By On June 18, 2026, Google will cut off authentication for Gemini CLI — and the clock is running for anyone on a Google AI Pro, Ultra, or free Gemini Code Assist individual account. The replacement is Antigravity CLI, a closed-source Go binary with the command name agy, multi-model support, and a migration that takes about five minutes. The hard question is not whether to switch; it is whether this swap is actually good news for developers.
Who Needs to Act (and Who Doesnt)
First, the important carveout: if your organization uses Gemini CLI through a Gemini Code Assist Standard or Enterprise license — or via Gemini Code Assist for GitHub on Google Cloud — nothing changes. Google is leaving enterprise access untouched.
Everyone else — Google AI Pro, Ultra, and free individual Gemini Code Assist users — loses access on June 18. That is a hard cutoff, not a deprecation warning with a year-long tail.
Migration Checklist: Do This Today
The migration is straightforward. Install Antigravity CLI and it handles the rest.
# Install via npm
npm install -g @google/agy
# Or via Homebrew (macOS/Linux)
brew install google/agy/agy
# First run auto-detects your ~/.gemini/ config
agy
# Explicit migration (non-destructive — old config stays)
agy plugin import geminiOn first launch, agy detects your existing Gemini CLI configuration and walks you through an interactive migration. Your old ~/.gemini/ directory stays intact until June 18, so you can roll back if needed. After migration, agy replaces gemini in your terminal. Update the binary later with agy update.
One step people commonly miss: update any CI/CD scripts or shell aliases that call gemini directly. Those will break silently after the cutoff.
What You Actually Get With Antigravity CLI
Antigravity CLI is not just a rename. Built in Go versus Gemini CLIs Node.js base, it starts faster. More importantly, it is multi-model from day one: alongside Gemini 3.5 Flash and Gemini 3.1 Pro, you can invoke Claude Sonnet, Claude Opus, and GPT-OSS 120B. Gemini CLI was Gemini-only — that model flexibility is a real upgrade.
The agentic layer steps up as well. Antigravity CLI orchestrates multiple background agents in parallel without locking your terminal, which matters for large refactors or parallel research tasks. Agent Skills, Hooks, Subagents, and MCP server support all carry over. Extensions become “Antigravity plugins,” and while there is not 1:1 feature parity at launch, the critical workflows migrate cleanly.
Antigravity CLI is the terminal surface of a larger platform: Antigravity 2.0 ships with a desktop app, SDK, Managed Agents API, and Enterprise Agent Platform. The desktop app and CLI share a single agent harness, so improvements to core agents apply automatically across both.
The Open Source Problem Google Has Not Answered
Here is where it gets uncomfortable. Gemini CLI was MIT-licensed and open source. The community filed and merged more than 6,000 pull requests — bug reports, extensions, edge-case fixes. Antigravity CLI has no published source code and no open-source commitment, and Google has not responded to the obvious question raised in the GitHub issue thread.
The reaction on Hacker News was immediate. The top comment — “Google really cannot help themselves but kill off public things people use” — cleared 410 upvotes. Developers who contributed real labor to Gemini CLI are being handed a closed-source binary and told to migrate in under a month. Compare it to Claude Code and OpenAI Codex CLI, both of which remain fully open source. Antigravity is now the only major agentic CLI without a public repo.
Google may open source Antigravity later — but “may” and “later” do not reassure developers who have watched this pattern before. The Register coverage summarized community sentiment accurately: this is a bait-and-switch, full stop.
Bottom Line
Migrate today if you are on Pro, Ultra, or a free individual plan. The five-minute install is worth doing now rather than hitting an auth wall on June 18. Antigravity CLI has real improvements — faster startup, multi-model support, better agentic orchestration — and the migration is non-destructive.
But hold Google accountable for the open source pivot. The official announcement and the migration guide tell you how to move. What they do not tell you is what happens to the thousands of developers who built the tool Google is now replacing with a closed binary. That question deserves an answer before the deadline, not after.
