/**
 * Registration flow registry: at most one live registration/kickoff flow per
 * agent session, bound to the PTY it was started for.
 *
 * Background (2026-09-25 startup-prompt loop): two launchers brought the same
 * agent up at boot. The second one killed the first one's PTY and built a new
 * one under the same session name, but the first one's background
 * registration flow was never cancelled. It kept polling the session by name,
 * found the replacement PTY, and typed its own kickoff into it, so the agent
 * saw two kickoffs in one resumed conversation.
 *
 * A flow is therefore cancelled when:
 * - a newer flow starts for the same session (it supersedes the old one),
 * - the session is killed or recreated ({@link RegistrationFlowRegistry.cancel}), or
 * - the PTY now registered under the session name is not the one the flow was
 *   started for. This catches kills from any code path, including ones that
 *   never call `cancel`.
 *
 * Senders must check {@link RegistrationFlowRegistry.isCancelled} right before
 * every write to the terminal.
 *
 * @module services/agent/registration-flow-registry
 */
/** A live registration flow for one session incarnation. */
export interface RegistrationFlow {
    /** Session name the flow delivers into. */
    readonly sessionName: string;
    /** Monotonic per-session generation; a newer flow has a higher number. */
    readonly generation: number;
    /** Aborted when the flow is superseded, cancelled or its PTY is replaced. */
    readonly signal: AbortSignal;
}
/** Why a flow was cancelled (logged by the caller). */
export type RegistrationFlowCancelReason = 'superseded' | 'session-killed' | 'session-replaced' | 'runtime-exited';
/**
 * Tracks the single live registration flow per session.
 *
 * @typeParam TSession - Identity object of a live PTY (compared by reference)
 */
export declare class RegistrationFlowRegistry<TSession extends object = object> {
    private readonly current;
    private readonly bySignal;
    private readonly generations;
    /**
     * Start a flow for a session. Any earlier flow for the same session is
     * aborted first: only the newest incarnation may deliver a kickoff.
     *
     * @param sessionName - Session the flow delivers into
     * @param boundSession - The PTY currently registered under that name (undefined for in-process runtimes)
     * @returns The new flow and whether an older one was superseded
     */
    begin(sessionName: string, boundSession: TSession | undefined): {
        flow: RegistrationFlow;
        superseded: boolean;
    };
    /**
     * Abort the live flow for a session, if any.
     *
     * @param sessionName - Session whose flow to abort
     * @param reason - Why (recorded on the abort signal)
     * @returns True when a live flow was aborted
     */
    cancel(sessionName: string, reason: RegistrationFlowCancelReason): boolean;
    /**
     * Decide whether a flow may still write to its session. Aborts the flow
     * (and says so) when the session's PTY has been replaced or removed since
     * the flow started, or a newer flow took over.
     *
     * Signals the registry does not know are judged by `aborted` alone, so
     * callers can pass any AbortSignal.
     *
     * @param signal - The flow's abort signal (undefined = not a guarded flow)
     * @param currentSession - The PTY registered under the session name right now
     * @returns True when the flow must not write anything further
     */
    isCancelled(signal: AbortSignal | undefined, currentSession: TSession | undefined): boolean;
    /**
     * Mark a flow finished. Only removes it while it is still the live flow,
     * so a finishing old flow can never drop its successor's entry.
     *
     * @param flow - The finished flow
     */
    end(flow: RegistrationFlow): void;
    /**
     * Whether a session has a live (not yet finished or aborted) flow.
     *
     * @param sessionName - Session to check
     * @returns True when a flow is in progress
     */
    has(sessionName: string): boolean;
}
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