/gemini

name: gemini
description: Use when the user asks to run Gemini CLI for code review, plan review, or big context (>200k) processing. Ideal for comprehensive analysis requiring large context windows. Uses Gemini 3 Pro by default for state-of-the-art reasoning and coding.

Gemini Skill Guide

When to Use Gemini

• WHEN ASKED TO BE ACTIVATED
• **Code Review**: Comprehensive code reviews across multiple files
• **Plan Review**: Analyzing architectural plans, technical specifications, or project roadmaps
• **Big Context Processing**: Tasks requiring >200k tokens of context (entire codebases, documentation sets)
• **Multi-file Analysis**: Understanding relationships and patterns across many files

⚠️ Critical: Background/Non-Interactive Mode Warning

**NEVER use `--approval-mode default` in background or non-interactive shells** (like Claude Code tool calls). It will hang indefinitely waiting for approval prompts that cannot be provided.

**For automated/background reviews:**

• ✅ Use `--approval-mode yolo` for fully automated execution
• ✅ OR wrap with timeout: `timeout 300 gemini ...`
• ❌ NEVER use `--approval-mode default` without interactive terminal

**Symptoms of hung Gemini:**

• Process running 20+ minutes with 0% CPU usage
• No network activity
• Process state shows 'S' (sleeping)

**Fix hung process:**

# Check if hung
ps aux | grep gemini | grep -v grep

# Kill if necessary
pkill -9 -f "gemini.*gemini-3-pro-preview"

Running a Task

1. Ask the user (via `AskUserQuestion`) which model to use in a **single prompt**. Available models:

• `gemini-3-pro-preview` ⭐ (flagship model, best for coding & complex reasoning, 35% better at software engineering than 2.5 Pro)
• `gemini-3-flash` (sub-second latency, distilled from 3 Pro, best for speed-critical tasks)
• `gemini-2.5-pro` (legacy option, strong all-around performance)
• `gemini-2.5-flash` (legacy option, cost-efficient with thinking capabilities)
• `gemini-2.5-flash-lite` (legacy option, fastest processing)

2. Select the approval mode based on the task:

• `default`: Prompt for approval (⚠️ ONLY for interactive terminal sessions)
• `auto_edit`: Auto-approve edit tools only (for code reviews with suggestions)
• `yolo`: Auto-approve all tools (✅ REQUIRED for background/automated tasks)

3. Assemble the command with appropriate options:

• `-m, --model <MODEL>` - Model selection
• `--approval-mode <default|auto_edit|yolo>` - Control tool approval
• `-y, --yolo` - Alternative to `--approval-mode yolo`
• `-i, --prompt-interactive "prompt"` - Execute prompt and continue interactively
• `--include-directories <DIR>` - Additional directories to include in workspace
• `-s, --sandbox` - Run in sandbox mode for isolation

4. **For background/automated tasks, ALWAYS use `--approval-mode yolo`** or add timeout wrapper. NEVER use `default` in non-interactive shells.

5. Run the command and capture the output. For background/automated mode:

   # Recommended: Use yolo for background tasks
   gemini -m gemini-3-pro-preview --approval-mode yolo "Review this codebase for security issues"

   # Or with timeout (5 min limit)
   timeout 300 gemini -m gemini-3-pro-preview --approval-mode yolo "Review this codebase"

6. For interactive sessions with an initial prompt:

   gemini -m gemini-3-pro-preview -i "Review the authentication system" --approval-mode auto_edit

7. **After Gemini completes**, inform the user: "The Gemini analysis is complete. You can start a new Gemini session for follow-up analysis or continue exploring the findings."

Quick Reference

| Use case | Approval mode | Key flags | | --- | --- | --- | | Background code review | `yolo` ✅ | `-m gemini-3-pro-preview --approval-mode yolo` | | Background analysis | `yolo` ✅ | `-m gemini-3-pro-preview --approval-mode yolo` | | Background with timeout | `yolo` ✅ | `timeout 300 gemini -m gemini-3-pro-preview --approval-mode yolo` | | Interactive code review | `default` | `-m gemini-3-pro-preview --approval-mode default` (interactive terminal only) | | Code review with auto-edits | `auto_edit` | `-m gemini-3-pro-preview --approval-mode auto_edit` | | Automated refactoring | `yolo` | `-m gemini-3-pro-preview --approval-mode yolo` | | Speed-critical background | `yolo` ✅ | `-m gemini-3-flash --approval-mode yolo` | | Cost-optimized background | `yolo` ✅ | `-m gemini-2.5-flash --approval-mode yolo` | | Multi-directory analysis | `yolo` (if background) | `--include-directories <DIR1> --include-directories <DIR2>` | | Interactive with prompt | `auto_edit` or `default` | `-i "prompt" --approval-mode <mode>` |

Model Selection Guide

| Model | Best for | Context window | Key features | | --- | --- | --- | --- | | `gemini-3-pro-preview` ⭐ | **Flagship model**: Complex reasoning, coding, agentic tasks | 1M input / 64k output | Vibe coding, 76.2% SWE-bench, $2-4/M input | | `gemini-3-flash` | Sub-second latency, speed-critical applications | 1M input / 64k output | Distilled from 3 Pro, TPU-optimized | | `gemini-2.5-pro` | Legacy: Strong all-around performance | 1M input / 65k output | Thinking mode, mature stability | | `gemini-2.5-flash` | Legacy: Cost-efficient, high-volume tasks | 1M input / 65k output | Best price ($0.15/M), thinking mode | | `gemini-2.5-flash-lite` | Legacy: Fastest processing, high throughput | 1M input / 65k output | Maximum speed, minimal latency |

**Gemini 3 Advantages**: 35% higher accuracy in software engineering, state-of-the-art on SWE-bench (76.2%), GPQA Diamond (91.9%), and WebDev Arena (1487 Elo). Knowledge cutoff: January 2025.

**Coming Soon**: `gemini-3-deep-think` for ultra-complex reasoning with enhanced thinking capabilities.

Common Use Cases

Code Review (Background/Automated)

# For background execution (Claude Code, CI/CD, etc.)
gemini -m gemini-3-pro-preview --approval-mode yolo \
  "Perform a comprehensive code review focusing on:
   1. Securit