/**
 * Per-file pre-mutation snapshot stack.
 *
 * Both Edit and Write push a snapshot immediately AFTER each successful
 * mutation. The UndoEdit tool pops the most recent snapshot to revert
 * a file to its prior state, as long as the on-disk state still matches
 * what we recorded when the mutation completed (so we never undo on top
 * of unrelated external changes).
 *
 * Scoped per-agent via `CortexToolRuntime`, cleared on each loop reset
 * — history does not persist across agentic loops or across agents.
 *
 * The stack is intentionally bounded (`MAX_STACK_DEPTH`). An unbounded
 * stack would accumulate full file contents during long refactors and
 * bloat memory. A deep stack is also rarely useful for the agentic
 * loop: if the model wants to roll back more than a few edits, it's
 * more reliable to Read the file and write the intended content
 * directly.
 */
export interface EditHistoryEntry {
    /**
     * File contents BEFORE the mutation, or `null` when the file did not
     * exist before the mutation (created by Write). Undoing a `null`
     * entry deletes the file.
     */
    originalContent: string | null;
    /** mtime (ms since epoch) of the file immediately AFTER the mutation. */
    postMutationMtimeMs: number;
    /** SHA-256 hex digest of the file bytes immediately AFTER the mutation. */
    postMutationContentHash: string;
    /** Which tool created the entry (for diagnostics / undo messaging). */
    source: 'Edit' | 'Write';
}
/** Upper bound on snapshots retained per file. */
export declare const MAX_STACK_DEPTH = 5;
export declare class EditHistory {
    private readonly stacks;
    /**
     * Push a snapshot for `filePath`. When the per-file stack is at its
     * depth cap, the oldest entry is dropped so newer edits remain
     * undoable.
     */
    record(filePath: string, entry: EditHistoryEntry): void;
    /**
     * Pop and return the most recent entry for `filePath`, or `undefined`
     * when the file has no recorded history.
     */
    pop(filePath: string): EditHistoryEntry | undefined;
    /** Current stack depth for `filePath` (0 when absent). Diagnostic use. */
    depth(filePath: string): number;
    /** Drop all history. Called from `CortexToolRuntime.resetForLoop`. */
    clear(): void;
    private normalize;
}
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