/**
 * Shared FastMCP tool registration.
 *
 * Every tool goes through `registerTool()` so two protocol-level details are
 * handled in one place rather than in 14 files:
 *
 * 1. **Advertised JSON Schema** — FastMCP auto-generates `inputSchema` from the
 *    Zod schema in *output* mode, which marks fields with `.default()` as
 *    `required`. Clients (and models) would then believe `lang` etc. must be
 *    sent. We generate the schema ourselves in *input* mode so defaults stay
 *    optional, exactly as with the raw MCP SDK.
 *
 * 2. **Validation errors** — FastMCP turns failed input validation into a
 *    JSON-RPC `-32602` protocol error whose message drops the field paths.
 *    Many clients surface protocol errors as hard failures the model cannot
 *    read. We validate here and return an `isError: true` tool result that
 *    lists every issue with its path, so the model can self-correct.
 */
import type { FastMCP, ToolResult } from "@prefecthq/fastmcp-ts/server";
import { z } from "zod";
/** Result shape every tool handler may return. */
export type ToolHandlerResult = string | ToolResult;
export interface ToolDefinition<S extends z.ZodObject> {
    /** MCP tool name (snake_case). */
    name: string;
    /** One-line description shown to the client. */
    description: string;
    /** Zod schema describing the tool arguments. */
    input: S;
}
/**
 * Formats Zod issues into a single user-facing message, one issue per line
 * with the offending field path (e.g. `projectId: Invalid UUID`).
 */
export declare function formatValidationError(toolName: string, error: z.ZodError): string;
/**
 * Registers a tool on the FastMCP server with an input-mode JSON Schema and
 * tool-result validation errors (see module doc).
 */
export declare function registerTool<S extends z.ZodObject>(server: FastMCP, definition: ToolDefinition<S>, handler: (params: z.output<S>) => Promise<ToolHandlerResult> | ToolHandlerResult): void;