Builder tip: run Knip after your coding agent is done

• src/utils-old.ts, an earlier attempt that nothing imports
• lodash and axios in dependencies, never imported
• dayjs imported in src/index.ts but missing from package.json
• formatPriceV2 and TAX_RATE exported from src/utils.ts, never used

No config file, no AI model, no API key.

What Knip found. One plain npx knip run caught all six, with file and line numbers, and exited with code 1:

• Unused files (1): src/utils-old.ts
• Unused dependencies (2): axios, lodash
• Unlisted dependencies (1): dayjs
• Unused exports (2): formatPriceV2, TAX_RATE

That exit code is the useful part. It means you can drop npx knip into CI or into an agent's "before you say done" checklist and it fails loudly.

The catch: --fix is a partial cleanup. We ran npx knip --fix on a copy of the repo:

• It removed axios and lodash from package.json. But axios was still in node_modules (npm listed it as extraneous) until we ran npm install again.
• It removed the export keyword from formatPriceV2 and TAX_RATE and left the code in place. Knip stopped flagging them, but tsc --noEmit --noUnusedLocals then reported both as declared but never read.
• It did not delete src/utils-old.ts. That needs --fix --allow-remove-files, which did remove it.
• It did not add dayjs. Knip's docs say auto-fix does not add unlisted dependencies, because it can't know whether they belong in dependencies or devDependencies. TypeScript also failed on the missing module.

All of this matches Knip's own auto-fix docs, which tell you to review changes in Git, use ESLint or Biome for unused variables afterward, and reinstall dependencies.

Our verdict. Worth adding to any repo where an agent writes code. It is fast, local and catches the cleanup an agent skips. Treat the report as a to-do list, not --fix as the cleanup.

The tip.

1. Run npx knip and read the report.
2. Run npx knip --fix, then add --allow-remove-files only after you've checked the file list.
3. Run your linter or tsc --noUnusedLocals to catch code the export removal left behind.
4. Install any unlisted dependency yourself, run npm install, and review the diff.

Limits of our test. This was one small repo with leftovers we planted, not a large codebase or a real agent session. Big monorepos and framework projects usually need a Knip config or plugins to avoid false positives. We did not test those.

Disclosure: Tested by MODEL on Nov 8, 2026. Not sponsored. No affiliate links.

MODEL Editors