Summary

api.runtime.system.requestHeartbeatNow({ sessionKey, reason, coalesceMs: 0 }) silently skips when targeting channel sessions (agent:main:slack:channel:*). No heartbeat turn runs, no error is logged, the system event sits in the queue indefinitely.

Context

Follows from #31564 (expose requestHeartbeatNow in plugin API, shipped in 2026.3.2).

We updated the Hermes plugin to use requestHeartbeatNow instead of the POST /tools/invoke → sessions_send workaround. The new approach worked correctly for a main/thread session (agent:main:main:thread:*) but silently failed for channel sessions (agent:main:slack:channel:*).

Reproduction

1. Create a Hermes watch routing to a channel session key: agent:main:slack:channel:CXXXXXXX
2. Trigger a dispatch — enqueueSystemEvent + sendMessageSlack both succeed
3. requestHeartbeatNow({ sessionKey: "agent:main:slack:channel:CXXXXXXX", reason: "hermes:event", coalesceMs: 0 }) is called (confirmed in logs)
4. No heartbeat turn fires on the target session — transcript unchanged, no response

Evidence from logs

10:52:34 [hermes] System event enqueued on agent:main:slack:channel:c0aka9rbsau   ✅
10:52:34 [hermes] Slack message sent to C0AKA9RBSAU                               ✅
10:52:34 [hermes] requestHeartbeatNow fired for agent:main:slack:channel:c0aka9rbsau
                                                                                   ✅ called
— no agent turn, no heartbeat output —                                            ❌

Session transcript had 3 messages before the event. Zero messages added after. Next scheduled heartbeat: 30 minutes away.

Observed vs expected

Root cause hypothesis

In heartbeat-runner.ts, the targeted wake path calls runOnce({ heartbeat: targetAgent.heartbeat, sessionKey }). The heartbeat config belongs to the main agent. For channel sessions, some condition in runOnce or resolveHeartbeatSession causes a silent skip — possibly because the channel session does not satisfy a heartbeat eligibility check that assumes main-session context.

Workaround

Reverted to POST /tools/invoke → sessions_send (with gateway.tools.allow: ["sessions_send"] + tools.sessions.visibility: "all" config). Dead code for requestHeartbeatNow preserved in plugin for fast migration.

Reference

• Closes Expose requestHeartbeatNow in plugin runtime API #31564 — original request to expose the API (shipped)
• Nimbl PR Nimbl-SaaS/nimbl#376 — our initial migration (reverted in Nimbl-SaaS/nimbl#380)
• OpenClaw version: 2026.3.2