# Connect DealScore to ChatGPT

DealScore is a remote MCP server that grades a used-car asking price, and you connect it to ChatGPT by turning on Developer mode, adding the DealScore MCP URL as an app, and signing in by email. The server is Streamable HTTP at `https://cardealscore.com/api/mcp`. Sign-in is OAuth 2.1 with PKCE, the same email link used on https://cardealscore.com/keys. After you approve access, the chat can call `score_deal`, `explain_grade`, and `health`.

Page: https://cardealscore.com/integrations/chatgpt

Get a free API key: https://cardealscore.com/login?next=%2Fkeys. Used car price API: https://cardealscore.com/used-car-price-api

## Add the app in Developer mode

Add the server from Developer mode. DealScore has no listing in the public ChatGPT app directory.

1. In ChatGPT, open Settings, then Security and login, and turn on Developer mode.
2. Add an app and paste the MCP URL below. Do not put an API key in the app. DealScore registers a public OAuth client and uses the email sign-in.
3. When ChatGPT asks you to sign in, approve access in the browser.
4. In a new chat, give a year, make, model, asking price, and mileage and ask for a grade. ChatGPT should call `score_deal`.

Developer mode:

```text
https://cardealscore.com/api/mcp
```

Turn on Developer mode in ChatGPT settings, add an app with this MCP URL, and sign in when asked. Full setup: /integrations/chatgpt.

ChatGPT can read the tool list before sign-in. `initialize` and `tools/list` are public methods. Calling `score_deal` requires the OAuth grant or an API key.

## Quick answers

### Is DealScore in the ChatGPT app directory?

No. DealScore has no listing in the public ChatGPT app directory. You add it from Developer mode with the MCP URL.

### How does ChatGPT sign in to DealScore?

With OAuth 2.1 and PKCE. DealScore registers a public OAuth client, and you approve access through the same email sign-in used on /keys.

### Should I put an API key in the ChatGPT app?

No. Paste the MCP URL and sign in when ChatGPT asks. API keys are for curl and scripts, and you create them on /keys.

### Which tools does ChatGPT get, and what do they cost?

score_deal, explain_grade, and health. Free includes 5 scored calls a month. Only results with coverage: scored count, and explain_grade and health are never metered.

## Leave the API key out of the chat

Paste the MCP URL, then sign in. An API key stays on https://cardealscore.com/keys for curl and scripts. The request example is on https://cardealscore.com/used-car-price-api.

## If the app does not connect

- Developer mode has to be on before the app can be added.
- The URL is `https://cardealscore.com/api/mcp`, with no API key in the app fields.
- Finish the browser sign-in when ChatGPT asks. An unfinished consent leaves `score_deal` unauthorized.
- `coverage: cannot_score` means the connection worked and the comps were too thin to grade.

## What the agent can call

`score_deal` grades a deal. Send `asking_price` and `mileage`, plus a VIN or year, make, and model. `trim` and `zip` are optional. `explain_grade` maps a `delta_pct` to a grade without fetching comps. `health` reports coverage and limits. Free includes 5 scored calls a month and Builder is $19/mo (founding price) for 1,000 scored calls a month. Only `coverage: scored` counts, and `explain_grade` and `health` are never metered. Plans: https://cardealscore.com/pricing. Argument details: https://cardealscore.com/docs/api. Test arguments in the browser first: https://cardealscore.com/try.

## Other clients

[Cursor](https://cardealscore.com/integrations/cursor), [VS Code](https://cardealscore.com/integrations/vs-code), [Claude Code](https://cardealscore.com/integrations/claude-code), [Claude Desktop](https://cardealscore.com/integrations/claude-desktop), [Codex](https://cardealscore.com/integrations/codex), [n8n](https://cardealscore.com/integrations/n8n). The REST call and a recorded response are on https://cardealscore.com/used-car-price-api. Every client is also listed on https://cardealscore.com/agents.