/**
 * Session checkpoints — `/checkpoint` and `/rewind`.
 *
 * A checkpoint is a snapshot of the agent conversation at a point in time:
 * session history, provider/model state, and the list of files the agent has
 * touched in this session. It does NOT snapshot file content — that's git's
 * job, and trying to do it ourselves means either a 100KB-per-file ceiling
 * with surprise truncation, or a real-time disk hog. We surface a hint at
 * rewind time telling the user how to restore files via git.
 *
 * Use cases this is for:
 *   - User suspects the agent is going off the rails after N steps and
 *     wants to roll the conversation back to before that turn.
 *   - User is about to start a risky multi-step refactor and wants a
 *     named bookmark to return to if it gets messy.
 *
 * Use cases this is NOT for:
 *   - Replacing git. If you only need file rollback, `git restore` /
 *     `git stash` is faster and reliable.
 *   - Cross-session persistence beyond the workspace's `.codeep/checkpoints/`
 *     folder — checkpoints are per-project, not global.
 *
 * On-disk shape (`.codeep/checkpoints/<id>.json`):
 * {
 *   "id": "ck-2026-05-18-abc123",
 *   "name": "before big refactor",
 *   "createdAt": "...",
 *   "sessionId": "session-2026-05-18-...",
 *   "provider": "z.ai",
 *   "model": "glm-5.2",
 *   "messages": [ ... ],
 *   "filesTouched": ["src/a.ts", "src/b.ts"],
 *   "gitHead": "abcdef0"        // optional, recorded only if cwd is a git repo
 * }
 */
import type { Message } from '../config/index.js';
export interface Checkpoint {
    id: string;
    name?: string;
    createdAt: string;
    sessionId: string;
    provider: string;
    model: string;
    messages: Message[];
    filesTouched: string[];
    gitHead?: string;
}
/** Lightweight metadata for `/checkpoints` list — avoids loading full message arrays. */
export interface CheckpointMeta {
    id: string;
    name?: string;
    createdAt: string;
    sessionId: string;
    messageCount: number;
    filesTouchedCount: number;
    gitHead?: string;
}
/**
 * Create a new checkpoint snapshot of the current session state.
 * Returns the persisted checkpoint object.
 */
export declare function createCheckpoint(opts: {
    workspaceRoot: string;
    sessionId: string;
    provider: string;
    model: string;
    messages: Message[];
    filesTouched: string[];
    name?: string;
}): Checkpoint;
/**
 * Load a single checkpoint by id. Returns null if not found or unreadable.
 */
export declare function loadCheckpoint(workspaceRoot: string, id: string): Checkpoint | null;
/**
 * List checkpoints in the workspace, newest first. Returns metadata only —
 * the full `messages` array is not loaded so this is cheap for `/checkpoints`.
 */
export declare function listCheckpoints(workspaceRoot: string): CheckpointMeta[];
/**
 * Delete a checkpoint by id. Returns true if a file was removed.
 */
export declare function deleteCheckpoint(workspaceRoot: string, id: string): boolean;
/**
 * Format a checkpoint list as a Markdown block for `/checkpoints` output.
 */
export declare function formatCheckpointList(metas: CheckpointMeta[]): string;
/**
 * Build the user-facing hint shown after a successful /rewind. Tells the
 * user how to bring their files back to checkpoint state — checkpoints
 * don't snapshot file content, so this is the only restore path.
 */
export declare function buildRewindGitHint(cp: Checkpoint): string;