CalcMark
I really wanted a tiny little version of Jupyter notebooks but for personal calculations that can also
have Markdown in them. So I started chatting with my buddy, Claude, who gave me an inflated sense …
Cross-compiling Go code to WebAssembly (WASM) is really powerful.
It also produces massive files to download.
So how can we shrink this down?
I wrote an agent skill so Claude Code can use CalcMark for calculations. Then I asked Claude what was hard, and it taught me a few things about building tools for agents.
What I learned building CalcMark — a calculation language embedded in markdown — in Go.
Lexers, parsers, type systems, and the tradeoffs that bit me.
Claude kept apologizing for skipping my expectation-based testing rules…and then skipping then again 2 minutes later.
This is how I replaced best-effort written instructions with two …