Most apps show long-running work as a pile of toasts. An upload pops one, the agent pops another, and the music player lives somewhere else entirely.

Activity replaces that with a single surface. It sits small when you glance at it and opens up when you look. Start something new and it morphs into it instead of stacking another toast. Uploads, agent runs, music, calls and timers all share it.

It installs with the shadcn CLI and lands in your project as plain source, so you own every line.

• Quick start gets you running in three steps.
• Activity covers everything it can do.
• The playground lets you try each one and copy the code.