sequenceDiagram
  participant Coordinator
  participant DB as Durable attempt status
  participant Steps as Child step owners
  participant TB as T-Bank and public sources
  participant API as Resource GET

  Coordinator->>DB: Reserve attempt for current connection
  DB-->>Coordinator: Attempt with connection revision
  Coordinator->>Steps: Run required steps (membership, portfolios, operations, events)
  Steps->>TB: Fetch missing data
  Steps->>DB: Publish complete successful step result
  Steps->>DB: Record terminal step result (success or failure with code)
  Coordinator->>DB: Read step results after terminal barrier
  alt All required steps succeeded
    Coordinator->>DB: Settle succeeded
  else Some required steps succeeded
    Coordinator->>DB: Settle partial with safe problem sections
  else No required step succeeded
    Coordinator->>DB: Settle failed with safe problem sections
  end
  API->>DB: Read last attempt result
  DB-->>API: Time, outcome, safe problem list