diff --git a/.changeset/heartbeat-staleness-10min.md b/.changeset/heartbeat-staleness-10min.md
new file mode 100644
index 0000000000..543d12b360
--- /dev/null
+++ b/.changeset/heartbeat-staleness-10min.md
@@ -0,0 +1,5 @@
+---
+"@runfusion/fusion": patch
+---
+
+Raise the minimum agent heartbeat staleness floor from 5 to 10 minutes. Agents go silent during long-running but legitimate work (notably a verification step running a multi-minute test command, where the agent is blocked awaiting the command and cannot tick/heartbeat). The 5-minute floor could misread such a busy agent as dead and reclaim its in-progress task mid-run; 10 minutes gives long operations room before the liveness gate acts.
diff --git a/packages/engine/src/__tests__/heartbeat-executor.test.ts b/packages/engine/src/__tests__/heartbeat-executor.test.ts
index ade0b5a345..9b0420a53d 100644
--- a/packages/engine/src/__tests__/heartbeat-executor.test.ts
+++ b/packages/engine/src/__tests__/heartbeat-executor.test.ts
@@ -460,15 +460,18 @@ describe("executeHeartbeat", () => {
       expect(section).toMatch(/\| Long Interval \| active \| FN-209 \| .* \| healthy \|/);
     });
 
-    it("buildReportsHealthSection enforces a 5-minute minimum staleness floor", async () => {
+    it("buildReportsHealthSection enforces a 10-minute minimum staleness floor", async () => {
       const now = Date.now();
       const store = createStoreWithAgentForExec();
       vi.mocked(store.getCachedAgent).mockImplementation((id: string) => ({
         id,
         runtimeConfig: { heartbeatIntervalMs: 1_000 },
       }) as unknown as Agent);
+      // 7 minutes silent with a 1s interval: under the old 5-minute floor this
+      // would read as stale, but the 10-minute floor must still treat a busy
+      // long-running agent as healthy (e.g. mid multi-minute test command).
       vi.mocked(store.getAgentsByReportsTo).mockResolvedValue([
-        { id: "agent-fast", name: "Fast Poller", state: "active", taskId: "FN-210", lastHeartbeatAt: new Date(now - 2 * 60_000).toISOString(), updatedAt: new Date(now - 2 * 60_000).toISOString() } as Agent,
+        { id: "agent-fast", name: "Fast Poller", state: "active", taskId: "FN-210", lastHeartbeatAt: new Date(now - 7 * 60_000).toISOString(), updatedAt: new Date(now - 7 * 60_000).toISOString() } as Agent,
       ]);
       const monitor = new HeartbeatMonitor({ store, taskStore: mockTaskStore, rootDir: "/tmp" });
 
diff --git a/packages/engine/src/agent-heartbeat.ts b/packages/engine/src/agent-heartbeat.ts
index 66008ab61b..c5b2d69fe5 100644
--- a/packages/engine/src/agent-heartbeat.ts
+++ b/packages/engine/src/agent-heartbeat.ts
@@ -204,8 +204,11 @@ const REPORTS_STALE_INTERVAL_MULTIPLIER = 1.5;
 
 /**
  * Minimum staleness threshold floor for very short heartbeat intervals.
+ * 10 minutes: long-running but legitimately-busy agents (e.g. a verification
+ * step running a multi-minute test command, during which the agent does not
+ * tick/heartbeat) must not be misread as dead and reclaimed mid-run.
  */
-const MIN_HEARTBEAT_STALENESS_MS = 5 * 60_000;
+const MIN_HEARTBEAT_STALENESS_MS = 10 * 60_000;
 
 /** Format milliseconds into a human-readable duration string (e.g. "5m", "1h 20m", "2h"). */
 export function formatDuration(ms: number): string {