mcpcraft

A lightweight and elegant SDK for building Model Context Protocol (MCP) servers fast.

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Why mcpcraft?

The official MCP SDK is powerful but requires significant JSON-RPC boilerplate and manual schema definitions. mcpcraft wraps it to provide a streamlined, zero-config API with automatic TypeScript type inference and Zod runtime schema validation.

Install

npm install mcpcraft zod

Quick Start

import { createServer, tool } from "mcpcraft";

const server = createServer({ name: "my-mcp-server" });

server.add(tool({
  name: "get_weather",
  description: "Get the current weather for a location",
  input: {
    location: { type: "string", description: "City name" }
  },
  run: async ({ location }) => {
    return { temp: 22, condition: "Sunny", city: location };
  }
}));

server.start();

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API Reference

createServer(options)

Creates a new server instance.

• options:
  • name: string (required) - Name of the server.
  • version?: string (optional) - Version of the server (default: 0.1.0).
  • description?: string (optional) - Description of the server.

Returns: A server instance with:

• add(item: Tool | Resource): Register a tool or a resource (chainable).
• start(): Starts the server listening on the standard input/output (stdio) transport.
• server: Access the underlying official Server instance if low-level control is needed.

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tool(options)

Defines an MCP tool with schema validation.

• options:
  • name: string - The name of the tool (alphanumeric and underscores).
  • description: string - A description explaining what the tool does (used by the LLM).
  • input?: Record<string, { type: "string" | "number" | "boolean"; description?: string; required?: boolean }> - Parameter schemas.
  • run: (args) => Promise<any> | any - The execution logic. The args parameter is fully typed and inferred automatically based on input.

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resource(options)

Defines an MCP resource or resource template.

• options:
  • name: string - The name of the resource.
  • description: string - Description of the resource.
  • uri: string - The URI (e.g. info://system) or URI Template (e.g. users://{userId}/profile).
  • mimeType?: string - The MIME type (e.g., application/json, text/plain).
  • fetch: (params) => Promise<any> | any - Handler that returns the resource content. If the URI is a template, params is populated with parsed dynamic variables.

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Built on top of the official MCP SDK

mcpcraft is designed to play nicely with the official ecosystem. It runs directly on top of @modelcontextprotocol/sdk and uses the standard stdio transport, meaning it works out-of-the-box with Cursor, Claude Desktop, and all other MCP hosts.

License

MIT