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>

commands/cancel.md

@@ -0,0 +1,15 @@
+---
+description: Cancel a background Antigravity (agy) job
+argument-hint: "<jobId>"
+allowed-tools: Bash(node:*)
+---
+
+Run:
+
+```bash
+node "${CLAUDE_PLUGIN_ROOT}/scripts/agy-companion.mjs" cancel $ARGUMENTS
+```
+
+If no job id is supplied, run `/antigravity:status` first and ask the user which job they want to cancel.
+
+Present the output to the user as-is.

commands/rescue.md

@@ -0,0 +1,47 @@
+---
+description: Delegate investigation, an explicit fix request, or follow-up rescue work to the Antigravity (Gemini) rescue subagent
+argument-hint: "[--background|--wait] [--resume|--fresh] [--sandbox] [--add-dir <path>] [--timeout <10m|300s>] [what Antigravity should investigate, solve, or continue]"
+allowed-tools: Bash(node:*), AskUserQuestion, Agent
+---
+
+Invoke the `antigravity:antigravity-rescue` subagent via the `Agent` tool (`subagent_type: "antigravity:antigravity-rescue"`), forwarding the raw user request as the prompt.
+`antigravity:antigravity-rescue` is a subagent, not a skill — do not call `Skill(antigravity:antigravity-rescue)` (no such skill).
+The final user-visible response must be Antigravity's output verbatim.
+
+Raw user request:
+$ARGUMENTS
+
+Execution mode:
+
+- If the request includes `--background`, run the `antigravity:antigravity-rescue` subagent in the background.
+- If the request includes `--wait`, run the `antigravity:antigravity-rescue` subagent in the foreground.
+- If neither flag is present, default to foreground.
+- `--background` and `--wait` are execution flags for Claude Code. Forward `--background` to the helper; strip `--wait` from the prompt text.
+- `--resume`, `--fresh`, `--sandbox`, `--add-dir`, `--timeout` are runtime-selection flags. Preserve them for the forwarded `task` call, but do not include them in the natural-language task text.
+- If the request includes `--resume`, do not ask whether to continue. The user already chose.
+- If the request includes `--fresh`, do not ask whether to continue. The user already chose.
+- Otherwise, before starting Antigravity, check for a resumable rescue thread from this Claude session by running:
+
+```bash
+node "${CLAUDE_PLUGIN_ROOT}/scripts/agy-companion.mjs" task-resume-candidate --json
+```
+
+- If that helper reports `available: true`, use `AskUserQuestion` exactly once to ask whether to continue the current Antigravity thread or start a new one.
+- The two choices must be:
+  - `Continue current Antigravity thread`
+  - `Start a new Antigravity thread`
+- If the user is clearly giving a follow-up instruction such as "continue", "keep going", "resume", "dig deeper", put `Continue current Antigravity thread (Recommended)` first.
+- Otherwise put `Start a new Antigravity thread (Recommended)` first.
+- If the user chooses continue, add `--resume` before routing to the subagent.
+- If the user chooses a new thread, add `--fresh` before routing to the subagent.
+- If the helper reports `available: false`, do not ask. Route normally.
+
+Operating rules:
+
+- The subagent is a thin forwarder only. It should use one `Bash` call to invoke `node "${CLAUDE_PLUGIN_ROOT}/scripts/agy-companion.mjs" task ...` and return that command's stdout as-is.
+- Return the Antigravity companion stdout verbatim to the user.
+- Do not paraphrase, summarize, rewrite, or add commentary before or after it.
+- Do not ask the subagent to inspect files, monitor progress, poll `/antigravity:status`, fetch `/antigravity:result`, call `/antigravity:cancel`, summarize output, or do follow-up work of its own.
+- Leave `--resume` and `--fresh` in the forwarded request. The subagent handles that routing when it builds the `task` command.
+- If the helper reports that Antigravity is missing, stop and tell the user to run `/antigravity:setup`.
+- If the user did not supply a request, ask what Antigravity should investigate or fix.

commands/result.md

@@ -0,0 +1,13 @@
+---
+description: Print the full log of an Antigravity (agy) background job
+argument-hint: "[<jobId>]"
+allowed-tools: Bash(node:*)
+---
+
+Run:
+
+```bash
+node "${CLAUDE_PLUGIN_ROOT}/scripts/agy-companion.mjs" result $ARGUMENTS
+```
+
+Present the output (raw Antigravity log) to the user verbatim. If the output is very long, just stream it as-is; do not summarize.

commands/setup.md

@@ -0,0 +1,39 @@
+---
+description: Check whether the local Antigravity (agy) CLI is ready
+allowed-tools: Bash(node:*), Bash(curl:*), Bash(bash:*), AskUserQuestion
+---
+
+Run:
+
+```bash
+node "${CLAUDE_PLUGIN_ROOT}/scripts/agy-companion.mjs" setup --json
+```
+
+Parse the JSON output.
+
+If `installed` is `false`:
+- Use `AskUserQuestion` exactly once to ask whether Claude should install Antigravity now.
+- Put the install option first and suffix it with `(Recommended)`.
+- Use these two options:
+  - `Install Antigravity (Recommended)`
+  - `Skip for now`
+- If the user chooses install, run:
+
+```bash
+curl -fsSL https://antigravity.google/cli/install.sh | bash
+```
+
+- Then rerun:
+
+```bash
+node "${CLAUDE_PLUGIN_ROOT}/scripts/agy-companion.mjs" setup --json
+```
+
+If `installed` is already `true`:
+- Do not ask about installation.
+
+Output rules:
+- Present the final setup output to the user in a human-readable summary.
+- If the install was skipped, present the original setup output.
+- Mention the headless invocation command (`headless_mode`) so the user knows what's under the hood.
+- If installation succeeded but agy is not yet authenticated, instruct the user to run `agy` once interactively in a terminal to complete Google sign-in.

commands/status.md

@@ -0,0 +1,23 @@
+---
+description: Show status of background Antigravity (agy) tasks
+argument-hint: "[<jobId>] [--json]"
+allowed-tools: Bash(node:*)
+---
+
+Run:
+
+```bash
+node "${CLAUDE_PLUGIN_ROOT}/scripts/agy-companion.mjs" status $ARGUMENTS
+```
+
+Present the output to the user as-is.
+
+If no jobs are found, suggest:
+- Running a foreground task: `/antigravity:rescue <your task>`
+- Or a background task: `/antigravity:rescue --background <your task>`
+
+If a job is shown as `exited`, suggest viewing the result:
+
+```
+/antigravity:result <jobId>
+```