Four schedulers and the constraints that pick between them. /loop for polling while you work, routines for work that outlives your laptop, and the payload wrapper that stops a leaked token becoming an instruction.

Three levels of integration, from Claude running git for you to Claude as a CI step. The @claude bot, the two modes a workflow can run in, and what a headless run does with permissions when nobody is there to answer.

The layer that turns an instruction into a guarantee. Where each event fires in a turn, which ones can block, the exit-code contract, and the asymmetry that lets a hook tighten your permissions but never loosen them.