fix(openai): sanitize chat completions text content blocks (#35217)

- GitHub releases have not been created for partner package releases
since #34784 (Jan 16). PyPI publishes were unaffected.

#34784 added `test-dependents` to the `publish` job's dependency chain.
`test-dependents` only runs for core/langchain releases, so it's skipped
for everything else. `publish` handles this with `if: ${{ !cancelled()
&& !failure() }}`, but `mark-release` (which creates the GitHub release)
doesn't have the same guard — so GitHub Actions skips it whenever
`test-dependents` is skipped.

## Missing GitHub releases
`langchain-xai==1.2.2`, `langchain-standard-tests==1.1.3`,
`langchain-groq==1.1.2`, `langchain-anthropic==1.3.2`,
`langchain-standard-tests==1.1.4`, `langchain-openai==1.1.8`,
`langchain-openai==1.1.9`, `langchain-anthropic==1.3.3`,
`langchain-openrouter==0.0.2`

.github/workflows/_release.yml

@@ -586,6 +586,8 @@ jobs:
       - test-pypi-publish
       - pre-release-checks
       - publish
+    # Run if all needed jobs succeeded or were skipped (test-dependents only runs for core/langchain_v1)
+    if: ${{ !cancelled() && !failure() }}
     runs-on: ubuntu-latest
     permissions:
       # This permission is needed by `ncipollo/release-action` to

.github/workflows/check_diffs.yml

@@ -219,6 +219,7 @@ jobs:
           MISTRAL_API_KEY: ${{ secrets.MISTRAL_API_KEY }}
           NOMIC_API_KEY: ${{ secrets.NOMIC_API_KEY }}
           OPENAI_API_KEY: ${{ secrets.OPENAI_API_KEY }}
+          OPENROUTER_API_KEY: ${{ secrets.OPENROUTER_API_KEY }}
           PPLX_API_KEY: ${{ secrets.PPLX_API_KEY }}
           XAI_API_KEY: ${{ secrets.XAI_API_KEY }}
         with:

libs/partners/openai/langchain_openai/chat_models/base.py

@@ -236,6 +236,26 @@ def _convert_dict_to_message(_dict: Mapping[str, Any]) -> BaseMessage:
     return ChatMessage(content=_dict.get("content", ""), role=role, id=id_)  # type: ignore[arg-type]
 
 
+def _sanitize_chat_completions_content(content: str | list[dict]) -> str | list[dict]:
+    """Sanitize content for chat/completions API.
+
+    For list content, filters text blocks to only keep 'type' and 'text' keys.
+    """
+    if isinstance(content, list):
+        sanitized = []
+        for block in content:
+            if (
+                isinstance(block, dict)
+                and block.get("type") == "text"
+                and "text" in block
+            ):
+                sanitized.append({"type": "text", "text": block["text"]})
+            else:
+                sanitized.append(block)
+        return sanitized
+    return content
+
+
 def _format_message_content(
     content: Any,
     api: Literal["chat/completions", "responses"] = "chat/completions",
@@ -368,7 +388,9 @@ def _convert_message_to_dict(
     elif isinstance(message, ToolMessage):
         message_dict["role"] = "tool"
         message_dict["tool_call_id"] = message.tool_call_id
-
+        message_dict["content"] = _sanitize_chat_completions_content(
+            message_dict["content"]
+        )
         supported_props = {"content", "role", "tool_call_id"}
         message_dict = {k: v for k, v in message_dict.items() if k in supported_props}
     else:
@@ -1520,7 +1542,15 @@ class BaseChatOpenAI(BaseChatModel):
             raise KeyError(msg) from e
 
         if choices is None:
-            msg = "Received response with null value for `choices`."
+            # Some OpenAI-compatible APIs (e.g., vLLM) may return null choices
+            # when the response format differs or an error occurs without
+            # populating the error field. Provide a more helpful error message.
+            msg = (
+                "Received response with null value for `choices`. "
+                "This can happen when using OpenAI-compatible APIs (e.g., vLLM) "
+                "that return a response in an unexpected format. "
+                f"Full response keys: {list(response_dict.keys())}"
+            )
             raise TypeError(msg)
 
         token_usage = response_dict.get("usage")

libs/partners/openai/tests/unit_tests/chat_models/test_base.py

@@ -1264,6 +1264,23 @@ def test__get_request_payload() -> None:
     assert payload == expected
 
 
+def test_sanitize_chat_completions_text_blocks() -> None:
+    messages = [
+        ToolMessage(
+            content=[{"type": "text", "text": "foo", "id": "lc_abc123"}],
+            tool_call_id="def456",
+        ),
+    ]
+    payload = ChatOpenAI(model="gpt-5.2")._get_request_payload(messages)
+    assert payload["messages"] == [
+        {
+            "content": [{"type": "text", "text": "foo"}],
+            "role": "tool",
+            "tool_call_id": "def456",
+        }
+    ]
+
+
 def test_init_o1() -> None:
     with warnings.catch_warnings(record=True) as record:
         warnings.simplefilter("error")  # Treat warnings as errors

libs/partners/openrouter/langchain_openrouter/chat_models.py

@@ -239,7 +239,7 @@ class ChatOpenRouter(BaseChatModel):
     """
 
     route: str | None = None
-    """Route preference for OpenRouter. E.g. `'fallback'`."""
+    """Route preference for OpenRouter, e.g. `'fallback'`."""
 
     plugins: list[dict[str, Any]] | None = None
     """Plugins configuration for OpenRouter."""