🛰️ Imagine

June 29, 2026 · View on GitHub

🛰️ Imagine

A second brain for your coding agent — Google Gemini inside Claude Code & Codex.

Hand the hard thinking — reasoning, independent code review, deep research, and automatic prompt-engineering — to Google Gemini. It runs on your Google AI Pro / Ultra subscription (agy), not on your agent's tokens.

⚡ One install · 4 skills · Claude Code & Codex · no API key · no extra bill — just your existing AI Pro plan.

License: MIT Claude Code Codex Shell

⚠️ Security: every gemini call sends your prompt + piped files to Google verbatim. Never pipe secrets (.env, keys, tokens). Never run Gemini's output unread — piped files can carry prompt injection, and Gemini can be wrong. See SECURITY.md.


Why Imagine

Your coding agent is brilliant — and it has three blind spots:

  • 🪞 It reviews its own code. Same model, same blind spots. Before you merge, you want a genuinely different pair of eyes.
  • 🔥 Research burns your tokens. Digesting a huge module or comparing five libraries chews through your agent's budget fast.
  • 🎲 It acts on whatever you typed. A rushed, half-formed prompt → a rushed, half-formed result.

Imagine fixes all three by giving your agent a second, independent model — Google Gemini — to hand work to. And because generation runs through Google's Antigravity CLI on your AI Pro / Ultra subscription, that heavy thinking is effectively free: a flat monthly fee you already pay, never metered against your agent's tokens.

A second brain for your coding agent — that you've already paid for.

✨ The four skills

SkillWhat it gives youJust say…
🧠 gemini-proOne-shot delegation to Gemini (default 3.1 Pro, High), with model selection via -m. Offload hard reasoning and save your agent's credits."ask Gemini Pro to…", "use Gemini", "юзай Gemini"
🔍 gemini-reviewAn independent, adversarial review of code / a diff / a PR / a plan — a different model, different blind spots, severity-tagged findings. Catch what self-review can't."let Gemini review this", "second opinion before I merge"
📚 gemini-researchDeep research & large-context digestion — summaries, comparisons, "find X across all of this", sourced reports — without spending agent tokens on the reading."have Gemini dig into this module", "compare these options"
gemini-proxyAutomatic prompt-engineering. For your next N prompts, Gemini quietly rewrites each message into a sharper version before your agent acts."enable gemini proxy", "polish my prompts", "переделывай мои промты через гемини"

Plus bin/gemini — a dependency-free Bash wrapper over agy -p (model shortcuts + stdin context), and install.sh to wire it all up for both Claude Code and Codex.

⭐ The one people love: gemini-proxy

The other three skills are one-shot. gemini-proxy turns Gemini into your agent's built-in prompt engineer. Enable it, and for your next N substantive prompts (default 10) Gemini rewrites each message you type into a sharper, more detailed first-person version of itself — as a senior prompt engineer would — before your agent acts. Your agent still answers with the full chat context, your project rules, and memory; Gemini only sharpens the wording. A smart filter routes real work (build / fix / review / design) and skips trivial / config / meta chatter, so the counter only spends on substance. It self-disables after N.

Ground it first — this is what makes it great. Drop a rules file in your project (canon + safety invariants + standing expectations) and Gemini rewrites with your project in mind:

cp skills/gemini-proxy/prompt-rules.template.txt ./.gemini-proxy-rules.txt
# then fill in: PROJECT CANON · STANDING EXPECTATIONS (tracker, finish-to-plan,
#               use-the-right-skills, independent review on risky changes, goal-drift) · HARD GUARDRAILS

Resolution order: $GEMINI_PROXY_RULES → ./.gemini-proxy-rules.txt → ./.claude/gemini-proxy-rules.txt → shipped template. The richer that file, the sharper and safer every rewrite. The rewrite is a brief, not an override — it never outranks your real instructions, your project's safety rules, or your agent's own verification. Never pipe secrets into it.

/gemini-proxy            # enable for the next 10 prompts (or /gemini-proxy <N>)
python3 ~/.claude/skills/gemini-proxy/proxy_state.py peek      # prompts remaining (0 = off)
python3 ~/.claude/skills/gemini-proxy/proxy_state.py disable   # stop early
python3 ~/.claude/skills/gemini-proxy/verify_gemini_proxy.py   # TDD: exactly-N, auto-off, fail-safe (21/21)

Optional hard enforcement (Claude Code): opt in to the bundled UserPromptSubmit hook (copy the snippet from skills/gemini-proxy/hook/settings-hook-snippet.json into .claude/settings.json). It's fail-open and makes no network calls. Codex uses the skill + counter (no hook).

🧠 How it works

 You ─▶ Claude Code / Codex ─▶ /gemini-* skill ─▶ `gemini` wrapper ─▶ `agy -p` ─▶ Gemini (your AI Pro quota)

 You ◀── synthesised, verified answer ◀── your agent ◀───────────────────────────────┘

Your agent writes a self-contained prompt, optionally pipes files as context, runs the wrapper, sanity-checks the result, and relays it. Generation is billed to your Google subscription's weekly compute quota — not to your agent.

📦 Requirements

  • macOS or Linux with bash.
  • A Google AI Pro or Ultra subscription. (The subscription quota is reached through Google's own CLI — a pay-per-token Gemini API key is a different thing and won't use your subscription.)
  • Antigravity CLI (agy) — Google's headless client:
    brew install --cask antigravity-cli
    
  • A coding agent that loads skills: Claude Code (~/.claude/skills/) or Codex (~/.agents/skills/).

Why agy and not the old gemini CLI? Google retired the consumer Gemini CLI for AI Pro/Ultra/free tiers in mid-2026 and replaced it with the Antigravity CLI (agy). Quota is now a weekly compute cap, not a daily request count.

🚀 Install

Option A — as a Claude Code plugin (one command)

/plugin marketplace add freestyler-arb/imagine-gemini-for-claude-codex
/plugin install imagine@imagine-gemini-for-claude-codex

This loads the four skills. You still need the agy CLI (above) and the gemini wrapper — grab it from this repo, read it (it's short, mostly comments), then put it on your PATH:

# clone or download bin/gemini, review it, then:
mkdir -p ~/.local/bin && cp bin/gemini ~/.local/bin/gemini && chmod +x ~/.local/bin/gemini

Don't curl | bash a script onto your PATH without reading it. Option B's ./install.sh does the same copy after you've cloned and can inspect the source.

Option B — script install (Claude Code and Codex)

git clone https://github.com/freestyler-arb/imagine-gemini-for-claude-codex.git
cd imagine-gemini-for-claude-codex
./install.sh

Installs the gemini wrapper to ~/.local/bin/ and the four skills to both ~/.claude/skills/ (Claude Code) and ~/.agents/skills/ (Codex). Override with BIN_DIR=… / SKILLS_DIRS=….

Then: one-time Antigravity login + PATH

agy                                                        # pick your Google AI Pro account (browser OAuth)
echo 'export PATH="$HOME/.local/bin:$PATH"' >> ~/.zshrc    # or ~/.bashrc, if ~/.local/bin isn't on PATH
exec $SHELL
gemini "reply with one word: ok"                           # smoke test

In Claude Code / Codex the skills are Agent Skills — the model loads them automatically when your request matches their description (e.g. "ask Gemini Pro to…"). You can also name one: "use the gemini-review skill on this diff."

🛠 Usage

# Default = Gemini 3.1 Pro (High)
gemini "explain the trade-offs of optimistic vs pessimistic locking"

# Pipe a file (or several) as context
cat src/order_engine.py | gemini "review this for correctness bugs"
cat a.py b.py | gemini "trace the order flow across these two files"

# Cheaper / faster on the weekly quota
gemini -m flash "summarise this changelog in 5 bullets" < CHANGELOG.md

From your agent, just ask in natural language — the right skill fires on its own:

  • "Ask Gemini Pro to explain this regex."gemini-pro
  • "Let Gemini review this diff before I merge."gemini-review
  • "Have Gemini dig through this module and summarise the data flow."gemini-research

Model selection (-m)

FlagModelUse for
(none) / -m proGemini 3.1 Pro (High)Default. Hard reasoning, reviews, architecture.
-m pro-lowGemini 3.1 Pro (Low)Pro quality, lighter budget, faster.
-m flashGemini 3.5 Flash (High)Fast & cheap; summaries, bulk tasks.
-m flash-mid / -m flash-lowFlash (Medium / Low)Middle ground / cheapest.
-m "<full name>"anything from agy modelse.g. "Claude Opus 4.6", "GPT-OSS 120B".

Run agy models for everything your subscription exposes. Set a different default with GEM_MODEL; point at a non-standard binary with AGY_BIN.

🤖 Using with Codex

The skills are plain SKILL.md files, so the same four work in Codex unchanged: ./install.sh copies them to ~/.agents/skills/, Codex loads skills natively, and the gemini wrapper + agy login are shared across both agents — install once, use from either.

💸 Cost & where the usage shows up

  • Gemini runs on your Google AI Pro / Ultra subscription (the Antigravity weekly compute quota), NOT the pay-per-token Gemini API. If you check Gemini API usage (AI Studio / Cloud console) you'll see zero — that's expected; nothing goes through the API.
  • gemini-proxy is a quality tool, not a token-saver. The Gemini generation is free (your sub), but the proxy adds a small agent-side round-trip per routed prompt (~hundreds–few-thousand tokens to send + read the rewrite back). That's why the smart filter skips trivial / config / meta. The one-shot skills have no standing overhead — they fire only when asked.
Cost
Gemini's generation$0 of agent credits — billed to your AI Pro / Antigravity weekly quota
Extra agent tokens per routed proxy prompt~200–400 in + ~200–500 out (one round-trip + reading the rewrite)
≈ extra agent spend per routed prompt~$0.02–0.05
As % over answering directly~5–15% (higher on tiny prompts, lower on big tasks)
Trivial / config / meta prompts$0 — skipped by the smart filter

Tight on agent credits? proxy_state.py disable and write directly; enable the proxy only when a sharper prompt is worth the round-trip.

🔒 Security & privacy

This tool sends your prompt and any piped context to Google Gemini by design. Read SECURITY.md. The essentials:

  • Never pipe secrets. Strip keys, tokens, .env, private data — the wrapper sends whatever you give it, verbatim.
  • Treat output as untrusted. Gemini can be wrong, and a reviewed file can carry prompt injection. Never run returned commands/code without reading them.
  • No credentials in this repo. Auth lives only in your local agy login; nothing sensitive is committed.
  • install.sh makes no network calls, uses no sudo, and only copies files into your own home directory. Read it first — it's ~45 lines of plain Bash.

🧩 Writing a skill — and its description

Each skill is a folder with one SKILL.md: YAML frontmatter, then Markdown the agent reads on demand. The description is the single most important line — it's all the agent sees when deciding whether to load the skill.

  • Describe when to use, not what it does. Start with "Use when…" and list concrete triggers. (Summarise the workflow here and the agent follows the one-liner instead of reading the skill.)
  • Third person (it's injected into the system prompt), packed with real trigger phrases (multiple languages if you use them — these ship English and Russian), name the technology, and keep it under ~500 chars with distinct triggers so the right skill fires.
# ❌ summarises the workflow → agent skips the body
description: Reviews code by piping it to Gemini and printing severity-tagged findings.
# ✅ triggers only → agent loads the skill and follows it
description: Use when the user wants an independent second-opinion review of code, a diff,
  a PR, or a plan from Gemini — "let Gemini review this", "second opinion before merge".

🗺 Repo layout

imagine-gemini-for-claude-codex/
├── .claude-plugin/{marketplace.json, plugin.json}   # Claude Code plugin + marketplace
├── .codex-plugin/plugin.json                        # Codex plugin manifest
├── skills/
│   ├── gemini-pro/SKILL.md
│   ├── gemini-review/SKILL.md
│   ├── gemini-research/SKILL.md
│   └── gemini-proxy/                                 # the N-prompt rewrite protocol
│       ├── SKILL.md
│       ├── proxy_state.py            # the counter (atomic, fail-safe, fcntl-locked)
│       ├── proxy_route.py            # one-shot route: rules → Gemini → consume once
│       ├── prompt-rules.template.txt # ground-it template (copy into your project)
│       ├── verify_gemini_proxy.py    # TDD: exactly-N, auto-off, fail-safe, concurrency (21/21)
│       └── hook/                     # optional Claude Code UserPromptSubmit hook (opt-in)
├── bin/gemini                        # the wrapper over `agy -p`
├── install.sh                        # installs wrapper + skills (Claude + Codex)
├── SECURITY.md · README.md · LICENSE

🤝 Contributing

Issues and PRs welcome — new model shortcuts as Google ships tiers, extra skills (gemini-translate, gemini-explain), and fixes to track agy. Keep skills focused and follow the description rules above.

📄 License

MIT.


🇷🇺 Кратко по-русски

Imagine — второй мозг для твоего кодинг-агента: даёт Claude Code и Codex четыре навыка делегирования Google Gemini через Antigravity CLI (agy). Оплачивается подпиской AI Pro, а не токенами агента.

  • gemini-pro — делегация + выбор модели (-m flash|pro|…).
  • gemini-review — независимый разбор кода / диффа / плана (другая модель = другие слепые зоны).
  • gemini-research — ресёрч и переваривание больших контекстов.
  • gemini-proxy — авто-промт-инжиниринг: следующие N промтов (деф.10) Gemini переписывает в более чёткую версию ОТ ПЕРВОГО ЛИЦА перед тем, как агент их выполнит. Умный фильтр пропускает тривиал; сам выключается после N. Заземли его файлом ./.gemini-proxy-rules.txt (канон + standing-правила + гайдрейлы) — это и делает прокси по-настоящему полезным.

Установка: плагином — /plugin marketplace add freestyler-arb/imagine-gemini-for-claude-codex/plugin install imagine@imagine-gemini-for-claude-codex; скриптом (Claude + Codex) — git clone …./install.sh. Дальше: ~/.local/bin в PATH, один раз agy (вход в Google AI Pro), проверка gemini "скажи ок".

⚠️ Безопасность: всё, что передаёшь в gemini, уходит в Google. Не передавай ключи/токены/.env; вывод считай непроверенным. Подробности — SECURITY.md.