Duobox for ChatGPT
io.duobox/mail
Business email on your domain for AI agents: read, draft and send with the permissions you choose.
client:ChatGPT
transport:streamable-http
Install Duobox in ChatGPT
Settings → Connectors → Advanced → Developer mode
https://mcp.duobox.io/v1/mcpCustom connectors are a paid-plan feature and take a remote URL only. ChatGPT cannot run a packaged server locally. ChatGPT docs