Merge master into codex/session-title

packages/core/session/src/index.ts

@@ -158,6 +158,7 @@ function assertSessionEventEnvelope(value: Record<string, unknown>, index: numbe
     throw new Error(`seed event at index ${index} has an invalid event envelope`)
   }
   assertCurrentLlmShape(event, index)
+  assertCurrentTurnEndShape(event, index)
 }
 
 /** Reject pre-provider request headers and assistant messages at the seed/load boundary. */
@@ -175,6 +176,22 @@ function assertCurrentLlmShape(event: Record<string, unknown>, index: number): v
   }
 }
 
+/** Reject legacy aborted outcomes that persisted caller-owned reason detail. */
+function assertCurrentTurnEndShape(event: Record<string, unknown>, index: number): void {
+  if (event['type'] !== 'turn/end') return
+  const data = event['data']
+  /* v8 ignore next -- this migration recognizes only the legacy object shape; format-wide payload validation is separate. */
+  if (typeof data !== 'object' || data === null) return
+  const reason = (data as Record<string, unknown>)['reason']
+  /* v8 ignore next -- non-object reasons cannot carry the legacy aborted detail this migration removes. */
+  if (typeof reason !== 'object' || reason === null || Array.isArray(reason)) return
+  const record = reason as Record<string, unknown>
+  if (record['kind'] === 'aborted'
+    && (Object.keys(record).length !== 1 || !Object.hasOwn(record, 'kind'))) {
+    throw new Error(`seed turn/end at index ${index} uses unsupported reason-bearing aborted format`)
+  }
+}
+
 /** Whether an unknown value carries the current provider/model pair. */
 function hasProviderModel(value: unknown): boolean {
   if (typeof value !== 'object' || value === null) return false

packages/core/session/src/types.ts

@@ -101,7 +101,8 @@ export type TurnTrigger = TurnTriggerMap[keyof TurnTriggerMap]
  */
 export interface TurnEndReasonMap {
   completed: { kind: 'completed' }
-  aborted: { kind: 'aborted'; reason?: string }
+  /** A cancellation request interrupted the live turn. */
+  aborted: { kind: 'aborted' }
   /**
    * The turn failed: a step threw or the model reported a failure. `step` is the
    * step number the failure occurred on (the operational error's location — the