{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "title": "Event Envelope",
  "type": "object",
  "properties": {
    "event_id": { "type": "string" },
    "event_type": { "type": "string" },
    "occurred_at": { "type": "string", "format": "date-time" },
    "actor_id": { "type": "string" },
    "correlation_id": { "type": "string" },
    "causation_id": { "type": "string" },
    "context_id": { "type": "string" },
    "context_hash": { "type": "string" },
    "policy_version": { "type": "string" },
    "code_revision": { "type": "string" },
    "risk_class": { "type": "string" },
    "payload_hash": { "type": "string" },
    "provenance_id": { "type": "string" },
    "schema_version": { "type": "integer" },
    "data": { "type": "object" }
  },
  "required": ["event_id", "event_type", "occurred_at", "actor_id", "risk_class", "schema_version"]
}