diff --git a/src/infra/heartbeat-runner.ts b/src/infra/heartbeat-runner.ts
index 11390af43a4..753c9b31fb3 100644
--- a/src/infra/heartbeat-runner.ts
+++ b/src/infra/heartbeat-runner.ts
@@ -44,7 +44,6 @@ import { CommandLane } from "../process/lanes.js";
 import {
   isSubagentSessionKey,
   normalizeAgentId,
-  parseAgentSessionKey,
   resolveAgentIdFromSessionKey,
   toAgentStoreSessionKey,
 } from "../routing/session-key.js";
@@ -593,11 +592,7 @@ export async function runHeartbeatOnce(opts: {
 }): Promise<HeartbeatRunResult> {
   const cfg = opts.cfg ?? loadConfig();
   const explicitAgentId = typeof opts.agentId === "string" ? opts.agentId.trim() : "";
-  const forcedSessionAgentId =
-    explicitAgentId.length > 0 ? undefined : parseAgentSessionKey(opts.sessionKey)?.agentId;
-  const agentId = normalizeAgentId(
-    explicitAgentId || forcedSessionAgentId || resolveDefaultAgentId(cfg),
-  );
+  const agentId = normalizeAgentId(explicitAgentId || resolveDefaultAgentId(cfg));
   const heartbeat = opts.heartbeat ?? resolveHeartbeatConfig(cfg, agentId);
   if (!areHeartbeatsEnabled()) {
     return { status: "skipped", reason: "disabled" };