langchain-ai/langgraph · error · DeprecationWarning

Setting attribute ' ' on ToolCallRequest is deprecated. Use…

Error message

Setting attribute '{name}' on ToolCallRequest is deprecated. Use the override() method instead to create a new instance with modified values.

What it means

Deprecation warning from ToolCallRequest.__setattr__: ToolCallRequest is a frozen-style dataclass, and directly assigning to its fields after construction is deprecated. The assignment is still applied via object.__setattr__, but mutation should go through override(), which returns a new instance.

Solutions

1. Replace 'req.state = new_state' with 'req = req.override(state=new_state)'
2. Build modified copies via override() for tool, state, or runtime fields instead of mutating in place

When it happens

Trigger: Thrown at libs/prebuilt/langgraph/prebuilt/tool_node.py:162 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of langchain-ai/langgraph@38031739e5 (2026-08-26). Data as JSON: /api/errors/35ec789a389ed6a8. Report an issue: GitHub.

Appendix: source

Thrown at libs/prebuilt/langgraph/prebuilt/tool_node.py:162

    """

    tool_call: ToolCall
    tool: BaseTool | None
    state: Any
    runtime: ToolRuntime

    def __setattr__(self, name: str, value: Any) -> None:
        """Raise deprecation warning when setting attributes directly.

        Direct attribute assignment is deprecated. Use the `override()` method instead.
        """
        import warnings

        # Allow setting attributes during initialization
        if not hasattr(self, "__dataclass_fields__") or not hasattr(self, name):
            object.__setattr__(self, name, value)
        else:
            warnings.warn(
                f"Setting attribute '{name}' on ToolCallRequest is deprecated. "
                "Use the override() method instead to create a new instance with modified values.",
                DeprecationWarning,
                stacklevel=2,
            )
            object.__setattr__(self, name, value)

    def override(
        self, **overrides: Unpack[_ToolCallRequestOverrides]
    ) -> ToolCallRequest:
        """Replace the request with a new request with the given overrides.

        Returns a new `ToolCallRequest` instance with the specified attributes replaced.
        This follows an immutable pattern, leaving the original request unchanged.

        Args:
            **overrides: Keyword arguments for attributes to override.

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