Tonejs

This wraps Tone.js, the Web Audio framework that gives you synthesizers, samplers, effects chains, and precise musical scheduling without fighting the raw Web Audio API directly. You'd reach for it when building anything from a browser-based drum machine to audio visualizations to game sound effects. The skill documentation does a solid job explaining the critical timing concepts, like why you must pass the time parameter through callbacks for sample-accurate playback and why you need to call Tone.start() from a user interaction. The routing examples are clear, and the step sequencer patterns are practical. If you're doing any serious audio work in the browser, this is the standard tool.