{
  "schema": "woc.engagement-sample-freeze.v1",
  "engagement": "MOCK-ENGAGEMENT-1",
  "buyer": "Example Health Plan (SYNTHETIC)",
  "frozen_at": "2026-09-13T14:38:33.536Z",
  "population": {
    "roster_rows": 60,
    "real": 55,
    "synthetic": 5
  },
  "sampling_rules": [
    "RISK-BASED: every SYNTHETIC row is sampled — the buyer flagged them in its own exception report (rows from a suspect data migration). This is stated openly: the sampler does not pretend the flags were unknown.",
    "SEEDED BASELINE: 20 real rows drawn uniform WITHOUT replacement, mulberry32, seed 20260914, drawn from the 55 real rows of the frozen roster.",
    "Sample size: 25 (5 synthetic + 20 real)."
  ],
  "prng": "mulberry32",
  "seeds": {
    "roster_draw": 20260913,
    "sample_draw": 20260914
  },
  "selected_row_ids": [
    "ROW-056",
    "ROW-057",
    "ROW-058",
    "ROW-059",
    "ROW-060",
    "ROW-021",
    "ROW-028",
    "ROW-016",
    "ROW-020",
    "ROW-033",
    "ROW-010",
    "ROW-019",
    "ROW-051",
    "ROW-023",
    "ROW-001",
    "ROW-007",
    "ROW-012",
    "ROW-052",
    "ROW-022",
    "ROW-055",
    "ROW-034",
    "ROW-030",
    "ROW-039",
    "ROW-031",
    "ROW-048"
  ],
  "statement": "NO FINDING HAS RUN at freeze time: no authority comparison, no verification, no record publication, no closure receipt exists for this engagement. The rules, seeds, roster, and the exact selected IDs are committed before any of that. The findings machinery starts only against this frozen list.",
  "commitment_binding": {
    "roster_sha256": "91e96b6a59b7bea52648ff5edbef687ae7c7e9c4bfb008e4fda8546172583393",
    "sampling_frame_sha256": "5d0fb34f8078c66cd7fc6c00fb3e6693f49010b182dcde85c81ca1adeaaebf36",
    "sampling_frame_definition": "sha256 over JSON.stringify(row_ids) — the roster's rows in FILE ORDER; changing the roster under unchanged selected_row_ids and frozen_at changes this digest (the SAMPLE-COMMIT-1 falsifier, enforced by engagement-package-check leg [12])",
    "pre_run_commitment": {
      "commit": "a2031937",
      "committed_at": "2026-09-13T14:23Z",
      "frozen_at": "2026-09-13T14:38:33.536Z",
      "evidence": "MOCK-ENGAGEMENT-1 FREEZE — the sample is FROZEN AND COMMITTED BEFORE ANY FINDING RAN. Verified read-back: the tree at a2031937 under engagement-mock/ holds engagement-scope.md, roster.json, sample-freeze.json ONLY — no findings/, no findings.json, no closure receipts, no follow-up artifacts existed at that commit. The digests above bind the roster and the ordered frame the CURRENT package ships to what that pre-run commit froze; leg [12] recomputes both and fails the package on any divergence."
    }
  }
}