A new browser extension, Browser Code, allows users to embed a coding agent directly into their browser. The extension treats the webpage and its DOM as a file system, enabling the agent to generate and maintain userscripts and CSS. This innovative approach allows developers to manipulate web pages more efficiently than traditional methods.

This technology provides a virtual file system on top of browser storage, mapping URLs to directories. The agent mimics an environment where it can read, edit, and run scripts and code. It is especially useful for tasks like extracting data to CSV files. The extension has been tested with Opus 4.5 and offers reliable performance.

Browser Code uses a two-phase workflow to ensure safe operation. Initially, the agent operates in plan mode, where it explores and proposes changes. After user approval, it enters execute mode to modify the DOM and run scripts. Also, it allows bidirectional synchronization of userscripts with the local filesystem, enhancing developer workflow.

Why does this matter? Developers often write userscripts to customize their browsing experience or automate web tasks. The ability to leverage AI to generate and maintain these scripts could significantly streamline this process, making web development more accessible and efficient. This advancement represents a step towards AI-assisted web development.