Fix type checking errors for CachePoint

- Fix TypedDict mutation in anthropic.py using cast()
- Handle CachePoint in otel message conversion (skip for telemetry)
- Add CachePoint handling in all model providers for compatibility
- Models without caching support (Bedrock, Gemini, Google, HuggingFace, OpenAI) now filter out CachePoint markers

All pyright type checks now pass.

Author: ronakrm

pydantic_ai_slim/pydantic_ai/messages.py

@@ -742,6 +742,9 @@ def otel_message_parts(self, settings: InstrumentationSettings) -> list[_otel_me
                 if settings.include_content and settings.include_binary_content:
                     converted_part['content'] = base64.b64encode(part.data).decode()
                 parts.append(converted_part)
+            elif isinstance(part, CachePoint):
+                # CachePoint is a marker, not actual content - skip it for otel
+                pass
             else:
                 parts.append({'type': part.kind})  # pragma: no cover
         return parts

pydantic_ai_slim/pydantic_ai/models/anthropic.py

@@ -654,11 +654,12 @@ def _add_cache_control_to_last_param(params: list[BetaContentBlockParam]) -> Non
 
         # Only certain types support cache_control
         cacheable_types = {'text', 'tool_use', 'server_tool_use', 'image', 'tool_result'}
-        if params[-1]['type'] not in cacheable_types:
-            raise UserError(f'Cache control not supported for param type: {params[-1]["type"]}')
+        last_param = cast(dict[str, Any], params[-1])  # Cast to dict for mutation
+        if last_param['type'] not in cacheable_types:
+            raise UserError(f'Cache control not supported for param type: {last_param["type"]}')
 
         # Add cache_control to the last param
-        params[-1]['cache_control'] = BetaCacheControlEphemeralParam(type='ephemeral')
+        last_param['cache_control'] = BetaCacheControlEphemeralParam(type='ephemeral')
 
     @staticmethod
     async def _map_user_prompt(

pydantic_ai_slim/pydantic_ai/models/bedrock.py

@@ -19,6 +19,7 @@
     BinaryContent,
     BuiltinToolCallPart,
     BuiltinToolReturnPart,
+    CachePoint,
     DocumentUrl,
     FinishReason,
     ImageUrl,
@@ -632,6 +633,9 @@ async def _map_user_prompt(part: UserPromptPart, document_count: Iterator[int])
                         content.append({'video': video})
                 elif isinstance(item, AudioUrl):  # pragma: no cover
                     raise NotImplementedError('Audio is not supported yet.')
+                elif isinstance(item, CachePoint):
+                    # Bedrock doesn't support prompt caching via CachePoint in this implementation
+                    pass
                 else:
                     assert_never(item)
         return [{'role': 'user', 'content': content}]

pydantic_ai_slim/pydantic_ai/models/gemini.py

@@ -21,6 +21,7 @@
     BinaryContent,
     BuiltinToolCallPart,
     BuiltinToolReturnPart,
+    CachePoint,
     FilePart,
     FileUrl,
     ModelMessage,
@@ -391,6 +392,9 @@ async def _map_user_prompt(self, part: UserPromptPart) -> list[_GeminiPartUnion]
                     else:  # pragma: lax no cover
                         file_data = _GeminiFileDataPart(file_data={'file_uri': item.url, 'mime_type': item.media_type})
                         content.append(file_data)
+                elif isinstance(item, CachePoint):
+                    # Gemini doesn't support prompt caching via CachePoint
+                    pass
                 else:
                     assert_never(item)  # pragma: lax no cover
         return content

pydantic_ai_slim/pydantic_ai/models/google.py

@@ -19,6 +19,7 @@
     BinaryContent,
     BuiltinToolCallPart,
     BuiltinToolReturnPart,
+    CachePoint,
     FilePart,
     FileUrl,
     FinishReason,
@@ -602,6 +603,9 @@ async def _map_user_prompt(self, part: UserPromptPart) -> list[PartDict]:
                     else:
                         file_data_dict: FileDataDict = {'file_uri': item.url, 'mime_type': item.media_type}
                         content.append({'file_data': file_data_dict})  # pragma: lax no cover
+                elif isinstance(item, CachePoint):
+                    # Google Gemini doesn't support prompt caching via CachePoint
+                    pass
                 else:
                     assert_never(item)
         return content

pydantic_ai_slim/pydantic_ai/models/huggingface.py

@@ -18,6 +18,7 @@
     BinaryContent,
     BuiltinToolCallPart,
     BuiltinToolReturnPart,
+    CachePoint,
     DocumentUrl,
     FilePart,
     FinishReason,
@@ -447,6 +448,9 @@ async def _map_user_prompt(part: UserPromptPart) -> ChatCompletionInputMessage:
                     raise NotImplementedError('DocumentUrl is not supported for Hugging Face')
                 elif isinstance(item, VideoUrl):
                     raise NotImplementedError('VideoUrl is not supported for Hugging Face')
+                elif isinstance(item, CachePoint):
+                    # Hugging Face doesn't support prompt caching via CachePoint
+                    pass
                 else:
                     assert_never(item)
         return ChatCompletionInputMessage(role='user', content=content)  # type: ignore