Ask Gemini

Tool: ask-gemini

Delegate a bounded subtask to the user's locally-installed Google gemini CLI. The subagent runs on the user's Gemini subscription (not this harness's API key), does its own tool use internally, and returns a final text answer.

⚠ Terms-of-service warning. Invoking the gemini CLI programmatically from this harness may fall outside the Acceptable Use terms of your Google/Gemini subscription (automated/derivative use, rate-limit considerations, etc). The user is responsible for confirming their subscription permits this kind of use before activating this tool. See policies.google.com/terms for the current terms.

Requires

The shell MCP (@wonderwhy-er/desktop-commander, exposed via the shell alias) must be configured and connected. The harness auto-installs it when this tool is activated during harness init. To invoke gemini, you call the shell MCP's start_process tool with the bash command as its argument.

When to reach for this

• Large-context synthesis — Gemini models have very long context windows. Useful for summarizing huge documents or entire codebases in one shot.
• Bounded research — one-shot questions with a clear answer.
• Parallel delegation — fork multiple shell calls for independent research threads.
• Alternative model perspective — second opinion from a Google model without reconfiguring this harness's primary provider.

When NOT to reach for this

• Multi-turn iterative work — each non-interactive call is a fresh session.
• Tasks that need this harness's MCP servers — the CLI doesn't see them.
• Tasks that must return structured tool calls — the CLI absorbs tools internally; you only see final text.

Activation

1. Confirm the CLI is installed:

   which gemini && gemini --version
   

2. Confirm auth:

   gemini -p "say hi"
   

   First run will prompt for authentication.
3. Flip this file's frontmatter from status: draft to status: active.

How to invoke

Non-interactive prompt mode:

gemini -p "Summarize the architecture of this repo based on the README and package.json."

Specifying a model:

gemini -m gemini-3.1-pro -p "<prompt>"

Including files in the prompt context:

gemini -p "Review the attached file for bugs." --include-directories ~/repo/src/runtime

Check gemini --help for the flags available in the installed version — names and defaults vary by release.

Usage pattern

Call the shell MCP's start_process tool with the full command:

start_process({
  command: "gemini -p \"Read all files under ~/repo/docs/ and produce a one-line summary of each. Return as a markdown list.\"",
  timeout_ms: 300000
})

Then read_process_output (and possibly force_terminate on timeout) until the subprocess exits. Treat the captured stdout as if it came from a subagent you spawned.

Gotchas

• Free-tier rate limits are tight — expect failures under load on the free plan. Paid plans are more generous but still capped.
• Output can be very large — Gemini's long context cuts both ways. Tell the CLI explicitly to return a short summary if you don't want a wall of text.
• Non-TTY mode required — use -p / prompt mode. Interactive mode will hang inside a bash subprocess.
• Auth flow — typically OAuth via browser on first run. Cannot be re-authenticated purely programmatically. The user must sign in once.
• Model availability — flag names and model IDs shift across CLI versions. Prefer checking gemini --help over relying on memory.

Notes

• Reach for this when the task specifically needs long-context capability (summarizing a huge document, understanding an entire large codebase) or when the user prefers a Google model.
• If gemini isn't installed, don't fall back silently — tell the user what's missing.

Related: [research], [ask-claude], [ask-codex]

Available scripts

• scripts/call.sh — Auto-generated from this tool's Operations section. Review before relying on it.