Gemini Code Review

Gemini Code Review

Get code reviews from Google Gemini CLI. Useful for getting a second AI perspective on your changes.

Prerequisites

1. Install Gemini CLI:

   npm install -g @google/gemini-cli
   

2. Authenticate (one of):

   • Google Login: Run gemini once and follow OAuth flow (free tier: 60 req/min, 1000/day)
   • API Key: Set GEMINI_API_KEY environment variable
   • Vertex AI: Set GOOGLE_GENAI_USE_VERTEXAI=true + GCP credentials

3. Verify installation:

   gemini --version
   

Usage

Review staged changes

git diff --cached | gemini -p "Review this code for bugs, security issues, and code quality. Be specific with file names and line numbers." -m gemini-3-pro-preview --output-format text

Review unstaged changes

git diff | gemini -p "Review this code for bugs, security issues, and code quality. Be specific with file names and line numbers." -m gemini-3-pro-preview --output-format text

Review all uncommitted changes

git diff HEAD | gemini -p "Review this code for bugs, security issues, and code quality. Be specific with file names and line numbers." -m gemini-3-pro-preview --output-format text

Review changes on branch (vs main)

git diff main...HEAD | gemini -p "Review this code for bugs, security issues, and code quality. Be specific with file names and line numbers." -m gemini-3-pro-preview --output-format text

Review specific file

git diff HEAD -- path/to/file.ts | gemini -p "Review this code change." -m gemini-3-pro-preview --output-format text

Get JSON output (for parsing)

git diff --cached | gemini -p "Review this code. Return JSON with: {issues: [{file, line, severity, message}], summary: string}" -m gemini-3-pro-preview --output-format json

Review Prompts

Standard review

Review this code for:
1. Bugs and logic errors
2. Security vulnerabilities
3. Performance issues
4. Code quality and maintainability
Be specific with file names and line numbers.

Security-focused

Security review this code. Look for:
- Injection vulnerabilities (SQL, command, XSS)
- Authentication/authorization issues
- Data exposure risks
- Input validation gaps

Quick sanity check

Quick review: any obvious bugs or issues in this diff?

Flags Reference

When to Use

• Before committing: get a second opinion on your changes
• PR review: supplement human review with AI analysis
• Learning: understand potential issues in your code
• Security audit: catch common vulnerabilities

Notes

• Gemini CLI reads from stdin, so pipe your diff directly
• For large diffs, consider reviewing file-by-file
• Output goes to stdout; redirect to file if needed

Source: matteo1222/agent-skills — distributed by TomeVault.