/**
 * Anchor dispersion guard for cross-pillar primitives.
 *
 * The phase-gap and shape-similarity tools partition an anchor's time
 * buckets into high-phase / low-phase by anchor median. If the anchor
 * itself doesn't have a real busy/quiet split (e.g. a constant-rate
 * pattern), the partition is arbitrary and everything downstream is
 * noise dressed up as signal.
 *
 * `computeAnchorDispersion()` returns coefficient of variation (std/mean)
 * of the anchor values. If the result is below ANCHOR_DISPERSION_FLOOR,
 * the caller MUST refuse with `status: "anchor_no_phase_separation"`.
 *
 * Statistic choice — CV (std/mean), not MAD/median.
 *
 * MAD/median avoids the well-known "CV blows up near zero mean" failure,
 * which is correct for steady-state metric series with non-zero
 * baselines. But MAD/median has its own pathology: when more than half
 * the anchor values sit at the baseline (sparse-spike incident anchors,
 * common for log patterns that emit only during incidents), median =
 * baseline and MAD = 0, so MAD/median = 0 and the guard refuses anchors
 * that ARE valid signals.
 * Real chaos-shape anchors with zero baselines fall in this trap.
 *
 * CV handles those:
 *   - Sparse-spike (e.g. [0×15, 1, 5, 10, 5, 1]) → mean > 0, std > 0,
 *     CV ≈ 2.3 → passes (correct).
 *   - Flat constant [5×20] → std = 0, CV = 0 → refuses (correct).
 *   - Bimodal [1×5, 10×5] → CV ≈ 0.82 → passes (correct).
 *   - Chaos ramp [2,2,5,10,20,32,...] → CV ≈ 0.88 → passes (correct).
 *
 * The CV-near-zero-mean concern remains, but it's structurally fine:
 * when mean is exactly zero, the guard returns 0 (refuse). When mean
 * is small-but-nonzero AND CV is high, the data DOES have real
 * relative spread, so passing it through is correct behavior.
 */
/**
 * Below this dispersion, the anchor has no real busy/quiet phase and
 * any phase-partition-based analysis is meaningless. Hand-picked from
 * the chaos-test calibration; surfaced in tool output as
 * `unvalidated_default` so callers can override per backend.
 */
export declare const ANCHOR_DISPERSION_FLOOR = 0.15;
/**
 * Coefficient of variation (std / mean) of a numeric series.
 *
 * Returns 0 for empty input, single-value input, or zero-mean input
 * (degenerate cases). Callers interpret 0 as "no phase separation."
 */
export declare function computeAnchorDispersion(values: number[]): number;
/**
 * Convenience: does this anchor have enough phase separation for the
 * cross-pillar partition math to be meaningful?
 */
export declare function hasPhaseSeparation(values: number[]): boolean;