Adding a custom MCP server to Claude and ChatGPT

TIL Adding a custom MCP server to Claude and ChatGPT — I've started exploring [MCP](https://modelcontextprotocol.io/) in more detail. The web chat UIs for both Claude and ChatGPT can access MCP servers but it's not obvious how to set them up. Here's what I figured out.

Source: Simon Willison — Published July 29, 2026 at 00:13 UTC — Category: Tools