ExMCP Test Server

What is ExMCP Test Server?

An MCP (Model Context Protocol) server implementation in Elixir that provides a test implementation for experimenting with the protocol. It is designed for developers who want to explore MCP using a JSON-RPC 2.0 compliant server built with Elixir.

How to use ExMCP Test Server?

Run the server locally with mix run --no-halt. For production use, generate a release with mix release and add it to your claude_desktop_config.json using the command path/to/your/release/bin/my_app start under the mcpServers key.

Key features of ExMCP Test Server

• JSON-RPC 2.0 compliant server implementation
• Standard MCP protocol methods are supported
• Pluggable validation and middleware pipeline
• Schema-driven request/response validation
• OpenRPC specification is included

Use cases of ExMCP Test Server

• Experimenting with the Model Context Protocol (MCP)
• Testing MCP clients against a local server
• Learning MCP through a minimal reference implementation

FAQ from ExMCP Test Server

What runtime dependencies are required?

Elixir 1.14+ and Mix. The server relies on PhxJsonRpc, ExJsonSchema, and Jason.

Which MCP methods does the server implement?

initialize, notifications/initialized, prompts/list, resources/list, tools/list, and tools/call.

How can I run the server locally or as a release?

Run locally with mix run --no-halt. For a release, use mix release and configure the binary in claude_desktop_config.json with the start argument.

Where is the OpenRPC specification located?

It can be found at priv/static/mcp-openrpc.json in the project.