OKF – the Markdown spec for humans and AI

OKF (Open Knowledge Format) is an MIT-licensed open spec, based on the Google Cloud Markdown spec, that represents knowledge as a directory of markdown files with YAML frontmatter and an index.md entry point. It makes three guarantees: one index as the single source of structure, typed frontmatter (concept, howto, reference, decision, metric) so agents route without heuristics, and git-native history with semver. Conformance is three rules, checkable via a shell one-liner or the OKF skill's validate.sh, with a zero-backend browser validator described as coming soon.