Codex Imagegen

Codex's image generation, in every coding agent.
Generate and edit images from opencode, Claude Code, Codex, Cursor, VS Code, Gemini CLI and 20 more tools.
It runs on the ChatGPT plan you already pay for, so there's no API key and no per-image bill.

Quick start  ·  See it work  ·  Tools  ·  Sign-in  ·  Clients  ·  All docs

What it does

Your ChatGPT plan, not an API bill Sign in once with ChatGPT, or reuse the sign-in Codex or opencode already has. Every image counts against the plan you already pay for.	One installer, 25+ tools npx -y codex-imagegen-mcp install finds your coding tools, shows every file it will touch, and edits only its own entry, keeping your comments.	Real transparent PNGs Ask for background: "transparent" and get genuine alpha, checked on every file. A local chroma-key tool handles the rest.
Any canvas shape Eleven aspect ratios from 21:9 to 9:21, and up to four variants of a prompt in parallel.	Saves into your project, safely Paths resolve to your workspace. An existing file is never overwritten; you get hero-2.png instead.	Codex's own playbook Ships the Codex app's imagegen skill as imagegen-mcp, adapted to these tools: prompt structure, edit invariants, save rules.

See it work

Two real opencode sessions in a scratch project. The images are exactly what came back:

You: I need a sticker-style illustration of a cute cartoon cactus with a transparent background for this project. Save it as assets/cactus-sticker.png.

opencode · openai/gpt-5.5 loads the skill → imagegen_generate_image with background: "transparent" → "Saved assets/cactus-sticker.png, 1254×1254 PNG with a transparent background."

You: Make a 16:9 hero banner for the Cactus Shop landing page, and a variant of the sticker where the cactus wears a tiny straw hat. Keep everything else identical.

opencode · github-copilot/claude-sonnet-5 → imagegen_auth_status → imagegen_generate_image (aspect_ratio: "16:9") and imagegen_edit_image (images: ["assets/cactus-sticker.png"]) in parallel → both saved, the edit with "transparent background (alpha verified)".

One prompt, three canvases. aspect_ratio doesn't crop. The service composes a new picture for each shape:

A green screen becomes alpha on your machine. remove_background keys out a flat backdrop locally, with no network call and no quota:

[!TIP] Every image in this repository was made with codex-imagegen-mcp itself. That covers the posters, the badges, the logo and the examples; the installer screenshots are real terminal output. The prompts and the art-direction record are in docs/assets.

Quick start

[!NOTE] You need Node.js 22+ and a ChatGPT plan that includes Codex (Plus, Pro, Business, Enterprise, Edu…). Codex image generation isn't available on the Free plan.

1 · Run the installer. npx fetches the latest release, so there's nothing to install first. The installer finds the coding tools on this machine, shows exactly which files it will create or change, and writes nothing until you confirm. Each config keeps its comments and formatting.

npx -y codex-imagegen-mcp install

The configs it writes start the server through npx as well; npm downloads it on first use and caches it. The installer also runs without questions, for scripts and dotfiles:

npx -y codex-imagegen-mcp install opencode cursor claude-code   # named tools (see --list)
npx -y codex-imagegen-mcp install --all --dry-run               # every detected tool, preview only

npm install --global codex-imagegen-mcp
codex-imagegen-mcp install

npm install --global https://github.com/ShalomObongo/codex-imagegen-mcp/releases/latest/download/codex-imagegen-mcp.tgz

git clone https://github.com/ShalomObongo/codex-imagegen-mcp.git && cd codex-imagegen-mcp
npm ci && npm run build
npm link                                  # puts `codex-imagegen-mcp` on your PATH

2 · Sign in with ChatGPT. The installer offers this at the end. Skip it if Codex or opencode is already signed in with ChatGPT.

npx -y codex-imagegen-mcp login           # opens the browser; use --device on a headless machine

3 · Check, then ask for pictures

npx -y codex-imagegen-mcp doctor          # Node, credentials, quota, and every tool it's installed in

you › Make a 16:9 hero image of a lighthouse at dusk and save it to assets/hero.png

[!TIP] From here on, commands use the short codex-imagegen-mcp from a global install. Without one, run them through npx the same way, for example npx -y codex-imagegen-mcp status.

How it works

sequenceDiagram
    autonumber
    participant A as Your agent<br/>(opencode, Claude Code…)
    participant M as imagegen MCP server<br/>(local · stdio)
    participant O as auth.openai.com
    participant C as chatgpt.com<br/>/backend-api/codex
    A->>M: generate_image {prompt, aspect_ratio, background}
    M->>M: pick credentials: own sign-in → Codex → opencode
    opt token expires within 5 minutes
        M->>O: refresh (under a cross-process lock)
        O-->>M: new access token + rotated refresh token
    end
    M->>C: POST /images/generations · Bearer token · ChatGPT-Account-ID
    loop every 5 s while the image renders
        M-->>A: progress notification (keeps the client's timeout alive)
    end
    C-->>M: PNG + usage headers
    M->>M: save without overwriting · verify alpha · build preview
    M-->>A: path, size, background + a 1024 px preview

It sends the same request as the image tool built into the Codex app, byte for byte. As OpenAI improves Codex's image model on the server, this server gets the same upgrade. How that was reverse-engineered →

Signing in

codex-imagegen-mcp login            # browser → sign in → "You're signed in to Codex ImageGen MCP"
codex-imagegen-mcp login --device   # SSH/headless: enter a code at auth.openai.com/codex/device
codex-imagegen-mcp status           # account, plan, credential source and usage windows
codex-imagegen-mcp logout           # remove and revoke this tool's own sign-in

[!IMPORTANT] OpenAI refresh tokens are single-use. Borrowed sign-ins are therefore never refreshed or modified, so this server can't sign you out of Codex or opencode. Its own tokens are stored 0600 and refreshed under a lock shared by every server process. Authentication in depth →

Tools

The server also exposes the resources imagegen://history, imagegen://images/{id} and imagegen://skill/*, and the prompts generate and edit. In opencode the prompts appear as /imagegen:generate and /imagegen:edit. Full reference →

From the terminal

The CLI uses the same engine as the MCP tools:

codex-imagegen-mcp generate "a watercolor fox in a snowy forest" -a 16:9 -o art/fox.png
codex-imagegen-mcp generate "Image 1: add a tiny straw hat; keep everything else" \
  -i assets/cactus.png -b transparent -o assets/cactus-hat.png
codex-imagegen-mcp remove-bg sprite-on-green.png -o sprite.png
codex-imagegen-mcp config zed              # print a tool's config snippet to add by hand

Supported tools

Each tool gets its own config format, timeout field and skill folder. install --list shows which ones are on your machine. Files, timeouts and skill folders per tool →

Documentation

Tools Every tool, parameter, result field, resource and error.	Authentication PKCE and device-code sign-in, token rotation, borrowing, security.	Clients The installer, and the 25+ supported tools: files, timeouts, skills.
Backend How Codex's image generation really works: extracted and measured.	Architecture Modules, the request flow and the design decisions behind them.	Development Build, the mock-backed test suite, live testing, the release pipeline.

FAQ

npm audit signatures        # in a project that depends on codex-imagegen-mcp
gh attestation verify codex-imagegen-mcp-X.Y.Z.tgz --repo ShalomObongo/codex-imagegen-mcp

Configuration

Troubleshooting

Start with codex-imagegen-mcp doctor. It checks Node, the data directory, credentials, backend reachability and quota, the sign-in ports, every tool that has imagegen configured, and the skill copies.

Contributing

Bug reports, docs fixes, support for more clients and backend measurements are welcome. Start with CONTRIBUTING.md; security issues go through SECURITY.md, never public issues. Every release is listed in the changelog.

Changelog  ·  Contributing  ·  Security  ·  Code of Conduct  ·  Support
_{Unofficial; not affiliated with or endorsed by OpenAI. Usage counts against your ChatGPT plan and is subject to OpenAI's Terms of Use.
Generated images carry OpenAI's C2PA provenance metadata. Apache-2.0; the bundled skill is adapted from OpenAI Codex (Apache-2.0), see NOTICE.}