Rotunda - A browser built for agents with simulated typing
Hi HN! Pierce here. Rotunda is a firefox fork primarily intended for agent use, which I’ve been hacking on nights/weekends. There was a [lengthy](https://news.ycombinator.com/item?id=48024859) discussion last week on how expensive computer use models are. The cost is going to drop eventually, but I think on some level it's still usually the wrong primitive. The web gives us access to beautiful structured formats, plaintext, etc... why throw that away if we don't have to? I realized at some point that for 99% of automations I just want agents to be able to control my…
In plain words
Rotunda is a Firefox fork designed for use by AI agents to automate web tasks. It addresses the limitations of existing browser automation by providing a cleaner interface that doesn't leak signals of programmatic control. The browser allows agents to interact with web content directly rather than relying on expensive vision-based computer control models, preserving access to structured data and plain text formats available on the web.
written from the facts on this page · September 2026
From the sources
In the maker’s words, at launch
Hi HN! Pierce here. Rotunda is a firefox fork primarily intended for agent use, which I’ve been hacking on nights/weekends. There was a [lengthy](https://news.ycombinator.com/item?id=48024859) discussion last week on how expensive computer use models are. The cost is going to drop eventually, but I think on some level it's still usually the wrong primitive. The web gives us access to beautiful structured formats, plaintext, etc... why throw that away if we don't have to? I realized at some point that for 99% of automations I just want agents to be able to control my Chrome instance. But that’s easier said that done: CDP (the Chrome automation protocol) leaks a ton of state about being programmatically controlled, either by toggling window attributes or by running `page.evaluate()` commands right in the page context. Plus if you look at an automation running it's pretty obvious what happens: the mouse jumps around, fields are filled instantly, etc. Rotunda tries to fix this. Its standout features: - Realistic simulation of mouse movements and keyboard commands, powered by a trained RNN on my own timing patterns from the last week. (still feel weird about opting-in to a key logger but whatever) - Doesn’t lie about its host specs, only fibs about some client side details. Stealth browsers are too easy to flag statistically when you’re adding noise to canvas pixels or audio pipelines. - It runs on your local device with a CLI or Playwright API accessible to Claude, Codex, or whatever your harness-de-jure today looks like. - Patches modern Firefox (150) with an agentic harness to keep this updated over time MPL-2.0 on GitHub: https://github.com/monkeysee-ai/rotunda Longer writeup on the design choices: https://pierce.dev/notes/a-browser-for-agents Also check out the demo on the site! https://www.rotunda.sh/ Pretty excited by how this turned out but we’re still super early. Give it a try and please flag any issues!
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