run-llama/llama_index · error · ValueError

Context is required for this tool

Error message

Context is required for this tool

What it means

Error "Context is required for this tool" thrown in run-llama/llama_index.

Source

Thrown at llama-index-core/llama_index/core/tools/function_tool.py:340

        elif isinstance(raw_output, (BaseNode, Document)):
            return [TextBlock(text=raw_output.get_content())]
        elif isinstance(raw_output, list) and all(
            isinstance(item, (BaseNode, Document)) for item in raw_output
        ):
            return [TextBlock(text=item.get_content()) for item in raw_output]
        else:
            return [TextBlock(text=str(raw_output))]

    def __call__(self, *args: Any, **kwargs: Any) -> ToolOutput:
        all_kwargs = {**self.partial_params, **kwargs}
        return self.call(*args, **all_kwargs)

    def call(self, *args: Any, **kwargs: Any) -> ToolOutput:
        """Sync Call."""
        all_kwargs = {**self._field_defaults, **self.partial_params, **kwargs}
        if self.requires_context and self.ctx_param_name is not None:
            if self.ctx_param_name not in all_kwargs:
                raise ValueError("Context is required for this tool")

        raw_output = self._fn(*args, **all_kwargs)

        # Exclude the Context param from the tool output so that the Context can be serialized
        tool_output_kwargs = {
            k: v for k, v in all_kwargs.items() if k != self.ctx_param_name
        }

        # Parse tool output into content blocks
        output_blocks = self._parse_tool_output(raw_output)

        # Default ToolOutput based on the raw output
        default_output = ToolOutput(
            blocks=output_blocks,
            tool_name=self.metadata.get_name(),
            raw_input={"args": args, "kwargs": tool_output_kwargs},
            raw_output=raw_output,
        )

View on GitHub (pinned to afd0fef371)

Solutions

1. Pass ctx=... when calling a tool that requires context.
2. Remove the ctx parameter from the function signature if context is not needed.

When it happens

Trigger: Thrown at llama-index-core/llama_index/core/tools/function_tool.py:340 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of run-llama/llama_index@afd0fef371 (2026-08-15). Data as JSON: /api/errors/1bed4010f1b69d40. Report an issue: GitHub.