Gemini CLI Custom Commands FAQ & Answers

Gemini CLI custom commands (2025): reusable workflow templates enforcing team standards. Configuration: create ~/.gemini/commands.json or project-local .gemini/commands.json (project overrides global). Format: {"commands": {"security-review": {"prompt": "Review this code for OWASP Top 10 vulnerabilities (SQL injection, XSS, CSRF), authentication/authorization issues...", "files": true, "outputFormat": "markdown", "model": "gemini-2.0-flash-exp"}, "api-docs": {"prompt": "Generate OpenAPI 3.1 spec with: endpoint descriptions, request/response schemas...", "files": true, "outputFormat": "yaml"}}}. Usage: gemini security-review --file src/auth.ts executes custom command with standardized prompt.

Advanced patterns: (1) Parameterized commands - {"prompt": "Analyze ${FILE} for ${CONCERN}"}, pass: gemini analyze --file app.js --var CONCERN="performance bottlenecks", (2) Multi-step workflows - {"steps": [{"prompt": "Analyze architecture", "checkpoint": "arch-analysis"}, {"prompt": "List improvements from previous analysis"}]}, (3) Conditional logic - {"if": "${LANG} == 'typescript'", "prompt": "Check type safety"}, (4) Output templates - include JSON schema in prompt for structured parsing. Model selection: specify per-command ("model": "gemini-2.0-flash-exp" for speed, "gemini-1.5-pro" for complex reasoning).

Team collaboration: (1) Commit .gemini/commands.json to repo (version control commands alongside code), (2) Document in README.md: available commands (gemini --list-commands), usage examples, expected outputs, (3) Code review commands as code - PR reviews for command updates, (4) Shared command registry - internal npm package with company-wide commands. Production use cases: Security review (OWASP compliance checks before deployment), API documentation (auto-generate OpenAPI specs), Test generation (maintain >80% coverage automatically), Code migration (React Class → Hooks, JavaScript → TypeScript), Accessibility audits (WCAG 2.1 AA compliance). Essential for scaling AI-assisted development across teams (100+ engineers using standardized commands = consistent code quality).

Best practices: (1) Name convention: verb-noun (review-security, generate-tests, migrate-typescript), (2) Include concrete examples in prompts (few-shot learning improves output quality 40%), (3) Version commands with semantic versioning (review-security v1.2.0), (4) Test commands on sample data before team rollout (validate output format/quality), (5) Monitor usage: gemini metrics shows command execution frequency, (6) Iterate based on feedback - update prompts as team needs evolve. Integration: combine with CI/CD (run gemini security-review in GitHub Actions), pre-commit hooks (gemini lint-commit-message), IDE extensions (VS Code task integration). Performance: zero overhead vs manual prompts (commands expand to full prompts at runtime), caching applies normally.