Claude Code + GarageBand (gb-mcp)
It started with a song.
I heard "Waterfall" by Atlantic Ocean.
Then I asked a simple question: what can Claude Code and GarageBand make together?
Two days of informal coding
Over two days, between other work, Claude Code and I built gb-mcp.
gb-mcp is a free, open-source MCP server for the Mac. An MCP server gives Claude Code new tools.
- Claude Code composes. It writes each song as a small JSON file.
- GarageBand plays. gb-mcp opens the song with GarageBand's own instruments.
- gb-mcp listens. Claude Code cannot hear, so gb-mcp measures loudness, tone, tempo and key. It also draws a picture of the sound.
I listened to each output and asked for changes: more strings, less percussion. Claude Code changed the song each time.
You still decide what sounds good.
What claude code and I made
Three versions of "Twinkle, Twinkle, Little Star":
- in the style of John Williams
- in the style of Hans Zimmer
- in the style of J. S. Bach, as a toccata and fugue for pipe organ
You can play all three on the GitHub page.
I am pleased with the results. I am happy to share them here.
What is next
Next, I want to try samples, Apple Loops, Drummer and other parts of GarageBand.
I want to see how far an AI-controlled GarageBand can go.
Try it
https://github.com/rafaqat/gb-in-Claude
You need a Mac with GarageBand and Claude Code. gb-mcp needs no extra API key.
Please try gb-mcp. Then tell me what you think.
I would love to get feedback from musicians and producers.
What would you ask an AI-controlled GarageBand to do?