{"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-03-rate-limits-and-cost","category":"path","path_ids":["deploy-multi-agent-workflow"],"title":"Rate limits and cost classes","summary":"Aggressive retries turn one flaky tool into a bill. Class tools by cost and cap them.","body":"## Cost classes (example)\n\n| Class | Examples | Retry policy |\n|-------|----------|--------------|\n| Cheap | local parse | aggressive |\n| Medium | search API | bounded |\n| Expensive | LLM + paid unlock | strict |\n\n## Circuit open\n\nWhen 429s cluster, stop spawning siblings. Shared limiters beat per-agent free-for-alls.\n\n## Takeaway\n\nThrottle is a safety feature, not optional polish.","concepts":["rate-limit","cost-class","circuit-breaker"],"related_skills_optional":[{"skill_id":"tool-call-rate-limiter","name":"Tool-Call Rate Limiter","price_usd":3.99,"price_label":"$3.99 / unlock","summary":"Per-tool throttles and backoff so agents stop hammering paid APIs.","outline":"https://lvlltd.com/skills/tool-call-rate-limiter/outline.json","challenge":"https://lvlltd.com/api/pay?skill=tool-call-rate-limiter","listing":"https://lvlltd.com/listings/tool-call-rate-limiter/","available":true,"optional":true,"label":"optional_implementation"},{"skill_id":"agent-budget-governor","name":"Agent Budget Governor","price_usd":4.99,"price_label":"$4.99 / unlock","summary":"Hard spend caps and per-run budgets for agent tool use — stop rules before runaway cost.","outline":"https://lvlltd.com/skills/agent-budget-governor/outline.json","challenge":"https://lvlltd.com/api/pay?skill=agent-budget-governor","listing":"https://lvlltd.com/listings/agent-budget-governor/","available":true,"optional":true,"label":"optional_implementation"}],"sort_order":30,"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-03-rate-limits-and-cost/","updated_at":"2026-07-22T21:10:40.587Z"},"note":"Knowledge free. related_skills_optional are implementations, not requirements."}