Haunted DevTools: A Local AI Debugger for Errors That Refuse to Stay Dead

This is a story about Haunted DevTools, an innovative Chrome DevTools extension developed by a coder named CodersVader. The extension turns browser errors into structured case files instead of endless console output. It monitors the inspected page for uncaught JavaScript errors, unhandled Promise rejections, and failed HTTP requests. All related errors are grouped under a unique fingerprint, making each bug incident identifiable and manageable.

Haunted DevTools uses local open-weight models, like Ollama, to diagnose the issues. It sends a sanitized event summary to the chosen model and asks for a structured JSON response containing severity, likely cause, observed evidence, confidence level, and a suggested fix. The model's response is validated before it is displayed. If the model's response doesn't match the expected format, Haunted DevTools classifies it as an unstructured fallback rather than a verified diagnosis.

The extension allows developers to choose their diagnostic model and control how data is handled. Up to three unexorcised incidents exist in the current DevTools session, while exorcised case files are stored securely in the developer's Chrome extension local storage. The extension doesn't send any sensitive information, such as request and response bodies, cookies, authorization headers, or local storage values, to the AI model.

The project's source code is available on GitHub, enabling developers to customize the extension according to their needs. Debugging, often considered a spooky and elusive task, becomes more structured and manageable with Haunted DevTools. The extension's local diagnosis, stable grouping of incidents, and persistent history create a practical workflow that helps developers tackle recurring errors effectively.