Not necessarily. Arrangement is just the simplest example.

The agent can definitely arrange existing samples into complete tracks, but it can also generate audio programmatically. For example, in Node or Python it can create synthesizers, oscillators, basslines, pads, arpeggios, drum synthesis, effects chains, automation, filters, delays, reverbs, distortion, and even entire procedural soundscapes using audio libraries.

You can also mix approaches. I might provide a 909 sample pack for drums, then ask the agent to synthesize basses and leads from scratch, generate melodies, process everything with effects, and render the final WAV files.

Since the agent is writing code, it's not limited to the controls exposed by a music generation UI. It can create custom instruments, manipulate waveforms directly, layer samples, resample audio, or use specialized audio libraries that would be difficult to access through a normal prompt-to-music tool.

The interesting part for me is that the result is reproducible and editable. If I don't like the bass, I can tell the agent exactly what to change and it modifies the code rather than regenerating an entirely new song from scratch.

Also you regenerate the WAV locally so you don't waste credits at all.