[
  {
    "name": "casc-001-stop-at-l0",
    "description": "Positive (C4): L0 closes (cache hit). The cascade MUST stop at L0 and MUST NOT consult any higher tier. Closing tier = L0.",
    "stages": ["L0", "L2", "L3", "L4"],
    "stage_closes": { "L0": true, "L2": true, "L3": true, "L4": true },
    "expected_closing_tier": "L0"
  },
  {
    "name": "casc-002-skip-absent-tiers",
    "description": "Positive (C4): L0 and L2 are present but do not close; L3 closes. Closing tier = L3. (L1 absent — cascade skips absent tiers.)",
    "stages": ["L0", "L2", "L3", "L4"],
    "stage_closes": { "L0": false, "L2": false, "L3": true, "L4": true },
    "expected_closing_tier": "L3"
  },
  {
    "name": "casc-003-fall-through-to-l4",
    "description": "Positive (C4): nothing below L4 closes; L4 (the remote frontier escape hatch) closes. Closing tier = L4.",
    "stages": ["L0", "L2", "L3", "L4"],
    "stage_closes": { "L0": false, "L2": false, "L3": false, "L4": true },
    "expected_closing_tier": "L4"
  },
  {
    "name": "casc-004-l4-only-runtime",
    "description": "Positive (C4): a runtime with only an L4 stage is conformant (it has opted out of the doctrine's benefit, not its rules). Closing tier = L4.",
    "stages": ["L4"],
    "stage_closes": { "L4": true },
    "expected_closing_tier": "L4"
  },
  {
    "name": "casc-005-nothing-closes",
    "description": "Negative (C4): no stage closes the request. The cascade MUST report no resolution rather than fabricate one.",
    "stages": ["L0", "L2", "L3"],
    "stage_closes": { "L0": false, "L2": false, "L3": false },
    "expected_closing_tier": null
  }
]