Rewriting this site with AI agents

Disclosure: this post was written by an AI — GLM 5.3 Flash, running as the orchestrator in opencode — about the very site you are reading it on. Every fact and number was pulled from the actual session log, and Yannick reviewed and edited it before publishing.

This site used to be a neglected Jekyll page on GitHub Pages. It is now a single Rust binary that renders Markdown, highlights code, sets Typst math and diagrams as inline SVG, and serves everything itself. And it was built almost entirely by AI agents in one session. The fun facts:

The planning cost more than the build. Before a single line of Rust was written, Opus 5.5 spent $12.26 of AI credits writing the plan: eight Markdown documents describing architecture, content, design, task breakdown and deployment — down to pinned crate versions and the exact signature of every shared type. Implementing all of that took a fleet of GLM 5.3 Flash agents exactly $3.43. Planning is expensive. Guessing is more expensive. How that played out is its own post: how the AI orchestration worked.

Twelve tasks, four waves, zero merge conflicts. The agents never saw each other’s code. Each one got its own git worktree, its own branch and its own port, worked only on files its task owned, and reported back to an orchestrator that merged one branch at a time. The trick that made this possible: the plan defined shared types up front, so agents compiled against a contract instead of against each other.

The site renders math like it’s 2026. Write inline math like $e^(i pi) + 1 = 0$ and it comes out rendered: — and full CeTZ/Lilaq/Fletcher diagrams are compiled by Typst into self-contained inline SVG at startup, baseline-aligned with your text, colored by your theme — no JavaScript, no web fonts, no CDN. There is a whole post about that: one Rust binary and Typst math.

One browser found what 208 tests didn’t. The test suite is green, Lighthouse scores 100/100/100 on accessibility, best practices and SEO, and the Docker image is 41.5 MB. None of that caught the bug where every visitor could cache a stale WebAssembly demo forever. A paranoid human question — “what happens when the wasm changes?” — did. That story is in how the AI orchestration worked, too.

One agent froze. Twice. Long-running commands without timeouts turned out to be the way to lose an agent; explicit timeouts on every command brought the third attempt home. Small operational lessons like that ended up mattering as much as the architecture.

Here is the money shot, rendered by the site itself the moment you loaded it:

That chart is a Typst snippet in a Markdown file, compiled to SVG when the server booted. The total bill for a complete rewrite of this website — tests, design, deployment pipeline and all: $15.69.