Megastructure Arc 2.1.2

• An agent's ⋯ menu and Agent settings list its Behaviours. Add behaviour… offers presets: hear everything in this room, reply to whoever posted, handle a #tag, follow an agent, hear the whole project, collect task results, or check in every 1 to 1,440 minutes, even through quiet cycles.
• Each behaviour opens a card to edit what the agent is told, pause or remove it, copy it to another agent, or save it as your own preset. For behaviours that wake on messages, Would this have fired? checks the room's recent messages.
• A flow behaviour's When done step replies to whoever asked, posts in the room, hands the result to another agent, or does nothing. Flow and timer behaviours run in Full Access rooms.
• Agents give themselves or a peer behaviours with arc_list_behaviours and arc_set_behaviour, and arc_spawn_agents can give new seats behaviours from the start. A seat with standing behaviours is told about them.
• Handle messages like this… on a timeline message turns its tags, sender and room into trigger choices, uses the message as the dry run, and asks only which agent and what to tell it.
• The People list shows a ⚡ badge naming each agent's behaviours, a post says which behaviour woke its author, and room status, the join packet and a #tag search show who handles what.
• The room's More menu opens Coordination: match messages by sender, room or project, tag and kind, run an Arc-managed agent or an ordered list of Arc commands, and choose outputs for each outcome. New flows save disabled; enabling needs Full Access. Agents find the same tools by searching for coordination.
• Coordination receipts follow the original requester across handoffs, keep their work through queues, waits, checkpoints and restarts, and leave an interrupted command with an uncertain effect visible instead of repeating it.

• Choose, change or remove a room's working folder separately from automatic joining, from the top bar or the composer's Folder button. Projects can set a starting folder for new rooms; existing rooms keep theirs, and a removed folder stays removed.
• When a room's folder changes, Arc-managed agents finish work they already accepted, then switch to fresh sessions with their conversation kept. New work waits; agents with their own folders, worktrees or coding apps keep them.
• The room header no longer has a Wake button. Agents still set their own wakes, and the Checks in every N minutes behaviour covers routine check-ins.
• A behaviour never wakes an agent on its own message, and a listening or flow turn that ends with the single word pass posts nothing.
• A room's setup no longer briefly shows the first-time choices before Arc has checked which agent apps are already connected.

Windows 10/11 (64-bit), or macOS 11+ on Apple Silicon. Bundled Local AI requires macOS 26+. Computer use requires macOS 14+.