run-llama/llama_index · error · ValueError

Cannot call query engine without specifying `input`…

Error message

Cannot call query engine without specifying `input` parameter.

What it means

Error "Cannot call query engine without specifying `input` parameter." thrown in run-llama/llama_index.

Solutions

1. Pass an input parameter when calling the query engine tool.
2. Check the tool metadata so the agent knows to supply 'input'.

When it happens

Trigger: Thrown at llama-index-core/llama_index/core/tools/query_engine.py:110 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/7a6684f630ef38ad. Report an issue: GitHub.

Appendix: source

Thrown at llama-index-core/llama_index/core/tools/query_engine.py:110

        )

        tool_config = IndexToolConfig(
            query_engine=self.query_engine,
            name=self.metadata.get_name(),
            description=self.metadata.description,
        )
        return LlamaIndexTool.from_tool_config(tool_config=tool_config)

    def _get_query_str(self, *args: Any, **kwargs: Any) -> str:
        if args is not None and len(args) > 0:
            query_str = str(args[0])
        elif kwargs is not None and "input" in kwargs:
            # NOTE: this assumes our default function schema of `input`
            query_str = kwargs["input"]
        elif kwargs is not None and self._resolve_input_errors:
            query_str = str(kwargs)
        else:
            raise ValueError(
                "Cannot call query engine without specifying `input` parameter."
            )
        return query_str

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