Bug type

Behavior bug: wrong user-visible output, no crash.

Beta release blocker

No.

Summary

A heartbeat run triggered by a relayable async exec completion can deliver the raw protocol token HEARTBEAT_OK to the user. HEARTBEAT_OK is a heartbeat no-op/ack token and should be swallowed regardless of whether the heartbeat was triggered by a timer, cron event, or exec completion.

Observed on the shiki-tokyo host on 2026-05-06 (hostname, paths, config, and transcript contents redacted). Reproduced against current main source at 7f71e84248.

Steps to reproduce

1. Enable heartbeat delivery to a user-visible target, for example target: "last" with directPolicy: "allow".
2. Queue a relayable exec completion system event, for example Exec completed (review-run, code 0) :: review-worker spawn finished.
3. Run heartbeat processing for the exec event and have the model/provider return exactly HEARTBEAT_OK.
4. Observe that outbound delivery receives and sends text: "HEARTBEAT_OK".

Expected behavior

If the final normalized heartbeat response is pure HEARTBEAT_OK, gateway should treat it as a protocol no-op and skip user delivery. Exec completion reminders should still be delivered when the model returns a real summary or warning.

Actual behavior

normalizeHeartbeatReply correctly strips a pure HEARTBEAT_OK reply to shouldSkip=true, but the relayable exec completion branch restores the original reply text and clears the skip flag. That turns the protocol token into ordinary alert text.

Relevant current-source path:

• src/agents/bash-tools.exec-runtime.ts:318 queues the exec completion event and requests heartbeat for exec-event.
• src/infra/heartbeat-runner.ts:1040 collects exec completion events.
• src/infra/heartbeat-runner.ts:1046 computes hasRelayableExecCompletion.
• src/infra/heartbeat-events-filter.ts:36 treats structured exec completions with output, or failed completions, as relayable.
• src/auto-reply/heartbeat.ts:147 strips heartbeat ack tokens.
• src/infra/heartbeat-runner.ts:1689 intentionally prevents skip for exec completion events.
• src/infra/heartbeat-runner.ts:1693 restores the original reply text when the normalized text is empty.
• src/infra/heartbeat-runner.ts:1704 excludes relayable exec completions from shouldSkipMain.
• src/infra/heartbeat-runner.ts:1861 sends normalized.text as an outbound payload.

OpenClaw version

Current-source repro: upstream/main at 7f71e84248.

Observed shiki-tokyo installed version: NOT_ENOUGH_INFO. The fresh logs show npm-global runtime paths and Node v22.22.0, but openclaw was not on the noninteractive SSH PATH for an exact --version check.

Operating system

Source-level repro: macOS development checkout.

Observed host: shiki-tokyo, Ubuntu Linux kernel 5.15.0-164-generic, x86_64.

Install method

Local repro: source checkout with pnpm.

Observed host: appears to be npm-global install from runtime log paths. Exact launch/install method: NOT_ENOUGH_INFO.

Model

Observed host logs: openai-codex/gpt-5.5.

Local deterministic repro: mocked heartbeat model boundary returning exactly HEARTBEAT_OK.

Provider / routing chain

Observed host: OpenClaw gateway -> openai-codex -> gpt-5.5, channel delivery through Feishu.

Local deterministic repro: runHeartbeatOnce with a lightweight test messaging plugin and mocked model response.

Additional provider/model setup details

Observed host heartbeat config, redacted to non-secret fields: target=last, directPolicy=allow, ackMaxChars=300, lightContext=true, skipWhenBusy=true, active hours in Asia/Shanghai.

Logs, screenshots, and evidence

Issue template/rules checked before filing: .github/ISSUE_TEMPLATE/bug_report.yml, .github/ISSUE_TEMPLATE/config.yml, and CONTRIBUTING.md.

Duplicate search was performed for HEARTBEAT_OK exec completion, notifyOnExit heartbeat, and HEARTBEAT_OK. Related issues are listed below, but this issue has a narrower deterministic current-source reproducer.

Local deterministic repro output, redacted:

event = Exec completed (review-run, code 0) :: review-worker spawn finished
model reply = HEARTBEAT_OK
result = {"status":"ran"}
outbound send = {"text":"HEARTBEAT_OK","to":"<redacted-target>"}

Targeted existing tests around adjacent behavior pass but do not cover this regression:

pnpm test src/infra/heartbeat-runner.ghost-reminder.test.ts -t "metadata-only successful exec completions|includes untrusted exec completion details"
=> 1 file passed, 2 tests passed, 18 skipped

Fresh shiki-tokyo log excerpts, redacted:

2026-05-06T09:13:29+08 Stripped stray HEARTBEAT_OK token <redacted> reply
2026-05-06T09:21:52+08 Stripped stray HEARTBEAT_OK token <redacted> reply
2026-05-06T09:21:57+08 Feishu final delivery preview referenced that HEARTBEAT_OK had been shown to the user and should have been swallowed.
2026-05-06T09:30:09+08 Stripped stray HEARTBEAT_OK token <redacted> reply

A plain heartbeat poll control case in the same log family showed assistantTexts:["HEARTBEAT_OK"] with didSendViaMessagingTool:false, which is the expected silent path. The failing path is the relayable exec completion branch above.

Impact and severity

Affected users: anyone with tools.exec.notifyOnExit enabled and heartbeat delivery allowed to a user-visible target.

Severity: medium-low but user-visible. It leaks an internal protocol token, creates confusing background notifications, and undermines the intended no-op semantics for heartbeat. The feature should still keep useful background exec completion notifications; disabling tools.exec.notifyOnExit is only a workaround.

Frequency: deterministic when a relayable exec completion is inspected and the model decides no user notification is needed by returning pure HEARTBEAT_OK.

Suggested fix

Do not restore or deliver original reply text when the normalized heartbeat response is a skip token. In particular, a pure normalized HEARTBEAT_OK should remain shouldSkip=true even when hasRelayableExecCompletion is true.

A regression test should cover: structured relayable exec completion with output + model reply HEARTBEAT_OK -> no outbound send, while the inspected exec event is still consumed/recorded according to the existing event lifecycle.

Related issues

• #74257: similar symptom around Telegram async exec followup and context overflow, but this reproducer does not require overflow and points to the current relayable exec fallback branch.
• #73149: broader cron/heartbeat no-op leak class; this issue isolates exec completion heartbeat handling.
• #75322: adjacent heartbeat exec prompt/no-reply branch, but this issue is specifically deliverable exec completion + pure HEARTBEAT_OK.