Sprint Mail for ChatGPT

io.sprintmail/mcp

Print and mail US letters by USPS First-Class, with tracking.

client:ChatGPT transport:streamable-http

Install Sprint Mail in ChatGPT

Settings → Connectors → Advanced → Developer mode

https://api-production.sprintmail.io/mcp

Custom connectors are a paid-plan feature and take a remote URL only. ChatGPT cannot run a packaged server locally. ChatGPT docs