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.

Connect

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 /keys. After you approve access, the chat can call score_deal, explain_grade, and health.

Get a free API key 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.

In ChatGPT, open Settings, then Security and login, and turn on Developer mode.
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.
When ChatGPT asks you to sign in, approve access in the browser.
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

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 /keys for curl and scripts. The request example is on /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: /pricing. Argument details: /docs/api. Test arguments in the browser first: /try.

Other clients

Cursor, VS Code, Claude Code, Claude Desktop, Codex, n8n. The REST call and a recorded response are on /used-car-price-api. Every client is also listed on /agents.