/** Comfortably past Firefox's 5 s reconnect, short enough that a closed tab costs one breath. */
export declare const TAB_REUSE_WINDOW_MS = 7000;
export interface DevViewRecord {
    /** Epoch ms when a tab last attached to a `dev` on this port. */
    watcherSeenAt: number;
    editorPort: number;
}
export declare function devViewRecordPath(root: string): string;
export declare function readDevViewRecord(root: string): DevViewRecord | null;
export declare function writeDevViewRecord(root: string, record: DevViewRecord): void;
export interface TabDecisionInput {
    /** A tab attached to a previous `dev` on this very port — worth waiting for.  */
    evidence: boolean;
    /** Epoch ms when the sidecar began listening; the wait is measured from here, not from now. */
    listeningAt: number;
    hasWatcher: () => boolean;
}
export interface TabDecisionDeps {
    now?: () => number;
    sleep?: (ms: number) => Promise<void>;
}
/** True when a tab should be opened; false when one is already watching this server. */
export declare function shouldOpenTab(input: TabDecisionInput, deps?: TabDecisionDeps): Promise<boolean>;