Skills & Rules: how Devin works in this repo
Knowledge and Playbooks live in the Devin platform. Skills and Rules live as files in your repository, version-controlled like everything else, readable by any AI coding tool your team uses. The one-line distinction: constraint = rule, procedure = skill.
Rules live in AGENTS.md and are always-on constraints: what Devin should and shouldn't do here. "Use pnpm, not npm." "Never edit generated files." They branch, review, and merge like code.
Skills are repo-scoped procedures, loaded only when relevant or explicitly invoked. They answer "how do you do X here": how to run the integration test harness, how to deploy to staging. Each skill is a SKILL.md file at .agents/skills/<skill-name>/SKILL.md. To invoke one explicitly in a prompt, use @skills:skill-name (with arguments if needed, e.g. @skills:deploy staging).
Skills are organic and build up through usage:
- Auto-discovered: Devin figures something out mid-session and proposes saving it as a skill. You review the skill PR and merge.
- On demand: Tell Devin to save what it just did as a skill.
- Manually: Write one yourself.
Why this matters: Devin's competence in your repo compounds over time. Session 10 is meaningfully better than session 1, because the repo itself now carries the how-to.