Scaled MCP Server

What is Scaled MCP Server?

Scaled MCP Server is a Go library that implements the MCP (Message Context Protocol) 2025-03 specification with support for horizontal scaling. It is designed to be embedded in applications and provides flexible configuration options for load-balanced deployments.

How to use Scaled MCP Server?

Install with go get github.com/traego/scaled-mcp@latest (requires Go 1.24+). Create a server using server.NewMcpServer with a configuration and tool registry, then start it. The library supports static tool registries, dynamic tool registries, struct-based reflection, and generics-based tool registration.

Key features of Scaled MCP Server

• HTTP transport with main /mcp endpoint and optional SSE endpoint
• Distributed session management via Redis or in-memory store
• Actor-based architecture for session handling and message routing
• Horizontal scaling support for load-balanced deployments
• Flexible tool registration: static, dynamic, struct-based, and generics
• Supports embedding into external HTTP servers and custom routers

Use cases of Scaled MCP Server

• Building scalable AI assistants with tool-calling capabilities
• Deploying MCP servers behind load balancers for high availability
• Embedding MCP protocol support into existing Go applications
• Creating multi-node services with distributed session state

FAQ from Scaled MCP Server

What transport options does Scaled MCP Server support?

It provides HTTP-based transport with a main /mcp endpoint and optional SSE (Server-Sent Events) endpoint. It can be used as a standalone server or integrated into an external HTTP server (e.g., using Chi router) with CORS configuration.

What are the runtime requirements?

The library requires Go 1.24 or higher. Session management can use an in-memory store (no extra dependencies) or Redis for distributed sessions.

How do I define tool inputs for my server?

Scaled MCP Server supports three approaches: 1) struct-based reflection with mcp tags, 2) fluent WithInputs builder methods, and 3) individual parameter methods (e.g., WithString, WithNumber). A generics-based approach (new in June 2025) provides compile-time type safety for both input and output.

Can I use Scaled MCP Server with an external HTTP server?

Yes. You can create the MCP server without starting its HTTP server, attach the HTTP transport to a custom router (e.g., Chi), and start the transport alongside your own HTTP server. CORS middleware must be added when using an external server.