🛰️ Antigravity for Claude Code

Run the Antigravity CLI (Gemini) as a collaborating sub-agent, right inside Claude Code.

Claude conducts the judgement; Gemini does the heavy lifting — intelligent model routing across the SDLC.

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⚡ Quick look

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

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💡 Why

	Claude (conductor)	Gemini / agy (executor)
Owns	requirements · architecture · the hard 20% · verification · review	scaffold · implementation · test generation · search
Strength	judgement	cheap, fast throughput

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.
• Hears audio, watches video — /antigravity:media delegates the perception to Gemini (natively multimodal, no local ffmpeg/Whisper stack): you get a timestamped digest while the full transcript is written to a file, so a 1-hour recording never lands in Claude's context.
• Cross-model verification — an independent, different-model opinion on your code.
• Background jobs — fire a long delegation, keep working, collect later.
• Internal fan-out — one delegation, and agy spawns its own subagents on the cheap side (dynamic define_subagent on agy ≥ 1.0.16; TypeName "self" + Role on any version); each leaves a readable trajectory you audit with agy-trace.
• 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.
• No slash command required — the delegate subagent is picked up proactively for bulk work, and a prompt-level nudge flags bulk-looking requests as delegation candidates. Both are advisory: the break-even judgment stays with Claude (full auto-routing is a measured net loss below the break-even), and the nudge is toggleable (delegation_nudge).

📊 Measured results

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

	Claude solo @high	solo @max	hybrid
frontier cost (COST-WEIGHTED)	2.62M	5.34M	1.91M
quality (adk eval)	✅ 3/3	✅ 3/3	✅ 3/3

→ −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.

Platform support: macOS, Linux, and WSL are the supported targets for headless delegation. Native Windows (Git Bash/MSYS) is not recommended — agy -p can hang with a 0-byte log when run without a real console (ConPTY); see issue #6. The wrapper now bounds this with a wall-clock guard (GNU timeout/gtimeout, returning a clean TIMEOUT instead of hanging), and doctor distinguishes a hang from an auth failure — but for reliable headless use, run from WSL/macOS/Linux.

🧩 Slash commands

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

command	what it does
/antigravity:setup	health check — agy installed + authenticated, scripts ready
/antigravity:delegate [--tier flash|pro] <task>	delegate a subtask to agy under cost discipline, then verify
/antigravity:review [--adversarial]	independent cross-model review of the current diff; Claude reconciles
/antigravity:research <topic>	Claude-orchestrated deep research — agy does grounded web legwork, Claude verifies citations across ≥2 sources
/antigravity:media <file> [focus] [--convert]	understand audio / video / images — agy transcribes + analyzes, returns a timestamped digest; full transcript goes to a file, not your context
/antigravity:cloud-run-debug [--service <s>] [--region <r>] [--project <id>] [--since 1h] [--apply]	diagnose a failing Cloud Run service — agy digests the error logs, Claude infers the root cause + fix; read-only by default (--apply writes to a branch)
/antigravity:status [id] · :result <id> · :cancel <id>	manage background delegation jobs
/antigravity:migrate [--apply] [--include-repos]	move an existing Claude Code setup onto agy — skills, CLAUDE.md, memory, MCP, plugins, permissions; dry-run by default, --uninstall reverses it

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.

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📦 Bringing your Cl