Initial commit — Antigravity plugin v0.1.0

Plugin Claude Code miroir du plugin codex officiel d'OpenAI, mais
pour Google Antigravity (agy CLI). Headless via:

  agy --print --dangerously-skip-permissions --print-timeout 10m

Includes:
- 1 forwarder agent (antigravity-rescue)
- 5 slash commands (setup, rescue, status, result, cancel)
- 3 internal skills (cli-runtime, result-handling, gemini-prompting)
- agy-companion.mjs runtime (task / setup / status / result / cancel)
- marketplace.json for `/plugin marketplace add`

Tested: setup OK, foreground task OK, background workflow OK
(except OAuth refresh which requires interactive TTY).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

README.md

@@ -0,0 +1,119 @@
+# Antigravity plugin for Claude Code
+
+Use **Google Antigravity (Gemini)** from inside Claude Code to delegate tasks in headless mode.
+
+Mirror of the [OpenAI Codex plugin](https://github.com/openai/codex) pattern, but for Google's `agy` CLI.
+
+## What it does
+
+Adds 5 slash commands and 1 agent to Claude Code:
+
+| Command | What it does |
+|---|---|
+| `/antigravity:setup` | Check if `agy` is installed, offer to install it |
+| `/antigravity:rescue <prompt>` | Delegate a task to Gemini via `agy --print --dangerously-skip-permissions` |
+| `/antigravity:status [<jobId>]` | List background jobs and their state |
+| `/antigravity:result [<jobId>]` | Print the full log of a background job |
+| `/antigravity:cancel <jobId>` | SIGTERM a background job |
+
+Plus an agent `antigravity:antigravity-rescue` used internally by `/antigravity:rescue` (and that Claude can invoke proactively).
+
+## Headless mode
+
+Under the hood, the plugin invokes:
+
+```bash
+agy --print --dangerously-skip-permissions --print-timeout <T> "<prompt>"
+```
+
+- `--print` runs a single prompt non-interactively (no TUI)
+- `--dangerously-skip-permissions` auto-approves all tool calls (necessary for unattended execution)
+- `--print-timeout` is set to 10 min foreground / 30 min background by default
+
+## Prerequisites
+
+1. Install Antigravity CLI:
+   ```bash
+   curl -fsSL https://antigravity.google/cli/install.sh | bash
+   ```
+2. **Run `agy` once interactively** in a terminal to complete Google OAuth sign-in.
+   This stores credentials so headless / background calls don't get stuck on auth.
+3. Add this plugin to Claude Code (see below).
+
+> ⚠️ **Auth note** — Background jobs cannot complete an OAuth flow (no TTY).
+> If your `agy` token expires, the next foreground call will refresh it via browser.
+> Always do one foreground rescue (or a manual `agy` call) before relying on `--background`.
+
+## Install in Claude Code
+
+From Claude Code:
+
+```
+/plugin marketplace add file:///Users/olivierdupont/Desktop/diversclaude/antigravity-plugin
+/plugin install antigravity
+```
+
+Then verify:
+
+```
+/antigravity:setup
+```
+
+## Usage examples
+
+```
+/antigravity:rescue Investigate the failing test in src/utils.test.ts and propose a fix.
+
+/antigravity:rescue --background Refactor the entire payment module to use Stripe Connect Express instead of the current generic Stripe integration. Apply the changes directly.
+
+/antigravity:rescue --sandbox --add-dir /tmp/sandbox-experiment Create a quick prototype that reads CSV and outputs JSON.
+
+/antigravity:rescue --resume Apply the top fix from the previous diagnosis.
+```
+
+After a background job:
+
+```
+/antigravity:status
+/antigravity:result agy-abc-12345
+/antigravity:cancel agy-abc-12345
+```
+
+## Project layout
+
+```
+antigravity-plugin/
+├── .claude-plugin/plugin.json          # plugin manifest
+├── agents/
+│   └── antigravity-rescue.md           # forwarder subagent
+├── commands/
+│   ├── setup.md
+│   ├── rescue.md
+│   ├── status.md
+│   ├── result.md
+│   └── cancel.md
+├── skills/
+│   ├── antigravity-cli-runtime/        # internal: how to invoke agy-companion
+│   ├── antigravity-result-handling/    # internal: how to display output
+│   └── gemini-prompting/               # internal: how to write good Gemini prompts
+└── scripts/
+    └── agy-companion.mjs               # central wrapper (task / setup / status / result / cancel)
+```
+
+## Differences with the Codex plugin
+
+| Codex plugin (1.0.4) | This Antigravity plugin (0.1.0) |
+|---|---|
+| `codex` CLI from OpenAI | `agy` CLI from Google |
+| GPT-5.x family of models | Gemini family |
+| `codex --json` headless mode | `agy --print` headless mode |
+| Full job persistence (state.mjs, jobs DB) | Minimal jobs dir at `~/.cache/antigravity-plugin/jobs/` |
+| Review / adversarial-review / stop-gate hooks | Not in v0.1 (just `task`) |
+| Multi-model support, effort tuning | Not in v0.1 (Gemini default) |
+| Resume-last logic via thread IDs | Naive `--continue` (agy's default) |
+
+For most rescue/delegation use cases, the v0.1 surface is sufficient.
+
+## License
+
+MIT. This plugin is not affiliated with Google or OpenAI.