/**
 * The activation exchange a prepared session answers, and nothing else.
 *
 * A prepared session holds discoverable endpoint authority while its readiness
 * stays withheld; activation is the one request that asks it to publish that
 * readiness. Every caller shares this exchange whatever proved the endpoint
 * authority beforehand: the `gjc notify activate-thread` CLI resolves it from
 * the local session index, and the Coordinator resolves it from the broker's
 * incarnation-bound binding.
 *
 * It lives outside `sdk/bus` on purpose. The existing-thread module reaches the
 * chat-daemon and settings graph to prove a Slack binding, and the Coordinator
 * MCP entrypoint may not reach that graph at all, so the exchange the machine
 * entrypoint needs carries no notification, daemon, or settings dependency.
 */
export type SessionActivationErrorCode = "session_not_live" | "not_prepared" | "not_bound" | "activation_unavailable" | "activation_outcome_unknown";
/** A fail-closed rejection while activating a prepared session. */
export declare class SessionActivationError extends Error {
    readonly code: SessionActivationErrorCode;
    constructor(code: SessionActivationErrorCode, message: string);
}
/** Safe confirmation of an activation. It carries identifiers only. */
export interface ActivatedPreparedSession {
    sessionId: string;
    endpointGeneration: number;
    status: "activated" | "already";
}
/** The narrow transport surface activation needs from an SDK connection. */
export interface PreparedSessionActivationClient {
    request(frame: Record<string, unknown>): Promise<Record<string, unknown>>;
    close(): Promise<void>;
}
/**
 * Ask one already-connected session to publish the readiness it withheld.
 *
 * The frame names the exact session and endpoint generation, and the answer is
 * accepted only when it proves both, so a replacement session can never be
 * activated in place of the requested one. Activation is idempotent: an exact
 * retry answers `already` without a second readiness signal.
 */
export declare function requestPreparedSessionActivation(client: PreparedSessionActivationClient, sessionId: string, endpointGeneration: number): Promise<ActivatedPreparedSession>;