Collaborating with Gemini CLI

Use this skill when you want a second model (Gemini) to sanity-check a solution, spot edge cases, propose tests, or suggest an alternative implementation approach.

This skill provides a small JSON bridge script that runs gemini (Gemini CLI) in non-interactive headless mode and returns structured output.

Compared to collaborating-with-claude-code, this skill defaults to read-only and is optimized for file-scoped, one-shot requests to avoid practical effective-context degradation.

Requirements

• Gemini CLI installed (gemini --version).
  • Install via npm: npm i -g @google/gemini-cli
• Gemini CLI authenticated (Google account login or API key auth, depending on your local setup).
• Python 3 (to run the bridge script).

Quick start

python scripts/gemini_cli_bridge.py --cd "/path/to/repo" --PROMPT "Review src/auth/login.py for bypasses; propose fixes as a unified diff."

Recommended (explicit file scope, best for effective context):

python scripts/gemini_cli_bridge.py --cd "/path/to/repo" --file "src/auth/login.py" --PROMPT "Review this file for bypasses; propose fixes as a unified diff."

Multi-turn sessions

Always capture the returned SESSION_ID and pass it back on follow-ups:

# Start a new session (one-shot by default)
python scripts/gemini_cli_bridge.py --cd "/repo" --file "src/auth/login.py" --PROMPT "Summarize issues and propose a patch."

# Continue the same session
python scripts/gemini_cli_bridge.py --cd "/repo" --SESSION_ID "uuid-from-response" --PROMPT "Now propose 5 targeted tests for the fix."

Access modes

This skill defaults to --no-full-access (read-only).

• Read-only (default): --no-full-access → maps to gemini --approval-mode default
• Full access (edits allowed): --full-access → maps to gemini --approval-mode auto_edit
• YOLO (auto-approve everything): --yolo → maps to gemini --approval-mode yolo

Examples:

# Allow edits (auto-approve edit tools)
python scripts/gemini_cli_bridge.py --full-access --cd "/repo" --file "src/foo.py" --PROMPT "Refactor for clarity; keep behavior; apply edits."

# YOLO mode (dangerous): allow any tool calls without confirmation
python scripts/gemini_cli_bridge.py --yolo --cd "/repo" --PROMPT "Run tests, fix failures, and apply edits."

Effective-context guardrails (default ON)

By default the bridge enables conservative guardrails designed for practical effective context:

• Adds a preamble instructing Gemini to stop and ask before reading additional files.
• Strongly encourages file-scoped runs (use --file and keep each call small).
• Uses --max-files as a preference for “how many files per turn” and as a cap for auto-extracted files (only when you did not pass explicit --file).

User override options:

• --file PATH (repeatable): explicitly decide the focus file set (recommended; not blocked by --max-files).
• --max-files N: raise the preferred cap / auto-extraction cap.
• --no-guardrails: disable guardrails (Gemini may read many files; treat like a normal agent).

Session rotation guidance (effective context)

The bridge exposes Gemini CLI token stats when available:

• meta.prompt_tokens: prompt tokens reported by Gemini CLI
• meta.over_effective_context_limit: true when prompt_tokens > --effective-context-tokens

When meta.over_effective_context_limit is true, prefer starting a new session for the next turn (omit --SESSION_ID) and/or reduce the focus scope.

Parameters (bridge script)

• --PROMPT (required): Instruction to send to Gemini.
• --cd (required): Working directory to run Gemini CLI in (typically repo root).
• --SESSION_ID (optional): Resume an existing Gemini CLI session (uuid).
• --model (optional): Defaults to gemini-3-pro-preview.
• --full-access / --no-full-access (optional): Defaults to --no-full-access.
• --yolo (optional): YOLO approval mode (implies full access).
• --sandbox (optional): Run Gemini CLI in sandbox mode (requires Docker). Default: off.
• --return-all-messages (optional): Return the full streamed event list (debugging).
• --file PATH (repeatable): Focus files to prepend as @PATH (recommended).
• --max-files / --no-guardrails / --effective-context-tokens: Guardrail controls (--max-files is a preference + auto-extraction cap; it does not block explicit --file).
• --timeout-s (optional): Defaults to 1800 seconds.

Output format

The bridge prints JSON:

{
  "success": true,
  "SESSION_ID": "uuid",
  "agent_messages": "…Gemini output…",
  "all_messages": [],
  "meta": {}
}

meta includes the normalized focus file list and (when available) token stats extracted from Gemini CLI output.