FastMCP-Scala

fast-mcp-scala is a developer-friendly library for building Model Context Protocol servers. Extend one trait, declare your tools, done:

Local serverstdio

What is the FastMCP-Scala MCP Server?

FastMCP-Scala is an MCP project maintained in the arcaputo3/fast-mcp-scala repository. The maintainer describes its purpose as “fast-mcp-scala is a developer-friendly library for building Model Context Protocol servers. Extend one trait, declare your tools, done”. Read the project documentation for the complete scope.

Local setup

The project provides a local client configuration using scala-cli. Follow the repository’s build and installation steps before copying it, and replace example paths with the paths on your own computer.

Source

Project documentation · Repository · Discovery listing. This profile records the public documentation checked on 2026-10-08.

Recorded tools

Check the linked publisher documentation and your connected client's tool list. Names and availability can vary with the server version and account permissions.

Tool	What it does
Hint	Meaning
title	Human-readable display name (distinct from the wire-level name)
readOnlyHint	The tool only reads state; safe to call without confirmation
destructiveHint	The tool may irreversibly modify state; clients should confirm
idempotentHint	Repeated calls with the same args have the effect of one call
openWorldHint	The tool reaches outside the local process (network, filesystem, APIs)
returnDirect	Return the result directly to the user, skipping LLM post-processing

How to install the FastMCP-Scala MCP Server

{
  "mcpServers": {
    "fast-mcp-scala-example": {
      "command": "scala-cli",
      "args": [
        "-e",
        "//> using scala 3.9.0",
        "-e",
        "//> using dep com.tjclp::fast-mcp-scala:1.0.1",
        "--main-class",
        "com.tjclp.fastmcp.examples.AnnotatedServer"
      ]
    }
  }
}

From the project documentation. Replace placeholders and example paths before connecting.