{"ok":true,"kind":"lesson","integrity":{"knowledge":"free","capability":"paid_x402_optional","rule":"Every concept on a path is fully teachable without purchase. Skills are optional implementations, never required reading.","display":"Learn free. Buy only if you want a ready-to-run sealed pack."},"lesson":{"schema_version":"lvl-knowledge-lesson-v1","id":"path-ma-02-health-and-stuck-agents","category":"path","path_ids":["deploy-multi-agent-workflow"],"title":"Health signals: alive vs making progress","summary":"Heartbeat is not progress. Detect stuck agents before budgets burn.","body":"## Two signals\n\n- **Heartbeat** — process is running  \n- **Progress** — step N advanced  \n\nA hung tool call can heartbeat while progress freezes.\n\n## Patterns\n\n- Missed heartbeats → restart budget  \n- Heartbeat OK, progress stalled → different budget (slow vs dead)  \n- Escalate after N stalls  \n\n## Production habit\n\nLog stage id + progress token in every long job. Dashboards should show both.\n\n## Takeaway\n\nWithout health contracts, multi-agent fleets silently spend.","concepts":["agent-health","heartbeat","progress"],"related_skills_optional":[{"skill_id":"agent-health-check-protocol","name":"Agent Health Check Protocol","price_usd":2.99,"price_label":"$2.99 / unlock","summary":"Heartbeat and liveness checks so orchestrators detect silent sub-agent death.","outline":"https://lvlltd.com/skills/agent-health-check-protocol/outline.json","challenge":"https://lvlltd.com/api/pay?skill=agent-health-check-protocol","listing":"https://lvlltd.com/listings/agent-health-check-protocol/","available":true,"optional":true,"label":"optional_implementation"}],"sort_order":20,"estimated_minutes":8,"last_updated":"2026-07-22T12:00:00.000Z","freshness":{"last_updated_at":"2026-07-22T12:00:00.000Z","days_since_update":0,"band":"fresh","score_0_100":95,"label":"Fresh","display":"Fresh · updated 2026-07-22 (0d ago)"},"integrity":{"knowledge_free":true,"skills_optional":true,"note":"This lesson is complete without purchasing any skill."},"related_bundles_optional":[],"url":"https://lvlltd.com/learn/lessons/path-ma-02-health-and-stuck-agents/","updated_at":"2026-07-22T21:10:40.587Z"},"note":"Knowledge free. related_skills_optional are implementations, not requirements."}