JustPlay CLI

You don't even type it yourself

The app is for sitting down and playing music. The CLI is for everything you'd rather have done for you across a whole library — and here's the twist: you don't have to run it by hand. Because every command is a plain request in and a plain report out, an AI agent — like Claude — can drive it for you. You just ask, in normal words:

• "Analyse my new tracks."
• "Order this crate so it mixes in key."
• "Find the duplicates in my library."
• "Write the detected keys into the files."

…and the agent runs the right commands and hands you the result. No menus, no manual — you talk, it works.

It's called JustPlayCLI.exe and ships in the same install as JUST PLAY, JUST STREAM and JUST TAG, sharing one copy of the engine — so a track the agent analyses reads identically in the player. Every command takes a folder or an index file and prints a plain, readable report: exactly what makes it easy for an agent (or you) to read back.

What you can do

scan

Take stock of a folder — how many tracks, which formats, total size. A quick "what's in here".

analyze

Listen to every track and work out BPM, Camelot key, a 1–10 energy score, loudness and the "feel" features (groove, brightness, how hypnotic/repetitive it is, and more). Results go into an index file. It never changes your audio files.

stats

Turn that index into a picture of your library — how your tracks spread across tempo, energy, danceability, brightness and so on. Useful for spotting what you have too much (or too little) of.

dedup

Find duplicates — both exact copies and near-copies (same track, different rip) — so you can clean house without deleting the wrong file.

tag write

Write the detected key, BPM and energy into each file's own tags, so the analysis travels with the track and other apps (Traktor, rekordbox) can read it.

tag clean

Tidy the comment field — strip old machine gibberish and leave one clean, human line (e.g. 8A · Energy 7).

promote

Make JustPlay's analysis the file's single source of truth — stamp the standard Key/BPM/Energy tags so nothing disagrees. Backs up your original tags first.

squeeze

Give it a big pile of tracks and a number; it keeps the ones that actually mix well together and drops the outliers — and tells you honestly if only a handful really fit.

spectrum

Draw a tonal-balance picture of a track (or a whole set) against the "golden" reference curve, saved as an image — so you can see whether something is too bright, too dull, or just right.

Safe by default

• Nothing is written unless you ask. tag write and promote do a dry run first — they show you exactly what would change. You add --apply when you're happy.
• analyze never touches your audio. It only writes its own index file.
• Backups before writes. promote saves your original tags first, so any change is undoable.

Built for agents

Because every command is a single call in, a plain report out — and writes are opt-in — the CLI is an easy thing for an AI agent (like Claude) to drive. It can scan your library, analyse the new arrivals, find duplicates, build a mix-ready crate and (with your say-so) tag the files, all without ever opening a window. The heavy analysis lives in one shared engine, so what the agent measures is exactly what you'd hear in the player.