diff --git a/src/paired-execution-context-shared.test.ts b/src/paired-execution-context-shared.test.ts
index ed5befe..8f6bb59 100644
--- a/src/paired-execution-context-shared.test.ts
+++ b/src/paired-execution-context-shared.test.ts
@@ -166,6 +166,26 @@ describe('paired execution context shared verdict helpers', () => {
     ).toEqual({ kind: 'request_arbiter' });
   });
 
+  it('routes reviewer step_done to arbiter once round trips hit the deadlock threshold', () => {
+    // Below threshold: keep iterating with the owner.
+    expect(
+      resolveReviewerCompletionSignal({
+        visibleVerdict: 'step_done',
+        roundTripCount: 1,
+        deadlockThreshold: 2,
+      }),
+    ).toEqual({ kind: 'request_owner_changes' });
+    // At/above threshold: break the owner⇄reviewer step_done oscillation by
+    // escalating to the arbiter instead of looping forever.
+    expect(
+      resolveReviewerCompletionSignal({
+        visibleVerdict: 'step_done',
+        roundTripCount: 2,
+        deadlockThreshold: 2,
+      }),
+    ).toEqual({ kind: 'request_arbiter' });
+  });
+
   it('maps reviewer failure verdicts to explicit failure signals', () => {
     expect(
       resolveReviewerFailureSignal({
diff --git a/src/paired-execution-context-shared.ts b/src/paired-execution-context-shared.ts
index b5b51ba..dcd995c 100644
--- a/src/paired-execution-context-shared.ts
+++ b/src/paired-execution-context-shared.ts
@@ -112,6 +112,9 @@ export function resolveReviewerCompletionSignal(args: {
     case 'done':
       return { kind: 'request_owner_finalize' };
     case 'step_done':
+      if (roundTripCount >= deadlockThreshold) {
+        return { kind: 'request_arbiter' };
+      }
       return { kind: 'request_owner_changes' };
     case 'blocked':
     case 'needs_context':