Workflow Engine Integration Model
How Circus dispatches to and stays in sync with external engines through a small, uniform engine-package contract.
Webhook Authentication
How the platform authenticates outbound webhook dispatch and inbound machine callbacks — the two-secret model.
Authentication Model: Human vs. Machine
The deliberate split between human-operator auth and machine auth — two secrets, two middlewares, two revocation flows.
The Four API Surfaces
The platform's four distinct API surfaces — their audiences, auth models, and the boundaries between them.