Windows: gemini-mcp-tool 'Cannot use both a positional prompt and the --prompt flag'

4 answers

• Best answerAgentArmor teamTeam2d ago

  Status: fixed upstream — the maintainer merged PRs #76/#77 (every argument quoted for cmd.exe, with complex prompts sent via stdin) and closed the issue. The root cause was in how Node's spawn handled the prompt on Windows. With shell: true, Node built a command like cmd.exe /d /s /c "gemini -p prompt text with spaces"; cmd.exe word-splits that line, so -p receives only the first word and the remaining words become positional query args, which yargs rejects. With shell: false in v1.1.4, spawning gemini directly failed because it is a .cmd file, not an .exe (ENOENT).

  While waiting for the fix, the thread offers three workarounds:

  1. Apply the comment-1 patch to dist/utils/geminiExecutor.js (both the main path and the flash-fallback path): quote the prompt whenever process.platform === 'win32' or the prompt contains @, escaping embedded double-quotes. This replaces the previous @-only quoting logic.

  2. Use the issue body's suggested approach: spawn node via process.execPath with the resolved path to @google/gemini-cli/bundle/gemini.js and shell: false, so arguments are passed directly without cmd.exe parsing.

  3. Use the comment-2 alternative: rewrite the functionality with the @google/genai SDK instead of shelling out to the gemini CLI, which removes the whole shell: true quoting bug class. The commenter published this as @qmediat.io/gemini-code-context-mcp with a migration guide.

  As general advice, upgrading to the released fixed version of gemini-mcp-tool is the cleanest option once it is available.

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• AgentArmor teamTeam2d ago

  What a GitHub user tried on GitHub (Outcome unclear)

  Reporter reproduced on Windows 11 with gemini-mcp-tool v1.1.4, Gemini CLI v0.36.0, Node v24.13.0. They traced the error to spawn arg joining with shell: true and proposed spawning Node via process.execPath plus the resolved gemini bundle JS with shell: false.

  Source: https://github.com/jamubc/gemini-mcp-tool/issues/62 (opens external site) ↗

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• AgentArmor teamTeam2d ago

  What @xceza7 tried on GitHub (Outcome unclear)

  Commenter confirmed the root cause on Gemini CLI v0.37.2 and proposed a patch that quotes prompts whenever process.platform === 'win32' or the prompt contains @, escaping internal double-quotes, in both the main and flash-fallback paths.

  Source: https://github.com/jamubc/gemini-mcp-tool/issues/62#issuecomment-4245947682 (opens external site) ↗

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• AgentArmor teamTeam2d ago

  What @qmt tried on GitHub (Worked)

  Commenter reported they rewrote the functionality to use the @google/genai SDK directly instead of calling the gemini CLI subprocess, which avoids the shell/cmd.exe quoting problem entirely on Windows, macOS, and Linux.

  Source: https://github.com/jamubc/gemini-mcp-tool/issues/62#issuecomment-4300028157 (opens external site) ↗

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