Shadow Cljs MCP

🚀 shadow-cljs-MCP

A Model Context Protocol (MCP) server that monitors shadow-cljs builds and provides real-time build status updates.

🚀 Quick Start

This MCP server connects to a running shadow-cljs instance and tracks build progress, failures, and completion status. It offers an MCP tool for LLMs to verify the build status after making changes to ClojureScript files.

✨ Features

• Monitors shadow-cljs builds and provides real-time build status updates.
• Offers an MCP tool for LLMs to verify the build status.
• Displays detailed compilation errors for easy debugging.
• Shows compiled files and their compilation time upon successful builds.

📦 Installation

Add the following to your settings in Cline/Cursor/Claude, etc.:

{
  "mcpServers": {
    "shadow-cljs-mcp": {
      "command": "npx",
      "args": [
        "shadow-cljs-mcp"
      ],
      "disabled": false,
      "autoApprove": [],
      "timeout": 60
    }
  }
}

Optional server location:

{
  "mcpServers": {
    "shadow-cljs-mcp": {
      "command": "npx",
      "args": [
        "shadow-cljs-mcp",
        "--host",
        "localhost",
        "--port",
        "9630"
      ],
      "disabled": false,
      "autoApprove": [],
      "timeout": 60
    }
  }
}

The --host and --port parameters are optional. If not provided, the default server will connect to localhost:9630.

💻 Usage Examples

LLM Integration

Add to Your LLM Notes

Add the following to your LLM's notes file (e.g., CLAUDE.md, cursorrules.md):

After any edits to ClojureScript files, use the get_last_build_status tool of the shadow-cljs-mcp server to verify if the build was successful:

<use_mcp_tool>
<server_name>shadow-cljs-mcp</server_name>
<tool_name>get_last_build_status</tool_name>
<arguments>
{}
</arguments>
</use_mcp_tool>

This will display:
- Build status (completed/failed)
- Compiled files
- Any errors or warnings
- Build duration and metrics

Example Tool Responses

Successful Build

{
  "status": "completed",
  "resources": 317,
  "compiled": 1,
  "warnings": 0,
  "duration": 0.609,
  "compiledFiles": [
    "path/to/your/file.cljs (505ms)"
  ]
}

Failed Build

{
  "status": "failed",
  "message": "Build failed",
  "details": {
    // Error information
  }
}

⚠️ Important Note

• The LLM should call the get_last_build_status after each edit to a ClojureScript file.
• Compilation errors will be displayed in detail for easy debugging.
• Successful builds show the compiled files and their compilation time.
• Ensure that shadow-cljs is running before starting this server.

📚 Documentation

Requirements

• A running shadow-cljs instance (defaulting to localhost:9630 if no other address is configured).