Gemini CLI Steps Down, Antigravity CLI Takes Over: A Comprehensive Guide to Google's Agent Terminal Strategy

Google released Antigravity CLI at 2026 I/O, which shares the Agent Harness with Antigravity 2.0 and comes pre-installed with jointly optimized Gemini 3.5 Flash by default. The Gemini CLI for individual users was discontinued on June 18, while enterprise/API Key users are not affected. This article sorts out the migration timeline, core capabilities (Agent Skills, MCP, multi-agent orchestration) and installation and migration steps to help you quickly understand Google's Agent terminal strategy.