{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://contenttelemetry.org/schema/v0.1/telemetry-event.json",
  "title": "Content Telemetry Standalone Event",
  "description": "Schema for standalone Content Telemetry events delivered outside a session document",
  "type": "object",
  "required": ["document_type", "schema_version", "event"],
  "properties": {
    "document_type": {
      "type": "string",
      "const": "event",
      "description": "Document type discriminator. MUST be 'event' for standalone events."
    },
    "schema_version": {
      "type": "string",
      "const": "0.1",
      "description": "Content Telemetry schema version"
    },
    "session_id": {
      "type": "string",
      "format": "uuid",
      "description": "Session identifier. MAY be omitted by origin-side emitters with no session context. REQUIRED for emitters at Grounding conformance or above (unless ctx_token is carried instead - see section 7.1)."
    },
    "ctx_token": {
      "type": "string",
      "description": "Opaque click-token issued by the originating agent, carried on content_engaged events emitted from a landing page after a click-out in place of session_id. Resolved by the attribution consumer to the owning session (the click manifest). See section 7.1. An event MUST carry either session_id or ctx_token at Grounding conformance and above."
    },
    "agent_id": {
      "type": "string",
      "description": "Responding agent identifier. REQUIRED for emitters at Grounding conformance or above when using standalone event delivery. Mirrors the session-level agent_id field."
    },
    "started_at": {
      "type": "string",
      "format": "date-time",
      "description": "Session start timestamp (UTC). Mirrors the session-level started_at field. REQUIRED for emitters at Grounding conformance or above when using standalone event delivery."
    },
    "event": {
      "$ref": "telemetry-session.json#/$defs/TelemetryEvent",
      "description": "The telemetry event"
    }
  }
}