⚡ Quick look

Claude stays the conductor; the bulk, token-heavy read ran on cheaper Gemini, and Claude verified the result.

💡 Why

you → Claude Code (conduct: design / verify / review)
         └── agy → Gemini (execute: implement / test / search)

Generation is solved; verification, judgement, and direction are the craft.

✨ What it does

• Routes work across the SDLC — Claude keeps the judgement calls; Antigravity handles scaffolding, test generation, first-pass review, and migrations under a shared AGENTS.md.
• Adds tools Claude lacks natively — live Google/web search, Vertex AI Search over your internal data, deep research, Cloud Logging. Claude reviews and re-checks the results.
• Cross-model verification — an independent, different-model opinion on your code.
• Background jobs — fire a long delegation, keep working, collect later.
• Built-in cost discipline — measured, not guessed (see below).
• Drops in with the discipline on — a SessionStart hook injects the cost-aware routing policy automatically (toggle in plugin settings), and the antigravity-delegate subagent does file writing on Gemini, so Claude spends no tokens generating file contents.

📊 Measured results

On a large ADK multi-agent build (+ adk eval), same task / same model, 3 ways:

→ −27% vs solo@high, −64% vs solo@max, at equal quality — and the cheap Gemini work isn't even counted. Savings scale with task size; tiny one-off tasks are cheaper to just run on Claude. Full A/B: docs/AB-RESULTS.md.

Note on cost figures: numbers are estimates — token counts are approximated and rates live in prices.json. Set your real Vertex rates there before quoting any figure.

🚀 Install

In Claude Code:

/plugin marketplace add yuting0624/antigravity-for-claude-code
/plugin install antigravity@antigravity-for-claude-code
/antigravity:setup        # verifies agy is installed + authenticated

Prerequisites: the Antigravity CLI (agy) installed & authenticated (agy models lists Gemini models), and Claude Code. For the same-bill cost benefit, run Claude Code on Vertex too.

🧩 Slash commands

The plugin's commands show up natively in Claude Code's / menu.

Background jobs are for interactive sessions (fire-and-collect). In headless claude -p (one-shot), delegate synchronously — there's no later turn to collect a result.

# one-shot delegation (plain text on stdout)
scripts/agy-delegate.sh --tier flash "Summarize this changelog in 3 bullets: ..."

# give Antigravity a workspace for multi-file agentic work
scripts/agy-delegate.sh --tier pro --dir ./src "List every TODO with file:line"

# live web / Google search (tools need --yolo in headless mode)
scripts/agy-delegate.sh --tier pro --yolo "Web-search <X>. Give URLs + dates."

# Vertex AI Search over internal data
scripts/agy-delegate.sh --tier pro --yolo "List Vertex AI Search engines (list_engines)."

# cross-model review / stdin / background job
scripts/agy-delegate.sh --tier pro "Review for bugs, be skeptical: <paste>"
cat big-prompt.txt | scripts/agy-delegate.sh -
ID=$(scripts/agy-job.sh start --tier pro --dir . "big task"); scripts/agy-job.sh result "$ID"

.claude-plugin/   plugin (+ userConfig: default_tier, timeout, coding_policy) + marketplace manifests
skills/antigravity/SKILL.md   WHEN + HOW Claude collaborates with agy
agents/           antigravity-delegate subagent (file work runs on Gemini, not Claude)
commands/         slash commands (delegate, review, research, setup, status, result, cancel)
hooks/            SessionStart: agy health check + auto-inject the cost-aware policy
scripts/          agy-delegate · agy-job · agy-cost-compare · measure-session · doctor
docs/             AB-RESULTS (measured A/B) · DEMO-KIT
prices.json       Vertex rate config (verify before quoting)

git clone https://github.com/yuting0624/antigravity-for-claude-code ~/antigravity-for-claude-code
claude --plugin-dir ~/antigravity-for-claude-code

bash tests/run-tests.sh

🤝 Contributing

Early-stage and MIT — issues, PRs, and ⭐ all welcome. See CONTRIBUTING.md and the good first issue list.

⚠️ Disclaimer

Community project. Not affiliated with, endorsed by, or supported by Google or Anthropic. "Antigravity", "Gemini", "Claude", and "Claude Code" are trademarks of their respective owners. This plugin orchestrates the third-party agy CLI; you are responsible for your own API/cloud costs, credentials, and data-sharing choices. MIT licensed — see LICENSE.