{
  "tool_id": "art-541-best-execution-recompute",
  "note": "golden_hash filled by golden-parity.test.mjs --update. Vector 1: seeded default, mixed buy/sell fills all at-or-better NBBO. Vector 2: a fill missing its needed NBBO leg (rejected) alongside one worse-than-NBBO fill. Vector 3: zero-input edge (finite gate, no NaN/Infinity, all totals resolve to null/0). The FILL_SET_CEILING truncation path is exercised in kernels/art-541-best-execution-recompute.kernel.mjs's own unit coverage, not as a golden-hash vector here -- a 5,000+-element fixture is impractical to hand-author and verify.",
  "vectors": [
    {
      "name": "seeded_default_all_at_or_better",
      "description": "Two fills, one buy and one sell, both executing inside the NBBO (price improvement positive).",
      "policy_parameters": {
        "fills": [
          {
            "side": "buy",
            "execution_price": 10.02,
            "nbbo_bid": 10,
            "nbbo_ask": 10.05,
            "quantity": 100
          },
          {
            "side": "sell",
            "execution_price": 10.03,
            "nbbo_bid": 10,
            "nbbo_ask": 10.05,
            "quantity": 200
          }
        ]
      },
      "output_payload": {
        "fills": [
          {
            "index": 0,
            "side": "buy",
            "execution_price": 10.02,
            "nbbo_bid": 10,
            "nbbo_ask": 10.05,
            "quantity": 100,
            "price_improvement_bps": 29.85,
            "at_or_better": true,
            "rejection_reason": null
          },
          {
            "index": 1,
            "side": "sell",
            "execution_price": 10.03,
            "nbbo_bid": 10,
            "nbbo_ask": 10.05,
            "quantity": 200,
            "price_improvement_bps": 30,
            "at_or_better": true,
            "rejection_reason": null
          }
        ],
        "fill_count": 2,
        "scored_count": 2,
        "rejected_count": 0,
        "pct_at_or_better": 100,
        "avg_price_improvement_bps": 29.93,
        "fill_set_ceiling": 5000,
        "fill_set_truncated": false,
        "rules_version": "best-execution-nbbo-recompute-2026.1",
        "regulatory_basis": "Reg NMS best-execution obligations (17 CFR 242) and FINRA Rule 5310; the price-improvement-vs-NBBO recompute is the generic shape any best-execution regime ultimately checks.",
        "note": "Deterministic per-fill recompute of price improvement against the caller-supplied NBBO at execution time. Does not verify the source of the execution-price or NBBO figures, does not fetch live market data, and is not a determination of regulatory compliance."
      },
      "compliance_flags": [
        "ALL_SCORED_FILLS_AT_OR_BETTER"
      ],
      "golden_hash": "441f75893a88a3c03541779399935422e78806788eb5fe997318bd3e32d52461"
    },
    {
      "name": "missing_nbbo_and_worse_than_nbbo",
      "description": "One buy fill missing its NBBO ask leg (rejected), one sell fill executed worse than the NBBO bid.",
      "policy_parameters": {
        "fills": [
          {
            "side": "buy",
            "execution_price": 10.02,
            "nbbo_bid": 10,
            "quantity": 50
          },
          {
            "side": "sell",
            "execution_price": 9.95,
            "nbbo_bid": 10,
            "nbbo_ask": 10.05,
            "quantity": 75
          }
        ]
      },
      "output_payload": {
        "fills": [
          {
            "index": 0,
            "side": "buy",
            "execution_price": 10.02,
            "nbbo_bid": 10,
            "nbbo_ask": null,
            "quantity": 50,
            "price_improvement_bps": null,
            "at_or_better": null,
            "rejection_reason": "MISSING_NBBO_ASK"
          },
          {
            "index": 1,
            "side": "sell",
            "execution_price": 9.95,
            "nbbo_bid": 10,
            "nbbo_ask": 10.05,
            "quantity": 75,
            "price_improvement_bps": -50,
            "at_or_better": false,
            "rejection_reason": null
          }
        ],
        "fill_count": 2,
        "scored_count": 1,
        "rejected_count": 1,
        "pct_at_or_better": 0,
        "avg_price_improvement_bps": -50,
        "fill_set_ceiling": 5000,
        "fill_set_truncated": false,
        "rules_version": "best-execution-nbbo-recompute-2026.1",
        "regulatory_basis": "Reg NMS best-execution obligations (17 CFR 242) and FINRA Rule 5310; the price-improvement-vs-NBBO recompute is the generic shape any best-execution regime ultimately checks.",
        "note": "Deterministic per-fill recompute of price improvement against the caller-supplied NBBO at execution time. Does not verify the source of the execution-price or NBBO figures, does not fetch live market data, and is not a determination of regulatory compliance."
      },
      "compliance_flags": [
        "SOME_FILLS_REJECTED_MISSING_NBBO",
        "SOME_SCORED_FILLS_WORSE_THAN_NBBO"
      ],
      "golden_hash": "06a3744262a254bcad7c937619a6eca53f6c359b53b2efcb05e5c13384eac01e"
    },
    {
      "name": "zero_input_edge",
      "description": "No fills supplied at all. Finite gate: every total resolves to 0 or null, never NaN/Infinity.",
      "policy_parameters": {
        "fills": []
      },
      "output_payload": {
        "fills": [],
        "fill_count": 0,
        "scored_count": 0,
        "rejected_count": 0,
        "pct_at_or_better": null,
        "avg_price_improvement_bps": null,
        "fill_set_ceiling": 5000,
        "fill_set_truncated": false,
        "rules_version": "best-execution-nbbo-recompute-2026.1",
        "regulatory_basis": "Reg NMS best-execution obligations (17 CFR 242) and FINRA Rule 5310; the price-improvement-vs-NBBO recompute is the generic shape any best-execution regime ultimately checks.",
        "note": "Deterministic per-fill recompute of price improvement against the caller-supplied NBBO at execution time. Does not verify the source of the execution-price or NBBO figures, does not fetch live market data, and is not a determination of regulatory compliance."
      },
      "compliance_flags": [
        "NO_FILLS_SUPPLIED"
      ],
      "golden_hash": "162a7a01195da0437a522ffc5fa2239d2ae0c192dcaa17f41034ca25d920d133"
    }
  ]
}