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Adebuggerthatlivesontopofyourscreen.

Jeradin uses on-device screen understanding and semantic code analysis to detect bugs in any vibecoding environment — Lovable, Cursor, Replit, Gemini and beyond. It points to the exact line. It explains the cause. It shows the correction. You stay in control.

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Detected · 3 issues
App.tsx:42
critical
Undefined state on render
api/auth.ts:18
warn
Missing await on fetch
ui/Modal.tsx:71
info
Hydration mismatch hint
Resolved · today
Stale closure in useEffect
Missing dep in array
App.tsx · line 42

user is undefined when profile.name renders

App.tsxread-only · jeradin will not write
  const { data: user } = useUser()
- return <h1>Hello, {user.profile.name}</h1>
+ return <h1>Hello, {user?.profile?.name ?? "there"}</h1>
Semantic explanation

useUser() resolves asynchronously, so on the first render user is undefined. Reading .profile.name throws before the fetch completes. Add optional chaining or guard with a loading state.

Semantic, not syntactic

Most linters catch typos. Jeradin catches intent mismatches — when your code runs but doesn't do what you meant.

Zero write access

Jeradin has no permission to edit, commit or push. It is, by design, observation-only.

Local first

Screen frames and stack traces are processed on-device when possible. Cloud is opt-in for heavy reasoning.

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