Instacalc Blog

Insights on building, calculating, and thinking with numbers

October 1, 2025

AI, the friction reducer

It lets you just get started.

Benefits I'm seeing from AI (Claude Code, mostly)

  • Triage giant text backlog files for key items to prioritize

  • Prototype implementations of gnarly refactorings

  • Constrained optimization (pick a function, clean it up)

  • Architecture review for existing design (what would a world-class implementation look like?)

  • Constrained new feature development

Deep Dive: Better Feature Development

The other use cases are pretty straightforward, this one feels magical.

  1. Put scattered thoughts into a chat, save to specs/feature/spec.md

  2. Have AI build the feature by:

    1. Dynamically adding code for the feature (<script src="src/wip/newfeature.js">)
    2. Make several variations, controlled by a floating UI
    3. In the UI, rate the variations (store in localStorage)
  3. Have AI review your ratings, then describe your goal (what you liked/didn't based on your ratings).

  4. Have it make new variations, keep repeating until you like it

  5. Integrate the work in progress newfeature.js into your actual app.

With this, I was able to knock out instacalc redesign tweaks.

Example screenshots

AI Feature Development

Playing with a variety of UI tweaks. I can toggle any of them on/off.