Common Bugs in GPT Engineer-Generated Code

GPT Engineer builds the full UI first and the functionality second. If the generation is interrupted or the feature is complex, the UI exists without the backing logic

Features that look complete in the UI but don't actually work — buttons that don't submit, forms that don't save, links that navigate nowhere. Missing error handling means any failure shows a blank screen. State resets on navigation because it's not persisted

Start by running your app through its complete user flow — sign up, use every feature, try edge cases like empty inputs and invalid data. Most GPT Engineer bugs surface when you go off the happy path. Use your browser's developer tools to watch for console errors, failed network requests, and unhandled promise rejections. TypeScript's strict mode will catch many issues at compile time if it's not already enabled.

For async errors, wrap every server-side operation in try/catch blocks and return meaningful error messages. For state bugs, consider whether the state belongs in the URL, in a server component, or in client state — GPT Engineer often defaults to client state when server state would be more appropriate. For data fetching issues, implement proper loading and error states for every data-dependent component.

The best way to prevent GPT Engineer bugs from reaching production: enable TypeScript strict mode, add ESLint rules for common mistakes (no-floating-promises, exhaustive-deps), and write tests for critical user flows. Even basic smoke tests catch the majority of issues.