fix: filter 'SDK_UNKNOWN_MEMBER' from response content

Author: JackYPCOnline

src/strands/models/bedrock.py

@@ -256,6 +256,7 @@ def _format_bedrock_messages(self, messages: Messages) -> Messages:
         """Format messages for Bedrock API compatibility.
 
         This function ensures messages conform to Bedrock's expected format by:
+        - Filtering out SDK_UNKNOWN_MEMBER content blocks
         - Cleaning tool result content blocks by removing additional fields that may be
           useful for retaining information in hooks but would cause Bedrock validation
           exceptions when presented with unexpected fields
@@ -273,11 +274,17 @@ def _format_bedrock_messages(self, messages: Messages) -> Messages:
             https://docs.aws.amazon.com/bedrock/latest/APIReference/API_runtime_ToolResultBlock.html
         """
         cleaned_messages = []
+        filtered_unknown_members = False
 
         for message in messages:
             cleaned_content: list[ContentBlock] = []
 
             for content_block in message["content"]:
+                # Filter out SDK_UNKNOWN_MEMBER content blocks
+                if "SDK_UNKNOWN_MEMBER" in content_block:
+                    filtered_unknown_members = True
+                    continue
+
                 if "toolResult" in content_block:
                     # Create a new content block with only the cleaned toolResult
                     tool_result: ToolResult = content_block["toolResult"]
@@ -297,6 +304,11 @@ def _format_bedrock_messages(self, messages: Messages) -> Messages:
             cleaned_message: Message = Message(content=cleaned_content, role=message["role"])
             cleaned_messages.append(cleaned_message)
 
+        if filtered_unknown_members:
+            logger.warning(
+                "Filtered out SDK_UNKNOWN_MEMBER content blocks from messages, consider upgrading boto3 version"
+            )
+
         return cleaned_messages
 
     def _has_blocked_guardrail(self, guardrail_data: dict[str, Any]) -> bool:

tests/strands/models/test_bedrock.py

@@ -1301,3 +1301,27 @@ def test_format_request_cleans_tool_result_content_blocks(model, model_id):
     assert tool_result == expected
     assert "extraField" not in tool_result
     assert "mcpMetadata" not in tool_result
+
+
+def test_format_request_filters_sdk_unknown_member_content_blocks(model, model_id, caplog):
+    """Test that format_request filters out SDK_UNKNOWN_MEMBER content blocks."""
+    messages = [
+        {
+            "role": "assistant",
+            "content": [
+                {"text": "Hello"},
+                {"SDK_UNKNOWN_MEMBER": {"name": "reasoningContent"}},
+                {"text": "World"},
+            ],
+        }
+    ]
+
+    formatted_request = model.format_request(messages)
+
+    content = formatted_request["messages"][0]["content"]
+    assert len(content) == 2
+    assert content[0] == {"text": "Hello"}
+    assert content[1] == {"text": "World"}
+
+    for block in content:
+        assert "SDK_UNKNOWN_MEMBER" not in block