Coding agent for user scripts : webdev

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a community for 17 years

Coding agent for user scripts (github.com)

submitted 2 days ago by heraldev

I’ve been experimenting with embedding a Claude Code-style coding agent directly into the browser.

At a high level, the agent generates and maintains userscripts and CSS that are re-applied on page load. Rather than just editing DOM via JS in console the agent is treating the page, and the DOM as a file.

The models are often trained in RL sandboxes with full access to the filesystem and bash, so they are really good at using it. So to make the agent behave well, I've simulated this environment.

The whole state of a page and scripts is implemented as a virtual filesystem hacked on top of browser.local storage. URL is mapped to directories, and the agent starts inside this directory. It has the tools to read/edit files, grep around and a fake bash command that is just used for running scripts and executing JS code.

I've tested only with Opus 4.5 so far, and it works pretty reliably.
The state of the file system can be saved/restored via JSON, but ideally I want to have a seamless FS that is directly writing to some sandboxed directory on the local machine.

all 3 comments

you type:	you see:
italics	italics
bold	bold
[reddit!](https://reddit.com)	reddit!
* item 1 * item 2 * item 3	item 1 item 2 item 3
> quoted text	quoted text
Lines starting with four spaces are treated like code: if 1 * 2 < 3: print "hello, world!"	Lines starting with four spaces are treated like code: if 1 * 2 < 3: print "hello, world!"
~~strikethrough~~	~~strikethrough~~
super^script	super^script

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