I love this idea! I've also been using LLMs to build tiny utilities and automations for myself, but instead of using HTML, I'm building them as:

- Shell scripts, AppleScripts, etc. that I trigger from Alfred

- Obsidian plugins

- The occasional Emacs Lisp function

They serve a similar purpose for me as OP's HTML Tools, in the sense that they let me automate a small part of my workflow that I wouldn't otherwise have automated. If I have to choose between writing AppleScript and just doing something manually, I'll pick doing something manually 100% of the time. But if I can just ask an LLM to write the automation for me and then test it in a bunch of different scenarios, the choice becomes much easier.

After reading this post, I really want to try moving some of my automations to the web. Using HTML/JS/CSS for some of these tools will let me solve a whole different set of problems. E.g. I could more easily build automations for the non-techy folks in my family instead of just keeping them to myself.