Remove dead dict branch in _handle_call_tool and fix call_tool return type#2863
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agaonker wants to merge 1 commit into
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Remove dead dict branch in _handle_call_tool and fix call_tool return type#2863agaonker wants to merge 1 commit into
agaonker wants to merge 1 commit into
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… type `FuncMetadata.convert_result` only ever returns one of three shapes: a `CallToolResult`, a `Sequence[ContentBlock]`, or a `(unstructured_content, structured_content)` tuple. It never returns a raw `dict`, so the `isinstance(result, dict)` branch in `_handle_call_tool` was unreachable (already marked `# pragma: no cover` with a TODO). Remove the dead branch, correct `call_tool`'s return annotation to reflect the three real shapes, and drop the now-orphaned `json` import (used only inside the removed branch). Closes modelcontextprotocol#2695 Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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Closes #2695
What
MCPServer._handle_call_toolcontained a deadisinstance(result, dict)branch, already marked# pragma: no coverwith an inline TODO documenting both the dead code and the related incorrect return-type annotation onMCPServer.call_tool.FuncMetadata.convert_resultreturns exactly three shapes:CallToolResult— when the tool function returned one directlySequence[ContentBlock]— no output schema(unstructured_content, structured_content)tuple — output schema setIt never returns a raw
dict, so the branch was unreachable.Changes
isinstance(result, dict)branch.call_tool's return annotation fromSequence[ContentBlock] | dict[str, Any](claims adictit never returns, omits the two shapes it does) toCallToolResult | Sequence[ContentBlock] | tuple[Sequence[ContentBlock], dict[str, Any]].import json(used only inside the removed branch).The existing
len(result) == 2check and the two pre-existing# type: ignore[arg-type]comments on the tuple branch are left untouched — they silence a real pyrightSequence/tupleoverlap and are out of scope here.Validation
pyright— cleanruff check/ruff format— clean./scripts/test— full suite passes at 100% coverage;strict-no-coverclean (confirms the removed branch was genuinely dead — its removal drops no coverage)🤖 Generated with Claude Code