diff --git a/packages/app/e2e/browser/agent-heartbeat-track.spec.ts b/packages/app/e2e/browser/agent-heartbeat-track.spec.ts
index 2fb0819657..7b9ac862fd 100644
--- a/packages/app/e2e/browser/agent-heartbeat-track.spec.ts
+++ b/packages/app/e2e/browser/agent-heartbeat-track.spec.ts
@@ -51,13 +51,14 @@ test("an agent heartbeat stays visible and keeps its workspace running", async (
     await expectWorkspaceDone(page);
     await captureHeartbeatEvidence(page, testInfo, "heartbeat-removed-workspace-done");
 
-    const expiringHeartbeat = await scenario.createHeartbeat({
-      name: "Temporary watch",
-      expiresAt: new Date(Date.now() + 20_000).toISOString(),
-    });
+    const expiringHeartbeat = await scenario.createHeartbeat({ name: "Temporary watch" });
     await expectWorkspaceRunning(page);
     await page.getByRole("button", { name: "1 heartbeat" }).click();
     await expectHeartbeatVisible(page, expiringHeartbeat);
+    await scenario.setHeartbeatExpiry(
+      expiringHeartbeat.id,
+      new Date(Date.now() + 20_000).toISOString(),
+    );
     await expect(page.getByRole("button", { name: "1 heartbeat" })).toHaveCount(0, {
       timeout: 30_000,
     });
diff --git a/packages/app/e2e/support/helpers/heartbeats.ts b/packages/app/e2e/support/helpers/heartbeats.ts
index 71158b4777..60ec611423 100644
--- a/packages/app/e2e/support/helpers/heartbeats.ts
+++ b/packages/app/e2e/support/helpers/heartbeats.ts
@@ -14,6 +14,10 @@ interface HeartbeatScheduleClient {
   }): Promise<{ schedule: ScheduleSummary | null; error: string | null }>;
   scheduleDelete(input: { id: string }): Promise<{ error: string | null }>;
   scheduleList(): Promise<{ schedules: ScheduleSummary[]; error: string | null }>;
+  scheduleUpdate(input: {
+    id: string;
+    expiresAt: string;
+  }): Promise<{ schedule: ScheduleSummary | null; error: string | null }>;
 }
 
 export interface SeededHeartbeat {
@@ -27,6 +31,7 @@ export interface AgentHeartbeatScenario {
   parent: { id: string; title: string };
   child: { id: string; title: string };
   createHeartbeat(input?: { name?: string; expiresAt?: string }): Promise<SeededHeartbeat>;
+  setHeartbeatExpiry(id: string, expiresAt: string): Promise<void>;
   readWorkspaceStatus(): Promise<string | null>;
   readHeartbeatExists(id: string): Promise<boolean>;
   readAgentStatuses(): Promise<Record<string, string>>;
@@ -75,6 +80,12 @@ export async function seedAgentWithHeartbeat(): Promise<AgentHeartbeatScenario>
         heartbeatIds.add(created.schedule.id);
         return { id: created.schedule.id, name, cadence: "Every 15 minutes" };
       },
+      setHeartbeatExpiry: async (id, expiresAt) => {
+        const updated = await scheduleClient.scheduleUpdate({ id, expiresAt });
+        if (!updated.schedule) {
+          throw new Error(updated.error ?? "Failed to update heartbeat expiry");
+        }
+      },
       readWorkspaceStatus: async () => {
         const result = await workspace.client.fetchWorkspaces();
         return (