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>

skills/antigravity-cli-runtime/SKILL.md

@@ -0,0 +1,49 @@
+---
+name: antigravity-cli-runtime
+description: Internal helper contract for calling the agy-companion runtime from Claude Code
+user-invocable: false
+---
+
+# Antigravity Runtime
+
+Use this skill only inside the `antigravity:antigravity-rescue` subagent.
+
+Primary helper:
+- `node "${CLAUDE_PLUGIN_ROOT}/scripts/agy-companion.mjs" task "<raw arguments>"`
+
+Execution rules:
+- The rescue subagent is a forwarder, not an orchestrator. Its only job is to invoke `task` once and return that stdout unchanged.
+- Prefer the helper over hand-rolled `agy` strings, direct CLI calls, or any other Bash activity.
+- Do not call `setup`, `status`, `result`, or `cancel` from `antigravity:antigravity-rescue`.
+- Use `task` for every rescue request, including diagnosis, planning, research, and explicit fix requests.
+- You may use the `gemini-prompting` skill to rewrite the user's request into a tighter Antigravity prompt before the single `task` call.
+- That prompt drafting is the only Claude-side work allowed. Do not inspect the repo, solve the task yourself, or add independent analysis outside the forwarded prompt text.
+
+Command selection:
+- Use exactly one `task` invocation per rescue handoff.
+- If the forwarded request includes `--background`, forward it as `--background` to the helper.
+- If the forwarded request includes `--wait`, treat that as a hint to NOT use `--background` (foreground). Strip `--wait` from the task text.
+- If the forwarded request includes `--resume`, strip that token from the task text and add `--resume` to the helper invocation. This becomes `--continue` for the agy CLI.
+- If the forwarded request includes `--fresh`, strip that token and do not add `--resume`.
+- If the forwarded request includes `--sandbox`, pass `--sandbox` through to the helper (it enables agy's sandbox mode with terminal restrictions).
+- If the forwarded request includes `--add-dir <path>`, pass `--add-dir <path>` through to the helper (it adds a workspace directory).
+- If the forwarded request includes `--timeout <value>`, pass it through (format: `10m` or `300s`). Default foreground timeout is 10 minutes; background is 30 minutes.
+
+Bash invocation pattern:
+
+```bash
+node "${CLAUDE_PLUGIN_ROOT}/scripts/agy-companion.mjs" task [--background] [--resume] [--sandbox] [--add-dir <p>] [--timeout 10m] "<the user task text>"
+```
+
+Safety rules:
+- Always quote the prompt text to preserve spaces and special characters.
+- Preserve the user's task text as-is apart from stripping routing flags.
+- Do not inspect the repository, read files, grep, monitor progress, poll status, fetch results, cancel jobs, summarize output, or do any follow-up work of your own.
+- Return the stdout of the `task` command exactly as-is.
+- If the Bash call fails or Antigravity cannot be invoked, return nothing.
+
+Headless authorization:
+- Under the hood, the helper invokes `agy --print --dangerously-skip-permissions --print-timeout <T>`.
+- `--dangerously-skip-permissions` auto-approves all tool permission requests (necessary for headless work).
+- `--print` runs a single prompt non-interactively and prints the response.
+- This is the safe, documented headless mode of agy (per `agy --help`).