The engineering constitution for unbreakable software — functional core / imperative shell, types-first, mutation-tested. Stack-neutral, vendored across repos, enforced by AI coding agents.
2 files for Codex, OpenCode and Claude Code: constitution AGENTS.md, constitution CLAUDE.md — 1,468 tokens loaded in every session.
AGENTS.md A 1,463 tok CLAUDE.md A 5 tok These files are systemfsoftware/constitution's own configuration — they tell Codex, OpenCode and Claude Code how to work on this repository, so they are not mods to install elsewhere. Copy one as a starting point and replace the parts that are about this project.