The 3,000-line file
Changing a button's colour took your AI ten minutes, cost a pile of credits, and somehow broke the sign-up form.
This answers: Why do AI edits get slow and buggy in big files? No coding needed. 3 quick decisions.
- Supervising your AI
- Debugging without panic
Checking your access…
Why do AI edits get slow and buggy in big files?
When most of an app lives in one huge file, the AI has to read thousands of lines to find and change one small thing, which costs tokens and time, and accuracy drops as it loses track of distant parts. Split code by responsibility into small components, data modules and feature folders, and refactor in small steps that keep behaviour the same.
Breaks at Your laptop: Rereads 3,140 lines for one change
How it works
app/page.tsx3,140 lines
- Lines read
- 3,140
- Roughly, in tokens
- ≈ 37,680
Some files shown. Rough guide: about 12 tokens per line of code.
Why AI tools write this bug
AI builders keep adding to whichever file is open, so features pile into one page file unless you ask for structure.
How to fix it
- Find your largest files by line count.
3 more steps, and a prompt that checks your own app for this bug. Part of Pro.
UnlockCommon questions
- Does a bigger context window fix this?
- It lets the AI read more, but you still pay for every line and accuracy still drops on long, tangled files.