{
  "kind": "structural_zero",
  "lane": "introspection",
  "metrics": {
    "explain_api_present_rate": 0.0,
    "round_trip_surface_match_rate": null,
    "round_trip_trace_match_rate": 0.0,
    "overall_pass": false
  },
  "model_id": "frontier-structural-zero",
  "note": "Frontier LLMs do not emit the typed signals these sub-metrics score; see docs/frontier_baselines.md",
  "rationale": "round_trip_trace_match_rate requires identical trace_hash across fresh deterministic runs. explain_api_present_rate is a structural check for a CORE module. Frontier has no analog of either signal.",
  "timestamp": "2026-05-16T00:00:00+00:00",
  "version": "v1"
}
