import type { TodoItem } from '../core/context.js';
import type { ConversationState } from '../core/conversation-state.js';
import type { EventBus } from '../kernel/events.js';
/**
 * On-disk checkpoint for `ctx.todos`. Written atomically every time the
 * todo list changes, read once on session resume. This is the missing
 * piece that lets `wstack resume <id>` rehydrate where the previous run
 * stopped instead of starting with an empty board.
 *
 * Schema is intentionally small — a single JSON object so a future
 * format bump is easy. The `version` field is the only contract; the
 * shape under `todos` mirrors `TodoItem` so reading is a straight assign.
 */
export interface TodosCheckpointFile {
    version: 1;
    sessionId: string;
    updatedAt: string;
    todos: TodoItem[];
}
export type TodosCheckpointDetach = () => Promise<void>;
/** Read a checkpoint from disk. Returns null when the file doesn't
 *  exist or is corrupt — callers treat both cases as "no prior state".
 */
export declare function loadTodosCheckpoint(filePath: string, events?: EventBus, traceId?: string): Promise<TodoItem[] | null>;
/** Write the checkpoint atomically. Best-effort: a write failure is
 *  logged but does not throw — losing one checkpoint shouldn't bring
 *  down the agent run.
 */
export declare function saveTodosCheckpoint(filePath: string, sessionId: string, todos: readonly TodoItem[], events?: EventBus, traceId?: string, warn?: (msg: string) => void): Promise<void>;
/**
 * Subscribe a `ConversationState` so every `todos_replaced` mutation
 * triggers an atomic write to disk. Returns the unsubscribe function.
 *
 * Writes are debounced by 150ms so a flurry of edits (e.g. the LLM
 * marking three items done in the same tool call) coalesces into one
 * disk hit.
 */
export declare function attachTodosCheckpoint(state: ConversationState, filePath: string, sessionId: string, events?: EventBus, traceId?: string, warn?: (msg: string) => void): TodosCheckpointDetach;
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