Flagship
Bitter
A prepared workspace and command-line tool for building software with AI, from the first commit through deployment and support.
bitter.sh →How this started
A worksheet, then a lesson
SheetGenius began with a worksheet. Michael Ruescher was traveling with his family and homeschooling his kids when GPT‑3.5 came out. The model could help write a lesson, but it could not reliably turn one into the next day’s worksheet and a printable PDF. SheetGenius closed that gap.
Each new model took over more of the job on its own. By 2026 a capable frontier agent could make a decent worksheet and PDF directly, and Michael had moved most of his effort elsewhere. The app still has its uses. Its core trick was no longer something only the app could do.
Richard Sutton’s essay “The Bitter Lesson” later gave Michael a name for what he had watched happen. That experience changed where he put the work. Bitter is what he works on now: a prepared place where the agent a customer already uses can build and run real software, with the source, deployments, and history kept in order.
Bitter faces the question the worksheet app raised: will it become more useful as the models improve?
Michael Ruescher
Chairman & CEO