Editing Blog/2025-10-17/Custom GPTs (section)

== Final Solution ==

By the end, I thought perhaps it was the complexity of the API spec that made the whole thing hard to use. Besides, there are some problems that GPT-5 (even with Thinking enabled) just spazzes out on and others that Claude does that on. So I decided to try using Claude to write a constrained MCP that would only update this one Notion 'database' Julie by adding new notes, querying for notes, or updating notes. It did a marvelous job with a few edits, none of which I did with an IDE, and then I used [[One Quick Way To Host A WebApp|my standard flow for hosting this]]. It requires an `X-API-Key` header that is well-supported by ChatGPT's Actions feature, and the MCP server also generates an OpenAPI spec for use here.

This worked wonderfully, and with a little work with the prompt Julie and I were able to finish her custom Julie Notes GPT. The final architecture looks like:

# A minimal Notion API
# A wrapper around it to provide MCP functionality
# An auth check around that for an X-API-Key
# The whole thing wrapped into a container image and pushed to my homeserver registry (itself a quadlet)
# All that hosted as a quadlet on Ubuntu
# Cloudflare Tunnel proxying to the quadlet