sclang-mcp

MCP server for SuperCollider. Evaluate sclang code, boot the audio server, and inspect synths and node trees from any MCP client.

Installation

bunx @daanrongen/sclang-mcp

Tools (7)

| Tool | Description | |---|---| | eval | Evaluate SuperCollider code and return the result | | boot | Boot the scsynth audio server | | server_status | Query synth count, CPU usage, and sample rate | | free_all | Free all synths and groups (CmdPeriod) | | list_synthdefs | List all loaded SynthDef names | | node_tree | Get the server's node tree | | load_file | Load and evaluate an .scd file |

Configuration

| Environment variable | Default | Description | |---|---|---| | SCLANG_PATH | /Applications/SuperCollider.app/Contents/MacOS/sclang | Path to the sclang binary | | SCLANG_CONF | (none) | Optional path to a sclang_conf.yaml |

Setup

Claude Desktop

Add to ~/Library/Application Support/Claude/claude_desktop_config.json:

{
  "mcpServers": {
    "sclang": {
      "command": "bunx",
      "args": ["@daanrongen/sclang-mcp"],
      "env": {
        "SCLANG_PATH": "/Applications/SuperCollider.app/Contents/MacOS/sclang"
      }
    }
  }
}

Claude Code

claude mcp add sclang -e SCLANG_PATH=/Applications/SuperCollider.app/Contents/MacOS/sclang -- bunx @daanrongen/sclang-mcp

Development

bun install          # install dependencies
bun run dev          # run with file watching
bun test             # run tests
bun run lint         # lint with Biome
bun run format       # format with Biome
bun run typecheck    # type-check with tsc
bun run build        # compile to dist/
bun run inspect      # open MCP Inspector against built server

Inspecting Locally

Build first, then open the MCP Inspector:

bun run build
bun run inspect

The inspector connects to the server over stdio and lets you call tools interactively.

Architecture

src/
├── config.ts              # Effect Config (SCLANG_PATH, SCLANG_CONF)
├── main.ts                # Entry point — wires server + Layer
├── domain/
│   ├── errors.ts          # Tagged domain errors
│   ├── errors.test.ts
│   ├── models.ts          # Domain types (EvalResult, ServerStatus, …)
│   ├── models.test.ts
│   ├── SclangClient.ts    # Port: Effect.Tag service interface
│   └── SclangClient.test.ts
├── infra/
│   ├── SclangClientLive.ts   # Adapter: spawns sclang process
│   ├── SclangClientTest.ts   # Adapter: in-memory stub for tests
│   └── SclangClientTest.test.ts
└── mcp/
    ├── server.ts          # MCP Server setup
    ├── utils.ts           # Shared tool helpers
    └── tools/
        ├── eval.ts        # eval tool
        ├── files.ts       # load_file tool
        └── server-tools.ts  # boot, server_status, free_all, list_synthdefs, node_tree

License

MIT