From 834588df8feb1e72cc0211612f6e2d7e54c21332 Mon Sep 17 00:00:00 2001
From: Dotta <bippadotta@protonmail.com>
Date: Thu, 16 Jul 2026 15:09:27 +0000
Subject: [PATCH] fix heartbeat timer duplicate run race

---
 ...heartbeat-stale-queue-invalidation.test.ts | 33 +++++++++++++++++++
 server/src/services/heartbeat.ts              | 26 +++++++++++++++
 2 files changed, 59 insertions(+)

diff --git a/server/src/__tests__/heartbeat-stale-queue-invalidation.test.ts b/server/src/__tests__/heartbeat-stale-queue-invalidation.test.ts
index 35f33c9f460..afa06b06c62 100644
--- a/server/src/__tests__/heartbeat-stale-queue-invalidation.test.ts
+++ b/server/src/__tests__/heartbeat-stale-queue-invalidation.test.ts
@@ -367,6 +367,39 @@ describeEmbeddedPostgres("heartbeat stale queued-run invalidation", () => {
     expect(agent?.lastHeartbeatAt?.getTime()).toBeGreaterThan(now.getTime() - 120_000);
   });
 
+  it("atomically claims a due timer interval across overlapping scheduler ticks", async () => {
+    const { agentId } = await seedCompanyAndAgent({
+      heartbeatConfig: {
+        enabled: true,
+        intervalSec: 60,
+      },
+    });
+    const now = new Date();
+    await db
+      .update(agents)
+      .set({ lastHeartbeatAt: new Date(now.getTime() - 120_000) })
+      .where(eq(agents.id, agentId));
+
+    const results = await Promise.all([
+      heartbeat.tickTimers(now),
+      heartbeat.tickTimers(now),
+    ]);
+
+    expect(results.reduce((total, result) => total + result.enqueued, 0)).toBe(1);
+
+    const runs = await db
+      .select({ id: heartbeatRuns.id })
+      .from(heartbeatRuns)
+      .where(eq(heartbeatRuns.agentId, agentId));
+    const [agent] = await db
+      .select({ lastHeartbeatAt: agents.lastHeartbeatAt })
+      .from(agents)
+      .where(eq(agents.id, agentId));
+
+    expect(runs).toHaveLength(1);
+    expect(agent?.lastHeartbeatAt?.getTime()).toBeGreaterThanOrEqual(now.getTime());
+  });
+
   it("allows generic timer wakes when the agent has assigned todo work", async () => {
     const { companyId, agentId } = await seedCompanyAndAgent({
       heartbeatConfig: {
diff --git a/server/src/services/heartbeat.ts b/server/src/services/heartbeat.ts
index 47ee92625a0..445b5764e5c 100644
--- a/server/src/services/heartbeat.ts
+++ b/server/src/services/heartbeat.ts
@@ -10551,6 +10551,31 @@ export function heartbeatService(db: Db, options: HeartbeatServiceOptions = {})
       .where(eq(agents.id, agentId));
   }
 
+  async function claimDueTimerHeartbeat(
+    agent: typeof agents.$inferSelect,
+    now: Date,
+    intervalSec: number,
+  ) {
+    const dueBefore = new Date(now.getTime() - intervalSec * 1000);
+    const claimed = await db
+      .update(agents)
+      .set({
+        lastHeartbeatAt: now,
+        updatedAt: now,
+      })
+      .where(and(
+        eq(agents.id, agent.id),
+        eq(agents.companyId, agent.companyId),
+        or(
+          lte(agents.lastHeartbeatAt, dueBefore),
+          and(isNull(agents.lastHeartbeatAt), lte(agents.createdAt, dueBefore)),
+        ),
+      ))
+      .returning({ id: agents.id })
+      .then((rows) => rows[0] ?? null);
+    return Boolean(claimed);
+  }
+
   function parseMaxTurnContinuationPolicy(agent: typeof agents.$inferSelect): MaxTurnContinuationPolicy {
     const runtimeConfig = parseObject(agent.runtimeConfig);
     const heartbeat = parseObject(runtimeConfig.heartbeat);
@@ -16972,6 +16997,7 @@ export function heartbeatService(db: Db, options: HeartbeatServiceOptions = {})
         const baseline = new Date(agent.lastHeartbeatAt ?? agent.createdAt).getTime();
         const elapsedMs = now.getTime() - baseline;
         if (elapsedMs < policy.intervalSec * 1000) continue;
+        if (!(await claimDueTimerHeartbeat(agent, now, policy.intervalSec))) continue;
 
         const run = await enqueueWakeup(agent.id, {
           source: "timer",