fix(utils): skip malformed response block types (#6614)

Co-authored-by: songjianglin <270247441+2017955725@users.noreply.github.com>

README.md

@@ -1820,7 +1820,7 @@ Rebuild with `make up` after changing the managed extension set. See
 `config.example.yaml` and the
 [reference extension](examples/deerflow-extension-example/) for a complete example.
 
-Gateway-generated follow-up suggestions now normalize both plain-string model output and block/list-style rich content before parsing the JSON array response, so provider-specific content wrappers do not silently drop suggestions.
+Gateway-generated follow-up suggestions now normalize both plain-string model output and block/list-style rich content before parsing the JSON array response, so provider-specific content wrappers do not silently drop suggestions. Follow-up suggestions and input polishing skip content blocks with non-string types, preserving the surrounding text instead of failing the request
 
 Backend response cleanup preserves unrelated tag names such as `<think-tank>` and `<think:note>` in follow-up suggestions and polished drafts; only the exact `<think>` name (optionally followed by attributes) starts a reasoning block. Self-closing `<think/>` and `<think />` tags are empty reasoning blocks and leave the following answer intact. Delimiters inside quoted attributes, such as `<think note=">"/>`, also leave the following answer intact.
 

backend/packages/harness/deerflow/utils/AGENTS.md

@@ -30,6 +30,12 @@ which takes a whole message and uses different list/mapping semantics.
 Regression coverage lives in `tests/test_utils_messages.py`,
 `tests/test_subagent_executor.py`, and `tests/test_task_continuity.py`.
 
+`llm_text.py::extract_response_text` ignores content blocks with non-string
+`type` values, including lists and mappings, while retaining adjacent text and
+output-text blocks. Tests cover extraction and the one-shot input-polish path
+with real LangChain messages in `tests/test_utils_llm_text.py` and
+`tests/test_input_polish_router.py`.
+
 `llm_text.py::strip_think_blocks` scans opening and closing tags forward so
 repeated unclosed `<think>` prefixes in model output do not rescan the same
 suffix. Keep its case-insensitive tag handling, optional whitespace before

backend/packages/harness/deerflow/utils/llm_text.py

@@ -145,7 +145,7 @@ def extract_response_text(content: object) -> str:
         for block in content:
             if isinstance(block, str):
                 parts.append(block)
-            elif isinstance(block, dict) and block.get("type") in {"text", "output_text"}:
+            elif isinstance(block, dict) and block.get("type") in ("text", "output_text"):
                 text = block.get("text")
                 if isinstance(text, str):
                     parts.append(text)

backend/tests/test_input_polish_router.py

@@ -4,6 +4,8 @@ from unittest.mock import AsyncMock, MagicMock
 
 import pytest
 from fastapi import HTTPException
+from langchain_core.language_models.fake_chat_models import FakeMessagesListChatModel
+from langchain_core.messages import AIMessage
 
 from app.gateway.routers import input_polish
 from deerflow.utils import oneshot_llm
@@ -193,3 +195,26 @@ def test_polish_input_validates_and_sends_normalized_text(monkeypatch):
     human_content = messages[-1].content
     assert "summarize report" in human_content
     assert "   summarize report   " not in human_content
+
+
+@pytest.mark.parametrize("block_type", [[], {}])
+def test_polish_input_ignores_invalid_block_types(monkeypatch, block_type: object) -> None:
+    response = AIMessage(
+        content=[
+            {"type": block_type, "text": "ignored"},
+            {"type": "text", "text": "Please summarize the report."},
+        ],
+    )
+    model = FakeMessagesListChatModel(responses=[response])
+    monkeypatch.setattr(oneshot_llm, "create_chat_model", lambda **kwargs: model)
+
+    result = asyncio.run(
+        input_polish.polish_input.__wrapped__(
+            input_polish.InputPolishRequest(text="summarize report"),
+            request=None,
+            config=_config(),
+        ),
+    )
+
+    assert result.rewritten_text == "Please summarize the report."
+    assert result.changed is True

backend/tests/test_utils_llm_text.py

@@ -190,6 +190,17 @@ def test_extract_response_text_skips_blocks_with_non_string_text() -> None:
     assert extract_response_text(content) == "ok"
 
 
+@pytest.mark.parametrize("block_type", [[], {}, ["text"], {"type": "text"}, None, False, 0, "image"])
+def test_extract_response_text_skips_invalid_types_and_preserves_text(block_type: object) -> None:
+    content = [
+        "intro",
+        {"type": block_type, "text": "ignored"},
+        {"type": "text", "text": "body"},
+        {"type": "output_text", "text": "ending"},
+    ]
+    assert extract_response_text(content) == "intro\nbody\nending"
+
+
 def test_extract_response_text_returns_empty_for_empty_list() -> None:
     assert extract_response_text([]) == ""