From cf3afe2bac817ac6d114fb7b8026a86b575e9f18 Mon Sep 17 00:00:00 2001
From: WuWenbo <wuwenbo0626@gmail.com>
Date: Fri, 25 Sep 2026 14:18:09 +0800
Subject: [PATCH] fix(middleware): preserve human message metadata (#5823)

* fix(middleware): preserve human message metadata

* test(middleware): cover human message metadata injection
---
 .../middlewares/thread_data_middleware.py     | 14 ++++++----
 backend/tests/test_thread_data_middleware.py  | 28 +++++++++++++++++--
 2 files changed, 35 insertions(+), 7 deletions(-)

diff --git a/backend/packages/harness/deerflow/agents/middlewares/thread_data_middleware.py b/backend/packages/harness/deerflow/agents/middlewares/thread_data_middleware.py
index 2dcdcdc00f..9507ca6a6d 100644
--- a/backend/packages/harness/deerflow/agents/middlewares/thread_data_middleware.py
+++ b/backend/packages/harness/deerflow/agents/middlewares/thread_data_middleware.py
@@ -103,11 +103,15 @@ class ThreadDataMiddleware(AgentMiddleware[ThreadDataMiddlewareState]):
         last_message = messages[-1] if messages else None
 
         if last_message and isinstance(last_message, HumanMessage):
-            messages[-1] = HumanMessage(
-                content=last_message.content,
-                id=last_message.id,
-                name=last_message.name or "user-input",
-                additional_kwargs={**last_message.additional_kwargs, "run_id": context.get("run_id"), "timestamp": datetime.now(UTC).isoformat()},
+            messages[-1] = last_message.model_copy(
+                update={
+                    "name": last_message.name or "user-input",
+                    "additional_kwargs": {
+                        **last_message.additional_kwargs,
+                        "run_id": context.get("run_id"),
+                        "timestamp": datetime.now(UTC).isoformat(),
+                    },
+                },
             )
 
         return {
diff --git a/backend/tests/test_thread_data_middleware.py b/backend/tests/test_thread_data_middleware.py
index e239700a6b..479a5a2cdd 100644
--- a/backend/tests/test_thread_data_middleware.py
+++ b/backend/tests/test_thread_data_middleware.py
@@ -1,4 +1,5 @@
 import pytest
+from langchain_core.messages import HumanMessage
 from langgraph.runtime import Runtime
 
 from deerflow.agents.middlewares.thread_data_middleware import ThreadDataMiddleware
@@ -66,8 +67,6 @@ class TestThreadDataMiddleware:
     def test_before_agent_handles_none_context_with_trailing_human_message(self, tmp_path, monkeypatch):
         # Regression: run_id was read via the unguarded `runtime.context`, so a None context plus a
         # trailing HumanMessage raised AttributeError (thread_id still resolves from config.configurable).
-        from langchain_core.messages import HumanMessage
-
         middleware = ThreadDataMiddleware(base_dir=str(tmp_path), lazy_init=True)
         runtime = Runtime(context=None)
         monkeypatch.setattr(
@@ -80,6 +79,31 @@ class TestThreadDataMiddleware:
         assert result is not None
         assert runtime.context is None
 
+    def test_before_agent_preserves_human_message_response_metadata(self, tmp_path):
+        middleware = ThreadDataMiddleware(base_dir=str(tmp_path), lazy_init=True)
+        message = HumanMessage(
+            content="hello",
+            id="message-1",
+            response_metadata={"source": "gateway"},
+        )
+
+        result = middleware.before_agent(
+            state={"messages": [message]},
+            runtime=Runtime(
+                context={
+                    "thread_id": "thread-123",
+                    "run_id": "run-123",
+                },
+            ),
+        )
+
+        assert result is not None
+        updated_message = result["messages"][-1]
+        assert updated_message.response_metadata == {"source": "gateway"}
+        assert updated_message.name == "user-input"
+        assert updated_message.additional_kwargs["run_id"] == "run-123"
+        assert updated_message.additional_kwargs["timestamp"]
+
     def test_before_agent_raises_clear_error_when_thread_id_missing_everywhere(self, tmp_path, monkeypatch):
         middleware = ThreadDataMiddleware(base_dir=str(tmp_path), lazy_init=True)
         monkeypatch.setattr(