Nrepl MCP

🚀 Basilisp nREPL MCP Bridge

This project provides a bridge between Anthropic's Model Control Protocol (MCP) and Basilisp's nREPL server, enabling Claude Code to directly interact with a Basilisp REPL. Currently, it should work with any nREPL, but the current prompts are tailored for Basilisp.

🚀 Quick Start

Prerequisites

• uv
• basilisp

Steps

1. Start the Basilisp nREPL server:

   basilisp nrepl-server --port 36915
   

2. Add the MCP bridge to Claude Code:

   claude mcp add /home/a/subjective/snr/basilisp_mcp_bridge.py
   

3. Use Claude and call available tools:

   • eval_code(code) - Evaluate Basilisp code
   • get_docs(symbol) - Get documentation for a symbol
   • find_namespace_vars(namespace) - List variables in a namespace
   • list_namespaces() - List all available namespaces
   • check_connection() - Verify the nREPL connection status

✨ Features

• Execute code and receive beautifully printed and syntax-highlighted results
• Get documentation for symbols
• List all available namespaces
• Find all variables in a namespace
• Check the connection status of the nREPL server
• Basilisp: Support Python interoperability, with appropriate syntax to access attributes and call methods
• Enhanced error reporting and formatting

📦 Installation

This project requires the following dependencies:

• uv
• basilisp

💻 Usage Examples

Basic Usage

;; Import a module
(import [math :as math])

;; Access an attribute
(. math -pi)  ;; or (.-pi math)

;; Call a method
(.sin math 0)

;; Create a Python data structure
#py{"key" "value"}

Advanced Usage

The provided usage steps in the "Using the Bridge" section show how to start the server, add the bridge to Claude Code, and call various tools. Here is a summary of the available tools:

• eval_code(code) - Evaluate Basilisp code
• get_docs(symbol) - Get documentation for a symbol
• find_namespace_vars(namespace) - List variables in a namespace
• list_namespaces() - List all available namespaces
• check_connection() - Verify the nREPL connection status

Future Improvements

• Implement a full bencode parser (beyond regular expressions)
• Add session management to support multiple REPLs
• Add autocompletion functionality