gemini cli

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---
name: Gemini CLI
description: |
  Consult Google Gemini CLI for second opinions on architecture, debugging, and security audits. Use Gemini's 1M+
  context window for comprehensive code analysis. Compare Flash (fast) vs Pro (thorough) vs 3-Pro-Preview (cutting-edge).

  Use when: need second opinion on architectural decisions, stuck debugging after 2+ attempts, writing security-
  sensitive code, planning refactors (5+ files), approaching 70%+ context capacity, unfamiliar with tech stack,
  need peer review, or want Flash vs Pro vs 3-Pro-Preview comparison.

  Keywords: gemini-cli, google gemini, gemini command line, second opinion, model comparison, gemini-2.5-flash, gemini-2.5-pro, gemini-3-pro-preview, architectural decisions, debugging assistant, code review gemini, security audit gemini, 1M context window, AI pair programming, gemini consultation, flash vs pro, AI-to-AI prompting, peer review, codebase analysis, gemini CLI tool, shell gemini, command line AI assistant, gemini architecture advice, gemini debug help, gemini security scan, gemini code compare
license: MIT
metadata:
  version: 2.1.0
  production_tested: true
  gemini_cli_version: 0.13.0+
  last_verified: 2025-11-19
  token_savings: ~60-70%
  errors_prevented: 6+
  breaking_changes: Added Gemini 3 Pro Preview model (gemini-3-pro-preview)
---

# Gemini CLI

**Leverage Gemini's 1M+ context window as your AI pair programmer within Claude Code workflows.**

This skill teaches Claude Code how to use the official Google Gemini CLI (`gemini` command) to get second opinions, architectural advice, debugging help, and comprehensive code reviews. Based on production testing with the official CLI tool.

---

## Table of Contents

1. [Quick Start](#quick-start)
2. [When to Use Gemini Consultation](#when-to-use-gemini-consultation)
3. [Installation](#installation)
4. [Using Gemini CLI](#using-gemini-cli)
5. [Model Selection: Flash vs Pro](#model-selection-flash-vs-pro)
6. [Proactive Consultation Patterns](#proactive-consultation-patterns)
7. [AI-to-AI Prompting Best Practices](#ai-to-ai-prompting-best-practices)
8. [Common Use Cases](#common-use-cases)
9. [Integration Examples](#integration-examples)
10. [Troubleshooting & Known Issues](#troubleshooting--known-issues)

---

## Quick Start

**Prerequisites**:
- Gemini CLI installed (`npm install -g @google/gemini-cli`)
- Authenticated with Google account (run `gemini` once to authenticate)

**Basic Usage Patterns**:

```bash
# Quick question (non-interactive with -p flag)
gemini -p "Should I use D1 or KV for session storage?"

# Code review with file context (using --all-files)
gemini --all-files -p "Review this auth implementation for security issues"

# Architecture advice using Pro model
gemini -m gemini-2.5-pro -p "Best way to handle WebSockets in Cloudflare Workers?"

# Pipe file content for review
cat src/auth.ts | gemini -p "Review this authentication code for security vulnerabilities"

# Interactive mode for follow-up questions
gemini -i "Help me debug this authentication error"
```

---

## When to Use Gemini Consultation

### ALWAYS Consult (Critical Scenarios)

Claude Code should **automatically invoke Gemini** in these situations:

1. **Major Architectural Decisions**
   - Example: "Should I use D1 or KV for session storage?"
   - Example: "Durable Objects vs Workflows for long-running tasks?"
   - Why: Gemini provides complementary perspective, may prioritize different concerns
   - **Pattern**: `gemini -m gemini-2.5-pro -p "[architectural question]"`

2. **Security-Sensitive Code Changes**
   - Authentication systems
   - Payment processing
   - Data handling (PII, sensitive data)
   - API key/secret management
   - Why: Gemini 2.5 Pro excels at security audits
   - **Pattern**: `cat [security-file] | gemini -m gemini-2.5-pro -p "Security audit this code"`

3. **Large Refactors**
   - Affecting 5+ files
   - Core architecture changes
   - Database schema migrations
   - Why: Fresh perspective prevents tunne