Merge 0e1ec44e35 into aedaf4d0b0

litellm/litellm_core_utils/prompt_templates/factory.py

@@ -3365,14 +3365,14 @@ class BedrockImageProcessor:
         return base64_bytes, content_type
 
     @staticmethod
-    async def get_image_details_async(image_url) -> tuple[str, str]:
+    async def get_image_details_async(image_url, max_bytes: int | None = None) -> tuple[str, str]:
         try:
             client: Final = get_async_httpx_client(
                 llm_provider=httpxSpecialProvider.PromptFactory,
                 params={"concurrent_limit": 1},
             )
             # Send a GET request to the image URL
-            response: Final[httpx.Response] = await async_safe_get(client, image_url)
+            response: Final[httpx.Response] = await async_safe_get(client, image_url, max_bytes=max_bytes)
             response.raise_for_status()  # Raise an exception for HTTP errors
 
             return BedrockImageProcessor._post_call_image_processing(response, image_url)
@@ -3553,13 +3553,20 @@ class BedrockImageProcessor:
         return cls._create_bedrock_block(img_bytes, mime_type, image_format)
 
     @classmethod
-    async def process_image_async(cls, image_url: str, format: str | None) -> BedrockContentBlock:
-        """Asynchronous image processing."""
+    async def process_image_async(
+        cls, image_url: str, format: str | None, max_bytes: int | None = None
+    ) -> BedrockContentBlock:
+        """Asynchronous image processing.
+
+        ``max_bytes`` caps a remote fetch and is ignored for a base64 data URI,
+        whose size the caller already knows before calling. Omitting it keeps the
+        previous unbounded fetch.
+        """
 
         if "base64" in image_url:
             img_bytes, mime_type, image_format = cls._parse_base64_image(image_url)
         elif "http://" in image_url or "https://" in image_url:
-            img_bytes, mime_type = await BedrockImageProcessor.get_image_details_async(image_url)
+            img_bytes, mime_type = await BedrockImageProcessor.get_image_details_async(image_url, max_bytes=max_bytes)
             image_format = mime_type.split("/")[1]
         else:
             raise ValueError("Unsupported image type. Expected either image url or base64 encoded string")

litellm/litellm_core_utils/url_utils.py

@@ -44,6 +44,14 @@ class SSRFError(ValueError):
     """Raised when a URL targets a blocked network."""
 
 
+class PayloadTooLargeError(ValueError):
+    """Raised when a fetched body exceeds the caller's byte cap.
+
+    A ``ValueError`` subclass, like :class:`SSRFError`, so callers that already
+    treat a malformed remote response as a rejected fetch need no new except arm.
+    """
+
+
 def encode_url_path_segment(value: Any, *, field_name: str = "path parameter") -> str:
     """Percent-encode one user-controlled URL path segment.
 
@@ -412,21 +420,88 @@ def safe_get(client: Any, url: str, **kwargs: Any) -> Any:
     raise SSRFError("Too many redirects")
 
 
-async def async_safe_get(client: Any, url: str, **kwargs: Any) -> Any:
-    """Async version of safe_get."""
+# Headers that describe the wire encoding of the body. `aiter_bytes` yields
+# decoded bytes, so carrying these onto the rebuilt response would describe it
+# wrongly (a gzip label on already-inflated bytes, a length from before decoding).
+_TRANSFER_ENCODING_HEADERS: Final = frozenset({"content-encoding", "content-length"})
+
+
+def _underlying_httpx_client(client: object) -> httpx.AsyncClient:
+    """Return the object exposing ``stream``.
+
+    ``AsyncHTTPHandler``/``HTTPHandler`` wrap an httpx client and forward only
+    ``get``/``post``/..., so streaming has to go through the wrapped ``.client``.
+    A raw httpx client is returned unchanged.
+    """
+    inner: Final = getattr(client, "client", client)
+    if not isinstance(inner, httpx.AsyncClient):
+        raise TypeError(f"cannot stream from {type(client).__name__}: no httpx client to stream with")
+    return inner
+
+
+async def _async_get_capped(
+    client: object,
+    url: str,
+    max_bytes: int,
+    request_kwargs: dict[str, object],  # mutable-ok: forwarded straight to httpx as **kwargs
+) -> httpx.Response:
+    """GET ``url``, aborting the transfer once the body exceeds ``max_bytes``.
+
+    ``client.get`` buffers the whole body before returning, so a caller-supplied
+    URL serving an arbitrarily large or indefinitely chunked response is an
+    unbounded allocation. Streaming makes the cap effective during the transfer
+    rather than after it.
+
+    Returns a fully-read response so callers keep using ``.content`` as before.
+    """
+    async with _underlying_httpx_client(client).stream("GET", url, **request_kwargs) as response:
+        chunks: list[bytes] = []  # mutable-ok: accumulator for the capped body
+        total = 0
+        async for chunk in response.aiter_bytes():
+            total += len(chunk)
+            if total > max_bytes:
+                raise PayloadTooLargeError(f"remote body exceeds {max_bytes} bytes")
+            chunks.append(chunk)
+    kept_headers: Final = [  # mutable-ok: httpx.Response takes the header pairs as a list
+        (k, v) for k, v in response.headers.multi_items() if k.lower() not in _TRANSFER_ENCODING_HEADERS
+    ]
+    return httpx.Response(
+        status_code=response.status_code,
+        headers=kept_headers,
+        content=b"".join(chunks),
+        request=response.request,
+    )
+
+
+async def async_safe_get(client: Any, url: str, max_bytes: int | None = None, **kwargs: Any) -> Any:
+    """Async version of safe_get.
+
+    ``max_bytes`` caps the response body, rejecting an oversized transfer with
+    :class:`PayloadTooLargeError` while it is still in flight. Omitting it keeps
+    the previous unbounded buffering, so existing callers are unaffected.
+    """
+
+    async def _issue(
+        target_url: str,
+        request_kwargs: dict[str, object],  # mutable-ok: forwarded straight to httpx as **kwargs
+    ) -> httpx.Response:
+        if max_bytes is None:
+            return await client.get(target_url, **request_kwargs)
+        return await _async_get_capped(client, target_url, max_bytes, request_kwargs)
+
     if not getattr(litellm, "user_url_validation", True):
         kwargs.setdefault("follow_redirects", True)
-        return await client.get(url, **kwargs)
+        return await _issue(url, kwargs)
     kwargs.pop("follow_redirects", None)
     caller_headers: Final = kwargs.pop("headers", {})
     for _ in range(_MAX_REDIRECTS):
         validated_url, original_host = validate_url(url)
-        response = await client.get(
-            validated_url,
-            headers={**caller_headers, "Host": original_host},
-            follow_redirects=False,
+        hop_kwargs: dict[str, object] = {  # mutable-ok: a fresh per-hop kwargs dict, consumed by this call
             **kwargs,
-        )
+            "headers": {**caller_headers, "Host": original_host},  # mutable-ok: httpx takes headers as a dict
+            "follow_redirects": False,
+        }
+        response = await _issue(validated_url, hop_kwargs)
         if not response.is_redirect:
             return response
         # Resolve the next hop against the ORIGINAL (pre-rewrite) URL so

litellm/llms/anthropic/chat/guardrail_translation/handler.py

@@ -788,12 +788,40 @@ class AnthropicMessagesHandler(BaseTranslation):
 
     @staticmethod
     def _image_sources(block: Mapping[str, object]) -> tuple[str, ...]:
+        """Normalize an Anthropic image block into strings a guardrail can read.
+
+        `source` is one of three shapes (types/llms/anthropic.py:259):
+
+            {"type": "base64", "media_type": "image/png", "data": "<b64>"}
+            {"type": "url",    "url": "https://..."}
+            {"type": "file",   "file_id": "..."}
+
+        base64 is returned as a data URI rather than the bare payload: consumers of
+        ``GenericGuardrailAPIInputs["images"]`` otherwise have no way to know the
+        format, and an API like Bedrock's ApplyGuardrail requires it. url is passed
+        through so the consumer can fetch it under its own SSRF policy.
+
+        file is not resolvable here (the bytes live behind the Files API), so it
+        yields nothing. That is a silent gap for any consumer that treats a missing
+        entry as "no image to scan"; scanning a file_id needs a fetch this extractor
+        has no client for.
+        """
         source: Final = block.get("source")
         if not isinstance(source, Mapping):
             return ()
-        # Could be base64 or url
+
+        source_type: Final = source.get("type")
+        if source_type == "url":
+            url: Final = source.get("url")
+            return (url,) if isinstance(url, str) and url else ()
+
         data: Final = source.get("data")
-        return (data,) if data else ()
+        if not isinstance(data, str) or not data:
+            return ()
+        media_type: Final = source.get("media_type")
+        if isinstance(media_type, str) and media_type:
+            return (f"data:{media_type};base64,{data}",)
+        return (data,)
 
     async def _apply_guardrail_responses_to_input(
         self,

litellm/proxy/guardrails/guardrail_hooks/bedrock_guardrails.py

@@ -10,6 +10,7 @@ import sys
 
 sys.path.insert(0, os.path.abspath("../.."))  # Adds the parent directory to the system path
 import asyncio
+import binascii
 import copy
 import json
 import re
@@ -32,6 +33,8 @@ from litellm.exceptions import ModifyResponseException
 from litellm.integrations.custom_guardrail import CustomGuardrail
 from litellm.litellm_core_utils.core_helpers import redact_nested_match_and_regex_keys
 from litellm.litellm_core_utils.llm_cost_calc.guardrail_cost import bedrock_guardrail_cost
+from litellm.litellm_core_utils.prompt_templates.factory import BedrockImageProcessor
+from litellm.litellm_core_utils.url_utils import PayloadTooLargeError, SSRFError
 from litellm.llms.anthropic.chat.guardrail_translation.handler import AnthropicMessagesHandler
 from litellm.llms.base_llm.guardrail_translation.utils import (
     effective_scan_only_tool_results_for_guardrail,
@@ -53,16 +56,24 @@ from litellm.proxy.guardrails.anthropic_sse import (
 )
 from litellm.secret_managers.main import get_secret_str
 from litellm.types.guardrails import BedrockChecksConfigModel, GuardrailEventHooks
-from litellm.types.llms.openai import AllMessageValues, ChatCompletionUserMessage
+from litellm.types.llms.openai import (
+    AllMessageValues,
+    ChatCompletionImageObject,
+    ChatCompletionImageUrlObject,
+    ChatCompletionUserMessage,
+)
 from litellm.types.proxy.guardrails.guardrail_hooks.bedrock_guardrails import (
     BedrockChecksMessage,
     BedrockChecksViolation,
     BedrockContentItem,
     BedrockGuardrailChecksResponse,
+    BedrockGuardrailImageFormat,
+    BedrockGuardrailImageSource,
     BedrockGuardrailOutput,
     BedrockGuardrailQualifier,
     BedrockGuardrailResponse,
     BedrockGuardrailUsage,
+    BedrockImageContent,
     BedrockRequest,
     BedrockTextContent,
 )
@@ -133,6 +144,27 @@ _CONTENT_TYPE_TO_QUALIFIER: Final[dict[str, BedrockGuardrailQualifier]] = {
 # must not be graded against as if it were the application's own source material.
 _GROUNDING_SOURCE_TRUSTED_ROLES: Final = frozenset({"system", "developer"})
 
+# ApplyGuardrail only accepts png/jpeg image blocks. Anything else (gif, webp, ...)
+# has no representation in the payload, so it cannot be scanned at all.
+# AWS's hard limits for image content filters:
+# https://docs.aws.amazon.com/bedrock/latest/userguide/guardrails-mmfilter.html
+#   4 MB per image, 20 images per request, 8000x8000, PNG/JPEG only, 25 images/second,
+#   and only the first 100 words of text inside an image are evaluated.
+# Nothing in litellm checked these. BEDROCK_APPLY_GUARDRAIL_CHUNK_BUDGET_CHARS is the
+# text-side quota and says nothing about images, and the strings
+# _BEDROCK_TOO_LARGE_ERROR_SUBSTRINGS matches are all text-shaped, so an image-count
+# rejection would not even reach the chunking fallback.
+_MAX_IMAGE_BYTES: Final = 4 * 1024 * 1024
+_MAX_IMAGES_PER_APPLY_GUARDRAIL_CALL: Final = 20
+
+_APPLY_GUARDRAIL_IMAGE_FORMATS: Final[
+    dict[str, BedrockGuardrailImageFormat]
+] = {  # mutable-ok: module-level lookup table, never mutated
+    "png": "png",
+    "jpeg": "jpeg",
+    "jpg": "jpeg",
+}
+
 
 class QualifiedTextBlock(NamedTuple):
     """A piece of message text paired with its Bedrock grounding qualifier (if any)."""
@@ -221,6 +253,7 @@ class BedrockGuardrail(CustomGuardrail, BaseAWSLLM):
         prompt_attack_threshold: float | None = 0.5,
         pii_confidence_threshold: float | None = 0.5,
         chunk_budget_chars: int = BEDROCK_APPLY_GUARDRAIL_CHUNK_BUDGET_CHARS,
+        on_unscannable_image: Literal["block", "allow"] = "block",
         **kwargs,
     ):
         self.async_handler = get_async_httpx_client(llm_provider=httpxSpecialProvider.GuardrailCallback)
@@ -229,6 +262,10 @@ class BedrockGuardrail(CustomGuardrail, BaseAWSLLM):
         self.guardrail_provider = "bedrock"
         self.chunk_budget_chars = chunk_budget_chars
         self.experimental_use_latest_role_message_only = bool(kwargs.get("experimental_use_latest_role_message_only"))
+        # What to do with an image part ApplyGuardrail cannot scan (non png/jpeg, or a
+        # remote url we refuse to fetch). Defaults to blocking: the image reaches the
+        # model regardless, so allowing it would be a silent guardrail bypass.
+        self.on_unscannable_image: Literal["block", "allow"] = on_unscannable_image
 
         # Resource-less, detect-only InvokeGuardrailChecks mode. Present `checks`
         # routes the guardrail to InvokeGuardrailChecks; absent => ApplyGuardrail.
@@ -316,28 +353,180 @@ class BedrockGuardrail(CustomGuardrail, BaseAWSLLM):
             )
         return cleaned or None
 
-    def _create_bedrock_input_content_request(self, messages: list[AllMessageValues] | None) -> BedrockRequest:
-        """
-        Create a bedrock request for the input content - the LLM request.
-        """
+    async def _create_bedrock_input_content_request(self, messages: list[AllMessageValues] | None) -> BedrockRequest:
+        """Create a bedrock request for the input content - the LLM request."""
         bedrock_request: Final[BedrockRequest] = BedrockRequest(source="INPUT")
-        bedrock_request_content: Final[list[BedrockContentItem]] = []
         if messages is None:
             return bedrock_request
-        for message in messages:
-            blocks = self.get_content_items_for_message(message=message)
-            if blocks is None:
-                continue
-            for block in blocks:
-                # INPUT scans send plain text only. Grounding qualifiers are attached
-                # exclusively when assembling the OUTPUT request, so a caller cannot use
-                # a grounding_source/query tag to change how input-safety policies treat
-                # their content (which would be an input-guardrail bypass).
-                bedrock_request_content.append(BedrockContentItem(text=BedrockTextContent(text=block.text)))
 
-        bedrock_request["content"] = bedrock_request_content
+        per_message = await asyncio.gather(*(self._build_input_content_items(message=message) for message in messages))
+        # mutable-ok: BedrockRequest["content"] is a list in the AWS wire format
+        bedrock_request["content"] = [item for items in per_message for item in items]
         return bedrock_request
 
+    async def _build_input_content_items(self, message: AllMessageValues) -> tuple[BedrockContentItem, ...]:
+        """Flatten one request message into ApplyGuardrail INPUT content items.
+
+        Grounding qualifiers are attached only when assembling the OUTPUT request, so a
+        grounding_source/query tag cannot change how input-safety policies treat content
+        """
+        content = message.get("content")
+        if content is None:
+            return ()
+        if isinstance(content, str):
+            return (BedrockContentItem(text=BedrockTextContent(text=content)),)
+        if not isinstance(content, list):
+            return ()
+        parts: Final = cast(  # cast-ok: AllMessageValues content is a union of part TypedDicts
+            tuple[object, ...], tuple(content)
+        )
+        items: Final = await asyncio.gather(*(self._build_input_content_item(item=item) for item in parts))
+        return tuple(item for item in items if item is not None)
+
+    async def _build_input_content_item(self, item: object) -> BedrockContentItem | None:
+        if isinstance(item, str):
+            return BedrockContentItem(text=BedrockTextContent(text=item))
+        if not isinstance(item, dict):
+            return None
+        part: Final = cast(Mapping[str, object], item)  # cast-ok: narrowed to dict on the line above
+        # Provider transformations branch on `type`, so an image_url part reaches the
+        # model as an image even when it also carries `text`. Reading `text` first would
+        # scan that decoy and forward the image unscanned
+        if part.get("type") == "image_url":
+            image_url: Final = self._get_image_url(item=part)
+            if image_url is None:
+                return None
+            return await self._build_image_content_item(image_url=image_url)
+        text: Final = part.get("text")
+        if isinstance(text, str):
+            return BedrockContentItem(text=BedrockTextContent(text=text))
+        return None
+
+    @staticmethod
+    def _get_image_url(item: Mapping[str, object]) -> str | None:
+        if item.get("type") != "image_url":
+            return None
+        image_url: Final = item.get("image_url")
+        if isinstance(image_url, str):
+            return image_url
+        if isinstance(image_url, dict):
+            url: Final = cast(Mapping[str, object], image_url).get("url")  # cast-ok: narrowed to dict on the line above
+            return url if isinstance(url, str) else None
+        return None
+
+    def _handle_unscannable_image(self, reason: str) -> None:
+        """Block or warn for an image part ApplyGuardrail cannot scan.
+
+        The image reaches the model either way, so skipping it silently would let a
+        caller defeat an IMAGE-modality guardrail by picking a format the API rejects
+        """
+        if self.on_unscannable_image == "block":
+            raise HTTPException(
+                status_code=400,
+                detail={  # mutable-ok: HTTPException detail payload, serialized immediately
+                    "error": "Violated guardrail policy",
+                    "bedrock_guardrail_response": (
+                        f"Request contains an image the guardrail cannot scan ({reason}). "
+                        "ApplyGuardrail accepts png/jpeg images only. Set "
+                        "'on_unscannable_image: allow' on this guardrail to send such "
+                        "requests to the model unscanned."
+                    ),
+                    "guardrail_name": self.guardrail_name,
+                },
+            )
+        verbose_proxy_logger.warning(
+            "Bedrock Guardrail %s: image part will not be scanned (%s); on_unscannable_image=allow, forwarding it to the model anyway",
+            self.guardrail_name,
+            reason,
+        )
+
+    #: base64 magic-byte prefixes for the formats ApplyGuardrail accepts.
+    _BASE64_IMAGE_PREFIXES: ClassVar[tuple[tuple[str, str], ...]] = (
+        ("iVBORw0KGgo", "image/png"),
+        ("/9j/", "image/jpeg"),
+    )
+
+    @staticmethod
+    def _image_content_part(url: str) -> ChatCompletionImageObject:
+        """One OpenAI-format image content part, so the payload builder handles it."""
+        return ChatCompletionImageObject(type="image_url", image_url=ChatCompletionImageUrlObject(url=url))
+
+    @classmethod
+    def _normalize_image_input(cls, value: str) -> str:
+        """Return a data URI or URL that `_build_image_content_item` can consume.
+
+        `GenericGuardrailAPIInputs["images"]` is not a single shape. The OpenAI chat
+        translation appends the caller's `image_url` verbatim, so entries are already a
+        `data:` URI or an `https://` URL. The Anthropic translation's `_image_sources`
+        returns `source["data"]` only, which is bare base64 with the `media_type`
+        dropped. Sniff the format back from the base64 prefix so both shapes reach the
+        same decoder instead of the bare-base64 one failing as unreadable.
+        """
+        if value.startswith(("data:", "http://", "https://")):
+            return value
+        for prefix, media_type in cls._BASE64_IMAGE_PREFIXES:
+            if value.startswith(prefix):
+                return f"data:{media_type};base64,{value}"
+        # Unrecognized: hand it over as-is and let the decoder reject it, so the
+        # on_unscannable_image policy decides rather than this helper.
+        return value
+
+    async def _build_image_content_item(self, image_url: str) -> BedrockContentItem | None:
+        """Decode or fetch an image part into an ApplyGuardrail image block.
+
+        With `user_url_validation` off, `async_safe_get` degrades to an unrestricted,
+        redirect-following GET on a caller-supplied URL, so it is not fetched at all
+        """
+        if not image_url.startswith("data:") and not getattr(litellm, "user_url_validation", True):
+            self._handle_unscannable_image(
+                reason=f"remote image url not fetched because litellm.user_url_validation is disabled: {image_url}"
+            )
+            return None
+
+        try:
+            # Cap the fetch itself. The decoded-size check below runs after the
+            # bytes are already resident, so on its own it does not stop a caller
+            # from pointing the proxy at an arbitrarily large or chunked response
+            # -- and `_build_input_content_items` gathers these concurrently, so
+            # one request with several URLs multiplies the allocation.
+            block: Final = await BedrockImageProcessor.process_image_async(
+                image_url=image_url, format=None, max_bytes=_MAX_IMAGE_BYTES
+            )
+        except PayloadTooLargeError as e:
+            # Named before the ValueError arm it subclasses, so the operator sees
+            # "too large" rather than "could not be read" for a size rejection.
+            self._handle_unscannable_image(reason=f"remote image over ApplyGuardrail's 4 MB limit: {e}")
+            return None
+        except (httpx.HTTPError, SSRFError, ValueError, TypeError, KeyError, binascii.Error) as e:
+            self._handle_unscannable_image(reason=f"image content could not be read: {e}")
+            return None
+
+        image_block: Final = block.get("image")
+        image_format: Final = (
+            _APPLY_GUARDRAIL_IMAGE_FORMATS.get(str(image_block.get("format"))) if image_block else None
+        )
+        # mutable-ok: {} is an empty default for .get, never mutated
+        image_bytes: Final = image_block.get("source", {}).get("bytes") if image_block else None
+        if image_format is None or not image_bytes:
+            self._handle_unscannable_image(reason="attachment is not a png/jpeg image")
+            return None
+
+        # base64 decodes to roughly 3/4 of its length; estimate rather than decode the
+        # whole image a second time just to measure it.
+        decoded_size: Final = len(image_bytes) * 3 // 4
+        if decoded_size > _MAX_IMAGE_BYTES:
+            self._handle_unscannable_image(
+                reason=f"image is {decoded_size / 1024 / 1024:.1f} MB, over ApplyGuardrail's 4 MB limit"
+            )
+            return None
+
+        return BedrockContentItem(
+            image=BedrockImageContent(
+                format=image_format,
+                source=BedrockGuardrailImageSource(bytes=image_bytes),
+            )
+        )
+
     def _create_bedrock_output_content_request(
         self,
         response: Any | ModelResponse,
@@ -386,7 +575,7 @@ class BedrockGuardrail(CustomGuardrail, BaseAWSLLM):
                 items.append(self._build_content_item(block))
         return items
 
-    def convert_to_bedrock_format(
+    async def convert_to_bedrock_format(
         self,
         source: Literal["INPUT", "OUTPUT"],
         messages: list[AllMessageValues] | None = None,
@@ -403,7 +592,7 @@ class BedrockGuardrail(CustomGuardrail, BaseAWSLLM):
         """
         bedrock_request: BedrockRequest = BedrockRequest(source=source)
         if source == "INPUT":
-            bedrock_request = self._create_bedrock_input_content_request(messages=messages)
+            bedrock_request = await self._create_bedrock_input_content_request(messages=messages)
         elif source == "OUTPUT":
             bedrock_request = self._create_bedrock_output_content_request(response=response, messages=messages)
         return bedrock_request
@@ -839,7 +1028,7 @@ class BedrockGuardrail(CustomGuardrail, BaseAWSLLM):
         """
         start_time: Final = datetime.now(timezone.utc)
         bedrock_request_data: Final[dict] = dict(
-            self.convert_to_bedrock_format(source=source, messages=messages, response=response)
+            await self.convert_to_bedrock_format(source=source, messages=messages, response=response)
         )
         api_key: str | None = None
         if request_data:
@@ -955,7 +1144,48 @@ class BedrockGuardrail(CustomGuardrail, BaseAWSLLM):
         guardrail block on any (sub-)chunk raises immediately
         -- callers must not lose that signal by continuing to post the remaining
         chunks.
+
+        Images are the one case split up front rather than reactively. Chunking here
+        is a recovery path: the content goes out as a single call and is only
+        re-batched once AWS rejects it AND `_is_input_too_large_error` matches. Those
+        substrings ("text unit", "too long", ...) are all text-shaped, so a rejection
+        for exceeding 20 images per request may never reach this fallback at all, and
+        bisection cannot rescue it either -- `_split_bedrock_content` reads
+        `item["text"]` to halve a lone item, which is empty for an image, so it gives
+        up and re-raises the original error. Splitting before the first call keeps a
+        many-image request inside the documented limit instead.
         """
+        image_count: Final = sum(1 for item in content if "image" in item)
+        if allow_chunking and image_count > _MAX_IMAGES_PER_APPLY_GUARDRAIL_CALL:
+            preemptive_batches: Final = self._bin_pack_bedrock_content(content, budget=self.chunk_budget_chars)
+            if len(preemptive_batches) > 1:
+                verbose_proxy_logger.warning(
+                    "Bedrock Guardrail: %d image(s) exceeds ApplyGuardrail's limit of %d per request; "
+                    "splitting into %d calls before sending",
+                    image_count,
+                    _MAX_IMAGES_PER_APPLY_GUARDRAIL_CALL,
+                    len(preemptive_batches),
+                )
+                preemptive_results: Final = [  # mutable-ok: await needs a list comprehension; frozen to a tuple below
+                    await self._apply_guardrail_content_with_chunking(
+                        content=batch,
+                        base_request_data=base_request_data,
+                        credentials=credentials,
+                        aws_region_name=aws_region_name,
+                        api_key=api_key,
+                        request_data=request_data,
+                        event_type=event_type,
+                        start_time=start_time,
+                        # Safe to keep enabled: every batch _bin_pack_bedrock_content
+                        # returns holds at most 20 images, so the recursive call falls
+                        # straight through this branch and text chunking still applies.
+                        allow_chunking=allow_chunking,
+                        completed_chunk_usages=completed_chunk_usages,
+                    )
+                    for batch in preemptive_batches
+                ]
+                return tuple(result for results in preemptive_results for result in results)
+
         try:
             response: Final = await self._post_apply_guardrail_content_with_retry(
                 content=content,
@@ -1347,15 +1577,27 @@ class BedrockGuardrail(CustomGuardrail, BaseAWSLLM):
         if not content:
             return (tuple(content),)
 
-        lengths: Final = tuple(len((item.get("text") or BedrockTextContent()).get("text") or "") for item in content)
+        # An image item has no `text`, so it measures 0 against `budget` and
+        # `used + 0 <= budget` always holds: without a second dimension every image
+        # lands in whichever batch is open, however many there are. That measurement
+        # was complete when a content item could only be text. Packing also has to
+        # respect ApplyGuardrail's limit of 20 images per request, which is a count
+        # rather than a character budget, so the two are carried separately: image
+        # bytes are deliberately not charged against `budget`, which is the text-unit
+        # quota.
+        measured: Final = tuple(
+            (len((item.get("text") or BedrockTextContent()).get("text") or ""), 1 if "image" in item else 0)
+            for item in content
+        )
 
-        def assign(carried: tuple[int, int], length: int) -> tuple[int, int]:
-            batch_index, used = carried
-            if used + length <= budget:
-                return batch_index, used + length
-            return batch_index + 1, length
+        def assign(carried: tuple[int, int, int], item: tuple[int, int]) -> tuple[int, int, int]:
+            batch_index, used, images = carried
+            length, is_image = item
+            if used + length <= budget and images + is_image <= _MAX_IMAGES_PER_APPLY_GUARDRAIL_CALL:
+                return batch_index, used + length, images + is_image
+            return batch_index + 1, length, is_image
 
-        batch_numbers: Final = (index for index, _ in tuple(accumulate(lengths, assign, initial=(0, 0)))[1:])
+        batch_numbers: Final = (index for index, _, _ in tuple(accumulate(measured, assign, initial=(0, 0, 0)))[1:])
         return tuple(
             tuple(item for _, item in group)
             for _, group in groupby(zip(batch_numbers, content), key=lambda pair: pair[0])
@@ -2880,6 +3122,8 @@ class BedrockGuardrail(CustomGuardrail, BaseAWSLLM):
                     masking_index += 1
                 if item is not None:
                     new_content.append(item)
+            else:
+                new_content.append(item)
 
         return new_content, masking_index
 
@@ -3047,7 +3291,8 @@ class BedrockGuardrail(CustomGuardrail, BaseAWSLLM):
             logging_obj: Optional logging object
 
         Returns:
-            GenericGuardrailAPIInputs - processed_texts may be masked, images unchanged
+            GenericGuardrailAPIInputs - processed_texts may be masked, images are
+            scanned but returned unchanged (ApplyGuardrail does not rewrite images)
 
         Raises:
             Exception: If content is blocked by Bedrock guardrail
@@ -3055,10 +3300,24 @@ class BedrockGuardrail(CustomGuardrail, BaseAWSLLM):
         # NOTE: Use `or []` to handle case where inputs["texts"] is explicitly None.
         # dict.get("texts", []) would return None if the key exists with a None value.
         texts: Final = inputs.get("texts") or []
+        # Images only exist on the request side; ApplyGuardrail's OUTPUT source takes
+        # model-generated text. The endpoint translations already extract them:
+        # OpenAIChatCompletionsHandler from `image_url` parts, AnthropicMessagesHandler
+        # from `image`/`source` blocks. Five other guardrails already consume this
+        # field; Bedrock was the one that dropped it on the floor.
+        image_urls: Final = tuple(inputs.get("images") or ()) if input_type == "request" else ()
         try:
-            verbose_proxy_logger.debug("Bedrock Guardrail: Applying guardrail to %s text(s)", len(texts))
+            verbose_proxy_logger.debug(
+                "Bedrock Guardrail: Applying guardrail to %s text(s) and %s image(s)", len(texts), len(image_urls)
+            )
 
-            if input_type == "request":
+            # Both of the optimizations below decide what to scan by looking at
+            # `texts` alone, so an image rides along unscanned and the proxy still
+            # reports the guardrail as run. Neither tracks images in its session
+            # cache either, so "already seen" cannot be established for them.
+            # Presence of an image therefore forces the full image-aware path:
+            # correctness over the optimization, and it fails closed.
+            if input_type == "request" and not image_urls:
                 incremental_result: Final = await self._apply_incremental_request_scan(
                     texts=texts,
                     inputs=inputs,
@@ -3075,14 +3334,17 @@ class BedrockGuardrail(CustomGuardrail, BaseAWSLLM):
                 request_data=request_data,
                 input_type=input_type,
             )
-            if selection.skip_scan:
+            # `experimental_use_latest_role_message_only` marks a latest message with
+            # no text as skip_scan; an image-only message is exactly that shape.
+            if selection.skip_scan and not image_urls:
                 return inputs
             filtered_messages: Final = selection.filtered_messages
             scanned_slice: Final = selection.scanned_slice
             scanned_role_subset: Final = selection.scanned_role_subset
 
-            # Bedrock will throw an error if there is no text to process
-            if filtered_messages:
+            # Bedrock rejects an empty content list, so only skip when there is
+            # neither text nor an image to scan.
+            if filtered_messages or image_urls:
                 _log_hook = GuardrailEventHooks.pre_call if input_type == "request" else GuardrailEventHooks.post_call
                 # Map the abstract input_type to the Bedrock source parameter.
                 # "request"  -> INPUT  (scan user-supplied content)
@@ -3115,9 +3377,26 @@ class BedrockGuardrail(CustomGuardrail, BaseAWSLLM):
                         logging_event_type=_log_hook,
                     )
                 else:
+                    # Append the images as one extra user message. Reusing the normal
+                    # message path means `_create_bedrock_input_content_request` does the
+                    # decoding, format check and on_unscannable_image handling, so the
+                    # unified and native lifecycle paths cannot drift apart.
+                    image_parts: Final = [  # mutable-ok: OpenAI message content is a list in the wire format
+                        self._image_content_part(self._normalize_image_input(url)) for url in image_urls
+                    ]
+                    image_message: Final = (
+                        (ChatCompletionUserMessage(role="user", content=image_parts),) if image_parts else ()
+                    )
+                    # `filtered_messages` is Optional; the guard above only proves one of
+                    # it and `image_urls` is truthy, so it can still be None here when the
+                    # request carries an image and no text.
+                    scan_messages: Final = [  # mutable-ok: make_bedrock_api_request takes a list of messages
+                        *(filtered_messages or ()),
+                        *image_message,
+                    ]
                     bedrock_response = await self.make_bedrock_api_request(
                         source="INPUT",
-                        messages=filtered_messages,
+                        messages=scan_messages,
                         request_data=request_data,
                         logging_event_type=_log_hook,
                     )

litellm/proxy/guardrails/guardrail_initializers.py

@@ -21,6 +21,7 @@ def initialize_bedrock(litellm_params: LitellmParams, guardrail: Guardrail):
         prompt_attack_threshold=litellm_params.prompt_attack_threshold,
         pii_confidence_threshold=litellm_params.pii_confidence_threshold,
         chunk_budget_chars=litellm_params.chunk_budget_chars,
+        on_unscannable_image=litellm_params.on_unscannable_image,
         default_on=litellm_params.default_on,
         disable_exception_on_block=litellm_params.disable_exception_on_block,
         mask_request_content=litellm_params.mask_request_content,

litellm/types/guardrails.py

@@ -535,6 +535,13 @@ class BedrockGuardrailConfigModel(BaseModel):
         "still rejects is bisected automatically, so this value only trades round trips against "
         "batch size and cannot fail a request on its own.",
     )
+    on_unscannable_image: Literal["block", "allow"] = Field(
+        default="block",
+        description="What to do with an image the guardrail cannot scan - ApplyGuardrail "
+        "accepts png/jpeg only, and remote image URLs are not fetched while "
+        "litellm.user_url_validation is disabled. 'block' (default) rejects the request; "
+        "'allow' logs a warning and sends the image to the model unscanned.",
+    )
 
 
 class LakeraV2GuardrailConfigModel(BaseModel):

litellm/types/proxy/guardrails/guardrail_hooks/bedrock_guardrails.py

@@ -1,6 +1,6 @@
 from typing import Literal
 
-from typing_extensions import TypedDict
+from typing_extensions import ReadOnly, TypedDict
 
 # Bedrock contextual grounding tags each content block so the guardrail knows
 # which text is the reference source, the user question, and the content to grade.
@@ -12,8 +12,21 @@ class BedrockTextContent(TypedDict, total=False):
     qualifiers: list[BedrockGuardrailQualifier]
 
 
+BedrockGuardrailImageFormat = Literal["png", "jpeg"]
+
+
+class BedrockGuardrailImageSource(TypedDict, total=False):
+    bytes: ReadOnly[str]
+
+
+class BedrockImageContent(TypedDict, total=False):
+    format: ReadOnly[BedrockGuardrailImageFormat]
+    source: ReadOnly[BedrockGuardrailImageSource]
+
+
 class BedrockContentItem(TypedDict, total=False):
     text: BedrockTextContent
+    image: ReadOnly[BedrockImageContent]
 
 
 class BedrockRequest(TypedDict, total=False):

tests/guardrails_tests/test_bedrock_guardrails.py

@@ -945,7 +945,7 @@ async def test_convert_to_bedrock_format_input_source():
     ]
 
     # Call the method
-    result = guardrail.convert_to_bedrock_format(source="INPUT", messages=mock_messages)
+    result = await guardrail.convert_to_bedrock_format(source="INPUT", messages=mock_messages)
 
     # Verify the result structure
     assert isinstance(result, dict)
@@ -1007,7 +1007,7 @@ async def test_convert_to_bedrock_format_output_source():
     )
 
     # Call the method
-    result = guardrail.convert_to_bedrock_format(
+    result = await guardrail.convert_to_bedrock_format(
         source="OUTPUT", response=mock_response
     )
 

tests/test_litellm/llms/anthropic/chat/guardrail_translation/test_anthropic_guardrail_handler.py

@@ -1472,6 +1472,92 @@ class MockCanaryMaskingGuardrail(CustomGuardrail):
         return inputs
 
 
+class TestAnthropicMessagesImageSources:
+    """An Anthropic image block has three source shapes (types/llms/anthropic.py:259).
+
+    Only the base64 one carries "data", so reading that key alone drops url images
+    entirely -- for every guardrail consuming GenericGuardrailAPIInputs["images"],
+    not just Bedrock.
+    """
+
+    def _data(self, messages):
+        return {"model": "claude-sonnet-4-5", "messages": messages}
+
+    async def _images_seen(self, content) -> list[str]:
+        handler = AnthropicMessagesHandler()
+
+        class ImageRecordingGuardrail(MockCanaryMaskingGuardrail):
+            def __init__(self):
+                super().__init__()
+                self.seen_images: list[str] = []  # mutable-ok: accumulator for the assertion
+
+            async def apply_guardrail(self, inputs, request_data, input_type, logging_obj=None):
+                self.seen_images.extend(inputs.get("images") or [])
+                return await super().apply_guardrail(inputs, request_data, input_type, logging_obj)
+
+        guardrail = ImageRecordingGuardrail()
+        # The text block is what gets the guardrail invoked at all: a message with
+        # no text gives the handler nothing to scan, so it never reaches the
+        # guardrail and every source shape would look equally "dropped".
+        await handler.process_input_messages(
+            data=self._data([{"role": "user", "content": [{"type": "text", "text": "describe it"}, *content]}]),
+            guardrail_to_apply=guardrail,
+        )
+        return guardrail.seen_images
+
+    @pytest.mark.asyncio
+    async def test_url_source_reaches_the_guardrail(self):
+        """A url source has no "data" key, so it used to yield nothing at all."""
+        seen = await self._images_seen(
+            [{"type": "image", "source": {"type": "url", "url": "https://example.com/a.png"}}]
+        )
+
+        assert seen == ["https://example.com/a.png"]
+
+    @pytest.mark.asyncio
+    async def test_base64_source_carries_its_media_type(self):
+        """Bare base64 leaves the consumer no way to recover the format.
+
+        An API like Bedrock's ApplyGuardrail needs it to build the request, so the
+        media_type travels with the payload as a data URI.
+        """
+        seen = await self._images_seen(
+            [{"type": "image", "source": {"type": "base64", "media_type": "image/png", "data": "AAAA"}}]
+        )
+
+        assert seen == ["data:image/png;base64,AAAA"]
+
+    @pytest.mark.asyncio
+    async def test_base64_source_without_a_media_type_is_passed_through(self):
+        """There is no format to attach, so the payload goes through unchanged."""
+        seen = await self._images_seen([{"type": "image", "source": {"type": "base64", "data": "AAAA"}}])
+
+        assert seen == ["AAAA"]
+
+    @pytest.mark.asyncio
+    async def test_file_source_yields_nothing(self):
+        """The bytes live behind the Files API and this extractor has no client.
+
+        Documented as a known gap rather than silently handed on as a file_id string,
+        which a consumer would try to decode as an image.
+        """
+        seen = await self._images_seen([{"type": "image", "source": {"type": "file", "file_id": "file_abc"}}])
+
+        assert seen == []
+
+    @pytest.mark.asyncio
+    async def test_a_malformed_source_is_dropped_rather_than_passed_on(self):
+        seen = await self._images_seen(
+            [
+                {"type": "image", "source": {"type": "base64"}},
+                {"type": "image", "source": {"type": "url"}},
+                {"type": "image", "source": {"type": "base64", "data": ""}},
+            ]
+        )
+
+        assert seen == []
+
+
 class TestAnthropicMessagesToolResultScanning:
     """LIT-5251: tool_result blocks carry whatever a client's local tool fetched, so
     they are the request-path payload an indirect prompt injection actually arrives in.

tests/test_litellm/proxy/guardrails/guardrail_hooks/test_bedrock_guardrails.py

@@ -2,8 +2,12 @@
 Unit tests for Bedrock Guardrails
 """
 
+import asyncio
+import base64
+import contextlib
 import json
 import sys
+from datetime import datetime, timezone
 from unittest.mock import AsyncMock, MagicMock, patch
 
 import httpx
@@ -2408,12 +2412,14 @@ _GUARD_BLOCK = {"text": {"text": _GROUNDING_RESPONSE_TEXT, "qualifiers": ["guard
 
 def _input_request(messages: list) -> dict:
     """Arrange a guardrail and act: build the Bedrock INPUT payload."""
-    return _grounding_guardrail().convert_to_bedrock_format(source="INPUT", messages=messages)
+    return asyncio.run(_grounding_guardrail().convert_to_bedrock_format(source="INPUT", messages=messages))
 
 
 def _output_request(messages: list, response=None) -> dict:
     """Arrange a guardrail and act: build the Bedrock OUTPUT payload."""
-    return _grounding_guardrail().convert_to_bedrock_format(source="OUTPUT", response=response, messages=messages)
+    return asyncio.run(
+        _grounding_guardrail().convert_to_bedrock_format(source="OUTPUT", response=response, messages=messages)
+    )
 
 
 def test_grounding_input_strips_grounding_and_query_qualifiers():
@@ -2961,9 +2967,7 @@ async def test_streaming_hook_reraises_guardrail_service_failures():
     guardrail = _sse_guardrail()
 
     with patch.object(guardrail, "make_bedrock_api_request", new_callable=AsyncMock) as mock_api:
-        mock_api.side_effect = HTTPException(
-            status_code=500, detail="Bedrock guardrail throttle retries exhausted"
-        )
+        mock_api.side_effect = HTTPException(status_code=500, detail="Bedrock guardrail throttle retries exhausted")
         with pytest.raises(HTTPException) as exc:
             await _drain_streaming_hook(guardrail)
 
@@ -5274,3 +5278,466 @@ async def test_terminal_failure_logs_usage_and_cost_of_prior_passed_chunks(monke
     assert logged["guardrail_cost"] == pytest.approx(0.0003)
     assert logged["guardrail_response"]["usage"] == {"contentPolicyUnits": 2, "wordPolicyUnits": 1}
     assert "error" in logged["guardrail_response"]
+
+
+class TestBedrockGuardrailImageInput:
+    """Image parts must reach ApplyGuardrail, not just the text sitting next to them."""
+
+    _PNG_DATA_URI = "data:image/png;base64,iVBORw0KGgoAAAANSUhEUg=="
+    _GIF_DATA_URI = "data:image/gif;base64,R0lGODlhAQABAAAAACw="
+    _JPEG_BYTES = b"\xff\xd8\xff\xdb"
+    # A literal, globally-routable IP keeps validate_url's getaddrinfo off DNS; the
+    # transport is faked in every test below, so no request leaves the process.
+    _REMOTE_IMAGE_URL = "https://93.184.216.34/a.jpg"
+
+    def _jpeg_response(self, url: str) -> httpx.Response:
+        return httpx.Response(
+            200,
+            content=self._JPEG_BYTES,
+            headers={"content-type": "image/jpeg"},
+            request=httpx.Request("GET", url),
+        )
+
+    @staticmethod
+    def _fake_stream(chunks: list[bytes], served: list[int] | None = None):
+        """Stand in for httpx.AsyncClient.stream, serving `chunks` one at a time.
+
+        The guardrail caps the transfer, so the fetch goes through `stream` rather
+        than `get`. `served` counts the chunks actually pulled, which is how a test
+        tells "stopped mid-transfer" apart from "read everything, then rejected".
+        """
+
+        @contextlib.asynccontextmanager
+        async def _stream(self, method: str, url, **kwargs):
+            async def _aiter_bytes():
+                for chunk in chunks:
+                    if served is not None:
+                        served.append(len(chunk))
+                    yield chunk
+
+            response = MagicMock()
+            response.status_code = 200
+            response.headers = httpx.Headers({"content-type": "image/jpeg"})
+            response.request = httpx.Request("GET", str(url))
+            response.aiter_bytes = _aiter_bytes
+            yield response
+
+        return _stream
+
+    def _guardrail(self, **kwargs) -> BedrockGuardrail:
+        return BedrockGuardrail(
+            guardrail_name="bedrock-image",
+            guardrailIdentifier="gr-image",
+            guardrailVersion="DRAFT",
+            **kwargs,
+        )
+
+    @pytest.mark.asyncio
+    async def test_inline_image_is_sent_for_scanning(self):
+        messages = [
+            {
+                "role": "user",
+                "content": [
+                    {"type": "text", "text": "what does this say?"},
+                    {"type": "image_url", "image_url": {"url": self._PNG_DATA_URI}},
+                ],
+            }
+        ]
+
+        request = await self._guardrail().convert_to_bedrock_format(source="INPUT", messages=messages)
+
+        assert request["content"] == [
+            {"text": {"text": "what does this say?"}},
+            {"image": {"format": "png", "source": {"bytes": self._PNG_DATA_URI.split(",")[1]}}},
+        ]
+
+    @pytest.mark.asyncio
+    async def test_image_part_carrying_a_text_field_is_still_scanned_as_an_image(self):
+        """A part tagged image_url reaches the model as an image, text field or not.
+
+        Provider transformations branch on `type`, so reading `text` first would scan
+        the decoy and forward the image unscanned - the exact bypass this change closes.
+        """
+        messages = [
+            {
+                "role": "user",
+                "content": [
+                    {
+                        "type": "image_url",
+                        "image_url": {"url": self._PNG_DATA_URI},
+                        "text": "just a friendly note",
+                    }
+                ],
+            }
+        ]
+
+        request = await self._guardrail().convert_to_bedrock_format(source="INPUT", messages=messages)
+
+        assert request["content"] == [
+            {"image": {"format": "png", "source": {"bytes": self._PNG_DATA_URI.split(",")[1]}}}
+        ]
+
+    @pytest.mark.asyncio
+    async def test_unscannable_image_part_carrying_a_text_field_still_blocks(self):
+        """The decoy text must not turn an unscannable image into a scanned request."""
+        messages = [
+            {
+                "role": "user",
+                "content": [{"type": "image_url", "image_url": {"url": self._GIF_DATA_URI}, "text": "hello"}],
+            }
+        ]
+
+        with pytest.raises(HTTPException) as exc_info:
+            await self._guardrail().convert_to_bedrock_format(source="INPUT", messages=messages)
+
+        assert exc_info.value.status_code == 400
+
+    @pytest.mark.asyncio
+    async def test_unscannable_image_blocks_the_request_by_default(self):
+        """ApplyGuardrail takes png/jpeg only, and the image reaches the model either way.
+
+        Skipping it silently would let a caller defeat an IMAGE-modality guardrail by
+        sending a gif, so the default is to reject the request.
+        """
+        messages = [
+            {
+                "role": "user",
+                "content": [
+                    {"type": "text", "text": "hello"},
+                    {"type": "image_url", "image_url": {"url": self._GIF_DATA_URI}},
+                ],
+            }
+        ]
+
+        with pytest.raises(HTTPException) as exc_info:
+            await self._guardrail().convert_to_bedrock_format(source="INPUT", messages=messages)
+
+        assert exc_info.value.status_code == 400
+        assert exc_info.value.detail["error"] == "Violated guardrail policy"
+
+    @pytest.mark.asyncio
+    async def test_undecodable_image_blocks_the_request_by_default(self):
+        messages = [
+            {
+                "role": "user",
+                "content": [{"type": "image_url", "image_url": {"url": "not-an-image"}}],
+            }
+        ]
+
+        with pytest.raises(HTTPException) as exc_info:
+            await self._guardrail().convert_to_bedrock_format(source="INPUT", messages=messages)
+
+        assert exc_info.value.status_code == 400
+
+    @pytest.mark.asyncio
+    async def test_unscannable_image_is_skipped_when_explicitly_allowed(self):
+        """on_unscannable_image: allow restores the permissive behavior, opt-in only."""
+        messages = [
+            {
+                "role": "user",
+                "content": [
+                    {"type": "text", "text": "hello"},
+                    {"type": "image_url", "image_url": {"url": self._GIF_DATA_URI}},
+                    {"type": "image_url", "image_url": {"url": "not-an-image"}},
+                ],
+            }
+        ]
+
+        request = await self._guardrail(on_unscannable_image="allow").convert_to_bedrock_format(
+            source="INPUT", messages=messages
+        )
+
+        assert request["content"] == [{"text": {"text": "hello"}}]
+
+    @pytest.mark.asyncio
+    async def test_remote_image_is_fetched_and_scanned(self):
+        messages = [
+            {
+                "role": "user",
+                "content": [{"type": "image_url", "image_url": {"url": self._REMOTE_IMAGE_URL}}],
+            }
+        ]
+        with patch.object(httpx.AsyncClient, "stream", new=self._fake_stream([self._JPEG_BYTES])):
+            request = await self._guardrail().convert_to_bedrock_format(source="INPUT", messages=messages)
+
+        assert request["content"] == [
+            {
+                "image": {
+                    "format": "jpeg",
+                    "source": {"bytes": base64.b64encode(self._JPEG_BYTES).decode()},
+                }
+            }
+        ]
+
+    @pytest.mark.asyncio
+    async def test_remote_image_is_not_fetched_when_url_validation_is_disabled(self, monkeypatch):
+        """With validation off, async_safe_get is an unrestricted redirect-following GET.
+
+        The url comes straight from the caller, so fetching it here would make the
+        guardrail an SSRF primitive. Treat the image as unscannable instead, and make
+        no request at all.
+        """
+        monkeypatch.setattr(litellm, "user_url_validation", False, raising=False)
+        url = "http://169.254.169.254/latest/meta-data/"
+        messages = [{"role": "user", "content": [{"type": "image_url", "image_url": {"url": url}}]}]
+        get = AsyncMock(return_value=self._jpeg_response(url))
+        served: list[int] = []
+
+        with (
+            patch.object(httpx.AsyncClient, "get", new=get),
+            patch.object(httpx.AsyncClient, "stream", new=self._fake_stream([self._JPEG_BYTES], served)),
+        ):
+            with pytest.raises(HTTPException):
+                await self._guardrail().convert_to_bedrock_format(source="INPUT", messages=messages)
+
+            request = await self._guardrail(on_unscannable_image="allow").convert_to_bedrock_format(
+                source="INPUT", messages=messages
+            )
+
+        # Both transports are stubbed: neither the plain nor the capped fetch ran.
+        get.assert_not_awaited()
+        assert served == []
+        assert request["content"] == []
+
+    @pytest.mark.asyncio
+    async def test_incremental_scan_does_not_skip_a_request_carrying_an_image(self):
+        """`only_scan_new_messages` decides what to scan from `texts` alone.
+
+        With a session id and every text segment already seen, the incremental path
+        returns before the image-aware code runs, so benign text plus a violating
+        image is never scanned -- and the proxy still reports the guardrail as run.
+        Nothing caches images either, so "already seen" cannot cover them.
+        """
+        g = self._guardrail(only_scan_new_messages=True)
+        sent: list = []
+
+        async def spy(**kwargs):
+            sent.append(await g.convert_to_bedrock_format(source="INPUT", messages=kwargs["messages"]))
+            return {"action": "NONE", "outputs": []}
+
+        # Every text is already in the session cache: the exact state that made the
+        # incremental path return early.
+        with (
+            patch.object(g, "filter_new_texts_for_session", new=AsyncMock(return_value=[])),
+            patch.object(g, "make_bedrock_api_request", new=spy),
+        ):
+            await g.apply_guardrail(
+                inputs={"texts": ["look at this"], "images": [self._PNG_DATA_URI]},
+                request_data={"litellm_session_id": "sess-1"},
+                input_type="request",
+            )
+
+        assert sent, "image-carrying request was skipped entirely by the incremental path"
+        kinds = [k for item in sent[0]["content"] for k in item]
+        assert "image" in kinds, f"image never reached the payload: {kinds}"
+
+    @pytest.mark.asyncio
+    async def test_latest_message_only_does_not_skip_an_image_only_message(self):
+        """`experimental_use_latest_role_message_only` skips a latest message with no text.
+
+        An image-only user message is exactly that shape, so the whole request was
+        dropped from the scan.
+        """
+        g = self._guardrail(experimental_use_latest_role_message_only=True)
+        sent: list = []
+
+        async def spy(**kwargs):
+            sent.append(await g.convert_to_bedrock_format(source="INPUT", messages=kwargs["messages"]))
+            return {"action": "NONE", "outputs": []}
+
+        with patch.object(g, "make_bedrock_api_request", new=spy):
+            await g.apply_guardrail(
+                inputs={
+                    "texts": [],
+                    "images": [self._PNG_DATA_URI],
+                    "structured_messages": [
+                        {"role": "user", "content": [{"type": "image_url", "image_url": {"url": self._PNG_DATA_URI}}]}
+                    ],
+                },
+                request_data={},
+                input_type="request",
+            )
+
+        assert sent, "image-only latest message was skipped entirely"
+        kinds = [k for item in sent[0]["content"] for k in item]
+        assert "image" in kinds, f"image never reached the payload: {kinds}"
+
+    @pytest.mark.asyncio
+    async def test_oversized_remote_image_is_cut_off_during_the_transfer(self):
+        """A caller-supplied url can serve an unbounded or indefinitely chunked body.
+
+        The decoded-size check runs once the bytes are already resident, so the cap
+        has to apply while the transfer is in flight. Asserting on how much was
+        pulled is what separates that from buffering it all and rejecting after.
+        """
+        messages = [
+            {
+                "role": "user",
+                "content": [{"type": "image_url", "image_url": {"url": self._REMOTE_IMAGE_URL}}],
+            }
+        ]
+        # 8 MB offered one MB at a time against a 4 MB cap.
+        chunks: list[bytes] = [b"\0" * (1024 * 1024) for _ in range(8)]
+        served: list[int] = []
+
+        with patch.object(httpx.AsyncClient, "stream", new=self._fake_stream(chunks, served)):
+            with pytest.raises(HTTPException):
+                await self._guardrail().convert_to_bedrock_format(source="INPUT", messages=messages)
+
+        # Without the cap the fetch buffers through `get` instead, so `served` stays
+        # empty and the HTTPException above would come from an unstubbed transport
+        # rather than from the size rejection. Assert the capped path actually ran.
+        assert served, "the fetch did not go through the capped stream path"
+        assert sum(served) <= 5 * 1024 * 1024, f"read {sum(served)} bytes past a 4 MB cap"
+        assert len(served) < len(chunks), "the whole body was pulled before rejecting it"
+
+    @pytest.mark.asyncio
+    async def test_apply_guardrail_scans_images_from_inputs(self):
+        """The proxy reaches BedrockGuardrail through `apply_guardrail`, not the native hook.
+
+        ProxyLogging._execute_guardrail_hook routes any guardrail that defines
+        `apply_guardrail` through unified_guardrail, so a fix that only touches
+        async_pre_call_hook never runs on a real request. The endpoint translations
+        already put images in inputs["images"]; this asserts they reach the payload.
+        """
+        g = self._guardrail()
+        sent: list = []
+
+        async def spy(**kwargs):
+            sent.append(await g.convert_to_bedrock_format(source="INPUT", messages=kwargs["messages"]))
+            return {"action": "NONE", "outputs": []}
+
+        with patch.object(g, "make_bedrock_api_request", new=spy):
+            await g.apply_guardrail(
+                inputs={"texts": ["what does this say?"], "images": [self._PNG_DATA_URI]},
+                request_data={},
+                input_type="request",
+            )
+
+        kinds = [k for item in sent[0]["content"] for k in item]
+        assert "image" in kinds, f"image never reached the payload: {kinds}"
+
+    @pytest.mark.asyncio
+    async def test_apply_guardrail_scans_bare_base64_images(self):
+        """Anthropic's translation drops media_type and passes bare base64.
+
+        `_image_sources` returns source["data"] only, so the entry is not a data URI.
+        Without sniffing the format back it would be rejected as unreadable and, under
+        on_unscannable_image=block, turn a legitimate /v1/messages call into a 400.
+        """
+        g = self._guardrail()
+        sent: list = []
+
+        async def spy(**kwargs):
+            sent.append(await g.convert_to_bedrock_format(source="INPUT", messages=kwargs["messages"]))
+            return {"action": "NONE", "outputs": []}
+
+        bare_base64 = self._PNG_DATA_URI.split(",")[1]
+        with patch.object(g, "make_bedrock_api_request", new=spy):
+            await g.apply_guardrail(
+                inputs={"texts": [], "images": [bare_base64]},
+                request_data={},
+                input_type="request",
+            )
+
+        kinds = [k for item in sent[0]["content"] for k in item]
+        assert "image" in kinds, f"bare base64 image never reached the payload: {kinds}"
+
+    @pytest.mark.asyncio
+    async def test_apply_guardrail_ignores_images_on_the_response_side(self):
+        """ApplyGuardrail's OUTPUT source scans model-generated text, not input images."""
+        g = self._guardrail()
+        sent: list = []
+
+        async def spy(**kwargs):
+            sent.append(kwargs)
+            return {"action": "NONE", "outputs": []}
+
+        with patch.object(g, "make_bedrock_api_request", new=spy):
+            await g.apply_guardrail(
+                inputs={"texts": ["some model output"], "images": [self._PNG_DATA_URI]},
+                request_data={},
+                input_type="response",
+            )
+
+        assert sent and sent[0]["source"] == "OUTPUT"
+
+    @pytest.mark.asyncio
+    async def test_oversized_image_is_rejected_before_sending(self):
+        """ApplyGuardrail caps images at 4 MB; AWS's rejection is not worth a round trip.
+
+        Built as a real data URI rather than a patched decoder so the size check runs
+        against what the decoder actually produces.
+        """
+        oversized_png = base64.b64encode(b"\x89PNG\r\n\x1a\n" + b"\x00" * (5 * 1024 * 1024)).decode()
+
+        with pytest.raises(HTTPException) as exc_info:
+            await self._guardrail().convert_to_bedrock_format(
+                source="INPUT",
+                messages=[
+                    {
+                        "role": "user",
+                        "content": [
+                            {"type": "image_url", "image_url": {"url": f"data:image/png;base64,{oversized_png}"}}
+                        ],
+                    }
+                ],
+            )
+
+        assert "4 MB limit" in str(exc_info.value.detail)
+
+    def test_bin_packing_respects_the_twenty_image_limit(self):
+        """An image measures 0 against the character budget, so count them separately."""
+        image = {"image": {"format": "png", "source": {"bytes": "AAAA"}}}
+        batches = BedrockGuardrail._bin_pack_bedrock_content([image] * 45, budget=25_000)
+        sizes = [len(batch) for batch in batches]
+        assert all(size <= 20 for size in sizes), sizes
+        assert sum(sizes) == 45, sizes
+
+    def test_bin_packing_still_splits_on_the_text_budget(self):
+        text = {"text": {"text": "x" * 20_000}}
+        batches = BedrockGuardrail._bin_pack_bedrock_content([text] * 3, budget=25_000)
+        assert [len(batch) for batch in batches] == [1, 1, 1]
+
+    @pytest.mark.asyncio
+    async def test_many_images_are_split_before_the_first_call(self):
+        """Chunking is reactive; an image-count rejection may never match the too-large check."""
+        g = self._guardrail()
+        sent: list = []
+
+        async def fake_post(content, **kwargs):
+            sent.append(sum(1 for item in content if "image" in item))
+            return {"action": "NONE", "outputs": []}
+
+        image = {"image": {"format": "png", "source": {"bytes": "AAAA"}}}
+        with patch.object(g, "_post_apply_guardrail_content_with_retry", new=fake_post):
+            await g._apply_guardrail_content_with_chunking(
+                content=[image] * 45,
+                base_request_data={},
+                credentials=None,
+                aws_region_name="us-west-2",
+                api_key=None,
+                request_data=None,
+                event_type=GuardrailEventHooks.pre_call,
+                start_time=datetime.now(timezone.utc),
+                allow_chunking=True,
+                completed_chunk_usages=[],
+            )
+        assert sent == [20, 20, 5], sent
+
+    def test_masking_keeps_image_parts_in_the_request(self):
+        """Masking rewrites text in place; the image must survive to reach the model."""
+        image_part = {"type": "image_url", "image_url": {"url": self._PNG_DATA_URI}}
+        messages = [
+            {
+                "role": "user",
+                "content": [{"type": "text", "text": "my ssn is 123-45-6789"}, image_part],
+            }
+        ]
+
+        updated = self._guardrail()._apply_masking_to_messages(messages=messages, masked_texts=["my ssn is {SSN}"])
+
+        assert updated[0]["content"] == [
+            {"type": "text", "text": "my ssn is {SSN}"},
+            image_part,
+        ]

tests/test_litellm/proxy/guardrails/test_guardrail_endpoints.py

@@ -896,7 +896,9 @@ async def test_bedrock_guardrail_make_api_request_passes_api_key():
             guardrail_hook.async_handler, "post", AsyncMock(return_value=mock_response)
         ),
         patch.object(guardrail_hook, "_load_credentials") as mock_load_creds,
-        patch.object(guardrail_hook, "convert_to_bedrock_format") as mock_convert,
+        patch.object(
+            guardrail_hook, "convert_to_bedrock_format", new_callable=AsyncMock
+        ) as mock_convert,
         patch.object(
             guardrail_hook, "get_guardrail_dynamic_request_body_params"
         ) as mock_get_params,

tests/test_litellm/proxy/guardrails/test_init_guardrails.py

@@ -118,3 +118,37 @@ def test_initialize_guardrail_sets_run_in_parallel(config_value, expected):
 
     custom_guardrail = guardrail_handler.guardrail_id_to_custom_guardrail[result["guardrail_id"]]
     assert custom_guardrail.run_in_parallel is expected
+
+
+def test_initialize_bedrock_forwards_on_unscannable_image():
+    """Regression: `on_unscannable_image` set in config.yaml must reach the guardrail.
+
+    Same shape as chunk_budget_chars above: the field lives on
+    BedrockGuardrailConfigModel so LitellmParams parses it, but initialize_bedrock
+    enumerates its kwargs explicitly. Dropped here, an operator who opted into
+    `allow` would keep getting 400s on unscannable images with no indication why.
+    """
+    import litellm
+    from litellm.proxy.guardrails.guardrail_hooks.bedrock_guardrails import BedrockGuardrail
+
+    test_guardrail = {
+        "guardrail_name": "test_bedrock_unscannable_image",
+        "litellm_params": {
+            "guardrail": SupportedGuardrailIntegrations.BEDROCK.value,
+            "mode": "pre_call",
+            "guardrailIdentifier": "test-guardrail",
+            "guardrailVersion": "DRAFT",
+            "on_unscannable_image": "allow",
+        },
+    }
+
+    guardrail_handler = InMemoryGuardrailHandler()
+    guardrail_handler.initialize_guardrail(guardrail=test_guardrail)
+
+    initialized = [
+        callback
+        for callback in litellm.callbacks
+        if isinstance(callback, BedrockGuardrail) and callback.guardrail_name == "test_bedrock_unscannable_image"
+    ]
+    assert initialized, "bedrock guardrail was not registered as a callback"
+    assert initialized[-1].on_unscannable_image == "allow"