MCP

The Model Context Protocol lets an AI assistant call tools on your Mac. choruspop mcp is an MCP server, so Claude and other clients can make songs, versions and exports for you.

Set up

First install the command-line tool: the server is part of it.

Claude Code

claude mcp add choruspop -- choruspop mcp

Add --scope user to have it in every project. If choruspop isn't on your PATH, use the full path: /Applications/ChorusPop.app/Contents/Helpers/choruspop.

Claude Desktop

Settings ▸ Developer ▸ Edit Config opens ~/Library/Application Support/Claude/claude_desktop_config.json. Add ChorusPop under mcpServers, then quit and reopen Claude. Claude Desktop doesn't read your shell's PATH, so give the full path:

{
  "mcpServers": {
    "choruspop": {
      "command": "/Applications/ChorusPop.app/Contents/Helpers/choruspop",
      "args": ["mcp"]
    }
  }
}

Other clients

Any client that starts stdio servers takes the same two things: the command and the argument mcp. No environment variables or network ports are needed.

{
  "name": "choruspop",
  "transport": "stdio",
  "command": "/Applications/ChorusPop.app/Contents/Helpers/choruspop",
  "args": ["mcp"]
}

With the Python package installed, python3 -m choruspop.mcp (or choruspop-mcp) starts the same server.

Try it

• “Write a 30-second synthwave song about the harbor at night and make it with ChorusPop.”
• “Make three short lo-fi songs for my study playlist, one at a time, and put them in an album called Focus.”
• “Take the newest ChorusPop song, remove the vocals, and save the instrumental as FLAC on my Desktop.”
• “List my ChorusPop songs from this week and make stems of the one called Neon River.”
• “Make that last song again with the same seed, but with a male voice.”

The server hands every client the guide for AI agents when it connects, so the assistant knows songs take minutes, asks before long batches and reports where the files went.

How long jobs work

A song takes minutes, so the tools don't hold the call open by default:

1. make_song (or remove_vocals, vocals_only, stems) queues the job and returns its id at once.
2. get_job with wait_seconds (up to 600) holds until the job ends or that time passes. If the client sent a progressToken, the server sends notifications/progress (0–100, with the stage and time left) while it waits.
3. When the job is done, the result has song_id and files: absolute paths in ~/Music/ChorusPop/<album or Singles>/, or in the destination you gave make_song.

make_song also takes wait: true to hold the call itself, up to timeout_seconds. If the client cancels a call (notifications/cancelled), the job keeps going in ChorusPop; cancel_job stops it. Jobs run one at a time, in the order they were queued.

→ {"method":"tools/call","params":{"name":"make_song","arguments":{"lyrics":"[verse]\nNeon on the river\n[chorus]\nTurn it up","genre":"synthwave","moods":["dreamy"],"length_seconds":30}}}
← {"structuredContent":{"job":{"id":"8f3c…","kind":"song","status":"queued","progress":0,"stage":"waiting","title":"Neon on the river"}}}

→ {"method":"tools/call","params":{"name":"get_job","arguments":{"job_id":"8f3c…","wait_seconds":300},"_meta":{"progressToken":7}}}
← {"method":"notifications/progress","params":{"progressToken":7,"progress":42,"total":100,"message":"Neon on the river: running 42% · performing · about 0:48 left"}}
← {"structuredContent":{"job":{…,"status":"done"},"song_id":"8f3c…","files":["/Users/me/Music/ChorusPop/Singles/Neon on the river.m4a"]}}

Every result is also plain text in content (a one-line summary and the same JSON), for clients that don't read structuredContent. A tool that fails returns isError: true and {"error": {"code": …, "message": …}} with one of the error codes.

Server

Tools

Result objects

job in a result is the same object the command line prints:

Job

Song

App

If it doesn't connect

• Run choruspop version in Terminal. It opens ChorusPop and prints both versions; scripting needs ChorusPop 1.0 (6) or later, the direct download.
• Claude Desktop: check the path in the config, then Settings ▸ Developer shows the server's state and log.
• The server writes its own notes to stderr, which clients keep in their MCP logs.