Swap slow build tools and restructure a big codebase in small, measured steps
Idea + starter prompt, not run by us yet
For: Developers with a large TypeScript repo where lint and type checks take too long
In a seven app monorepo with roughly 1,670 TS files, the agent swapped Biome for oxlint and oxfmt, and tsc for tsgo, each in its own PR. It also moved the frontend into feature modules from a written spec. Lint plus type check went from 29.04s to 1.25s, and redesigning his site took two or so days where he expected roughly two weeks.
Steps
- Time your current lint, type check, test and build runs so you have a before number.
- Write a short spec for the change and ask Claude Code to split it into phases, one PR each.
- Have it run lint, type check, tests and build after every step and paste the output.
- Read every diff yourself. Do not merge a change you cannot explain.
- Measure again after each phase and keep a CLAUDE.md with the rules that worked.
Starter prompt
I want to replace [current tool] with [new tool] in my repo at [repo path]. Before changing any file, measure how long lint, type check, tests and build take now and report the numbers. Then propose a plan split into small phases, where each phase becomes one separate PR. Wait for my OK on the plan. Work on a new branch only. After each phase, run lint, type check, tests and build, show me the output, and list anything you are unsure about. Do not merge or push to main. I will review each PR myself.
Original post: sergioazocar.com · found via agentusecases.ai. Written up in our own words. We haven't run it, so test it on made-up data first.