/**
 * Async read/write lock.
 *
 * Many concurrent readers OR one exclusive writer. Used by the MCP
 * dispatcher to let read tools (`*_inspect`, `environment_status`, …)
 * run in parallel while still serializing writes against everything.
 *
 * **Writer preference.** Queued writers are admitted before queued
 * readers when a write releases. This is the right default for scai:
 * an agent issuing a steady stream of reads must not starve a queued
 * `recipe_push` waiting to grab the exclusive slot.
 *
 * **Cancellation.** This primitive does not unwind a queued acquire when
 * its caller is cancelled. Callers that care should check their
 * AbortSignal immediately after `withRead`/`withWrite` admits them and
 * bail before doing real work. Holding the lock for the duration of a
 * no-op bail is negligible.
 */
export interface RwLockSnapshot {
    readers: number;
    writerActive: boolean;
    waitingReaders: number;
    waitingWriters: number;
}
export declare class RwLock {
    private readers;
    private writerActive;
    private waitingReaders;
    private waitingWriters;
    withRead<T>(task: () => Promise<T>): Promise<T>;
    withWrite<T>(task: () => Promise<T>): Promise<T>;
    private acquireRead;
    private releaseRead;
    private acquireWrite;
    private releaseWrite;
    /** Snapshot of internal state — for tests and diagnostics. */
    snapshot(): RwLockSnapshot;
    /**
     * Drop all state. Used by tests to ensure no Promise-chain residue
     * carries across `describe` blocks. Production callers don't need this.
     */
    reset(): void;
}