Atrium

Atrium is a local-first macOS workspace app for running many AI coding agents in parallel (up to 49), organizing agent sessions, terminals, editors, and browsers into tiled, room-based mosaics that persist across crashes and reboots. It orchestrates work through tasks isolated in git worktrees, an activity sidebar showing every agent's status across workspaces, and a built-in CLI with JSON output that agents themselves can script to spawn and message each other. All workspace data stays on disk and users bring their own model accounts.