/**
 * Structured tool failure — the one way tools in this server fail.
 *
 * Pattern adapted from @mcp-kit/core (github.com/palimkarakshay/mcp-kit, MIT):
 * handlers throw `McpToolError` (or anything), the registration wrapper turns
 * it into an MCP error result instead of crashing the request.
 */
import type { CallToolResult } from "@modelcontextprotocol/sdk/types.js";
export type ToolErrorCode = "invalid_input" | "not_found" | "internal";
export declare class McpToolError extends Error {
    readonly code: ToolErrorCode;
    readonly details?: Record<string, unknown> | undefined;
    constructor(code: ToolErrorCode, message: string, details?: Record<string, unknown> | undefined);
}
/** The caller passed arguments the tool cannot work with. */
export declare function invalidInput(message: string, details?: Record<string, unknown>): McpToolError;
/** The named thing (rule key, …) does not exist. */
export declare function notFound(message: string, details?: Record<string, unknown>): McpToolError;
/** Convert any thrown value into a structured MCP error result. */
export declare function errorResult(err: unknown): CallToolResult;