/**
 * bridge.ts — Stable discovery pointer for host integration (the filesystem
 * artifact protocol).
 *
 * The single source of truth for host integration is the on-disk artifact
 * directory (<cwd>/.pi/context-optimizer/<session>/). Hosts that want to
 * discover the ACTIVE session's directory without globbing watch one stable
 * file written here: <cwd>/.pi/context-optimizer/active.json.
 *
 * active.json is ADDITIVE — it mirrors status.json plus the absolute
 * artifactDir. It is written on every phase transition (via index.ts
 * writeStatus) and on session resume. Hosts may also read per-session
 * status.json directly. See BRIDGE.md for the full contract.
 *
 * Everything here is pure + best-effort: a write/read failure degrades
 * gracefully (the workflow never blocks on this pointer).
 */
import { rm } from "node:fs/promises";
export declare const ACTIVE_FILE = "active.json";
/** The active.json shape — a stable, host-readable pointer to the live session. */
export interface ActivePointer {
    /** Absolute path to the active session's artifact directory. */
    artifactDir: string;
    /** Current phase (mirrors status.json): INERT | RESEARCHING | PLAN_DRAFTING | REVIEW_PENDING | EXECUTING. */
    phase: string;
    /** Approval state (mirrors status.json): none | pending | approved | rejected. */
    approval: string;
    /** Completed step count. */
    done: number;
    /** Total step count. */
    total: number;
    /** ISO timestamp of the last update. */
    updatedAt: string;
}
/** Input for writeActivePointer (updatedAt is stamped here). */
export interface ActivePointerInput {
    artifactDir: string;
    phase: string;
    approval: string;
    done: number;
    total: number;
}
/** Stable path to the active-session pointer: <cwd>/.pi/context-optimizer/active.json */
export declare function activeFilePath(cwd: string): string;
/**
 * Atomically write (overwrite) the active.json pointer. Writes are queued via
 * withFileMutationQueue to avoid torn writes; parent dirs are created.
 * Throws on filesystem errors so callers can decide to swallow — index.ts
 * wraps every call in try/catch so a failure never breaks the workflow.
 */
export declare function writeActivePointer(cwd: string, input: ActivePointerInput): Promise<void>;
/**
 * Read + validate active.json. Returns null when missing or malformed (never
 * throws) so callers can treat an absent pointer as "no active session yet".
 */
export declare function readActivePointer(path: string): Promise<ActivePointer | null>;
export { rm };
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