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

== Things We Learned ==

# The GPT Builder is pretty good at getting a software newbie up to quite a distance
# Cloudflare Tunnels don't work on nested domains (so you can't do a.b.julieyukang.com)
# Writing constrained tools that an LLM can call actually allows for more useful LLMs
# Writing constrained tools allows for far easier testing than trying to implement the API with Actions
# An MCP is a decent structure, but auth etc. is complicated
# A HTTP API is good because Claude Code can test itself and loop on feedback
# You can use the `x-openai-isconsequential` header to allow ChatGPT to enable the option for the user to select "Always Allow" on action calls

Overall, the end result is pretty useful already, and I keep thinking that I should build some kind of MCP so that I can expose our Apple Reminders (which is what Julie and I use currently to track our home/personal to-do lists).