What kind of time frame do you ballpark this would have taken you on your own?
I know it's a little apples-and-oranges (you and the agent wouldn't produce the exact same thing), but I'm not asking because I'm interested in the man-hour savings. Rather, I want to get a perspective on what kind of expertise went into the guidance (without having to read all the guidance and be familiar with browser implementation myself). "How long this would have taken the author" seems like one possible proxy for "how much pre-existing experience went into this agent's guidance".
> What kind of time frame do you ballpark this would have taken you on your own?
I don't think I'd be able to do this on my own. Not that I don't know Rust, but because I don't know X11 (nor macOS or Windows) well enough to even know where to begin.
I've been a Linux user for almost two decades, so I know my way around my system, but never developed X11 applications or anything, I'm mostly a web developer who jumped around various roles through the years. Spent a lot of time caring deeply about testing, infrastructure, architecture/design and communication between humans, might have given me a slight edge in programming together with agents.
I have a fun little tool which runs the year-2000-era sloccount algorithm (which is Perl and C so I run it in WebAssembly) to estimate the time and cost of a project here: https://tools.simonwillison.net/sloccount
If you paste https://github.com/embedding-shapes/one-agent-one-browser into the "GitHub Repository" tab it estimates 4.58 person-years and $618,599 by year-2000 standards, or 5.61 years and $1,381,079 according to my very non-trustworthy 2025 estimate upgrade.