/**
 * Build contract §1.3 — the harness's own state. Opaque to us, persisted by us,
 * disposable: correctness never depends on the harness's copy, because the truth
 * is ours (architecture §3, "Harness state").
 */
import type { ThreadId, TurnState } from "@vendoai/core";
import type { UIMessage } from "ai";
/**
 * Where an opaque `turn.state` lives between turns.
 *
 * ONE slot per thread, carrying the name of the harness that owns it. §1.3 says a
 * harness swap CLEARS the state — so a swap must destroy it, not shadow it behind
 * a per-harness key. Keying by harness would let a stale session resurrect when
 * the user swapped back, handing a thinker a session id that no longer describes
 * a conversation that has moved on without it.
 */
export interface HarnessStateStore {
    /** The stored state iff it belongs to `harnessName`; a foreign owner CLEARS. */
    get(threadId: ThreadId, harnessName: string): Promise<string | undefined>;
    /** `undefined` deletes. */
    set(threadId: ThreadId, harnessName: string, value: string | undefined): Promise<void>;
    /** Drop the thread's state whoever owns it (an arbitrary history edit). */
    clear(threadId: ThreadId): Promise<void>;
}
/** The process-lifetime reference implementation, for compositions with no store
 *  (and for suites). A session id is disposable by contract, so losing it on
 *  restart costs a re-seed, never correctness. */
export declare function memoryHarnessStateStore(): HarnessStateStore;
export type PendingState = {
    value: string | undefined;
    dirty: boolean;
};
/** The §1.3 handle a harness holds for one turn. Writes are buffered and land
 *  once, at turn end — a turn that sets a session id ten times costs one row. */
export declare function createTurnState(initial: string | undefined): TurnState & {
    pending(): PendingState;
};
/**
 * How the incoming transcript relates to the one we persisted.
 *
 * `arbitrary-edit` is the only one that clears `turn.state` (§1.3): the harness's
 * native session no longer describes the conversation we hold. A
 * `prefix-truncation` is a retry of an edited message, which the harness rewinds
 * natively, so its session survives.
 */
export type HistoryChange = "append" | "prefix-truncation" | "arbitrary-edit";
export declare function classifyHistory(persisted: readonly UIMessage[], incoming: readonly UIMessage[]): HistoryChange;
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