Feature: Handle Bedrock redactedContent (strands-agents#848)

* feat: add ReasoningRedactedContentStreamEvent for proper redacted content handling

- Add ReasoningRedactedContentStreamEvent class to types/_events.py for typed streaming
- Refactor redacted content handling in streaming.py
- Fix state management for redactedContent with proper default handling
- Update tests to handle new event structure and skip problematic tests
- Add integration test for redacted content with thinking mode

This improves type safety and consistency in the streaming event system
when handling redacted reasoning content.

Co-authored-by: Yuki Matsuda <13781813+mazyu36@users.noreply.github.com>
Co-authored-by: Arron <139703460+awsarron@users.noreply.github.com>

Author: 3 people

src/strands/event_loop/streaming.py

@@ -10,6 +10,7 @@
     ModelStopReason,
     ModelStreamChunkEvent,
     ModelStreamEvent,
+    ReasoningRedactedContentStreamEvent,
     ReasoningSignatureStreamEvent,
     ReasoningTextStreamEvent,
     TextStreamEvent,
@@ -170,6 +171,10 @@ def handle_content_block_delta(
                 delta=delta_content,
             )
 
+        elif redacted_content := delta_content["reasoningContent"].get("redactedContent"):
+            state["redactedContent"] = state.get("redactedContent", b"") + redacted_content
+            typed_event = ReasoningRedactedContentStreamEvent(redacted_content=redacted_content, delta=delta_content)
+
     return state, typed_event
 
 
@@ -188,6 +193,7 @@ def handle_content_block_stop(state: dict[str, Any]) -> dict[str, Any]:
     text = state["text"]
     reasoning_text = state["reasoningText"]
     citations_content = state["citationsContent"]
+    redacted_content = state.get("redactedContent")
 
     if current_tool_use:
         if "input" not in current_tool_use:
@@ -231,6 +237,9 @@ def handle_content_block_stop(state: dict[str, Any]) -> dict[str, Any]:
 
         content.append(content_block)
         state["reasoningText"] = ""
+    elif redacted_content:
+        content.append({"reasoningContent": {"redactedContent": redacted_content}})
+        state["redactedContent"] = b""
 
     return state
 

src/strands/types/_events.py

@@ -169,6 +169,14 @@ def __init__(self, delta: ContentBlockDelta, reasoning_text: str | None) -> None
         super().__init__({"reasoningText": reasoning_text, "delta": delta, "reasoning": True})
 
 
+class ReasoningRedactedContentStreamEvent(ModelStreamEvent):
+    """Event emitted during redacted content streaming."""
+
+    def __init__(self, delta: ContentBlockDelta, redacted_content: bytes | None) -> None:
+        """Initialize with delta and redacted content."""
+        super().__init__({"reasoningRedactedContent": redacted_content, "delta": delta, "reasoning": True})
+
+
 class ReasoningSignatureStreamEvent(ModelStreamEvent):
     """Event emitted during reasoning signature streaming."""
 

tests/fixtures/mocked_model_provider.py

@@ -72,6 +72,10 @@ def map_agent_message_to_events(self, agent_message: Union[Message, RedactionMes
             stop_reason = "guardrail_intervened"
         else:
             for content in agent_message["content"]:
+                if "reasoningContent" in content:
+                    yield {"contentBlockStart": {"start": {}}}
+                    yield {"contentBlockDelta": {"delta": {"reasoningContent": content["reasoningContent"]}}}
+                    yield {"contentBlockStop": {}}
                 if "text" in content:
                     yield {"contentBlockStart": {"start": {}}}
                     yield {"contentBlockDelta": {"delta": {"text": content["text"]}}}

tests/strands/agent/hooks/test_agent_events.py

@@ -387,6 +387,84 @@ async def test_stream_e2e_throttle_and_redact(alist, mock_sleep):
     assert typed_events == []
 
 
+@pytest.mark.asyncio
+async def test_stream_e2e_reasoning_redacted_content(alist):
+    mock_provider = MockedModelProvider(
+        [
+            {
+                "role": "assistant",
+                "content": [
+                    {"reasoningContent": {"redactedContent": b"test_redacted_data"}},
+                    {"text": "Response with redacted reasoning"},
+                ],
+            },
+        ]
+    )
+
+    mock_callback = unittest.mock.Mock()
+    agent = Agent(model=mock_provider, callback_handler=mock_callback)
+
+    stream = agent.stream_async("Test redacted content")
+
+    tru_events = await alist(stream)
+    exp_events = [
+        {"init_event_loop": True},
+        {"start": True},
+        {"start_event_loop": True},
+        {"event": {"messageStart": {"role": "assistant"}}},
+        {"event": {"contentBlockStart": {"start": {}}}},
+        {"event": {"contentBlockDelta": {"delta": {"reasoningContent": {"redactedContent": b"test_redacted_data"}}}}},
+        {
+            **any_props,
+            "reasoningRedactedContent": b"test_redacted_data",
+            "delta": {"reasoningContent": {"redactedContent": b"test_redacted_data"}},
+            "reasoning": True,
+        },
+        {"event": {"contentBlockStop": {}}},
+        {"event": {"contentBlockStart": {"start": {}}}},
+        {"event": {"contentBlockDelta": {"delta": {"text": "Response with redacted reasoning"}}}},
+        {
+            **any_props,
+            "data": "Response with redacted reasoning",
+            "delta": {"text": "Response with redacted reasoning"},
+        },
+        {"event": {"contentBlockStop": {}}},
+        {"event": {"messageStop": {"stopReason": "end_turn"}}},
+        {
+            "message": {
+                "content": [
+                    {"reasoningContent": {"redactedContent": b"test_redacted_data"}},
+                    {"text": "Response with redacted reasoning"},
+                ],
+                "role": "assistant",
+            }
+        },
+        {
+            "result": AgentResult(
+                stop_reason="end_turn",
+                message={
+                    "content": [
+                        {"reasoningContent": {"redactedContent": b"test_redacted_data"}},
+                        {"text": "Response with redacted reasoning"},
+                    ],
+                    "role": "assistant",
+                },
+                metrics=ANY,
+                state={},
+            )
+        },
+    ]
+    assert tru_events == exp_events
+
+    exp_calls = [call(**event) for event in exp_events]
+    act_calls = mock_callback.call_args_list
+    assert act_calls == exp_calls
+
+    # Ensure that all events coming out of the agent are *not* typed events
+    typed_events = [event for event in tru_events if isinstance(event, TypedEvent)]
+    assert typed_events == []
+
+
 @pytest.mark.asyncio
 async def test_event_loop_cycle_text_response_throttling_early_end(
     agenerator,