Guides

Written while building this product, and held against each tool’s own documentation rather than against what a model remembers. Where a claim has a date on it, that is the date it was last checked.

• CLAUDE.md, AGENTS.md and Cursor rules: which file does what

  Three conventions, one job, and they are not interchangeable. What each tool actually reads, where the file goes, and how to keep one set of instructions without maintaining three copies.

• How to write a spec a coding agent can build from

  A prompt describes what you want. A spec describes what done means. The ten sections that make the difference, and what each one is for when the reader is a machine.

• Non-goals: the section that stops an agent inventing features

  Everything you did not ask for is a thing your agent may decide to build. Writing down what not to build is the cheapest correction available, and almost nobody does it.