Retainful MCP by usefulapi for ChatGPT

io.usefulapi/retainful

List contacts and lists; create contacts, add them to lists and record events in Retainful.

client:ChatGPT transport:streamable-http tools:7

Install Retainful MCP by usefulapi in ChatGPT

Settings → Connectors → Advanced → Developer mode

https://retainful.usefulapi.io/mcp

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