import type { PermissionMode, ToolPolicy } from "@hmbown/kytchen-protocol";
import type { ToolRegistry } from "./registry.js";
export interface PolicyDecision {
    tool: string;
    mode: PermissionMode;
    /** If mode is "deny", the reason for denial. */
    reason?: string;
    /** Timestamp of the decision. */
    decidedAt: string;
}
export interface ApprovalRequest {
    tool: string;
    args: Record<string, unknown>;
    reason: string;
}
/**
 * Callback for requesting user approval.
 * Returns true if approved, false if denied.
 */
export type ApprovalCallback = (request: ApprovalRequest) => Promise<boolean>;
export declare class PolicyEngine {
    private readonly policy;
    private readonly registry;
    private readonly onApproval?;
    private readonly decisions;
    constructor(policy: ToolPolicy, registry: ToolRegistry, onApproval?: ApprovalCallback | undefined);
    /**
     * Evaluate whether a tool call is permitted.
     * Returns the decision and records it for audit.
     */
    evaluate(toolName: string, args: Record<string, unknown>): Promise<PolicyDecision>;
    /** Get the audit log of all decisions. */
    getAuditLog(): readonly PolicyDecision[];
    /** Clear the audit log. */
    clearAuditLog(): void;
    /**
     * Preview the policy mode that will be evaluated for the given tool.
     * Useful for emitting status events before asynchronous approval flows.
     */
    getRequestedMode(toolName: string): PermissionMode;
    private resolveMode;
}
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