Debugging runbook

Something broke.
Find the symptom.

Most problems in vibe-coded apps fall into a handful of patterns. Find what you are seeing, check the likely cause, and send the prompt next to it. Precise beats polite.

Updated 2026-10-02 · 8 min read

$ The preview is a blank white page

Likely causes

  • A runtime error in a component
  • An import that points nowhere

Check

Open the browser console (F12) and copy the first red error.

Send this

The preview is blank. The console shows: "<paste the first error>". Fix the cause without changing the design.
$ "Module not found" or "Failed to resolve import"

Likely causes

  • A package was used but never installed
  • A file was renamed and an import was not

Check

Read the module name in the error — is it a package or one of your files?

Send this

Build fails with "Failed to resolve import <name>". Install the missing package if it is a dependency, or fix the import path if it is a local file.
$ A fix broke something that used to work

Likely causes

  • The change touched shared code
  • Several changes went in at once

Check

Open version history and compare with the last good version.

Send this

Since the last change, <feature> no longer works: <what you see>. Restore its previous behaviour and keep the new change.
$ It loads forever

Likely causes

  • A request that never resolves
  • An effect that re-runs in a loop

Check

Watch the Network tab: is a request pending or repeating?

Send this

The dashboard spinner never stops. The request to <endpoint> stays pending. Add a timeout and an error state, and make sure the effect runs once.
$ Styles are missing or look wrong

Likely causes

  • Utility classes not generated
  • Conflicting global CSS

Check

Inspect the element: are the classes there but unstyled?

Send this

The cards render without styling — the classes are present but have no effect. Find why the styles are not applied and fix it globally.
$ The form submits but nothing happens

Likely causes

  • The handler swallows errors
  • Validation fails silently

Check

Submit with the console open; look for a failed request or a caught error.

Send this

Submitting the contact form does nothing visible. Show inline validation errors, a loading state, and a success or error message after submit.
$ The AI keeps "fixing" the same bug

Likely causes

  • The description is too vague
  • The real cause is somewhere else

Check

Describe expected vs actual in one sentence each; include the exact error.

Send this

Stop and explain the likely root cause before changing code. Expected: <x>. Actual: <y>. Error: <z>. Then fix only the root cause.
$ Works in preview, broken after publish

Likely causes

  • Environment values missing in production
  • Paths that only exist in development

Check

Compare the published URL's console with the preview's.

Send this

After publishing, <feature> fails with "<error>" while it works in preview. Make it work in the production build without hard-coded development values.

Read next

Best practicesVibe coding for beginnersSecurity checklistGlossary

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