microsoft/autogen · error · InvalidToolArgumentsException

Error: Invalid arguments: {message.arguments}

Error message

Error: Invalid arguments: {message.arguments}

What it means

Error "Error: Invalid arguments: {message.arguments}" thrown in microsoft/autogen.

Source

Thrown at python/packages/autogen-core/src/autogen_core/tool_agent/_tool_agent.py:91

        Raises:
            ToolNotFoundException: If the tool is not found.
            InvalidToolArgumentsException: If the tool arguments are invalid.
            ToolExecutionException: If the tool execution fails.
        """
        tool = next((tool for tool in self._tools if tool.name == message.name), None)
        if tool is None:
            raise ToolNotFoundException(
                call_id=message.id, content=f"Error: Tool not found: {message.name}", name=message.name
            )
        else:
            try:
                arguments = json.loads(message.arguments)
                result = await tool.run_json(
                    args=arguments, cancellation_token=ctx.cancellation_token, call_id=message.id
                )
                result_as_str = tool.return_value_as_string(result)
            except json.JSONDecodeError as e:
                raise InvalidToolArgumentsException(
                    call_id=message.id, content=f"Error: Invalid arguments: {message.arguments}", name=message.name
                ) from e
            except Exception as e:
                raise ToolExecutionException(call_id=message.id, content=f"Error: {e}", name=message.name) from e
        return FunctionExecutionResult(content=result_as_str, call_id=message.id, is_error=False, name=message.name)

View on GitHub (pinned to 027ecf0a37)

Solutions

1. Supply arguments matching the tool's parameter schema

Example fix

Validate/parse arguments as JSON matching the tool schema before calling

When it happens

Trigger: Thrown at python/packages/autogen-core/src/autogen_core/tool_agent/_tool_agent.py:91 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of microsoft/autogen@027ecf0a37 (2026-08-15). Data as JSON: /api/errors/deb64b3ce5218a08. Report an issue: GitHub.