Gemini / Antigravity Companion for Claude Code

Use Gemini CLI or Antigravity CLI (agy) inside Claude Code for task delegation, pragmatic code review, and adversarial review.

Transition-ready for Google's Gemini CLI to Antigravity CLI migration. agy-plugin-cc keeps the familiar Claude Code slash-command workflow while letting you route work to Gemini CLI where available, or to Antigravity CLI (agy) during the post-June-2026 transition.

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Ported from openai/codex-plugin-cc (Apache-2.0), retaining a familiar slash-command and background-job workflow while adapting behavior to Gemini/AGY capabilities and documenting intentional divergences.

Independent project. agy-plugin-cc is community-maintained and is not affiliated with, endorsed by, or sponsored by Google LLC or Anthropic. "Gemini" and "Antigravity" are trademarks of Google LLC and "Claude" is a trademark of Anthropic; all are used here only to name the tools this plugin works with. You install and authenticate those tools yourself, and their terms govern what they do with what is sent to them.

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Why this plugin?

agy-plugin-cc is a Claude Code-native companion bridge for users who want both Gemini CLI and Antigravity CLI (agy) support during Google's Gemini CLI transition.

Compared with AGY-only, multi-host plugins, this project keeps the Gemini CLI path where available while providing an explicit --engine agy route for users migrating to Antigravity CLI.

• Claude Code-native /gemini:* slash commands.
• Pragmatic and adversarial code review over the current diff or branch.
• Background task delegation for longer-running companion-agent work.
• Gemini model aliases, graceful model fallback, and transient review retry.
• Version-gated AGY result retrieval: native JSON envelope on 1.1.8+, transcript recovery below it.
• Safer stdin prompt delivery on Gemini and AGY 1.1.2 or newer.

| Need | Use this plugin when... | |---|---| | Gemini CLI still works for you | You want model selection, JSON output, and stdin prompt delivery. | | You are migrating to AGY | Use --engine agy as the fully supported Antigravity CLI backend. | | You want adversarial review | Use /gemini:adversarial-review with optional focus text. | | You need AGY-only multi-host support | Consider an AGY-only plugin instead. |

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Features

• /gemini:rescue — Delegate investigation, debugging, or implementation tasks to the selected Gemini CLI or AGY engine. Runs in the foreground or detached in the background.
• /gemini:transfer — Export current session context (git status, diff, instructions) into a structured JSON snapshot and print a single-quoted launch command for AGY or Gemini CLI (POSIX Bash form everywhere, plus a PowerShell form on Windows).
• /gemini:review — Standard (pragmatic) code review over the current diff or branch. Finds real bugs, missing error handling, and incomplete code paths. Add --deep for an agentic pass that explores repo context beyond the diff.
• /gemini:adversarial-review — Adversarial code review that challenges design decisions over the current diff or branch. Returns structured findings with severity ratings.
• /gemini:setup — Check Gemini CLI / AGY availability and OAuth status.
• /gemini:status — Inspect active and completed background jobs.
• /gemini:result / /gemini:cancel — Retrieve or cancel a background job.
• Engine auto-detection — Both engines are first-class; auto checks gemini first for its JSON/model contract, then agy.
• Version-aware stdin prompt delivery — Gemini always uses stdin; AGY 1.1.2 or newer uses its auto-print stdin path, while older or unknown versions retain the compatible positional path.
• Session lifecycle hooks — Automatically injects GEMINI_COMPANION_SESSION_ID. On session end it terminates this session's still-running background jobs and removes their records; jobs from other sessions are left alone. Finished jobs' results are discarded with them, so retrieve anything you still need with /gemini:result before the session ends.

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Prerequisites

| Requirement | Version | Install | |---|---|---| | Node.js | ≥ 18 | nodejs.org | | Gemini CLI | ≥ 0.40; required for the gemini engine | npm install -g @google/gemini-cli | | AGY | ≥ 1.0.3; ≥ 1.1.2 recommended and live-verified on Windows/Ubuntu WSL2 | (see install note below) | | Claude Code | any | claude.ai/code |

Install AGY (required for --engine agy): curl -fsSL https://antigravity.google/cli/install.sh | bash

Authentication: Each engine authenticates independently. Run gemini once for the Gemini engine, or run agy once interactively for the AGY engine. AGY 1.1.10+ also supports Application Default Credentials (ADC) and Gemini Enterprise / Workforce Identity Federation (WIF), and 1.1.13+ accepts GEMINI_API_KEY with modelProvider: "gemini" in its settings.json — a settings-file route, which is why it appears in no agy --help output. AGY OAuth authentication cannot be verified reliably from a headless setup probe, so /gemini:setup --engine agy reports it as unknown until a real AGY command succeeds. --probe-agy settles it, and is verified on both an interactive login and a GEMINI_API_KEY route (AGY 1.1.15, isolated home, unkeyed control): keyed it reports verified, unkeyed it reports unknown with AGY's own diagnostic rather than a false logout. ADC and Enterprise/WIF are untested — treat a logged-out verdict on a working account there as a bug worth reporting.

The Gemini engine now needs a Standard/Enterprise account or an API key. Google ended consumer Gemini CLI access on 2026-06-18. On a personal account, gemini CLI 0.53.1 still installs and answers --version, but every request returns API key not valid (API_KEY_INVALID) — verified 2026-08-04. The AGY engine is unaffected and is the practical default; pass --engine agy, or set GEMINI_ENGINE=agy, if auto selects an unauthenticated gemini binary.

Heads-up (reality check):

• 2026-06-18 consumer transition: Google announced that free/personal, Google AI Pro, and Google AI Ultra Gemini CLI requests stop being served after this date; Standard/Enterprise access remains. See Google's Gemini CLI to Antigravity CLI announcement.
• Model availability drifts by CLI version. A 2026-08-05 probe of the live Gemini API listing found gemini-3.5-flash and gemini-3.6-flash are now GA, while gemini-3.5-pro is still absent — the 2026-06-02 probe had returned 404 ModelNotFound for both 3.5 ids. The plugin gracefully falls back to a GA model if a requested id is unavailable. See Model Aliases and docs/MODEL_COMPARISON.md.

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Installation

Release channel (marketplace follows main)

# 1. Add the marketplace
/plugin marketplace add arcobaleno64/agy-plugin-cc

# 2. Install the plugin
/plugin install gemini@agy-plugin-cc

# 3. Reload plugins
/reload-plugins

This marketplace source follows the repository's main branch, but that does not mean every Claude Code launch automatically installs and activates new code:

• Claude Code identifies this plugin by its explicit manifest version. Existing installations update only after that version is bumped (normally as part of a release); unversioned commits on main with the same manifest version are not delivered as plugin updates.
• Auto-update is disabled by default for third-party marketplaces. To opt in, open /plugin, select Marketplaces → agy-plugin-cc, and choose Enable auto-update. When enabled, Claude Code checks the marketplace at startup and updates installed plugins whose resolved version changed.
• If Claude Code reports that the plugin was updated, run /reload-plugins before using it in the current session. Opening Claude Code by itself is therefore not a reliable guarantee that a newly published version is already active.

For an explicit update without enabling auto-update, run:

/plugin marketplace update agy-plugin-cc
/plugin update gemini@agy-plugin-cc
/reload-plugins

Pinned release (a specific published version)

Pin the marketplace to a release tag — e.g. v0.24.1:

/plugin marketplace add arcobaleno64/agy-plugin-cc@v0.24.1
/plugin install gemini@agy-plugin-cc
/reload-plugins

Claude Code installs plugins from the git tree, not from GitHub Release tarballs — @<tag> selects the git tag behind a Release. A pinned marketplace stays on that tag even if marketplace auto-update is enabled. To move it to another release, remove the existing marketplace (which also uninstalls plugins installed from it), add the repository again with the new tag, reinstall the plugin, and run /reload-plugins.

Then run /gemini:setup for auto/Gemini, or /gemini:setup --engine agy for AGY. The selected engine is the only engine dependency that must be installed; setup offers the matching installer when it is missing.

If Gemini is installed but not authenticated yet, run:

!gemini

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Quick Start

# Delegate a task to Gemini (foreground)
/gemini:rescue Investigate why the auth middleware returns 401 on valid tokens

# Run in the background and check later
/gemini:rescue --background Add unit tests for the UserService class
/gemini:status

# Adversarial review of your current diff
/gemini:adversarial-review

# Review with a specific focus
/gemini:adversarial-review Focus on race conditions in the job queue

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Commands

/gemini:rescue [prompt]

Delegates a task to Gemini. Reads from stdin if no prompt is given.

| Flag | Description | |---|---| | --background | Run detached; returns a job ID immediately | | --write | State that edits are expected. Off by default. On gemini it adds --yolo, which genuinely gates whether write tools exist. On AGY it selects --new-project over --add-dir; both orient the run on your repository and neither withholds write, so there it is a statement of intent, not a boundary — see Security | | --resume-last | Continue the most recent Gemini session | | --fresh | Force a new Gemini session, ignoring any resumable thread | | --engine <gemini\|agy\|auto> | Override engine selection | | --model <alias\|id> | Model override. Gemini resolves its aliases; AGY 1.1.10+ requires an exact model ID from agy models. AGY model selection cannot be combined with --effort or a dual-engine (--engines gemini,agy) review. | | --effort <low\|medium\|high\|xhigh> | Gemini maps effort to a model; AGY 1.1.10+ forwards low, medium, or high as native reasoning effort when no AGY model is selected. |

/gemini:transfer [instructions...]

Exports current workspace context (git diff, status, instructions) and generates ready-to-run CLI commands (agy/gemini) to hand off work to an interactive terminal session. Includes automated secret redaction (.env*, credentials) and git conflict safeguards. The generated commands are printed for you to paste into a terminal; the plugin never runs them.

| Flag | Description | |---|---| | --engine <gemini\|agy\|auto> | Which handoff commands to print. auto (default) prints both | | --model <id> | Model override carried into the generated command. AGY requires an exact ID from agy models | | --effort <low\|medium\|high\|xhigh> | Reasoning effort carried into the generated AGY command. Cannot be combined with --model |

/gemini:review

Runs a standard, pragmatic review over the current working tree or branch diff — real bugs, missing error handling, and incomplete code paths. Not steerable and takes no focus text; use `/gemini: