flowchart LR
  S[Source] -->|Trigger| T[Thread]
  T -->|batch| E[Eval]
  T -->|Subscription fan-out| K[Ticket]
  E -->|accept with Mandate / stop| K
  E -->|ignore / unavailable| X[recorded]
  P[Policy change] -->|notice| K
  K -->|Assignment| W[Executor]
  K -->|Channel| S