A Claude Code mod plays MIDI music when it works

Important

Only tested on macOS. Not sure yet how it behaves on Linux or Windows.

I'm an engineer, but these days I solve the boring problems entirely by vibe coding. Somewhere along the way I felt I had lost the creativity and curiosity I used to have when writing code myself.

So I started thinking about how to make vibe coding fun again. miod is the first try: while the agent does the work, you get to hear it think, read, edit, fail and fix, with a little piece of music no one has heard before.

Feel free to add more moods, flavours and styles. Each mood is one row in hooks/moods.ts, each flavour one row in hooks/flavours.ts, each sound style one entry in hooks/styles.ts, and each wave look one file in hooks/waves/.

Feeling it's a bit too noisy? 🙉 No hard feelings. Just turn it off with /miod off.

A Claude Code mod (MIDI + mod) that writes music on the spot while Claude works. No music files, no library, no AI model.

• Every task picks its own flavour (lo-fi, chiptune, ambient, jazzy and 8 more), key, scale (16 of them), chord progression, tempo, sound and theme.

• The mood follows what the agent is doing. Every mood has 10 variants, and a new one is picked as the task goes: whenever the activity changes, and every 4 phrases. The task's flavour bends it too, so editing in a lo-fi task sounds nothing like editing in a chiptune one.

• The faster it spends tokens, the busier the music.

• Above the prompt, one line shows the mood, flavour, key, tempo and energy, with a wave under it that scrolls with the music, coloured by mood:

• Tasks flow into each other: the next task fades in, in a related key. If no new task comes, a closing chord fades out at the end of the phrase.

Needs Claude Code 2.1.290 or newer, on macOS.

claude plugin marketplace add delexw/miod
claude plugin install miod@miod

Then start a new session.

/miod        is it on or off?
/miod off    stop the music
/miod on     play again from the next task
/miod wave   list the wave looks: bars, line, mirror, dots, pulse
/miod wave dots   switch the wave to the dots look

Each row below is the mood's first variant. All 10 are in MOODS in hooks/moods.ts.

When several happen in one 8-beat phrase, the one higher in STRONGEST_FIRST (hooks/activity.ts) wins. A filling context window lifts the melody and, past 80%, adds a low drone.

The scales follow how musicians describe each mode (musical-u, Jiang et al. 2024).

• Mood variant: add a row to that mood's list inMOODS inhooks/moods.ts .
• New mood: add the name toActivity andSTRONGEST_FIRST inhooks/activity.ts , map tools or commands to it there, and give it a list of at least 10 variants inMOODS .
• Flavour: add a row toFLAVOURS inhooks/flavours.ts . Each field nudges every mood: brighter or darker scale, busier or calmer, drums up or down, swing, bass line.
• Scale or chords: add toSCALES orPROGRESSIONS inhooks/theory.ts .
• Wave look: add a file tohooks/waves/ that exports aWaveLook (how many rows, and adraw function), then list it inWAVES inhooks/waves/index.ts .
• Style: add a wave function toSTYLES inhooks/styles.ts . It must return values between -1 and 1.

Then check it:

claude plugin validate .
claude plugin test .

Run a checkout without installing it with claude --plugin-dir <path to this repo>.

• Only tested on macOS, where Claude Code plays the audio through afplay .
• The sound is simple chiptune-style tones.
• miod only hears the session it's loaded in.