export type TrailPoint = readonly [number, number, number];
export interface LeaderTrailConfig {
    /** Arc-length gap between consecutive followers. */
    spacing: number;
    /** Followers the trail must be able to serve; history is capped to cover them. Default `16`. */
    maxFollowers?: number;
    /** Minimum leader movement before a new trail sample is recorded; default `spacing / 8`. */
    sampleDistance?: number;
}
export interface TrailPose {
    position: TrailPoint;
    /** Yaw (radians) of the trail direction at this point, matching engine `rotationY`. */
    heading: number;
}
/**
 * A live breadcrumb trail recorded from a moving leader, with followers placed by arc-length
 * behind the head — conga lines, convoys, duckling chains, snake bodies. Call `record` with the
 * leader's position every tick; read `followerAt(i)` for the pose `spacing * (i + 1)` behind.
 */
export interface LeaderTrail {
    record(position: TrailPoint): void;
    /** Pose for follower `index` (0 = closest behind the leader); `null` until enough trail exists. */
    followerAt(index: number): TrailPose | null;
    /** Recorded arc length available behind the leader. */
    length(): number;
    /** Drop all history (teleport, respawn) and optionally restart from a position. */
    reset(position?: TrailPoint): void;
}
/**
 * A trailing follower formation that chases a leader along its past path — snake/convoy trails.
 *
 * @capability follow-trail trailing follower/snake formation that chases a leader
 */
export declare function createLeaderTrail(config: LeaderTrailConfig): LeaderTrail;