refactor: identify and freeze messages at creation

packages/telemetry/session-telemetry/src/coordinator.ts

@@ -251,7 +251,7 @@ function shutdownRecord(session: Session): TelemetryRecord {
 function severityOf(event: SessionEvent): TelemetrySeverity {
   switch (event.type) {
     case 'tool/result':
-      return event.data.isError ? 'error' : 'info'
+      return event.data.message.content[0].isError === true ? 'error' : 'info'
     case 'turn/end':
       return event.data.reason.kind === 'error' ? 'error' : 'info'
     default:

packages/telemetry/session-telemetry/src/index.ts

@@ -45,7 +45,7 @@ declare module 'cordis' {
 /**
  * Severity of a telemetry record, pre-mapped at capture so a receiver can
  * alert with zero configuration: `error` for events whose own outcome flag
- * says so (`tool/result.isError`, `turn/end` error reasons) and for
+ * says so (the tool-result block's `isError`, `turn/end` error reasons) and for
  * `agent-error` operational records. Captured events otherwise default to
  * `info`; `warn` remains available to `telemetry/record` policies and
  * backends.