diff --git a/packages/acp-bridge/src/permissionMediator.test.ts b/packages/acp-bridge/src/permissionMediator.test.ts
index d39d34025b9..0d612e0f064 100644
--- a/packages/acp-bridge/src/permissionMediator.test.ts
+++ b/packages/acp-bridge/src/permissionMediator.test.ts
@@ -169,6 +169,9 @@ describe('MultiClientPermissionMediator — first-responder', () => {
         data: {
           requestId: 'req-1',
           outcome: { outcome: 'selected', optionId: 'proceed_once' },
+          // A4: canonical voterClientId in data, same value as the
+          // (deprecated) envelope originatorClientId below.
+          voterClientId: 'client_B',
         },
         originatorClientId: 'client_B',
       },
@@ -189,7 +192,7 @@ describe('MultiClientPermissionMediator — first-responder', () => {
     });
   });
 
-  it('omits originatorClientId on permission_resolved when voter has no clientId', async () => {
+  it('omits both voterClientId and originatorClientId on permission_resolved when voter has no clientId', async () => {
     const { mediator, events } = makeMediator();
     const record = makeRecord();
     const promise = mediator.request(record, 5_000);
@@ -197,10 +200,11 @@ describe('MultiClientPermissionMediator — first-responder', () => {
     mediator.vote(makeVote({ clientId: undefined }));
     await promise;
 
-    // Loopback voter without X-Qwen-Client-Id — pre-F3 spread guard
-    // omits the field entirely (not `originatorClientId: undefined`).
+    // Loopback voter without X-Qwen-Client-Id — the spread guard omits
+    // both fields entirely (A4: no-voter resolutions carry neither).
     expect(events).toHaveLength(1);
     expect(events[0]!.event).not.toHaveProperty('originatorClientId');
+    expect(events[0]!.event.data).not.toHaveProperty('voterClientId');
   });
 
   it('returns already_resolved on a duplicate vote and re-emits the SSE notification', async () => {
diff --git a/packages/acp-bridge/src/permissionMediator.ts b/packages/acp-bridge/src/permissionMediator.ts
index 25969496e9c..942547211e9 100644
--- a/packages/acp-bridge/src/permissionMediator.ts
+++ b/packages/acp-bridge/src/permissionMediator.ts
@@ -1126,12 +1126,23 @@ export class MultiClientPermissionMediator implements PermissionMediator {
       data: {
         requestId: pending.requestId,
         outcome: this.toAcpOutcome(resolution),
+        // A4 (doudouOUC #4484 follow-up): `voterClientId` is the canonical,
+        // unambiguous name for "who cast the resolving vote". The envelope
+        // `originatorClientId` below carries the SAME value for pre-F3 wire
+        // compat (it is semantically the voter on `permission_resolved`,
+        // unlike on `permission_request` where it is the prompt originator).
+        // Both are optional and omitted together for no-voter resolutions
+        // (timer expiry / session-closed / loopback voter with no clientId).
+        ...(resolverClientId !== undefined
+          ? { voterClientId: resolverClientId }
+          : {}),
       },
       // O8 — preserve pre-F3 behavior: voter's clientId is stamped
       // here (not the prompt originator's). Documented inconsistency
       // with `permission_request.originatorClientId` (which IS the
       // prompt originator); F3 does not fix the inconsistency to
-      // avoid breaking the wire shape.
+      // avoid breaking the wire shape. A4 keeps it as a deprecated
+      // alias of `data.voterClientId`.
       ...(resolverClientId !== undefined
         ? { originatorClientId: resolverClientId }
         : {}),
diff --git a/packages/sdk-typescript/src/daemon/ui/normalizer.ts b/packages/sdk-typescript/src/daemon/ui/normalizer.ts
index a324782e42b..9cd0b63f3da 100644
--- a/packages/sdk-typescript/src/daemon/ui/normalizer.ts
+++ b/packages/sdk-typescript/src/daemon/ui/normalizer.ts
@@ -639,12 +639,19 @@ function normalizePermissionResolved(
       },
     ];
   }
+  // A4: the canonical voter is `data.voterClientId`; fall back to the
+  // envelope `originatorClientId` (deprecated alias) for daemons predating
+  // the rename. Both may be absent for no-voter resolutions (timer /
+  // session-closed). `originatorClientId` stays on the base unchanged.
+  const voterClientId =
+    getString(event.data, 'voterClientId') ?? base.originatorClientId;
   return [
     {
       ...base,
       type: 'permission.resolved',
       requestId,
       outcome: describePermissionOutcome(event.data),
+      ...(voterClientId ? { voterClientId } : {}),
     },
   ];
 }
diff --git a/packages/sdk-typescript/src/daemon/ui/types.ts b/packages/sdk-typescript/src/daemon/ui/types.ts
index 17c50a80b31..ef7029dc3c3 100644
--- a/packages/sdk-typescript/src/daemon/ui/types.ts
+++ b/packages/sdk-typescript/src/daemon/ui/types.ts
@@ -166,6 +166,16 @@ export interface DaemonUiPermissionResolvedEvent extends DaemonUiEventBase {
   type: 'permission.resolved';
   requestId: string;
   outcome: string;
+  /**
+   * A4: the client that cast the resolving vote (canonical name). On
+   * `permission_resolved` the base `originatorClientId` carries the same
+   * value for back-compat — but it means the *voter* here, vs the *prompt
+   * originator* on `permission_request`; prefer `voterClientId` for clarity.
+   * Absent for system-initiated resolutions (timer expiry / session-closed /
+   * loopback voter with no clientId). The prompt originator remains available
+   * by correlating with the matching `permission.request`.
+   */
+  voterClientId?: string;
 }
 
 export interface DaemonUiModelChangedEvent extends DaemonUiEventBase {
diff --git a/packages/sdk-typescript/test/unit/daemonUi.test.ts b/packages/sdk-typescript/test/unit/daemonUi.test.ts
index bfe976f0cab..1e2c65c9116 100644
--- a/packages/sdk-typescript/test/unit/daemonUi.test.ts
+++ b/packages/sdk-typescript/test/unit/daemonUi.test.ts
@@ -5081,3 +5081,95 @@ describe('cross-client event recognition (prompt_cancelled / replay_complete)',
     expect(state.blocks.length).toBe(before);
   });
 });
+
+describe('permission_resolved voterClientId (A4)', () => {
+  it('exposes voterClientId from data', () => {
+    const [evt] = normalizeDaemonEvent({
+      id: 1,
+      v: 1,
+      type: 'permission_resolved',
+      originatorClientId: 'client_B',
+      data: {
+        requestId: 'perm-1',
+        outcome: { outcome: 'selected', optionId: 'allow' },
+        voterClientId: 'client_B',
+      },
+    } as never);
+    expect(evt).toMatchObject({
+      type: 'permission.resolved',
+      requestId: 'perm-1',
+      voterClientId: 'client_B',
+    });
+  });
+
+  it('falls back to the envelope originatorClientId when data.voterClientId is absent (old daemon)', () => {
+    const [evt] = normalizeDaemonEvent({
+      id: 1,
+      v: 1,
+      type: 'permission_resolved',
+      originatorClientId: 'client_B',
+      data: {
+        requestId: 'perm-1',
+        outcome: { outcome: 'selected', optionId: 'allow' },
+      },
+    } as never);
+    expect(evt).toMatchObject({
+      type: 'permission.resolved',
+      voterClientId: 'client_B',
+    });
+  });
+
+  it('omits voterClientId for a no-voter resolution (neither field present)', () => {
+    const [evt] = normalizeDaemonEvent({
+      id: 1,
+      v: 1,
+      type: 'permission_resolved',
+      data: {
+        requestId: 'perm-1',
+        outcome: { outcome: 'cancelled' },
+      },
+    } as never);
+    expect(evt).toMatchObject({ type: 'permission.resolved' });
+    expect(evt).not.toHaveProperty('voterClientId');
+  });
+
+  it('distinguishes the prompt originator (request) from the voter (resolved) when they differ', () => {
+    // The whole point of A4: client A submits the prompt that triggers the
+    // permission request; a DIFFERENT client B casts the resolving vote.
+    // The request carries A as originator; the resolution carries B as voter.
+    const [request] = normalizeDaemonEvent({
+      id: 1,
+      v: 1,
+      type: 'permission_request',
+      originatorClientId: 'client_A',
+      data: {
+        requestId: 'perm-1',
+        toolCall: { name: 'Bash', command: 'rm -rf build' },
+        options: [{ optionId: 'allow', label: 'Allow', raw: null }],
+      },
+    } as never);
+    const [resolved] = normalizeDaemonEvent({
+      id: 2,
+      v: 1,
+      type: 'permission_resolved',
+      originatorClientId: 'client_B',
+      data: {
+        requestId: 'perm-1',
+        outcome: { outcome: 'selected', optionId: 'allow' },
+        voterClientId: 'client_B',
+      },
+    } as never);
+    expect(request).toMatchObject({
+      type: 'permission.request',
+      originatorClientId: 'client_A',
+    });
+    expect(resolved).toMatchObject({
+      type: 'permission.resolved',
+      voterClientId: 'client_B',
+    });
+    // The voter is NOT the prompt originator — the disambiguation A4 enables.
+    expect((resolved as { voterClientId?: string }).voterClientId).not.toBe(
+      (request as { originatorClientId?: string }).originatorClientId,
+    );
+  });
+});