IBM i MCP Server

/** * @fileoverview Provides a generic factory for creating MCP tool handlers. * This utility centralizes common logic for performance measurement, error handling, * and response formatting, reducing boilerplate in individual tool registration files. * @module src/mcp-server/tools/utils/tool-utils */ import { McpError } from "../../../types-global/errors.js"; import { ErrorHandler, getRequestContext, measureToolExecution, } from "../../../utils/index.js"; import { CallToolResult } from "@modelcontextprotocol/sdk/types.js"; /** * Defines the function signature for a core tool logic implementation. * @template TInput The type of the validated input parameters. * @template TOutput The type of the successful output from the logic. * @param params The validated input parameters for the tool. * @returns A promise that resolves with the tool's output. */ type ToolLogicFn<TInput, TOutput> = (params: TInput) => Promise<TOutput>; /** * Defines the function signature for formatting a successful tool logic result * into the final structure expected by the MCP server. * @template TOutput The type of the successful output from the logic. * @param result The successful output from the tool's logic function. * @returns The formatted tool response. */ export type ResponseFormatter<TOutput> = (result: TOutput) => CallToolResult; /** * A generic handler function for an MCP tool. * @template TInput The type of the validated input parameters. */ export type McpToolHandler<TInput> = ( params: TInput, ) => Promise<CallToolResult>; /** * Creates a standardized MCP tool handler. * This factory wraps the core business logic with cross-cutting concerns like * performance monitoring and centralized error handling. * * @template TInput The type of the validated input parameters. * @template TOutput The type of the successful output from the logic. * @param toolName The name of the tool, used for logging and metrics. * @param logicFn The core business logic function for the tool. * @param responseFormatter A function to format the successful output. * @returns A complete MCP tool handler function. */ export function createToolHandler<TInput, TOutput>( toolName: string, logicFn: ToolLogicFn<TInput, TOutput>, responseFormatter: ResponseFormatter<TOutput>, ): McpToolHandler<TInput> { return async (params: TInput) => { try { const result = await measureToolExecution( toolName, () => logicFn(params), params, ); return responseFormatter(result); } catch (error) { const mcpError = ErrorHandler.handleError(error, { operation: `tool:${toolName}`, context: getRequestContext(), input: params, }) as McpError; return { isError: true, content: [{ type: "text", text: `Error: ${mcpError.message}` }], structuredContent: { code: mcpError.code, message: mcpError.message, details: mcpError.details, }, }; } }; }