A worked walkthrough of wiring your own tool server into both Claude and ChatGPT web chat

Simon Willison published a step-by-step account of connecting a custom Model Context Protocol server to the standard Claude and ChatGPT chat interfaces. His summary of the state of play: it is possible in both, but it takes quite a few steps, and the setup path is not obvious from either product.

What it means If you have wanted your own data in front of a chat assistant without building an app, this is the current shortest real path, written down by someone who did it.