{
  "skill_id": "oracle-proof-ledger",
  "name": "Proof Ledger Oracle",
  "evaluation": "free",
  "quality": "agent-decision-grade",
  "price_usd": 0.01,
  "category": "Oracle",
  "tier": "foundation",
  "protocol": "SCO",
  "esp_skill": true,
  "tags": ["oracle", "sco", "proof", "ledger", "meta-oracle", "sealed"],
  "summary": "Meta-oracle over public /api/proof — unlock counts, volume, last_verified only. Never invents metrics.",
  "when_to_use": [
    "Need sealed snapshot of public proof ledger for a skill",
    "Downstream agents require challengeable quality evidence"
  ],
  "outline": [
    "Free eval reads honesty policy + sample unlock shape",
    "Canary seals current ledger slice for a skill_id query",
    "Challenge if counts diverge from live /api/proof"
  ],
  "capabilities": [
    "Proof-ledger-only stats",
    "Sealed challengeable meta-packs",
    "null quality when zero unlocks (honest zero)"
  ],
  "decision_criteria": [
    "quality_score null or derived only from confirmed ledger",
    "Cross-check pack value against GET /api/proof?skill="
  ],
  "free_eval": "https://lvlltd.com/api/sco?op=eval&oracle=oracle-proof-ledger",
  "esp": "https://lvlltd.com/api/esp?skill=oracle-proof-ledger",
  "canary_price_usd": 0.01,
  "challenge_stake_usd": 0.01,
  "providers": ["lvl-foundation-a"],
  "source_of_truth": "https://lvlltd.com/api/proof",
  "invariants": {
    "free_eval_always": true,
    "reputation_ledger_only": true,
    "no_invented_metrics": true,
    "every_result_challengeable": true
  }
}