nREPL MCP Server

nREPL MCP Server is an MCP server that bridges Model Context Protocol clients with a running Clojure nREPL instance. Developed for Clojure software engineers and developers using AI assistants like Claude Desktop or Cline in VSCode, this tool enables direct runtime interaction with Clojure projects. Users can instruct their AI client to establish a connection to an nREPL host and port, evaluate arbitrary Clojure code, and inspect public variables along with their docstrings and runtime values. Additionally, the server can list all project namespaces using tools.namespace and expose real-time status data, such as connection state, session IDs, and active namespaces via custom MCP resources. By operating over standard input and output, it provides a structured bridge for language models to verify syntax, run REPL-driven development tasks, explore project namespaces, and troubleshoot Clojure code directly within an active application context without leaving the editor or client interface.

Category: Developer Tools & Code Intelligence

Tags: clojure, code-evaluation, nrepl, repl

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How to install and configure nREPL MCP Server

To install and configure nREPL MCP Server with Claude Desktop or Cline in VSCode, add the server to your client's configuration file: 1. Open your client settings (such as MCP Settings in Claude Desktop or Cline). 2. Add the server entry under mcpServers: json { "mcpServers": { "nrepl-mcp-server": { "command": "npx", "args": [ "nrepl-mcp-server" ], "disabled": false, "autoApprove": [] } } } 3. Save the configuration file. 4. Restart the MCP client to start the server over stdio.

What you can do with nREPL MCP Server

• Connecting an AI coding assistant to an active local or remote Clojure nREPL server using host and port parameters. * Evaluating dynamic Clojure expressions and statements within specific or default namespaces to test code modifications. * Discovering and listing all project namespaces automatically utilizing Clojure's tools.namespace utility. * Inspecting public vars, docstrings, and current values in any loaded namespace to verify function behaviors. * Checking nREPL connection status, active session identifiers, and recent execution errors directly through MCP resources.

Key facts

• https://github.com/JohanCodinha/nrepl-mcp-server
• Developer Tools & Code Intelligence
• clojure, code-evaluation, nrepl, repl

Part of MCP Servers

What can nREPL MCP Server do?

nREPL MCP Server enables AI clients to connect to a running Clojure nREPL process. It allows the model to evaluate Clojure expressions, inspect public variables and docstrings, discover project namespaces via tools.namespace, and monitor connection status and active session IDs.

How do I install nREPL MCP Server?

You can configure it directly in your MCP client by adding an entry under mcpServers that executes npx with the argument nrepl-mcp-server. Alternatively, you can clone the repository from GitHub, run npm install, transpile the project with npm run build, and start it via npm start.

Which MCP clients work with nREPL MCP Server?

The server communicates over standard input and output (stdio), making it compatible with any MCP-compliant client. Supported clients explicitly mentioned in the documentation include Claude Desktop and Cline for Visual Studio Code.

Is nREPL MCP Server open source?

Yes, nREPL MCP Server is open source. The project is distributed under the terms of the MIT License, which permits users to freely inspect, modify, and distribute the software.