diff --git a/src/runtime/retained-run-binding.ts b/src/runtime/retained-run-binding.ts
index 7d60fff1..d79a5709 100644
--- a/src/runtime/retained-run-binding.ts
+++ b/src/runtime/retained-run-binding.ts
@@ -99,13 +99,14 @@ export function assertInteractionBinding(
   controlRef: AgentExactRunControlRef,
   command: InteractionResponseCommand,
 ): void {
+  // This digest identifies the interaction request, not the retained turn.
+  // The provider validates it against its durable interaction record.
   if (
     command.binding.runId !== controlRef.runId ||
     command.binding.provider !== controlRef.provider ||
     command.binding.environmentId !== controlRef.environmentId ||
     command.binding.sessionId !== controlRef.sessionId ||
-    command.binding.executionId !== controlRef.executionId ||
-    command.binding.requestDigest !== controlRef.requestDigest
+    command.binding.executionId !== controlRef.executionId
   ) {
     throw new Error('interaction response command does not target this retained run')
   }
diff --git a/tests/helpers/retained-run-child.ts b/tests/helpers/retained-run-child.ts
index 4e17e2eb..a70a8edb 100644
--- a/tests/helpers/retained-run-child.ts
+++ b/tests/helpers/retained-run-child.ts
@@ -104,6 +104,13 @@ if (phase === 'start') {
   const events = []
   for await (const event of run.events({ after: reference.after })) events.push(event)
   const statusBefore = await run.status()
+  const interactionEvent = events.find((event) => event.event.type === 'interaction')?.event
+  if (interactionEvent?.type !== 'interaction') {
+    throw new Error('retained provider replayed no interaction request')
+  }
+  if (interactionEvent.request.requestDigest === run.controlRef.requestDigest) {
+    throw new Error('interaction request digest unexpectedly matched the retained turn digest')
+  }
   const interactionBinding = {
     runId: run.controlRef.runId,
     provider: run.controlRef.provider,
@@ -111,7 +118,7 @@ if (phase === 'start') {
     sessionId: run.controlRef.sessionId,
     executionId: run.controlRef.executionId,
     interactionId: 'interaction-1',
-    requestDigest: run.controlRef.requestDigest,
+    requestDigest: interactionEvent.request.requestDigest,
   }
   const interactionResponse = { id: 'interaction-1', outcome: 'accepted' as const }
   const interaction = await run.respondToInteraction({