When the QuickBooks MCP server only returns sandbox data, you are on development keys. To reach your real company, create a production app in the Intuit developer portal and complete the production questionnaire. For the OAuth redirect step, note that production mode rejects YOUR_HOST URIs, so point it at a temporary public URL (ngrok works) just for the auth handshake, then store the tokens.

Context: GitHub issue intuit/quickbooks-online-mcp-server#3 (closed, 8 comments): the reporter set up the MCP server expecting to query their own company's books, but it could only see a sandbox dummy company. Commenters confirmed you need production API keys from the developer portal, which means completing the production questionnaire. One more wrinkle: production apps reject YOUR_HOST redirect URIs, and the workaround used was ngrok to expose a temporary public URL for the auth step.