Google's Gemini CLI now supports the Gemini 3 Preview models, bringing advanced reasoning and context management directly to the terminal. Developers need version 0.21.1 or later, installed via npm. The update enables smarter model routing between 'Pro' and 'Flash' versions, aiming to boost coding workflow for terminal-centric developers.

To enable Gemini 3, users must toggle Preview Features to True in the CLI settings and select the Auto (Gemini 3) model. This configuration is key for handling complex refactoring and large codebases without losing context. The CLI's intelligent routing helps save API quota by matching query complexity to model power.

For maximum benefit, creating a .geminiignore file is critical to filter out irrelevant directories like `node_modules`. Leveraging Context Caching during long sessions improves speed, and using the Codebase Investigator agent helps with deep-dive analysis. The author advises disabling auto-accept and treating AI output as a code review, not a final commit.