Google Gemini CLI fundamentals for code analysis, review, and validation. Use when (1) executing gemini commands for code review/analysis, (2) configuring models (gemini-3-pro-preview/2.5-pro/flash/flash-lite), output formats (text/json/stream-json), or sandbox modes, (3) managing Gemini sessions with /chat save/resume, (4) integrating Gemini into automation scripts and CI/CD pipelines. Do NOT use for orchestration patterns (use gemini-claude-loop instead).