mark3labs/mcp-go

What it solves

mcp-go is a Go implementation of the Model Context Protocol (MCP), which provides a standardized way for LLM applications to securely integrate with external data sources and tools. It removes the need for developers to handle the complex protocol details and server management when building these integrations.

How it works

The SDK allows developers to create an MCP server that exposes three primary capabilities to an LLM:

• Resources: Similar to GET endpoints, these allow the server to provide data (files, API responses, database queries) to the LLM's context.
• Tools: Similar to POST endpoints, these allow the LLM to execute code or perform actions (e.g., calculations, HTTP requests, system operations) through the server.
• Prompts: Reusable templates that define interaction patterns and system instructions to guide the LLM.

The library handles connection management, protocol compliance, and message routing, supporting various transport methods including stdio.

Who it’s for

Go developers building LLM-powered applications or plugins that need to expose local data or specific functional capabilities to an AI model in a standardized way.

Highlights

• Minimal Boilerplate: High-level interface designed for fast development of MCP servers.
• Task-Augmented Tools: Supports asynchronous execution for long-running operations via polling, with configurable concurrency limits.
• Protocol Compliance: Implements the MCP specification (version 2025-11-25) with backward compatibility for several previous versions.
• Type-Safe Access: Provides helper functions for type-safe argument access within tool handlers.