Shadow-cljs Mcp

@Bigsy

About Shadow-cljs Mcp

Read build information from shadow-cljs

Config

Add this server to your MCP-compatible client using the configuration below.

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

Tools

Get the status of the last shadow-cljs build including any warnings or errors. Call this after making edits to ClojureScript files to verify if the build succeeded or failed.

Overview

What is Shadow-cljs Mcp?

Shadow-cljs Mcp is a Model Context Protocol (MCP) server that monitors shadow-cljs builds and provides real-time build status updates. It connects to a running shadow-cljs instance, tracking build progress, failures, and completions, and is designed for LLMs used alongside ClojureScript development.

How to use Shadow-cljs Mcp?

Install by adding the server configuration to your MCP client settings (e.g., Cline, Cursor, Claude) using the npx command. Optionally provide --host and --port arguments if your shadow-cljs instance is not on localhost:9630. After each ClojureScript file edit, instruct your LLM to call the get_last_build_status tool to verify the build succeeded. Add the tool call example to your LLM’s notes file (e.g., CLAUDE.md, cursorrules.md).

Key features of Shadow-cljs Mcp

Provides a single get_last_build_status tool.
Returns build status (completed/failed) and compiled files.
Shows detailed error and warning information.
Includes build duration and metrics.
Defaults to connecting to localhost:9630.
Requires a running shadow-cljs instance.

Use cases of Shadow-cljs Mcp

Verify successful compilation after editing ClojureScript files.
Debug build failures with detailed error details.
Track which files were compiled and how long each took.

FAQ from Shadow-cljs Mcp

What does the get_last_build_status tool return?

It returns a JSON object with a status field (e.g., "completed" or "failed"), plus information about compiled files, warnings, duration, and any errors.

Do I need to have shadow-cljs running?

Yes, Shadow-cljs Mcp connects to a running shadow-cljs instance. By default it expects it on localhost:9630, but you can override with --host and --port.

How do I install Shadow-cljs Mcp?

Add the provided JSON configuration to your MCP client’s settings, using the command npx shadow-cljs-mcp. No additional installation steps are required.

What optional arguments does Shadow-cljs Mcp accept?

You can pass --host and --port to specify a different shadow-cljs server location. If omitted, defaults to localhost:9630.

Frequently asked questions

What does the get_last_build_status tool return?

It returns a JSON object with a `status` field (e.g., "completed" or "failed"), plus information about compiled files, warnings, duration, and any errors.

Do I need to have shadow-cljs running?

Yes, Shadow-cljs Mcp connects to a running shadow-cljs instance. By default it expects it on localhost:9630, but you can override with `--host` and `--port`.

How do I install Shadow-cljs Mcp?

Add the provided JSON configuration to your MCP client’s settings, using the command `npx shadow-cljs-mcp`. No additional installation steps are required.