OpenAI Image MCP

Tiny remote MCP server for OpenAI image generation, designed to be easy to deploy on Render.

What this is

This project exposes a remote MCP endpoint at /mcp with one main tool:

• generate_image: generate one or more images from a prompt using OpenAI.
• server_info: simple read-only check of the configured model and whether the API key is present.

It reads OPENAI_API_KEY from Render environment variables.

Important model note

This project defaults to:

• OPENAI_IMAGE_MODEL=gpt-image-1

That is a likely safe default, not a guaranteed final recommendation. OpenAI image model names can change over time. If you already know the exact model you want, set OPENAI_IMAGE_MODEL on Render to that value instead.

Files

• server.js - the remote MCP server
• package.json - Node package config
• render.yaml - optional Render blueprint
• Procfile - simple process declaration
• .gitignore
• README.md

Tool interface

generate_image

Inputs:

• prompt (required, string)
• size (optional): 1024x1024, 1536x1024, 1024x1536, auto
• quality (optional): auto, low, medium, high
• background (optional): auto, opaque, transparent
• output_format (optional): png, webp, jpeg
• moderation (optional): auto, low
• n (optional, 1-4)
• user (optional string)

Output:

• a text summary
• one inline MCP image item per generated image when OpenAI returns base64 data
• a short JSON text block per image with metadata like revised_prompt

Deploy on Render

Option A: easiest manual deploy

1. Put this folder in a GitHub repo.
2. Log into Render.
3. Create a New Web Service.
4. Connect the GitHub repo.
5. Use these settings:
   • Runtime: Node
   • Build Command: npm install
   • Start Command: npm start
6. Add environment variable:
   • OPENAI_API_KEY = your OpenAI API key
7. Optional environment variable:
   • OPENAI_IMAGE_MODEL = gpt-image-1
8. Deploy.
9. After deploy, note your service URL, for example:
   • https://your-app-name.onrender.com/mcp

Option B: Render Blueprint

If you prefer, commit render.yaml and create the service from that blueprint. You will still need to set OPENAI_API_KEY manually because secrets should not live in the repo.

Quick checks after deploy

Open these in a browser:

• https://your-app-name.onrender.com/
• https://your-app-name.onrender.com/health

/health should return JSON and show hasOpenAIKey: true after you add the environment variable.

How Sand should add this remote MCP

After Render is live, Sand should add the remote MCP server URL:

• MCP URL: https://your-app-name.onrender.com/mcp

If Sand asks for a remote MCP endpoint, use the /mcp URL exactly.

Local run (optional)

npm install
OPENAI_API_KEY=your_key_here npm start

Then the MCP endpoint is:

• http://localhost:3000/mcp

Notes and limitations

• This is intentionally tiny and simple.
• It does not store files or prompts.
• It returns inline image content from OpenAI base64 output.
• Transparent backgrounds only work on some image models and formats.
• Larger n values can increase cost quickly.
• If OpenAI changes supported model names or parameter rules, update OPENAI_IMAGE_MODEL or the tool schema accordingly.