name: cron_heartbeat
description: |
  arcrun cron infra 健康監控 — 每分鐘觸發一次，set 節點輸出 message。
  用 wrangler tail arcrun-cypher-executor 看：每分鐘應出現 `[scheduled] trigger cron_heartbeat ...`
  跟 `[scheduled] done cron_heartbeat true {ms}ms`。

  對應 SDD: matrix/arcrun/.agents/specs/arcrun/arcrun.md 三-A P1 #3。

flow:
  - "heartbeat_cron >> ON_SUCCESS >> log_heartbeat"

config:
  heartbeat_cron:
    component: cron
    cron_expr: "* * * * *"
    description: "每分鐘 cron infra heartbeat"

  log_heartbeat:
    component: set
    values:
      message: "alive at {{_scheduled_at}}"
      cron_triggered: true
      api_key_prefix: "{{api_key}}"