{
  "schema_id": "la.archive.substitution.v1",
  "schema_version": 1,
  "pack_id": "sub-ex-001",
  "created_at": "2026-07-26T00:00:00.000Z",
  "substitution": {
    "original_ref": "spec-tree-001",
    "substitute_ref": "installed-tree-014",
    "reason_note": "Stock unavailable at tender; functional equivalent approved"
  },
  "equivalency": {
    "basis": "functional",
    "confidence": "documented",
    "reviewer": null,
    "method_note": "Horticulturist sign-off recorded in project minutes"
  },
  "phase": "construction",
  "tla185_refs": {
    "record_id": null,
    "field_paths": ["planting.taxon", "planting.quantity"]
  }
}