Moontide MCP server

Moontide

The moon guides the tide.

A hobby project: Claude plays live music for you. Describe a mood, a theme or an idea, and Claude writes Strudel code that plays in your browser and changes without ever stopping.

▶ Watch the demo on YouTube (3 minutes, with sound)

How this was made

Moontide is a personal project. Most of the code, research and documentation was written by an AI coding assistant working under my direction. I set the goals, listened to every change, tried it on my own instruments, judged the results by ear, and made the decisions. I am responsible for what is here, errors included.

Why

Curiosity. I wanted to see how far an AI assistant can go at making real music, not a technical demo, when it is given a good instrument. Strudel is that instrument: a live-coding language where a change lands on the next cycle, with no cut, and where the music is plain text that both of us can read.

So Claude writes the code, and the code stays on screen while it plays. You can watch it, edit it by hand, go back to any earlier version, or point at something in the page and ask for a change.

What it does

Strudel code, and a browser page plays it at once. Each change takes over within a fraction of a second, without stopping the music.

• You talk ("start something dreamy in D minor", "darker", "add a bass"). Claude writes

bring any of them back.

• The code is always visible and editable. Every version that played is kept, and Claude can

the parts of a piece, the history as a list or a tree, a mixer whose moves rewrite the code, and a jam view with the scale on a piano or a guitar.

• Around the code, the page shows the music in several views: the named tracks on a timeline,

• A right-click on anything in the page sends Claude a request with that context.
• The same code can play real MIDI instruments from the page, through Web MIDI.

Moontide does not start from scratch. The music engine is Strudel, the JavaScript port of TidalCycles by Felix Roos, Alex McLean and the Strudel contributors. Moontide is the bridge between Claude and a Strudel page.

How it works

you ──talk──► Claude ──MCP (stdio)──► Moontide ──WebSocket (localhost)──► browser page
                                          │                                 Strudel plays
                                          └─ history file on your disk      the code, sound
                                                                            and Web MIDI out

for music or say "start Moontide".

1. Moontide runs as an MCP server that Claude connects to. It starts nothing until you ask

sends the moment under the pointer: the cycle and the beat, the version that was playing, and the notes sounding there or starting in the same sixteenth, with their velocities and, for a MIDI track, its instrument and channel. The Session drawer (the Session button in the top bar) says whether page requests are live (they reach Claude right away) or wait for Claude (they reach it with its next action). Its (i) explains how to switch.

1. It then opens a page in your browser with a Strudel editor.
2. Claude writes the code, the page plays it, and you watch the code come alive.
3. Claude can stop the music at any point. The page has its own Play and Stop button too.
4. Right-click anything in the page to ask Claude about it. A right-click on the Timeline also

Install

Shortened. The full README is on GitHub.