Lightfast Clerk Skill

Clerk auth primitives for local development. Strict scripts for operations with stable contracts (Clerk Backend API, filesystem). A playbook for the browser-driven sign-in flow, because Lightfast's auth UI changes and a hardcoded script would silently rot.

The split:

• Scripts talk to Clerk's Backend API and the local filesystem. These are stable contracts — a script is the right tool.
• Playbook (references/sign-in-playbook.md) drives the browser via agent-browser. The calling agent (Claude, a human, another skill) reads the playbook and executes it. Failures become observations instead of opaque exit 1 — which is exactly what you want when debugging auth.

Decision tree