{
  "version": "fak-calibrate/v1",
  "prediction": {
    "metric": "cache_hit_rate",
    "claimed": 0.94,
    "unit": "fraction",
    "basis": "router KV-affinity model, projected over the prior session mix",
    "lower_is_better": false
  },
  "measurement": {
    "realized": 0.80,
    "provenance": "OBSERVED",
    "source": "router_telemetry: served-from-cache / total over the billed window",
    "measured": true,
    "sample": 132
  },
  "band": { "calibrated_max": 0.10, "min_sample": 8 },
  "verdict": "OVER_CLAIM",
  "calib_err": 0.149,
  "reason": "realized 0.80 fell on the worse-than-claim side of 0.94 by 14.9% (> 10% band) — the router promised more cache reuse than telemetry delivered; recalibrate the claim down, never hide the verdict"
}