/**
 * Live traffic for a dispatched lane, as the relay daemon sees it (2026-09-17, owner decision: a
 * lane is stopped when it is IDLE, never because it passed a time budget).
 *
 * The MCP server gives every lane it starts a random TAG and sends it as the
 * `x-llm-relay-lane-activity` request header — through `ANTHROPIC_CUSTOM_HEADERS` for a spawned
 * `claude -p`, directly for an answer-mode call. Every request that carries a tag touches its
 * record here: the request start, every write to the response, and the request end. So the daemon
 * can say "this lane has a request in flight" or "its last traffic was N seconds ago" — which is
 * the one activity signal `claude -p` does not hide, because it buffers its own output until exit.
 *
 * ⚠ In memory only, in the daemon process. A restart forgets every tag, and the MCP server then
 * reads "no record", which is NO signal, never "idle": the walk still has the lane's output and
 * its working tree.
 * ⚠ The tag carries nothing: it is a random token the MCP server made, validated to a closed
 * alphabet so a caller cannot put prose into a map key. The header never leaves the relay
 * (`INTERNAL_REQUEST_HEADERS` in `candidate-runner.ts`).
 */
/** The request header that carries a lane's activity tag. */
export declare const LANE_ACTIVITY_HEADER = "x-llm-relay-lane-activity";
/** The tags the daemon keeps at once. The oldest record is dropped past it. */
export declare const MAX_LANE_ACTIVITY_TAGS = 1000;
/** Create one opaque activity tag carrying no lane/task meaning. */
export declare function createLaneActivityTag(): string;
/**
 * Add exactly one lane-activity header to an ANTHROPIC_CUSTOM_HEADERS value.
 * A nested dispatch may inherit its parent's value, so replace this header while preserving every
 * unrelated custom header.
 */
export declare function withLaneActivityHeader(existing: string | undefined, tag: string): string;
/** What the daemon knows about one tag. */
export interface LaneTrafficRecord {
    /** Requests with this tag the daemon is serving now. */
    inFlight: number;
    /** Requests with this tag the daemon has seen. */
    requests: number;
    /** Epoch ms of the last request start, response write or request end. */
    lastActivityAt: number;
}
/** The tag in a header value, or null when the value is absent or not a valid tag. */
export declare function laneActivityTag(value: string | string[] | undefined): string | null;
/** A request with this tag started. Returns the calls for its writes and its end. */
export declare function beginLaneRequest(tag: string, now?: () => number): {
    wrote: () => void;
    ended: () => void;
};
/** The record for a tag, or null when the daemon has none. */
export declare function readLaneActivity(tag: string): LaneTrafficRecord | null;
/** Test seam: forget every tag. */
export declare function resetLaneActivity(): void;