Simon Willison's Guide: Adding Custom MCP Servers to Claude and ChatGPT
JeremyCMorgan · x · 2026-08-08
Developer Simon Willison published a detailed TIL documenting how to connect custom MCP servers to the web chat UIs of Claude and ChatGPT.
- Claude Setup: Relatively straightforward. Users can add a custom connector via the "+" menu next to the chat prompt and input the URL.
- ChatGPT Setup: Much more complicated. Users must enable "Developer mode" in security settings, find a hidden "+" icon in the Plugins directory to add the MCP (referred to as a Plugin in the UI), set to "No Auth", and manually search to activate it in a chat.
The author also noted with disappointment that MCPs cannot currently be accessed via ChatGPT's Advanced Voice mode.
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