpected_members),
     )
 
@@ -267,7 +267,8 @@ def main(
             ),
             (
                 not native_size_within_limit,
-                f"native extension exceeds 30 MB: {native_member.file_size / 1_000_000:.2f} MB",
+                f"native extension exceeds {native_size_limit / 1_000_000:.0f} MB: "
+                f"{native_member.file_size / 1_000_000:.2f} MB",
             ),
             (bool(unexpected_members), f"wheel contains unexpected build artifacts: {', '.join(unexpected_members)}"),
         )

litellm-rust/Cargo.lock

@@ -2688,6 +2688,7 @@ dependencies = [
  "rstest",
  "serde",
  "serde_json",
+ "serde_with",
  "tokio",
  "tokio-tungstenite",
 ]

litellm-rust/crates/core-utils/src/serde_compat.rs

@@ -1,33 +1,91 @@
-use serde::{Deserialize, Deserializer, de::Error};
-use serde_json::Value;
+use serde::{
+    Deserializer,
+    de::{Error, Visitor},
+};
 use serde_with::DeserializeAs;
 
 pub struct LaxI64;
 pub struct FiniteF64;
 
+pub fn parse_str_bool(value: &str) -> Option<bool> {
+    let token = value.trim_matches(|character: char| {
+        character.is_whitespace() || matches!(character, '\u{1c}'..='\u{1f}')
+    });
+    if token.eq_ignore_ascii_case("true") {
+        return Some(true);
+    }
+    token.eq_ignore_ascii_case("false").then_some(false)
+}
+
 impl<'de> DeserializeAs<'de, i64> for LaxI64 {
     fn deserialize_as<D: Deserializer<'de>>(deserializer: D) -> Result<i64, D::Error> {
-        match Value::deserialize(deserializer)? {
-            Value::Number(number) if number.is_f64() => number.as_f64().and_then(integral_float),
-            Value::Number(number) => number.as_i64(),
-            Value::String(value) => integer_string(value.trim()),
-            Value::Bool(value) => Some(i64::from(value)),
-            _ => None,
-        }
-        .ok_or_else(|| D::Error::custom("expected an integer in the i64 range"))
+        deserializer.deserialize_any(Self)
+    }
+}
+
+impl<'de> Visitor<'de> for LaxI64 {
+    type Value = i64;
+
+    fn expecting(&self, formatter: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        formatter.write_str("an integer in the i64 range")
+    }
+
+    fn visit_i64<E: Error>(self, value: i64) -> Result<i64, E> {
+        Ok(value)
+    }
+
+    fn visit_u64<E: Error>(self, value: u64) -> Result<i64, E> {
+        i64::try_from(value).map_err(E::custom)
+    }
+
+    fn visit_f64<E: Error>(self, value: f64) -> Result<i64, E> {
+        integral_float(value).ok_or_else(|| E::custom("expected an integer in the i64 range"))
+    }
+
+    fn visit_str<E: Error>(self, value: &str) -> Result<i64, E> {
+        integer_string(value.trim())
+            .ok_or_else(|| E::custom("expected an integer in the i64 range"))
+    }
+
+    fn visit_bool<E: Error>(self, value: bool) -> Result<i64, E> {
+        Ok(i64::from(value))
     }
 }
 
 impl<'de> DeserializeAs<'de, f64> for FiniteF64 {
     fn deserialize_as<D: Deserializer<'de>>(deserializer: D) -> Result<f64, D::Error> {
-        match Value::deserialize(deserializer)? {
-            Value::Number(number) => number.as_f64(),
-            Value::String(value) => value.trim().parse::<f64>().ok(),
-            Value::Bool(value) => Some(f64::from(value)),
-            _ => None,
-        }
-        .filter(|value| value.is_finite())
-        .ok_or_else(|| D::Error::custom("expected a finite number"))
+        deserializer.deserialize_any(Self)
+    }
+}
+
+impl<'de> Visitor<'de> for FiniteF64 {
+    type Value = f64;
+
+    fn expecting(&self, formatter: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        formatter.write_str("a finite number")
+    }
+
+    fn visit_i64<E: Error>(self, value: i64) -> Result<f64, E> {
+        Ok(value as f64)
+    }
+
+    fn visit_u64<E: Error>(self, value: u64) -> Result<f64, E> {
+        Ok(value as f64)
+    }
+
+    fn visit_f64<E: Error>(self, value: f64) -> Result<f64, E> {
+        value
+            .is_finite()
+            .then_some(value)
+            .ok_or_else(|| E::custom("expected a finite number"))
+    }
+
+    fn visit_str<E: Error>(self, value: &str) -> Result<f64, E> {
+        self.visit_f64(value.trim().parse::<f64>().map_err(E::custom)?)
+    }
+
+    fn visit_bool<E: Error>(self, value: bool) -> Result<f64, E> {
+        Ok(f64::from(value))
     }
 }
 
@@ -66,7 +124,7 @@ fn integral_float(value: f64) -> Option<i64> {
 
 #[cfg(test)]
 mod tests {
-    use serde::Serialize;
+    use serde::{Deserialize, Serialize};
     use serde_json::json;
     use serde_with::serde_as;
 
@@ -81,6 +139,22 @@ mod tests {
         float: Option<f64>,
     }
 
+    #[test]
+    fn boolean_tokens_follow_python_string_trimming_without_redis_tokens() {
+        for (input, expected) in [
+            (" True ", Some(true)),
+            ("\u{1c}TRUE\u{1f}", Some(true)),
+            ("\u{a0}False\u{2003}", Some(false)),
+            ("true\u{200b}", None),
+            ("yes", None),
+            ("1", None),
+            ("", None),
+            ("unknown", None),
+        ] {
+            assert_eq!(parse_str_bool(input), expected, "{input:?}");
+        }
+    }
+
     #[test]
     fn adapters_compose_and_serialize_as_numbers() {
         let numbers: Numbers = serde_json::from_value(json!({

litellm-rust/crates/core-utils/src/settings.rs

@@ -1,5 +1,7 @@
 use std::str::FromStr;
 
+use crate::serde_compat::parse_str_bool;
+
 pub trait Lookup {
     fn get(&self, name: &str) -> Option<String>;
 
@@ -9,7 +11,7 @@ pub trait Lookup {
 
     fn enabled(&self, name: &str) -> Option<bool> {
         self.get(name)
-            .is_some_and(|value| value.trim().eq_ignore_ascii_case("true"))
+            .is_some_and(|value| parse_str_bool(&value) == Some(true))
             .then_some(true)
     }
 

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

@@ -45,7 +45,7 @@ where
     fn into_pyobject(self, py: Python<'py>) -> PyResult<Self::Output> {
         catch_unwind(AssertUnwindSafe(|| pythonize::pythonize(py, &self.0)))
             .map_err(panic_to_pyerr)?
-            .map_err(|error| PyValueError::new_err(error.to_string()))
+            .map_err(PyErr::from)
     }
 }
 
@@ -87,6 +87,19 @@ mod tests {
         });
     }
 
+    #[test]
+    fn pythonized_preserves_python_serialization_error_types() {
+        crate::initialize_python();
+        Python::attach(|py| {
+            let value = std::collections::BTreeMap::from([(vec![1], "value")]);
+            let direct = to_py(py, &value).unwrap_err();
+            let wrapped = Pythonized(value).into_pyobject(py).unwrap_err();
+            assert!(direct.is_instance_of::<pyo3::exceptions::PyTypeError>(py));
+            assert!(wrapped.is_instance_of::<pyo3::exceptions::PyTypeError>(py));
+            assert_eq!(wrapped.to_string(), direct.to_string());
+        });
+    }
+
     #[test]
     fn pythonized_maps_serializer_panics_to_a_base_exception() {
         crate::initialize_python();

litellm-rust/crates/http/src/config.rs

@@ -129,6 +129,7 @@ mod tests {
     use rstest::rstest;
 
     use super::*;
+    use crate::TlsSource;
 
     fn settings(ssl_verify: Option<SslVerify>, ssl_cert_file: Option<&str>) -> HttpSettings {
         HttpSettings {
@@ -298,7 +299,11 @@ mod tests {
         };
         assert!(matches!(
             reqwest::ClientBuilder::try_from(&config),
-            Err(Error::Read { path: reported, .. }) if reported == path
+            Err(Error::Read {
+                path: reported,
+                tls_source: TlsSource::CaBundle,
+                ..
+            }) if reported == path
         ));
     }
 
@@ -315,7 +320,11 @@ mod tests {
         std::fs::remove_file(&path).unwrap();
         assert!(matches!(
             result,
-            Err(Error::InvalidPem { path: reported, .. }) if reported == path
+            Err(Error::InvalidPem {
+                path: reported,
+                tls_source: TlsSource::CaBundle,
+                ..
+            }) if reported == path
         ));
     }
 }

litellm-rust/crates/http/src/error.rs

@@ -1,11 +1,25 @@
 use std::path::PathBuf;
 
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub enum TlsSource {
+    CaBundle,
+    ClientIdentity,
+}
+
 #[derive(Clone, Debug, thiserror::Error, PartialEq, Eq)]
 pub enum Error {
     #[error("could not read {}: {message}", path.display())]
-    Read { path: PathBuf, message: String },
+    Read {
+        path: PathBuf,
+        message: String,
+        tls_source: TlsSource,
+    },
     #[error("{} is not a PEM file: {message}", path.display())]
-    InvalidPem { path: PathBuf, message: String },
+    InvalidPem {
+        path: PathBuf,
+        message: String,
+        tls_source: TlsSource,
+    },
     #[error("could not build the HTTP client: {0}")]
     Client(String),
     #[error("request body could not be serialized: {0}")]

litellm-rust/crates/http/src/lib.rs

@@ -10,7 +10,7 @@ mod tls;
 pub mod transport;
 
 pub use config::{HttpClientConfig, Resolution, Verify};
-pub use error::Error;
+pub use error::{Error, TlsSource};
 pub use pool::{ClientVariant, HttpClientPool};
 pub use proxy::EnvironmentProxies;
 pub use settings::{HttpSettings, HttpSettingsLayer, SslVerify, TcpKeepalive};

litellm-rust/crates/http/src/media.rs

@@ -54,16 +54,39 @@ impl Default for UrlPolicy {
 impl UrlPolicy {
     fn allows(&self, host: &str, port: u16) -> bool {
         let host = normalize_host(host);
-        let with_port = format!("{host}:{port}");
         self.allowed_hosts
             .iter()
-            .map(|entry| normalize_host(entry))
-            .any(|entry| entry == host || entry == with_port)
+            .filter_map(|entry| parse_allowed_host(entry))
+            .any(|(entry_host, entry_port)| {
+                entry_host == host && entry_port.is_none_or(|entry_port| entry_port == port)
+            })
     }
 }
 
-fn normalize_host(host: &str) -> String {
-    host.to_ascii_lowercase().trim_end_matches('.').to_owned()
+pub fn normalize_host(host: &str) -> String {
+    let host = host.trim().trim_end_matches('.');
+    let host = host
+        .strip_prefix('[')
+        .and_then(|host| host.strip_suffix(']'))
+        .unwrap_or(host);
+    host.to_ascii_lowercase()
+}
+
+fn parse_allowed_host(entry: &str) -> Option<(String, Option<u16>)> {
+    let entry = entry.trim();
+    if let Some(entry) = entry.strip_prefix('[') {
+        let (host, suffix) = entry.split_once(']')?;
+        let port = match suffix {
+            "" => None,
+            suffix => Some(suffix.strip_prefix(':')?.parse().ok()?),
+        };
+        return Some((normalize_host(host), port));
+    }
+    let (host, port) = match entry.rsplit_once(':') {
+        Some((host, port)) if !host.contains(':') => (host, Some(port.parse().ok()?)),
+        _ => (entry, None),
+    };
+    Some((normalize_host(host), port))
 }
 
 type ProxyMatch = Arc<dyn Fn(&Url) -> bool + Send + Sync>;
@@ -670,6 +693,21 @@ mod tests {
         assert!(matches!(result, Err(Error::BlockedUrl)));
     }
 
+    #[test]
+    fn allowlist_matches_bracketed_ipv6_hosts_and_ports() {
+        let policy = UrlPolicy {
+            validate: true,
+            allowed_hosts: vec!["[2001:db8::1]".into(), "[2001:db8::1]:8443".into()],
+        };
+        assert!(policy.allows("2001:db8::1", 443));
+        assert!(policy.allows("2001:db8::1", 8443));
+        let port_specific = UrlPolicy {
+            validate: true,
+            allowed_hosts: vec!["[2001:db8::1]:8443".into()],
+        };
+        assert!(!port_specific.allows("2001:db8::1", 9443));
+    }
+
     #[tokio::test]
     async fn validation_off_fetches_private_hosts_and_follows_redirects() {
         let (url, server, _) = serve_named(

litellm-rust/crates/http/src/settings.rs

@@ -3,7 +3,10 @@ use std::{
     time::Duration,
 };
 
-use litellm_core_utils::settings::{Layer, Lookup, merge};
+use litellm_core_utils::{
+    serde_compat::parse_str_bool,
+    settings::{Layer, Lookup, merge},
+};
 
 use crate::proxy::EnvironmentProxies;
 
@@ -16,9 +19,9 @@ pub enum SslVerify {
 
 impl SslVerify {
     pub fn parse(value: &str) -> Self {
-        match value.trim().to_ascii_lowercase().as_str() {
-            "true" => Self::Enabled,
-            "false" => Self::Disabled,
+        match parse_str_bool(value) {
+            Some(true) => Self::Enabled,
+            Some(false) => Self::Disabled,
             _ => Self::CaBundle(PathBuf::from(value)),
         }
     }
@@ -152,9 +155,7 @@ impl HttpSettings {
         Self {
             ssl_verify: merged.ssl_verify,
             ssl_cert_file: merged.ssl_cert_file,
-            ssl_certificate: merged
-                .ssl_certificate
-                .filter(|path| !path.as_os_str().is_empty()),
+            ssl_certificate: merged.ssl_certificate,
             ssl_security_level: merged.ssl_security_level.filter(|level| !level.is_empty()),
             ssl_ecdh_curve: merged.ssl_ecdh_curve.filter(|curve| !curve.is_empty()),
             force_ipv4: merged.force_ipv4.unwrap_or(defaults.force_ipv4),
@@ -287,7 +288,7 @@ mod tests {
     }
 
     #[test]
-    fn empty_environment_values_clear_the_setting_like_python_truthiness() {
+    fn empty_certificate_is_retained_for_validation_while_empty_tuning_is_absent() {
         let configured = HttpSettingsLayer {
             ssl_certificate: Some("/configured/client.pem".into()),
             ssl_security_level: Some("configured".into()),
@@ -300,7 +301,7 @@ mod tests {
             ("SSL_ECDH_CURVE", ""),
         ]));
         let settings = HttpSettings::from_layers([environment, configured]);
-        assert_eq!(settings.ssl_certificate, None);
+        assert_eq!(settings.ssl_certificate, Some(PathBuf::new()));
         assert_eq!(settings.ssl_security_level, None);
         assert_eq!(settings.ssl_ecdh_curve, None);
     }

litellm-rust/crates/http/src/tls.rs

@@ -9,7 +9,7 @@ use rustls::{
 
 use crate::{
     config::{HttpClientConfig, Verify},
-    error::Error,
+    error::{Error, TlsSource},
 };
 
 #[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
@@ -197,15 +197,17 @@ impl TryFrom<&HttpClientConfig> for ClientConfig {
             Verify::BuiltInRoots => builder.with_root_certificates(RootCertStore {
                 roots: webpki_roots::TLS_SERVER_ROOTS.to_vec(),
             }),
-            Verify::CaBundle(path) => builder.with_root_certificates(bundle_roots(path)?),
+            Verify::CaBundle(path) => {
+                builder.with_root_certificates(bundle_roots(path, TlsSource::CaBundle)?)
+            }
         };
         let mut tls = match &config.client_certificate {
             None => verified.with_no_client_auth(),
             Some(path) => {
-                let (chain, key) = identity(path)?;
+                let (chain, key) = identity(path, TlsSource::ClientIdentity)?;
                 verified
                     .with_client_auth_cert(chain, key)
-                    .map_err(|error| invalid_pem(path, error))?
+                    .map_err(|error| invalid_pem(path, TlsSource::ClientIdentity, error))?
             }
         };
         tls.alpn_protocols = if config.http2 {
@@ -217,47 +219,52 @@ impl TryFrom<&HttpClientConfig> for ClientConfig {
     }
 }
 
-fn bundle_roots(path: &Path) -> Result<RootCertStore, Error> {
-    let certificates = certificates(path)?;
+fn bundle_roots(path: &Path, source: TlsSource) -> Result<RootCertStore, Error> {
+    let certificates = certificates(path, source)?;
     if certificates.is_empty() {
-        return Err(invalid_pem(path, "no certificates found"));
+        return Err(invalid_pem(path, source, "no certificates found"));
     }
     let mut store = RootCertStore::empty();
     for certificate in certificates {
         store
             .add(certificate)
-            .map_err(|error| invalid_pem(path, error))?;
+            .map_err(|error| invalid_pem(path, source, error))?;
     }
     Ok(store)
 }
 
-fn identity(path: &Path) -> Result<(Vec<CertificateDer<'static>>, PrivateKeyDer<'static>), Error> {
-    let chain = certificates(path)?;
+fn identity(
+    path: &Path,
+    source: TlsSource,
+) -> Result<(Vec<CertificateDer<'static>>, PrivateKeyDer<'static>), Error> {
+    let chain = certificates(path, source)?;
     if chain.is_empty() {
-        return Err(invalid_pem(path, "no certificates found"));
+        return Err(invalid_pem(path, source, "no certificates found"));
     }
-    let key =
-        PrivateKeyDer::from_pem_slice(&read(path)?).map_err(|error| invalid_pem(path, error))?;
+    let key = PrivateKeyDer::from_pem_slice(&read(path, source)?)
+        .map_err(|error| invalid_pem(path, source, error))?;
     Ok((chain, key))
 }
 
-fn certificates(path: &Path) -> Result<Vec<CertificateDer<'static>>, Error> {
-    CertificateDer::pem_slice_iter(&read(path)?)
+fn certificates(path: &Path, source: TlsSource) -> Result<Vec<CertificateDer<'static>>, Error> {
+    CertificateDer::pem_slice_iter(&read(path, source)?)
         .collect::<Result<_, _>>()
-        .map_err(|error| invalid_pem(path, error))
+        .map_err(|error| invalid_pem(path, source, error))
 }
 
-fn read(path: &Path) -> Result<Vec<u8>, Error> {
+fn read(path: &Path, source: TlsSource) -> Result<Vec<u8>, Error> {
     std::fs::read(path).map_err(|error| Error::Read {
         path: path.to_path_buf(),
         message: error.to_string(),
+        tls_source: source,
     })
 }
 
-fn invalid_pem(path: &Path, message: impl fmt::Display) -> Error {
+fn invalid_pem(path: &Path, source: TlsSource, message: impl fmt::Display) -> Error {
     Error::InvalidPem {
         path: path.to_path_buf(),
         message: message.to_string(),
+        tls_source: source,
     }
 }
 
@@ -405,7 +412,11 @@ mod tests {
         std::fs::remove_file(&path).unwrap();
         assert!(matches!(
             result,
-            Err(Error::InvalidPem { path: reported, .. }) if reported == path
+            Err(Error::InvalidPem {
+                path: reported,
+                tls_source: TlsSource::ClientIdentity,
+                ..
+            }) if reported == path
         ));
     }
 }

litellm-rust/crates/python-bridge/Cargo.toml

@@ -41,6 +41,8 @@ serde_json.workspace = true
 tokio = { workspace = true, features = ["sync"] }
 
 [dev-dependencies]
+serde.workspace = true
+serde_with.workspace = true
 criterion.workspace = true
 futures-util.workspace = true
 rstest.workspace = true

litellm-rust/crates/python-bridge/python_settings.json

@@ -1,26 +1,154 @@
 {
-  "http_settings": [
-    "ssl_verify",
-    "ssl_certificate",
-    "ssl_security_level",
-    "ssl_ecdh_curve",
-    "force_ipv4",
-    "http2",
-    "aiohttp_trust_env",
-    "disable_aiohttp_trust_env",
-    "disable_aiohttp_transport",
-    "user_agent"
-  ],
-  "url_policy": [
-    "user_url_validation",
-    "user_url_allowed_hosts"
-  ],
-  "provider_defaults": [
-    "vertex_project",
-    "vertex_location",
-    "enable_azure_ad_token_refresh"
-  ],
-  "secret_manager": [
-    "readable"
-  ]
+  "http_settings": {
+    "version": 1,
+    "fields": {
+      "ssl_verify": {
+        "adapter": "SslVerifyInput",
+        "required": true,
+        "precedence": "module_global",
+        "sensitive": false,
+        "shapes": [
+          "none",
+          "bool",
+          "str"
+        ],
+        "unsupported_live": "configuration_error"
+      },
+      "ssl_certificate": {
+        "adapter": "OptionalStrictString",
+        "required": true,
+        "precedence": "module_global",
+        "sensitive": false,
+        "shapes": [],
+        "unsupported_live": null
+      },
+      "ssl_security_level": {
+        "adapter": "TuningString",
+        "required": true,
+        "precedence": "module_global",
+        "sensitive": false,
+        "shapes": [],
+        "unsupported_live": null
+      },
+      "ssl_ecdh_curve": {
+        "adapter": "TuningString",
+        "required": true,
+        "precedence": "module_global",
+        "sensitive": false,
+        "shapes": [],
+        "unsupported_live": null
+      },
+      "force_ipv4": {
+        "adapter": "Truthy",
+        "required": true,
+        "precedence": "module_global",
+        "sensitive": false,
+        "shapes": [],
+        "unsupported_live": null
+      },
+      "http2": {
+        "adapter": "ExactTrue",
+        "required": true,
+        "precedence": "module_global",
+        "sensitive": false,
+        "shapes": [],
+        "unsupported_live": null
+      },
+      "aiohttp_trust_env": {
+        "adapter": "Truthy",
+        "required": true,
+        "precedence": "module_global",
+        "sensitive": false,
+        "shapes": [],
+        "unsupported_live": null
+      },
+      "disable_aiohttp_trust_env": {
+        "adapter": "Truthy",
+        "required": true,
+        "precedence": "module_global",
+        "sensitive": false,
+        "shapes": [],
+        "unsupported_live": null
+      },
+      "disable_aiohttp_transport": {
+        "adapter": "ExactTrue",
+        "required": true,
+        "precedence": "module_global",
+        "sensitive": false,
+        "shapes": [],
+        "unsupported_live": null
+      },
+      "user_agent": {
+        "adapter": "StrictString",
+        "required": true,
+        "precedence": "accessor",
+        "sensitive": false,
+        "shapes": [],
+        "unsupported_live": null
+      }
+    }
+  },
+  "url_policy": {
+    "version": 1,
+    "fields": {
+      "user_url_validation": {
+        "adapter": "Truthy",
+        "required": true,
+        "precedence": "module_global",
+        "sensitive": false,
+        "shapes": [],
+        "unsupported_live": null
+      },
+      "user_url_allowed_hosts": {
+        "adapter": "HostCollection",
+        "required": true,
+        "precedence": "module_global",
+        "sensitive": false,
+        "shapes": [],
+        "unsupported_live": null
+      }
+    }
+  },
+  "provider_defaults": {
+    "version": 1,
+    "fields": {
+      "vertex_project": {
+        "adapter": "FalsyOptionalString",
+        "required": true,
+        "precedence": "module_global",
+        "sensitive": true,
+        "shapes": [],
+        "unsupported_live": null
+      },
+      "vertex_location": {
+        "adapter": "FalsyOptionalString",
+        "required": true,
+        "precedence": "module_global",
+        "sensitive": true,
+        "shapes": [],
+        "unsupported_live": null
+      },
+      "enable_azure_ad_token_refresh": {
+        "adapter": "ExactTrue",
+        "required": true,
+        "precedence": "module_global",
+        "sensitive": false,
+        "shapes": [],
+        "unsupported_live": null
+      }
+    }
+  },
+  "secret_manager": {
+    "version": 1,
+    "fields": {
+      "readable": {
+        "adapter": "StrictBool",
+        "required": true,
+        "precedence": "accessor",
+        "sensitive": false,
+        "shapes": [],
+        "unsupported_live": null
+      }
+    }
+  }
 }

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

@@ -0,0 +1,231 @@
+use std::collections::BTreeSet;
+
+use litellm_core_utils::serde_compat::parse_str_bool;
+use litellm_http::SslVerify;
+use pyo3::{
+    exceptions::{PyAttributeError, PyRuntimeError, PyValueError},
+    prelude::*,
+    types::{PyBool, PyString},
+};
+
+#[derive(Debug)]
+pub(crate) enum ProjectionError {
+    Python(PyErr),
+    InvalidConfiguration(String),
+    UnsupportedLiveObject(String),
+    InternalSchemaFailure(String),
+}
+
+impl From<PyErr> for ProjectionError {
+    fn from(error: PyErr) -> Self {
+        Self::Python(error)
+    }
+}
+
+impl From<ProjectionError> for PyErr {
+    fn from(error: ProjectionError) -> Self {
+        match error {
+            ProjectionError::Python(error) => error,
+            ProjectionError::InvalidConfiguration(message)
+            | ProjectionError::UnsupportedLiveObject(message) => PyValueError::new_err(message),
+            ProjectionError::InternalSchemaFailure(message) => PyRuntimeError::new_err(message),
+        }
+    }
+}
+
+pub(crate) struct Truthy(pub bool);
+pub(crate) struct ExactTrue(pub bool);
+pub(crate) struct StrBool(pub Option<bool>);
+pub(crate) struct OptionalStrictString(pub Option<String>);
+pub(crate) struct FalsyOptionalString(pub Option<String>);
+pub(crate) struct TuningString(pub Option<String>);
+pub(crate) struct StringCollection(pub Vec<String>);
+pub(crate) struct SslVerifyInput(pub Option<SslVerify>);
+
+pub(crate) struct Field<'py> {
+    path: &'static str,
+    value: Bound<'py, PyAny>,
+}
+
+impl<'py> Field<'py> {
+    pub(crate) fn new(path: &'static str, value: Bound<'py, PyAny>) -> Self {
+        Self { path, value }
+    }
+
+    pub(crate) fn read(
+        snapshot: &Bound<'py, PyAny>,
+        path: &'static str,
+    ) -> Result<Self, ProjectionError> {
+        let name = path.rsplit('.').next().unwrap_or(path);
+        match snapshot.getattr(name) {
+            Ok(value) => Ok(Self::new(path, value)),
+            Err(error) if error.is_instance_of::<PyAttributeError>(snapshot.py()) => {
+                match Self::missing_field(snapshot, name) {
+                    Ok(true) => Err(ProjectionError::InternalSchemaFailure(format!(
+                        "{path}: missing snapshot field"
+                    ))),
+                    _ => Err(error.into()),
+                }
+            }
+            Err(error) => Err(error.into()),
+        }
+    }
+
+    fn missing_field(snapshot: &Bound<'_, PyAny>, name: &str) -> PyResult<bool> {
+        let py = snapshot.py();
+        let object = py.import("builtins")?.getattr("object")?;
+        let missing = object.call0()?;
+        let lookup = py.import("inspect")?.getattr("getattr_static")?;
+        let declared = lookup.call1((snapshot, name, &missing))?;
+        let fallback = lookup.call1((snapshot.get_type(), "__getattr__", &missing))?;
+        let getter = lookup.call1((snapshot.get_type(), "__getattribute__"))?;
+        Ok(declared.is(&missing)
+            && fallback.is(&missing)
+            && getter.is(object.getattr("__getattribute__")?))
+    }
+
+    fn expected(&self, expected: &'static str) -> Result<String, ProjectionError> {
+        Ok(format!(
+            "{}: expected {expected}, got {}",
+            self.path,
+            self.value.get_type().name()?
+        ))
+    }
+
+    fn invalid(&self, expected: &'static str) -> ProjectionError {
+        match self.expected(expected) {
+            Ok(message) => ProjectionError::InvalidConfiguration(message),
+            Err(error) => error,
+        }
+    }
+
+    pub(crate) fn truthy(&self) -> Result<Truthy, ProjectionError> {
+        Ok(Truthy(self.value.is_truthy()?))
+    }
+
+    pub(crate) fn exact_true(&self) -> ExactTrue {
+        ExactTrue(self.value.is(PyBool::new(self.value.py(), true)))
+    }
+
+    pub(crate) fn strict_string(&self) -> Result<String, ProjectionError> {
+        let value = self
+            .value
+            .cast::<PyString>()
+            .map_err(|_| self.invalid("a string"))?;
+        Ok(value.to_str()?.to_owned())
+    }
+
+    pub(crate) fn schema_string(&self) -> Result<String, ProjectionError> {
+        if !self.value.is_instance_of::<PyString>() {
+            return Err(ProjectionError::InternalSchemaFailure(
+                self.expected("a string")?,
+            ));
+        }
+        self.strict_string()
+    }
+
+    pub(crate) fn schema_bool(&self) -> Result<bool, ProjectionError> {
+        if !self.value.is_instance_of::<PyBool>() {
+            return Err(ProjectionError::InternalSchemaFailure(
+                self.expected("a Boolean")?,
+            ));
+        }
+        Ok(self.exact_true().0)
+    }
+
+    pub(crate) fn str_bool(&self) -> Result<StrBool, ProjectionError> {
+        if self.value.is_none() {
+            return Ok(StrBool(None));
+        }
+        Ok(StrBool(parse_str_bool(&self.strict_string()?)))
+    }
+
+    pub(crate) fn optional_strict_string(&self) -> Result<OptionalStrictString, ProjectionError> {
+        if self.value.is_none() {
+            return Ok(OptionalStrictString(None));
+        }
+        self.strict_string().map(Some).map(OptionalStrictString)
+    }
+
+    pub(crate) fn falsy_optional_string(&self) -> Result<FalsyOptionalString, ProjectionError> {
+        if !self.truthy()?.0 {
+            return Ok(FalsyOptionalString(None));
+        }
+        self.strict_string().map(Some).map(FalsyOptionalString)
+    }
+
+    pub(crate) fn tuning_string(&self) -> Result<TuningString, ProjectionError> {
+        if !self.truthy()?.0 || !self.value.is_instance_of::<PyString>() {
+            return Ok(TuningString(None));
+        }
+        self.strict_string().map(Some).map(TuningString)
+    }
+
+    pub(crate) fn string_collection(&self) -> Result<StringCollection, ProjectionError> {
+        if !self.truthy()?.0 {
+            return Ok(StringCollection(Vec::new()));
+        }
+        if self.value.is_instance_of::<PyString>() {
+            return self
+                .strict_string()
+                .map(|value| StringCollection(vec![value]));
+        }
+        let values = self
+            .value
+            .try_iter()?
+            .filter_map(|item| {
+                let member = match item {
+                    Ok(value) => Self::new(self.path, value),
+                    Err(error) => return Some(Err(error.into())),
+                };
+                match member.truthy() {
+                    Ok(Truthy(false)) => None,
+                    Ok(Truthy(true)) => Some(member.strict_string()),
+                    Err(error) => Some(Err(error)),
+                }
+            })
+            .collect::<Result<Vec<_>, ProjectionError>>()?;
+        Ok(StringCollection(values))
+    }
+
+    pub(crate) fn host_collection(&self) -> Result<StringCollection, ProjectionError> {
+        let values = self
+            .string_collection()?
+            .0
+            .into_iter()
+            .map(|host| litellm_http::media::normalize_host(&host))
+            .collect::<BTreeSet<_>>();
+        Ok(StringCollection(values.into_iter().collect()))
+    }
+
+    pub(crate) fn ssl_verify(&self) -> Result<SslVerifyInput, ProjectionError> {
+        if self.value.is_none() {
+            return Ok(SslVerifyInput(None));
+        }
+        if self.value.is_instance_of::<PyBool>() {
+            return Ok(SslVerifyInput(Some(if self.exact_true().0 {
+                SslVerify::Enabled
+            } else {
+                SslVerify::Disabled
+            })));
+        }
+        if self.value.is_instance_of::<PyString>() {
+            let parsed = match self.str_bool()?.0 {
+                Some(true) => SslVerify::Enabled,
+                Some(false) => SslVerify::Disabled,
+                None => SslVerify::CaBundle(self.strict_string()?.into()),
+            };
+            return Ok(SslVerifyInput(Some(parsed)));
+        }
+        let context = self.value.py().import("ssl")?.getattr("SSLContext")?;
+        if self.value.is_instance(&context)? {
+            return Err(ProjectionError::UnsupportedLiveObject(self.expected(
+                "a Boolean, Boolean string, CA path, or None; live SSLContext is unsupported",
+            )?));
+        }
+        Err(self.invalid("a Boolean, Boolean string, CA path, or None"))
+    }
+}
+
+#[cfg(test)]
+mod tests;

litellm-rust/crates/python-bridge/src/coercion/tests.rs

@@ -0,0 +1,372 @@
+use std::ffi::CString;
+
+use pyo3::{
+    exceptions::{PyLookupError, PyRuntimeError, PyValueError},
+    types::PyDict,
+};
+use rstest::rstest;
+
+use super::*;
+
+fn evaluate<'py>(py: Python<'py>, source: &str) -> Bound<'py, PyAny> {
+    py.eval(&CString::new(source).unwrap(), None, None).unwrap()
+}
+
+#[rstest]
+#[case("None", false, false)]
+#[case("False", false, false)]
+#[case("True", true, true)]
+#[case("0", false, false)]
+#[case("1", true, false)]
+#[case("''", false, false)]
+#[case("'false'", true, false)]
+#[case("[]", false, false)]
+#[case("[0]", true, false)]
+#[case("{}", false, false)]
+#[case("object()", true, false)]
+fn boolean_operations_have_distinct_python_semantics(
+    #[case] source: &str,
+    #[case] truth: bool,
+    #[case] exact: bool,
+) {
+    Python::initialize();
+    Python::attach(|py| {
+        let value = evaluate(py, source);
+        let field = Field::new("test.flag", value.clone());
+        assert_eq!(field.truthy().unwrap().0, truth);
+        assert_eq!(field.exact_true().0, exact);
+        assert_eq!(
+            field.truthy().unwrap().0,
+            py.import("builtins")
+                .unwrap()
+                .getattr("bool")
+                .unwrap()
+                .call1((value,))
+                .unwrap()
+                .extract::<bool>()
+                .unwrap()
+        );
+    });
+}
+
+#[rstest]
+#[case("None", Ok(None), Ok(None), Ok(None))]
+#[case("''", Ok(Some("")), Ok(None), Ok(None))]
+#[case(
+    "' value '",
+    Ok(Some(" value ")),
+    Ok(Some(" value ")),
+    Ok(Some(" value "))
+)]
+#[case("[]", Err(()), Ok(None), Ok(None))]
+#[case("0", Err(()), Ok(None), Ok(None))]
+#[case("1", Err(()), Err(()), Ok(None))]
+#[case("object()", Err(()), Err(()), Ok(None))]
+fn string_operations_do_not_conflate_absence_and_type_checks(
+    #[case] source: &str,
+    #[case] strict: Result<Option<&str>, ()>,
+    #[case] fallback: Result<Option<&str>, ()>,
+    #[case] tuning: Result<Option<&str>, ()>,
+) {
+    Python::initialize();
+    Python::attach(|py| {
+        let field = Field::new("test.string", evaluate(py, source));
+        let owned =
+            |expected: Result<Option<&str>, ()>| expected.map(|value| value.map(str::to_owned));
+        assert_eq!(
+            field
+                .optional_strict_string()
+                .map(|value| value.0)
+                .map_err(|_| ()),
+            owned(strict)
+        );
+        assert_eq!(
+            field
+                .falsy_optional_string()
+                .map(|value| value.0)
+                .map_err(|_| ()),
+            owned(fallback)
+        );
+        assert_eq!(
+            field.tuning_string().map(|value| value.0).map_err(|_| ()),
+            owned(tuning)
+        );
+    });
+}
+
+#[rstest]
+#[case("None", None)]
+#[case("' True '", Some(true))]
+#[case("' fAlSe '", Some(false))]
+#[case("'yes'", None)]
+#[case("'1'", None)]
+#[case("'unknown'", None)]
+fn string_boolean_tokens_remain_separate_from_truthiness(
+    #[case] source: &str,
+    #[case] expected: Option<bool>,
+) {
+    Python::initialize();
+    Python::attach(|py| {
+        assert_eq!(
+            Field::new("test.flag", evaluate(py, source))
+                .str_bool()
+                .unwrap()
+                .0,
+            expected
+        );
+    });
+}
+
+#[rstest]
+#[case("'EXAMPLE.TEST.'", vec!["example.test"])]
+#[case("['B.test', '', None, 0, [], 'A.test.', 'b.test']", vec!["a.test", "b.test"])]
+#[case("('B.test', 'a.test')", vec!["a.test", "b.test"])]
+#[case("{'B.test', 'a.test'}", vec!["a.test", "b.test"])]
+#[case("(host for host in ['B.test', 'a.test'])", vec!["a.test", "b.test"])]
+#[case("None", vec![])]
+#[case("False", vec![])]
+fn host_collection_is_owned_normalized_and_deterministic(
+    #[case] source: &str,
+    #[case] expected: Vec<&str>,
+) {
+    Python::initialize();
+    Python::attach(|py| {
+        assert_eq!(
+            Field::new("url_policy.user_url_allowed_hosts", evaluate(py, source))
+                .host_collection()
+                .unwrap()
+                .0,
+            expected
+        );
+    });
+}
+
+#[test]
+fn protocol_errors_preserve_exception_identity_traceback_cause_and_context() {
+    Python::initialize();
+    Python::attach(|py| {
+        let locals = PyDict::new(py);
+        py.run(
+            c"
+failure = LookupError('protocol failed')
+cause = ValueError('cause')
+context = RuntimeError('context')
+def fail():
+    try:
+        raise context
+    except RuntimeError:
+        raise failure from cause
+class Bool:
+    def __bool__(self): return fail()
+class Length:
+    def __len__(self): return fail()
+class Iter:
+    def __iter__(self): return fail()
+class Next:
+    def __iter__(self): return self
+    def __next__(self): return fail()
+class Descriptor:
+    @property
+    def flag(self): return fail()
+values = (Bool(), Length(), Iter(), Next(), [Bool()])
+descriptor = Descriptor()
+",
+            Some(&locals),
+            Some(&locals),
+        )
+        .unwrap();
+        let values = locals.get_item("values").unwrap().unwrap();
+        for value in values.try_iter().unwrap() {
+            let error = Field::new("test.flag", value.unwrap())
+                .host_collection()
+                .err()
+                .unwrap();
+            let error = PyErr::from(error);
+            assert!(
+                error
+                    .value(py)
+                    .is(locals.get_item("failure").unwrap().unwrap())
+            );
+            assert!(error.is_instance_of::<PyLookupError>(py));
+            assert!(error.traceback(py).is_some());
+            assert!(
+                error
+                    .value(py)
+                    .getattr("__cause__")
+                    .unwrap()
+                    .is(locals.get_item("cause").unwrap().unwrap())
+            );
+            assert!(
+                error
+                    .value(py)
+                    .getattr("__context__")
+                    .unwrap()
+                    .is(locals.get_item("context").unwrap().unwrap())
+            );
+        }
+        let error = Field::read(
+            &locals.get_item("descriptor").unwrap().unwrap(),
+            "test.flag",
+        )
+        .err()
+        .unwrap();
+        assert!(
+            PyErr::from(error)
+                .value(py)
+                .is(locals.get_item("failure").unwrap().unwrap())
+        );
+    });
+}
+
+#[test]
+fn identity_and_string_contents_do_not_invoke_unrelated_protocols() {
+    Python::initialize();
+    Python::attach(|py| {
+        let locals = PyDict::new(py);
+        py.run(
+            c"
+class Hostile:
+    def __bool__(self): raise AssertionError('bool called')
+    def __eq__(self, other): raise AssertionError('eq called')
+    def __str__(self): raise AssertionError('str called')
+class Text(str):
+    def __str__(self): raise AssertionError('str called')
+    def strip(self): raise AssertionError('strip called')
+    def lower(self): raise AssertionError('lower called')
+hostile = Hostile()
+text = Text(' False ')
+",
+            Some(&locals),
+            Some(&locals),
+        )
+        .unwrap();
+        let hostile = Field::new("test.flag", locals.get_item("hostile").unwrap().unwrap());
+        assert!(!hostile.exact_true().0);
+        assert!(matches!(
+            hostile.strict_string(),
+            Err(ProjectionError::InvalidConfiguration(_))
+        ));
+        let text = Field::new("test.flag", locals.get_item("text").unwrap().unwrap());
+        assert_eq!(text.strict_string().unwrap(), " False ");
+        assert_eq!(text.str_bool().unwrap().0, Some(false));
+    });
+}
+
+#[test]
+fn missing_snapshot_fields_and_descriptor_attribute_errors_are_distinct() {
+    Python::initialize();
+    Python::attach(|py| {
+        let locals = PyDict::new(py);
+        py.run(
+            c"
+failure = AttributeError('descriptor failed')
+class Snapshot:
+    @property
+    def flag(self): raise failure
+snapshot = Snapshot()
+class Dynamic:
+    def __getattr__(self, name): raise failure
+class Intercepted:
+    def __getattribute__(self, name): raise failure
+dynamic = Dynamic()
+intercepted = Intercepted()
+",
+            Some(&locals),
+            Some(&locals),
+        )
+        .unwrap();
+        let snapshot = locals.get_item("snapshot").unwrap().unwrap();
+        let descriptor = PyErr::from(Field::read(&snapshot, "test.flag").err().unwrap());
+        assert!(
+            descriptor
+                .value(py)
+                .is(locals.get_item("failure").unwrap().unwrap())
+        );
+        for name in ["dynamic", "intercepted"] {
+            let value = locals.get_item(name).unwrap().unwrap();
+            let error = PyErr::from(Field::read(&value, "test.flag").err().unwrap());
+            assert!(
+                error
+                    .value(py)
+                    .is(locals.get_item("failure").unwrap().unwrap())
+            );
+        }
+        let missing = PyErr::from(Field::read(&snapshot, "test.missing").err().unwrap());
+        assert!(missing.is_instance_of::<PyRuntimeError>(py));
+        assert!(missing.to_string().contains("test.missing"));
+    });
+}
+
+#[test]
+fn configuration_errors_name_fields_without_exposing_values() {
+    Python::initialize();
+    Python::attach(|py| {
+        for source in [
+            "{'secret': 'do-not-print'}",
+            "['host.test', {'secret': 'do-not-print'}]",
+        ] {
+            let field = Field::new("test.setting", evaluate(py, source));
+            let error = PyErr::from(field.falsy_optional_string().err().unwrap());
+            assert!(error.is_instance_of::<PyValueError>(py));
+            assert!(error.to_string().contains("test.setting"));
+            assert!(!error.to_string().contains("do-not-print"));
+        }
+        let hosts = Field::new(
+            "url_policy.user_url_allowed_hosts",
+            evaluate(py, "['host.test', 1]"),
+        );
+        assert!(matches!(
+            hosts.host_collection(),
+            Err(ProjectionError::InvalidConfiguration(_))
+        ));
+        assert!(matches!(
+            Field::new("test.flag", evaluate(py, "1")).str_bool(),
+            Err(ProjectionError::InvalidConfiguration(_))
+        ));
+    });
+}
+
+#[test]
+fn projection_releases_the_source_collection() {
+    Python::initialize();
+    Python::attach(|py| {
+        let source = evaluate(py, "['A.test']");
+        let projected = Field::new("test.hosts", source.clone())
+            .host_collection()
+            .unwrap()
+            .0;
+        source.call_method1("append", ("b.test",)).unwrap();
+        assert_eq!(projected, ["a.test"]);
+        assert_eq!(
+            Field::new("test.hosts", source)
+                .host_collection()
+                .unwrap()
+                .0,
+            ["a.test", "b.test"]
+        );
+    });
+}
+
+#[rstest]
+#[case("True", Some(true))]
+#[case("False", Some(false))]
+#[case("1", None)]
+#[case("None", None)]
+#[case("[]", None)]
+fn accessor_booleans_are_strict_schema_values(
+    #[case] source: &str,
+    #[case] expected: Option<bool>,
+) {
+    Python::initialize();
+    Python::attach(|py| {
+        let result = Field::new("secret_manager.readable", evaluate(py, source)).schema_bool();
+        match expected {
+            Some(expected) => assert_eq!(result.unwrap(), expected),
+            None => {
+                let error = PyErr::from(result.unwrap_err());
+                assert!(error.is_instance_of::<PyRuntimeError>(py));
+                assert!(error.to_string().contains("secret_manager.readable"));
+            }
+        }
+    });
+}

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

@@ -7,12 +7,12 @@ use std::{
 use litellm_core_utils::settings::ProcessEnvironment;
 use litellm_http::{
     HttpClientConfig, HttpClientPool, HttpSettings, HttpSettingsLayer, Resolution, SslVerify,
-    Unsupported,
+    TlsSource, Unsupported,
     media::{PublicDnsResolver, UrlPolicy},
 };
-use pyo3::{prelude::*, types::PyDict};
+use pyo3::{exceptions::PyValueError, prelude::*, types::PyDict};
 
-use crate::{errors::RustBridgeDeclined, python_settings::PythonSettings};
+use crate::{coercion::Field, python_settings::PythonSettings};
 
 static POOL: LazyLock<HttpClientPool> =
     LazyLock::new(|| HttpClientPool::new(Arc::new(PublicDnsResolver)));
@@ -41,6 +41,30 @@ pub(crate) fn call_config(
     Ok(resolution.config)
 }
 
+pub(crate) fn client_error(error: litellm_http::Error) -> PyErr {
+    match error {
+        litellm_http::Error::Read {
+            tls_source: TlsSource::ClientIdentity,
+            ..
+        }
+        | litellm_http::Error::InvalidPem {
+            tls_source: TlsSource::ClientIdentity,
+            ..
+        } => PyValueError::new_err(
+            "http_settings.ssl_certificate: expected a readable PEM certificate and private key",
+        ),
+        litellm_http::Error::Read {
+            tls_source: TlsSource::CaBundle,
+            ..
+        }
+        | litellm_http::Error::InvalidPem {
+            tls_source: TlsSource::CaBundle,
+            ..
+        } => PyValueError::new_err("http_settings.ssl_verify: expected a readable PEM CA bundle"),
+        _ => PyValueError::new_err("http_settings: native HTTP client configuration is invalid"),
+    }
+}
+
 fn unreported(
     reported: &Mutex<HashSet<Unsupported>>,
     unsupported: Vec<Unsupported>,
@@ -53,25 +77,25 @@ fn unreported(
 }
 
 pub(crate) fn url_policy(py: Python<'_>) -> PyResult<UrlPolicy> {
-    let policy: PythonUrlPolicy =
-        PythonSettings::UrlPolicy
-            .read(py)?
-            .extract()
-            .map_err(|error: PyErr| {
-                RustBridgeDeclined::new_err(format!(
-                    "litellm URL policy cannot be used by the Rust route: {error}"
-                ))
-            })?;
+    project_url_policy(&PythonSettings::UrlPolicy.read(py)?)
+}
+
+fn project_url_policy(value: &Bound<'_, PyAny>) -> PyResult<UrlPolicy> {
     Ok(UrlPolicy {
-        validate: policy.user_url_validation,
-        allowed_hosts: policy.user_url_allowed_hosts,
+        validate: Field::read(value, "url_policy.user_url_validation")?
+            .truthy()?
+            .0,
+        allowed_hosts: Field::read(value, "url_policy.user_url_allowed_hosts")?
+            .host_collection()?
+            .0,
     })
 }
 
 fn call_ssl_verify(kwargs: &Bound<'_, PyDict>) -> PyResult<Option<SslVerify>> {
-    Ok(kwargs
-        .get_item("ssl_verify")?
-        .and_then(|value| ssl_verify(&value)))
+    match kwargs.get_item("ssl_verify")? {
+        Some(value) => Ok(Field::new("request.ssl_verify", value).ssl_verify()?.0),
+        None => Ok(None),
+    }
 }
 
 fn for_call(call_ssl_verify: Option<SslVerify>, asynchronous: bool) -> HttpSettingsLayer {
@@ -82,64 +106,47 @@ fn for_call(call_ssl_verify: Option<SslVerify>, asynchronous: bool) -> HttpSetti
     }
 }
 
-#[derive(FromPyObject)]
-struct PythonUrlPolicy {
-    user_url_validation: bool,
-    user_url_allowed_hosts: Vec<String>,
-}
-
-#[derive(FromPyObject)]
-struct PythonHttpSettings<'py> {
-    ssl_verify: Bound<'py, PyAny>,
-    ssl_certificate: Option<String>,
-    ssl_security_level: Option<String>,
-    ssl_ecdh_curve: Option<String>,
-    force_ipv4: bool,
-    http2: bool,
-    aiohttp_trust_env: bool,
-    disable_aiohttp_trust_env: bool,
-    disable_aiohttp_transport: bool,
-    user_agent: String,
-}
-
 fn configured(value: &Bound<'_, PyAny>) -> PyResult<HttpSettingsLayer> {
-    let python: PythonHttpSettings = value.extract().map_err(|error: PyErr| {
-        RustBridgeDeclined::new_err(format!(
-            "litellm HTTP settings cannot be used by the Rust route: {error}"
-        ))
-    })?;
     Ok(HttpSettingsLayer {
-        ssl_verify: ssl_verify(&python.ssl_verify),
-        ssl_certificate: python.ssl_certificate.map(PathBuf::from),
-        ssl_security_level: python.ssl_security_level,
-        ssl_ecdh_curve: python.ssl_ecdh_curve,
-        force_ipv4: Some(python.force_ipv4),
-        http2: Some(python.http2),
-        aiohttp_trust_env: Some(python.aiohttp_trust_env),
-        disable_aiohttp_trust_env: Some(python.disable_aiohttp_trust_env),
-        disable_aiohttp_transport: Some(python.disable_aiohttp_transport),
-        user_agent: Some(python.user_agent),
+        ssl_verify: Field::read(value, "http_settings.ssl_verify")?
+            .ssl_verify()?
+            .0,
+        ssl_certificate: Field::read(value, "http_settings.ssl_certificate")?
+            .optional_strict_string()?
+            .0
+            .map(PathBuf::from),
+        ssl_security_level: Field::read(value, "http_settings.ssl_security_level")?
+            .tuning_string()?
+            .0,
+        ssl_ecdh_curve: Field::read(value, "http_settings.ssl_ecdh_curve")?
+            .tuning_string()?
+            .0,
+        force_ipv4: Some(Field::read(value, "http_settings.force_ipv4")?.truthy()?.0),
+        http2: Some(Field::read(value, "http_settings.http2")?.exact_true().0),
+        aiohttp_trust_env: Some(
+            Field::read(value, "http_settings.aiohttp_trust_env")?
+                .truthy()?
+                .0,
+        ),
+        disable_aiohttp_trust_env: Some(
+            Field::read(value, "http_settings.disable_aiohttp_trust_env")?
+                .truthy()?
+                .0,
+        ),
+        disable_aiohttp_transport: Some(
+            Field::read(value, "http_settings.disable_aiohttp_transport")?
+                .exact_true()
+                .0,
+        ),
+        user_agent: Some(Field::read(value, "http_settings.user_agent")?.schema_string()?),
         ..HttpSettingsLayer::default()
     })
 }
 
-fn ssl_verify(value: &Bound<'_, PyAny>) -> Option<SslVerify> {
-    if let Ok(enabled) = value.extract::<bool>() {
-        return Some(if enabled {
-            SslVerify::Enabled
-        } else {
-            SslVerify::Disabled
-        });
-    }
-    value
-        .extract::<String>()
-        .ok()
-        .map(|path| SslVerify::parse(&path))
-}
-
 #[cfg(test)]
 mod tests {
     use litellm_http::Verify;
+    use pyo3::exceptions::PyRuntimeError;
     use rstest::rstest;
 
     use super::*;
@@ -163,7 +170,7 @@ defaults = dict(
     user_agent='litellm/test',
 )
 defaults.update(dict({overrides}))
-settings = types.SimpleNamespace(**{{name: defaults[name] for name in json.loads(contract)['http_settings']}})
+settings = types.SimpleNamespace(**{{name: defaults[name] for name in json.loads(contract)['http_settings']['fields']}})
 "
         );
         let locals = PyDict::new(py);
@@ -189,6 +196,33 @@ settings = types.SimpleNamespace(**{{name: defaults[name] for name in json.loads
         });
     }
 
+    #[test]
+    fn client_error_uses_tls_source_when_paths_match() {
+        Python::initialize();
+        Python::attach(|py| {
+            let path = PathBuf::from("/shared.pem");
+            let ca_error = client_error(litellm_http::Error::InvalidPem {
+                path: path.clone(),
+                message: "invalid".into(),
+                tls_source: TlsSource::CaBundle,
+            });
+            assert_eq!(
+                ca_error.to_string(),
+                "ValueError: http_settings.ssl_verify: expected a readable PEM CA bundle"
+            );
+            let client_error = client_error(litellm_http::Error::InvalidPem {
+                path,
+                message: "invalid".into(),
+                tls_source: TlsSource::ClientIdentity,
+            });
+            assert!(client_error.is_instance_of::<PyValueError>(py));
+            assert_eq!(
+                client_error.to_string(),
+                "ValueError: http_settings.ssl_certificate: expected a readable PEM certificate and private key"
+            );
+        });
+    }
+
     #[test]
     fn python_settings_flow_into_the_configured_layer() {
         Python::initialize();
@@ -259,12 +293,16 @@ user_agent='litellm/9.9.9',
         });
     }
 
-    #[test]
-    fn ssl_context_global_is_ignored_so_environment_and_defaults_apply() {
+    #[rstest]
+    #[case("ssl_verify=object()")]
+    #[case("ssl_verify=__import__('ssl').SSLContext(__import__('ssl').PROTOCOL_TLS_CLIENT)")]
+    #[case("ssl_certificate=1")]
+    fn invalid_http_configuration_is_terminal(#[case] overrides: &str) {
         Python::initialize();
         Python::attach(|py| {
-            let layer = configured(&python_settings(py, "ssl_verify=object()")).unwrap();
-            assert_eq!(layer.ssl_verify, None);
+            let error = configured(&python_settings(py, overrides)).unwrap_err();
+            assert!(error.is_instance_of::<PyValueError>(py));
+            assert!(error.to_string().contains("http_settings.ssl_"));
         });
     }
 
@@ -281,11 +319,21 @@ user_agent='litellm/9.9.9',
     }
 
     #[test]
-    fn mistyped_python_settings_decline_instead_of_raising() {
+    fn mutable_globals_use_their_consumer_operations() {
         Python::initialize();
         Python::attach(|py| {
-            let error = configured(&python_settings(py, "force_ipv4='yes'")).unwrap_err();
-            assert!(error.is_instance_of::<RustBridgeDeclined>(py));
+            let layer = configured(&python_settings(py,
+                "force_ipv4='yes', http2=1, disable_aiohttp_transport=1, aiohttp_trust_env=[1], disable_aiohttp_trust_env=[], ssl_security_level=1, ssl_ecdh_curve=[]"
+            )).unwrap();
+            assert_eq!(layer.force_ipv4, Some(true));
+            assert_eq!(layer.http2, Some(false));
+            assert_eq!(layer.disable_aiohttp_transport, Some(false));
+            assert_eq!(layer.aiohttp_trust_env, Some(true));
+            assert_eq!(layer.disable_aiohttp_trust_env, Some(false));
+            assert_eq!(layer.ssl_security_level, None);
+            assert_eq!(layer.ssl_ecdh_curve, None);
+            let error = configured(&python_settings(py, "user_agent=1")).unwrap_err();
+            assert!(error.is_instance_of::<PyRuntimeError>(py));
         });
     }
 
@@ -323,17 +371,36 @@ user_agent='litellm/9.9.9',
     }
 
     #[test]
-    fn live_ssl_context_argument_is_ignored_so_the_configured_value_applies() {
+    fn live_ssl_context_argument_raises_instead_of_using_another_layer() {
         Python::initialize();
         Python::attach(|py| {
             let kwargs = PyDict::new(py);
-            kwargs
-                .set_item("ssl_verify", py.eval(c"object()", None, None).unwrap())
+            let ssl = py.import("ssl").unwrap();
+            let context = ssl
+                .getattr("SSLContext")
+                .unwrap()
+                .call1((ssl.getattr("PROTOCOL_TLS_CLIENT").unwrap(),))
                 .unwrap();
-            let call = for_call(call_ssl_verify(&kwargs).unwrap(), true);
-            let settings =
-                HttpSettings::from_layers([call, configured_ssl_verify(SslVerify::Disabled)]);
-            assert_eq!(settings.ssl_verify, Some(SslVerify::Disabled));
+            kwargs.set_item("ssl_verify", context).unwrap();
+            let error = call_ssl_verify(&kwargs).unwrap_err();
+            assert!(error.is_instance_of::<PyValueError>(py));
+            assert!(error.to_string().contains("request.ssl_verify"));
+            assert!(error.to_string().contains("SSLContext"));
+        });
+    }
+
+    #[test]
+    fn url_policy_uses_truthiness_and_normalized_owned_hosts() {
+        Python::initialize();
+        Python::attach(|py| {
+            let value = py.eval(c"__import__('types').SimpleNamespace(user_url_validation=[], user_url_allowed_hosts=['B.test', 'a.test.', 'b.test'])", None, None).unwrap();
+            assert_eq!(
+                project_url_policy(&value).unwrap(),
+                UrlPolicy {
+                    validate: false,
+                    allowed_hosts: vec!["a.test".into(), "b.test".into()],
+                }
+            );
         });
     }
 

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

@@ -1,4 +1,5 @@
 mod cache;
+mod coercion;
 mod credentials;
 mod diagnostics;
 mod errors;

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

@@ -172,6 +172,60 @@ mod tests {
         request_input_sources(&kwargs, names.iter().copied())
     }
 
+    #[serde_with::serde_as]
+    #[derive(Debug, serde::Deserialize, serde::Serialize, PartialEq)]
+    struct Numbers {
+        #[serde_as(deserialize_as = "Option<Vec<litellm_core_utils::serde_compat::LaxI64>>")]
+        integers: Option<Vec<i64>>,
+        #[serde_as(deserialize_as = "Option<litellm_core_utils::serde_compat::FiniteF64>")]
+        float: Option<f64>,
+    }
+
+    #[test]
+    fn numeric_adapters_agree_across_json_and_python_boundaries() {
+        Python::initialize();
+        Python::attach(|py| {
+            for input in [
+                json!({}),
+                json!({"integers": null, "float": null}),
+                json!({"integers": [i64::MIN, i64::MAX, "9007199254740993.0", " +1_000.00 ", true, 3.0], "float": " 1.25 "}),
+                json!({"integers": [u64::MAX]}),
+                json!({"integers": ["1.0000000000000001"]}),
+                json!({"integers": [2.5]}),
+                json!({"float": "NaN"}),
+                json!({"float": "inf"}),
+                json!({"float": "1e999"}),
+                json!({"float": true}),
+                json!({"float": u64::MAX}),
+            ] {
+                let expected = serde_json::from_value::<Numbers>(input.clone());
+                let python = litellm_host_python::to_py(py, &input).unwrap();
+                let actual = from_py::<Numbers>(python.bind(py));
+                match (expected, actual) {
+                    (Ok(expected), Ok(actual)) => {
+                        assert_eq!(actual, expected);
+                        let serialized = litellm_host_python::to_py(py, &actual).unwrap();
+                        assert_eq!(
+                            from_py::<Value>(serialized.bind(py)).unwrap(),
+                            serde_json::to_value(expected).unwrap()
+                        );
+                    }
+                    (Err(_), Err(_)) => {}
+                    mismatch => panic!("boundary mismatch for {input}: {mismatch:?}"),
+                }
+            }
+            for source in [
+                c"{'float': float('nan')}",
+                c"{'float': float('inf')}",
+                c"{'integers': [float('inf')]}",
+                c"{'integers': [2 ** 100]}",
+            ] {
+                let value = py.eval(source, None, None).unwrap();
+                assert!(from_py::<Numbers>(&value).is_err());
+            }
+        });
+    }
+
     #[test]
     fn argument_converters_keep_nested_values_and_accept_explicit_none() {
         Python::initialize();

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

@@ -43,32 +43,204 @@ pub(crate) const CONTRACT: &str = include_str!("../python_settings.json");
 
 #[cfg(test)]
 mod tests {
-    use std::{collections::BTreeSet, ffi::CString};
-
-    use pyo3::{prelude::*, types::PyDict};
-
     use super::{CONTRACT, PythonSettings};
+    use pyo3::prelude::*;
+    use serde_json::{Value, json};
+
+    struct SettingSpec {
+        group: &'static str,
+        name: &'static str,
+        adapter: &'static str,
+        precedence: &'static str,
+        sensitive: bool,
+        shapes: &'static [&'static str],
+        unsupported_live: Option<&'static str>,
+    }
+
+    const SETTINGS: &[SettingSpec] = &[
+        SettingSpec {
+            group: "http_settings",
+            name: "ssl_verify",
+            adapter: "SslVerifyInput",
+            precedence: "module_global",
+            sensitive: false,
+            shapes: &["none", "bool", "str"],
+            unsupported_live: Some("configuration_error"),
+        },
+        SettingSpec {
+            group: "http_settings",
+            name: "ssl_certificate",
+            adapter: "OptionalStrictString",
+            precedence: "module_global",
+            sensitive: false,
+            shapes: &[],
+            unsupported_live: None,
+        },
+        SettingSpec {
+            group: "http_settings",
+            name: "ssl_security_level",
+            adapter: "TuningString",
+            precedence: "module_global",
+            sensitive: false,
+            shapes: &[],
+            unsupported_live: None,
+        },
+        SettingSpec {
+            group: "http_settings",
+            name: "ssl_ecdh_curve",
+            adapter: "TuningString",
+            precedence: "module_global",
+            sensitive: false,
+            shapes: &[],
+            unsupported_live: None,
+        },
+        SettingSpec {
+            group: "http_settings",
+            name: "force_ipv4",
+            adapter: "Truthy",
+            precedence: "module_global",
+            sensitive: false,
+            shapes: &[],
+            unsupported_live: None,
+        },
+        SettingSpec {
+            group: "http_settings",
+            name: "http2",
+            adapter: "ExactTrue",
+            precedence: "module_global",
+            sensitive: false,
+            shapes: &[],
+            unsupported_live: None,
+        },
+        SettingSpec {
+            group: "http_settings",
+            name: "aiohttp_trust_env",
+            adapter: "Truthy",
+            precedence: "module_global",
+            sensitive: false,
+            shapes: &[],
+            unsupported_live: None,
+        },
+        SettingSpec {
+            group: "http_settings",
+            name: "disable_aiohttp_trust_env",
+            adapter: "Truthy",
+            precedence: "module_global",
+            sensitive: false,
+            shapes: &[],
+            unsupported_live: None,
+        },
+        SettingSpec {
+            group: "http_settings",
+            name: "disable_aiohttp_transport",
+            adapter: "ExactTrue",
+            precedence: "module_global",
+            sensitive: false,
+            shapes: &[],
+            unsupported_live: None,
+        },
+        SettingSpec {
+            group: "http_settings",
+            name: "user_agent",
+            adapter: "StrictString",
+            precedence: "accessor",
+            sensitive: false,
+            shapes: &[],
+            unsupported_live: None,
+        },
+        SettingSpec {
+            group: "url_policy",
+            name: "user_url_validation",
+            adapter: "Truthy",
+            precedence: "module_global",
+            sensitive: false,
+            shapes: &[],
+            unsupported_live: None,
+        },
+        SettingSpec {
+            group: "url_policy",
+            name: "user_url_allowed_hosts",
+            adapter: "HostCollection",
+            precedence: "module_global",
+            sensitive: false,
+            shapes: &[],
+            unsupported_live: None,
+        },
+        SettingSpec {
+            group: "provider_defaults",
+            name: "vertex_project",
+            adapter: "FalsyOptionalString",
+            precedence: "module_global",
+            sensitive: true,
+            shapes: &[],
+            unsupported_live: None,
+        },
+        SettingSpec {
+            group: "provider_defaults",
+            name: "vertex_location",
+            adapter: "FalsyOptionalString",
+            precedence: "module_global",
+            sensitive: true,
+            shapes: &[],
+            unsupported_live: None,
+        },
+        SettingSpec {
+            group: "provider_defaults",
+            name: "enable_azure_ad_token_refresh",
+            adapter: "ExactTrue",
+            precedence: "module_global",
+            sensitive: false,
+            shapes: &[],
+            unsupported_live: None,
+        },
+        SettingSpec {
+            group: "secret_manager",
+            name: "readable",
+            adapter: "StrictBool",
+            precedence: "accessor",
+            sensitive: false,
+            shapes: &[],
+            unsupported_live: None,
+        },
+    ];
 
     #[test]
-    fn every_settings_group_is_in_the_python_contract() {
-        Python::initialize();
-        Python::attach(|py| {
-            let locals = PyDict::new(py);
-            locals.set_item("contract", CONTRACT).unwrap();
-            let source = CString::new("import json\nkeys = list(json.loads(contract))").unwrap();
-            py.run(&source, Some(&locals), Some(&locals)).unwrap();
-            let declared: BTreeSet<String> = locals
-                .get_item("keys")
+    fn settings_manifest_matches_the_semantic_contract() {
+        pyo3::Python::initialize();
+        let manifest: Value = pyo3::Python::attach(|py| {
+            let value = py
+                .import("json")
                 .unwrap()
-                .unwrap()
-                .extract::<Vec<String>>()
-                .unwrap()
-                .into_iter()
-                .collect();
-            let read: BTreeSet<String> = PythonSettings::ALL
-                .map(|group| group.name().to_owned())
-                .into();
-            assert_eq!(read, declared);
+                .call_method1("loads", (CONTRACT,))
+                .unwrap();
+            litellm_host_python::from_py(&value).unwrap()
         });
+        let expected: serde_json::Map<String, Value> = PythonSettings::ALL
+            .into_iter()
+            .map(|group| {
+                let fields: serde_json::Map<String, Value> = SETTINGS
+                    .iter()
+                    .filter(|spec| spec.group == group.name())
+                    .map(|spec| {
+                        (
+                            spec.name.to_owned(),
+                            json!({
+                                "adapter": spec.adapter,
+                                "required": true,
+                                "precedence": spec.precedence,
+                                "sensitive": spec.sensitive,
+                                "shapes": spec.shapes,
+                                "unsupported_live": spec.unsupported_live,
+                            }),
+                        )
+                    })
+                    .collect();
+                (
+                    group.name().to_owned(),
+                    json!({"version": 1, "fields": fields}),
+                )
+            })
+            .collect();
+        assert_eq!(manifest, Value::Object(expected));
     }
 }

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

@@ -19,7 +19,7 @@ use pyo3::{
     types::{PyDict, PyTuple},
 };
 
-use crate::{errors::RustBridgeDeclined, http, python_settings::PythonSettings};
+use crate::{coercion::Field, errors::RustBridgeDeclined, http, python_settings::PythonSettings};
 
 const SURFACE: LegacySurface = LegacySurface {
     call_type: "ocr",
@@ -51,7 +51,7 @@ fn run_ocr(
         ocr_settings(py)?,
         secrets,
     )
-    .map_err(|error| RustBridgeDeclined::new_err(error.to_string()))?;
+    .map_err(http::client_error)?;
     run_legacy_call(
         py,
         if asynchronous { ASYNC_SURFACE } else { SURFACE },
@@ -62,14 +62,8 @@ fn run_ocr(
     )
 }
 
-#[derive(FromPyObject)]
-struct PythonSecretManager {
-    readable: bool,
-}
-
 fn process_environment_secrets(secret_manager: &Bound<'_, PyAny>) -> PyResult<Secrets> {
-    let manager: PythonSecretManager = secret_manager.extract()?;
-    if manager.readable {
+    if Field::read(secret_manager, "secret_manager.readable")?.schema_bool()? {
         return Err(RustBridgeDeclined::new_err(
             "a readable secret manager is configured and the Rust route only reads the process environment",
         ));
@@ -77,26 +71,24 @@ fn process_environment_secrets(secret_manager: &Bound<'_, PyAny>) -> PyResult<Se
     Ok(Arc::new(ProcessEnvironment))
 }
 
-#[derive(FromPyObject)]
-struct PythonProviderDefaults {
-    vertex_project: Option<String>,
-    vertex_location: Option<String>,
-    enable_azure_ad_token_refresh: Option<bool>,
+fn ocr_settings(py: Python<'_>) -> PyResult<OcrSettings> {
+    project_provider_defaults(&PythonSettings::ProviderDefaults.read(py)?)
 }
 
-fn ocr_settings(py: Python<'_>) -> PyResult<OcrSettings> {
-    let defaults: PythonProviderDefaults = PythonSettings::ProviderDefaults
-        .read(py)?
-        .extract()
-        .map_err(|error: PyErr| {
-            RustBridgeDeclined::new_err(format!(
-                "litellm provider defaults cannot be used by the Rust route: {error}"
-            ))
-        })?;
+fn project_provider_defaults(value: &Bound<'_, PyAny>) -> PyResult<OcrSettings> {
     Ok(OcrSettings {
-        vertex_project: defaults.vertex_project,
-        vertex_location: defaults.vertex_location,
-        enable_azure_ad_token_refresh: defaults.enable_azure_ad_token_refresh == Some(true),
+        vertex_project: Field::read(value, "provider_defaults.vertex_project")?
+            .falsy_optional_string()?
+            .0,
+        vertex_location: Field::read(value, "provider_defaults.vertex_location")?
+            .falsy_optional_string()?
+            .0,
+        enable_azure_ad_token_refresh: Field::read(
+            value,
+            "provider_defaults.enable_azure_ad_token_refresh",
+        )?
+        .exact_true()
+        .0,
         ..OcrSettings::from_environment(&ProcessEnvironment)
     })
 }
@@ -140,6 +132,35 @@ mod tests {
         locals.get_item("manager").unwrap().unwrap()
     }
 
+    #[test]
+    fn provider_defaults_distinguish_falsey_values_and_exact_true() {
+        Python::initialize();
+        Python::attach(|py| {
+            let value = py.eval(c"__import__('types').SimpleNamespace(vertex_project=[], vertex_location=0, enable_azure_ad_token_refresh=1)", None, None).unwrap();
+            let projected = super::project_provider_defaults(&value).unwrap();
+            assert_eq!(projected.vertex_project, None);
+            assert_eq!(projected.vertex_location, None);
+            assert!(!projected.enable_azure_ad_token_refresh);
+            value.setattr("vertex_project", "project").unwrap();
+            value.setattr("vertex_location", "region").unwrap();
+            value
+                .setattr("enable_azure_ad_token_refresh", true)
+                .unwrap();
+            let next = super::project_provider_defaults(&value).unwrap();
+            assert_eq!(next.vertex_project.as_deref(), Some("project"));
+            assert_eq!(next.vertex_location.as_deref(), Some("region"));
+            assert!(next.enable_azure_ad_token_refresh);
+            value.setattr("vertex_project", 1).unwrap();
+            let error = super::project_provider_defaults(&value).err().unwrap();
+            assert!(error.is_instance_of::<pyo3::exceptions::PyValueError>(py));
+            assert!(
+                error
+                    .to_string()
+                    .contains("provider_defaults.vertex_project")
+            );
+        });
+    }
+
     #[test]
     fn a_readable_secret_manager_sends_the_call_back_to_python() {
         Python::initialize();

litellm/rust_bridge/settings.py

@@ -1,34 +1,33 @@
 from __future__ import annotations
 
-from collections.abc import Sequence
 from dataclasses import dataclass
 
 
 @dataclass(frozen=True, slots=True)
 class HttpSettings:
-    ssl_verify: bool | str
-    ssl_certificate: str | None
-    ssl_security_level: str | None
-    ssl_ecdh_curve: str | None
-    force_ipv4: bool
-    http2: bool
-    aiohttp_trust_env: bool
-    disable_aiohttp_trust_env: bool
-    disable_aiohttp_transport: bool
+    ssl_verify: object
+    ssl_certificate: object
+    ssl_security_level: object
+    ssl_ecdh_curve: object
+    force_ipv4: object
+    http2: object
+    aiohttp_trust_env: object
+    disable_aiohttp_trust_env: object
+    disable_aiohttp_transport: object
     user_agent: str
 
 
 @dataclass(frozen=True, slots=True)
 class UrlPolicy:
-    user_url_validation: bool
-    user_url_allowed_hosts: Sequence[str]
+    user_url_validation: object
+    user_url_allowed_hosts: object
 
 
 @dataclass(frozen=True, slots=True)
 class ProviderDefaults:
-    vertex_project: str | None
-    vertex_location: str | None
-    enable_azure_ad_token_refresh: bool | None
+    vertex_project: object
+    vertex_location: object
+    enable_azure_ad_token_refresh: object
 
 
 @dataclass(frozen=True, slots=True)

tests/test_litellm/rust_bridge/test_settings.py

@@ -6,6 +6,7 @@ from typing import Final
 import httpx
 import pytest
 from pydantic import TypeAdapter
+from typing_extensions import ReadOnly, TypedDict
 
 import litellm
 from litellm.integrations.custom_secret_manager import CustomSecretManager
@@ -17,14 +18,28 @@ from litellm.types.secret_managers.main import KeyManagementSettings, KeyManagem
 CONTRACT_PATH: Final = Path(__file__).parents[3] / "litellm-rust/crates/python-bridge/python_settings.json"
 
 
-def test_the_rust_contract_matches_the_returned_fields() -> None:
-    contract: Final = TypeAdapter(dict[str, list[str]]).validate_json(CONTRACT_PATH.read_text())
+class SettingSpec(TypedDict):
+    adapter: ReadOnly[str]
+    required: ReadOnly[bool]
+    precedence: ReadOnly[str]
+    sensitive: ReadOnly[bool]
+    shapes: ReadOnly[list[str]]
+    unsupported_live: ReadOnly[str | None]
 
-    assert contract == {
-        "http_settings": [field.name for field in dataclasses.fields(settings.http_settings())],
-        "url_policy": [field.name for field in dataclasses.fields(settings.url_policy())],
-        "provider_defaults": [field.name for field in dataclasses.fields(settings.provider_defaults())],
-        "secret_manager": [field.name for field in dataclasses.fields(settings.secret_manager())],
+
+class SettingsGroup(TypedDict):
+    version: ReadOnly[int]
+    fields: ReadOnly[dict[str, SettingSpec]]
+
+
+def test_the_rust_contract_matches_the_returned_fields() -> None:
+    contract: Final = TypeAdapter(dict[str, SettingsGroup]).validate_json(CONTRACT_PATH.read_text())
+
+    assert {name: tuple(group["fields"]) for name, group in contract.items()} == {
+        "http_settings": tuple(field.name for field in dataclasses.fields(settings.http_settings())),
+        "url_policy": tuple(field.name for field in dataclasses.fields(settings.url_policy())),
+        "provider_defaults": tuple(field.name for field in dataclasses.fields(settings.provider_defaults())),
+        "secret_manager": tuple(field.name for field in dataclasses.fields(settings.secret_manager())),
     }
 
 

tests/test_litellm_rust/ocr/test_requests.py

@@ -3,14 +3,13 @@ from collections.abc import Callable
 from dataclasses import dataclass
 from io import BytesIO
 from pathlib import Path
-from typing import Final
+from typing import Final, NoReturn
 
 import httpx
 import pytest
 from pydantic import JsonValue
 
 import litellm
-from litellm.llms.base_llm.ocr.transformation import OCRResponse
 from tests.test_litellm_rust.support.callback_recorder import RecordingLogger
 from tests.test_litellm_rust.support.recording_server import RecordingServer, ResponseSpec
 from tests.test_litellm_rust.support.requests import (
@@ -503,3 +502,150 @@ async def test_native_failures_raise_the_public_exception_class(
     assert len(ocr_server.requests) == failure.provider_requests
     if failure.cause is not None:
         assert isinstance(caught.value.__context__, failure.cause)
+
+
+@pytest.mark.asyncio
+@pytest.mark.parametrize("asynchronous", [False, True], ids=["sync", "async"])
+@pytest.mark.parametrize(
+    "name,value",
+    [
+        ("ssl_verify", object()),
+        ("ssl_certificate", 1),
+        ("ssl_certificate", ""),
+        ("vertex_project", 1),
+        ("vertex_location", ["region"]),
+        ("user_url_allowed_hosts", ["example.test", 1]),
+    ],
+)
+async def test_native_settings_fail_before_provider_io(
+    ocr_server: RecordingServer,
+    monkeypatch: pytest.MonkeyPatch,
+    asynchronous: bool,
+    name: str,
+    value: object,
+) -> None:
+    ocr_server.expected_requests = 0
+    monkeypatch.setattr(litellm, name, value)
+    with pytest.raises(ValueError, match=r"http_settings|provider_defaults|url_policy"):
+        await call_native(ocr_server, asynchronous, num_retries=0)
+    assert ocr_server.requests == []
+
+
+@pytest.mark.asyncio
+@pytest.mark.parametrize("asynchronous", [False, True], ids=["sync", "async"])
+async def test_native_ssl_context_is_terminal_configuration(ocr_server: RecordingServer, asynchronous: bool) -> None:
+    import ssl
+
+    ocr_server.expected_requests = 0
+    context: Final = ssl.SSLContext(ssl.PROTOCOL_TLS_CLIENT)
+    with pytest.raises(ValueError, match=r"request\.ssl_verify.*SSLContext"):
+        await call_native(ocr_server, asynchronous, ssl_verify=context, num_retries=0)
+    assert ocr_server.requests == []
+
+
+@pytest.mark.asyncio
+@pytest.mark.parametrize("asynchronous", [False, True], ids=["sync", "async"])
+async def test_native_settings_preserve_protocol_failures(
+    ocr_server: RecordingServer, monkeypatch: pytest.MonkeyPatch, asynchronous: bool
+) -> None:
+    ocr_server.expected_requests = 0
+    failure: Final = LookupError("settings truth test failed")
+    cause: Final = RuntimeError("settings cause")
+
+    class RaisesBool:
+        def __bool__(self) -> bool:
+            raise failure from cause
+
+    monkeypatch.setattr(litellm, "force_ipv4", RaisesBool())
+    with pytest.raises(LookupError) as caught:
+        await call_native(ocr_server, asynchronous, num_retries=0)
+    assert caught.value is failure
+    assert caught.value.__cause__ is cause
+    assert caught.value.__traceback__ is not None
+    assert ocr_server.requests == []
+
+
+@pytest.mark.asyncio
+@pytest.mark.parametrize("asynchronous", [False, True], ids=["sync", "async"])
+async def test_native_settings_observe_mutation_between_calls(
+    ocr_server: RecordingServer, monkeypatch: pytest.MonkeyPatch, asynchronous: bool
+) -> None:
+    monkeypatch.setattr(litellm, "force_ipv4", "yes")
+    monkeypatch.setattr(litellm, "http2", 1)
+    monkeypatch.setattr(litellm, "vertex_project", [])
+    monkeypatch.setattr(litellm, "vertex_location", 0)
+    monkeypatch.setattr(litellm, "user_url_allowed_hosts", "EXAMPLE.TEST.")
+    response: Final = await call_native(ocr_server, asynchronous, num_retries=0)
+    assert response.pages[0].markdown == "native OCR response"
+    assert_native_request(ocr_server)
+    monkeypatch.setattr(litellm, "ssl_certificate", 1)
+    with pytest.raises(ValueError, match=r"http_settings\.ssl_certificate"):
+        await call_native(ocr_server, asynchronous, num_retries=0)
+    assert len(ocr_server.requests) == 1
+
+
+@pytest.mark.parametrize("required", [False, True])
+@pytest.mark.parametrize("failure", ["invalid", "live", "schema"])
+def test_native_projection_errors_never_select_python(
+    ocr_server: RecordingServer, monkeypatch: pytest.MonkeyPatch, required: bool, failure: str
+) -> None:
+    import dataclasses
+    import ssl
+
+    from litellm.rust_bridge import runtime, settings
+    from litellm.rust_bridge.catalog import Context, Route, Rule
+    from litellm.rust_bridge.configuration import Rollout
+    from litellm.rust_bridge.ocr.entrypoints import NATIVE_OCR, LiteLLMOcrRequest
+
+    ocr_server.expected_requests = 0
+    snapshot: Final = dataclasses.replace(settings.http_settings(), user_agent=1)
+    if failure == "schema":
+        monkeypatch.setattr(settings, "http_settings", lambda: snapshot)
+    else:
+        monkeypatch.setattr(
+            litellm, "ssl_verify", ssl.SSLContext(ssl.PROTOCOL_TLS_CLIENT) if failure == "live" else object()
+        )
+    request: Final = LiteLLMOcrRequest(
+        model="mistral/mistral-ocr-latest",
+        document=OCR_DOCUMENT,
+        api_key="test-key",
+        api_base=ocr_server.base_url,
+        timeout=None,
+        custom_llm_provider="mistral",
+        extra_headers=None,
+        kwargs={},
+    )
+
+    def python_fallback() -> NoReturn:
+        pytest.fail("projection failures must not select Python")
+
+    with pytest.raises(RuntimeError if failure == "schema" else ValueError, match="http_settings"):
+        runtime.run(
+            Context(Route.OCR, provider="mistral"),
+            binding=NATIVE_OCR,
+            native=lambda native: native(request, (), {}),
+            python=python_fallback,
+            rules=(Rule(Route.OCR, Rollout.RUST_REQUIRED if required else Rollout.RUST_OPT_OUT),),
+        )
+    assert ocr_server.requests == []
+
+
+@pytest.mark.asyncio
+@pytest.mark.parametrize("asynchronous", [False, True], ids=["sync", "async"])
+@pytest.mark.parametrize("present", [False, True], ids=["missing", "invalid-pem"])
+async def test_native_client_certificate_is_validated_before_io(
+    ocr_server: RecordingServer,
+    monkeypatch: pytest.MonkeyPatch,
+    tmp_path: Path,
+    asynchronous: bool,
+    present: bool,
+) -> None:
+    ocr_server.expected_requests = 0
+    certificate: Final = tmp_path / "client.pem"
+    if present:
+        certificate.write_text("invalid certificate")
+    monkeypatch.setattr(litellm, "ssl_certificate", str(certificate))
+    with pytest.raises(ValueError, match=r"http_settings\.ssl_certificate.*PEM") as caught:
+        await call_native(ocr_server, asynchronous, num_retries=0)
+    assert str(certificate) not in str(caught.value)
+    assert ocr_server.requests == []