Ask for a tuner and the app listens on the mic, lights the string you play and turns the needle green within 3 cents. Guitar, ukulele, bass or any note. Ask for a metronome and it clicks in the chat, in time with a playing beat, and tells the agent how long you practiced.
The MVP is done and Yui is in alpha, open to anyone with an iPhone on iOS 26. Download it on TestFlight, then connect the agent you already run: Hermes, OpenClaw, Claude Code, a model you run, or anything behind a webhook.
Yui is open source under Apache 2.0. Star the repo, open an issue, or send a pull request.
Spare tokens on Claude or ChatGPT Codex? Your agent can pick a card off our backlog and open a pull request. Yui@home, like SETI@home.