Nümtema Prompt Optimizer MCP

A minimal, open-source MCP server that turns a rough prompt into a clearer, structured prompt.

• One tool: optimize_prompt
• Zero runtime dependencies
• No API key
• No database or prompt storage
• No OAuth or widget in this MVP
• Stateless Streamable HTTP endpoint for ChatGPT

What the tool returns

{
  "optimized_prompt": "...",
  "improvements": ["..."],
  "missing_information": ["..."],
  "assumptions": ["..."],
  "score_before": 30,
  "score_after": 87,
  "mode": "balanced",
  "target_model": "chatgpt",
  "language": "fr"
}

The engine is deterministic. It does not call an LLM and never silently invents missing project facts. Missing details are exposed as placeholders.

Requirements

• Node.js 20 or newer

No npm install is necessary because the server has no dependencies.

Run locally

npm start

Default endpoints:

http://127.0.0.1:3000/health
http://127.0.0.1:3000/mcp

Development mode:

npm run dev

Test

npm test
npm run check

Quick protocol smoke test

Initialize:

curl -s http://127.0.0.1:3000/mcp \
  -H 'Content-Type: application/json' \
  -H 'Accept: application/json, text/event-stream' \
  -d '{
    "jsonrpc":"2.0",
    "id":1,
    "method":"initialize",
    "params":{
      "protocolVersion":"2025-11-25",
      "capabilities":{},
      "clientInfo":{"name":"curl","version":"1.0.0"}
    }
  }'

List tools:

curl -s http://127.0.0.1:3000/mcp \
  -H 'Content-Type: application/json' \
  -H 'Accept: application/json, text/event-stream' \
  -H 'MCP-Protocol-Version: 2025-11-25' \
  -d '{"jsonrpc":"2.0","id":2,"method":"tools/list","params":{}}'

Call the optimizer:

curl -s http://127.0.0.1:3000/mcp \
  -H 'Content-Type: application/json' \
  -H 'Accept: application/json, text/event-stream' \
  -H 'MCP-Protocol-Version: 2025-11-25' \
  -d '{
    "jsonrpc":"2.0",
    "id":3,
    "method":"tools/call",
    "params":{
      "name":"optimize_prompt",
      "arguments":{
        "prompt":"Crée-moi un site pour vendre des ebooks",
        "mode":"balanced",
        "target_model":"chatgpt"
      }
    }
  }'

Connect it to ChatGPT

ChatGPT needs a reachable HTTPS /mcp endpoint.

1. Run the server locally with npm start.
2. Expose port 3000 through the OpenAI Secure MCP Tunnel, Cloudflare Tunnel, ngrok, or deploy the Docker image to an HTTPS host.
3. In ChatGPT, enable Developer Mode under Settings → Security and login.
4. Open Settings → Plugins, create a developer-mode app, and enter:

Name: Nümtema Prompt Optimizer
Description: Improves rough prompts, identifies missing information, and returns a reusable structured prompt.
MCP server URL: https://YOUR-DOMAIN.example/mcp

5. Create a new conversation, enable the app from the composer, and ask:

Optimise ce prompt avec Nümtema Prompt Optimizer :
Crée-moi un site moderne pour vendre des ebooks sur l'intelligence artificielle.

When tool metadata changes, refresh the developer app from ChatGPT settings.

Tool inputs

Field	Required	Default	Description
prompt	yes	—	Raw prompt, 3–20,000 characters
mode	no	balanced	fast, balanced, or deep
target_model	no	chatgpt	Target assistant/model family
language	no	auto	auto, fr, or en
context	no	—	Project or situation context
audience	no	—	Intended audience
output_format	no	—	Required response format

Configuration

HOST=127.0.0.1
PORT=3000
ALLOWED_ORIGINS=https://chatgpt.com,https://www.chatgpt.com,https://chat.openai.com

Set HOST=0.0.0.0 inside containers. ALLOWED_ORIGINS=* is available for controlled testing but is not recommended for production.

Docker

docker build -t numtema-prompt-optimizer-mcp .
docker run --rm -p 3000:3000 numtema-prompt-optimizer-mcp

Deliberate MVP limits

This version does not include user accounts, history, profiles, OAuth, UI widgets, billing, async jobs, provider APIs, or multi-agent orchestration. Those belong in later versions only after this single tool proves useful.

License

MIT