image-gen-mcp

An MCP server that lets Claude Code generate real images to use in your projects (banners, icons, backgrounds, textures, etc.) with OpenAI gpt-image-2, and save them straight to a path you specify. It is meant for producing production assets — not for mocking up UI designs.

ภาษาไทย: ดู README.th.md

Tools

generate_image

Generate a new image from a text prompt and write it to a file.

edit_image

Edit / build on existing images. Pass 1-16 reference images, plus an optional mask for inpainting.

Both tools return only { path, bytes, size, quality, ... } — never the raw image bytes (to avoid flooding the agent's context). A relative output_path is resolved against the calling project's CWD, and parent directories are created automatically.

Related MCP server: openai-imagegen-mcp

Authentication

Two modes. IMAGE_GEN_AUTH_MODE picks between them (auto by default: an API key in the environment wins, otherwise a stored login is used).

api_key — OPENAI_API_KEY (recommended)

Calls api.openai.com/v1. Every parameter above works. Billed to your API account.

chatgpt — browser login

npx image-gen-mcp login     # opens a browser; also `status` and `logout`

Signs in with your ChatGPT account and generates on your ChatGPT plan quota instead of API credit. If you call a tool with no credential configured, the server asks the MCP client to open the same login URL (URL-mode elicitation) and retries the call once you're done — Claude Code supports this; claude -p does not, so use the CLI there.

Tokens are stored in ~/.image-gen-mcp/auth.json (0600) and refreshed automatically. Codex's own ~/.codex/auth.json is never read or written — sharing one rotating refresh token between two tools logs both out.

This mode is a reduced feature set. It goes through chatgpt.com/backend-api/codex, which accepts only prompt, model, quality, background, always returns PNG, and silently ignores everything else. Rather than hand back an asset that quietly isn't what was asked for, the tools reject the unsupported parameters:

Caveats. OpenAI publishes no OAuth flow for third-party apps: this reuses the login its own Codex CLI performs, including that client's ID and its two allow-listed loopback ports (1455/1457). It is undocumented, unsupported, and can break without notice. The resulting token is not accepted by the Platform API (GET /v1/models with one answers 403 Missing scopes: api.model.read), which is why the two modes talk to different hosts. api_key remains the supported path.

Install

cd image-gen-mcp
npm install

Connect to Claude Code

For api_key mode, provide the key via the server's env block in your MCP config (no .env file required) — in a project .mcp.json or a user-scoped config. For chatgpt mode, drop the env block and run npx image-gen-mcp login instead:

{
  "mcpServers": {
    "image-gen": {
      "command": "node",
      "args": ["/Users/palm/Desktop/projects/custom-mcp/image-gen-mcp/src/index.mjs"],
      "env": { "OPENAI_API_KEY": "sk-..." }
    }
  }
}

Or add it via the CLI:

claude mcp add image-gen -e OPENAI_API_KEY=sk-... -- node /Users/palm/Desktop/projects/custom-mcp/image-gen-mcp/src/index.mjs

Test

npm run selftest   # real in-memory MCP round-trip with a fake client — no key/network needed
OPENAI_API_KEY=sk-... npm run smoke   # one real API call (quality low) that verifies a valid PNG

Pricing (approx., gpt-image-2, 1024x1024)

low ~$0.006 · medium ~$0.053 · high ~$0.211 per image — start at medium, use high only for final assets.