export type ToolPhase = "selection" | "execution" | "observation_write" | "validation_write" | "hint_snapshot";
export interface ToolPhaseTimingStats {
    phase: ToolPhase;
    count: number;
    recentCount: number;
    p50Ms: number;
    p95Ms: number;
    maxMs: number;
}
/** Passive, allocation-free-on-record timing samples for the tool-call path. */
export declare class ToolPhaseTimings {
    private readonly capacity;
    private readonly samples;
    constructor(capacity?: number);
    record(phase: ToolPhase, durationMs: number): void;
    getStats(): ToolPhaseTimingStats[];
    formatReport(): string;
}
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