Show HN: Browser Code – Coding Agent Inside a Web Page

[mifydev]

I (vibe)coded a Claude Code like agent that runs directly in the web browser.

With it you can pretty much have a coding agent for the currently opened website. You can ask it things like:

- Extract all links from this page and save them to CSV - Switch this site to dark mode - Copy the page content into a Google Sheet - Remove ads

The agent writes JS script that automatically loads every time you visit the page. It is heavily using the userScripts API so you need to enable a lot of permissions to run the extension, and I'm not sure it can be published anywhere.

Under the hood, scripts and styles live in a virtual filesystem where each website is a directory. The agent can search and edit the DOM as a file, which makes it work more or less reliably similar to claude code. Currently it only support Claude models, and I've tested it on Opus 4.5.

Demo video: https://x.com/ichebykin/status/2014258108500177255

[mifydev]

The agent is extremely basic now, there is no context tracking, so create new sessions often.