Gemini CLI Integration Skill

This skill enables Claude Code to effectively orchestrate Gemini CLI (v0.16.0+) with Gemini 3 Pro for code generation, review, analysis, and specialized tasks.

When to Use This Skill

Ideal Use Cases

1. Second Opinion / Cross-Validation

   • Code review after writing code (different AI perspective)
   • Security audit with alternative analysis
   • Finding bugs Claude might have missed

2. Google Search Grounding

   • Questions requiring current internet information
   • Latest library versions, API changes, documentation updates
   • Current events or recent releases

3. Codebase Architecture Analysis

   • Use Gemini's codebase_investigator tool
   • Understanding unfamiliar codebases
   • Mapping cross-file dependencies

4. Parallel Processing

   • Offload tasks while continuing other work
   • Run multiple code generations simultaneously
   • Background documentation generation

5. Specialized Generation

   • Test suite generation
   • JSDoc/documentation generation
   • Code translation between languages

When NOT to Use

• Simple, quick tasks (overhead not worth it)
• Tasks requiring immediate response (rate limits cause delays)
• When context is already loaded and understood
• Interactive refinement requiring conversation

Core Instructions

1. Verify Installation

command -v gemini || which gemini

2. Basic Command Pattern

gemini "[prompt]" --yolo -o text 2>&1

Key flags:

• --yolo or -y: Auto-approve all tool calls
• -o text: Human-readable output
• -o json: Structured output with stats
• -m gemini-2.5-flash: Use faster model for simple tasks

3. Critical Behavioral Notes

YOLO Mode Behavior: Auto-approves tool calls but does NOT prevent planning prompts. Gemini may still present plans and ask "Does this plan look good?" Use forceful language:

• "Apply now"
• "Start immediately"
• "Do this without asking for confirmation"

Rate Limits: Free tier has 60 requests/min, 1000/day. CLI auto-retries with backoff. Expect messages like "quota will reset after Xs".

4. Output Processing

For JSON output (-o json), parse: { "response": "actual content", "stats": { "models": { "tokens": {...} }, "tools": { "byName": {...} } } }

5. Optimizing Tool & Extension Loading

To improve performance and reduce context, load only the extensions and MCP servers required for the task.

Manage Extensions (-e / --extensions): By default, all installed extensions are loaded. Specify only what you need:

Only load the postgres extension for database tasks

gemini "Analyze long running queries" -e postgres --yolo -o text

Load multiple specific extensions

gemini "Review this code" -e code-review gemini-cli-jules --yolo -o text

Run without any extensions (fastest for pure code logic)

gemini "Refactor this function" -e [] --yolo -o text

Manage MCP Servers (--allowed-mcp-server-names): Restrict which MCP servers are accessible:

gemini "Check browser logs" --allowed-mcp-server-names chrome-devtools --yolo -o text

Available Extensions:

• postgres: Database operations
• code-review: specialized code review
• chrome-devtools-mcp: Browser automation
• gemini-cli-jules: Jules integration
• context7: Context management
• agent-creator: Agent creation tools

Quick Reference Commands

Code Generation

gemini "Create [description] with [features]. Output complete file content." --yolo -o text

Code Review

gemini "Review [file] for: 1) features, 2) bugs/security issues, 3) improvements" -o text

Bug Fixing

gemini "Fix these bugs in [file]: [list]. Apply fixes now." --yolo -o text

Test Generation

gemini "Generate [Jest/pytest] tests for [file]. Focus on [areas]." --yolo -o text

Documentation

gemini "Generate JSDoc for all functions in [file]. Output as markdown." --yolo -o text

Architecture Analysis

gemini "Use codebase_investigator to analyze this project" -o text

Web Research

gemini "What are the latest [topic]? Use Google Search." -o text

Faster Model (Simple Tasks)

gemini "[prompt]" -m gemini-2.5-flash -o text

Error Handling

Rate Limit Exceeded

• CLI auto-retries with backoff
• Use -m gemini-2.5-flash for lower priority tasks
• Run in background for long operations

Command Failures

• Check JSON output for detailed error stats
• Verify Gemini is authenticated: gemini --version
• Check ~/.gemini/settings.json for config issues

Validation After Generation

Always verify Gemini's output:

• Check for security vulnerabilities (XSS, injection)
• Test functionality matches requirements
• Review code style consistency
• Verify dependencies are appropriate

Integration Workflow

Standard Generate-Review-Fix Cycle

1. Generate

gemini "Create [code]" --yolo -o text

2. Review (Gemini reviews its own work)

gemini "Review [file] for bugs and security issues" -o text

3. Fix identified issues

gemini "Fix [issues] in [file]. Apply now." --yolo -o text

Background Execution

For long tasks, run in background and monitor:

gemini "[long task]" --yolo -o text 2>&1 &

Monitor with BashOutput tool

Gemini's Unique Capabilities

These tools are available only through Gemini:

1. google_web_search - Real-time internet search via Google
2. codebase_investigator - Deep architectural analysis
3. save_memory - Cross-session persistent memory

Configuration

Project Context (Optional)

Create .gemini/GEMINI.md in project root for persistent context that Gemini will automatically read.

Session Management

List sessions: gemini --list-sessions Resume session: echo "follow-up" | gemini -r [index] -o text

See Also

• reference.md - Complete command and flag reference
• templates.md - Prompt templates for common operations
• patterns.md - Advanced integration patterns
• tools.md - Gemini's built-in tools documentation