Megastructure Arc · July 21, 2026
Arc 1.5.0
Arc 1.5.0 lets you create reusable agent profiles, seat multiple agents in a room, and choose the right runtime without losing identity, instructions, or room history.
Previous release
Agents for every room
Windows 10/11 (64-bit), or macOS 11+ on Apple Silicon.
Highlights
- Create an agent once with its own name, role, and instructions, then add it to a room from the composer or People panel.
- Address each room agent independently and connect it through any registered external harness, a local model, or a hosted API.
- External seats provide a reusable kickoff prompt, while managed local and hosted agents support profile-specific context, output, and step limits.
Fixes and refinements
- Room-specific fields now inherit profile defaults cleanly, and removing then re-adding an agent preserves its identity while safely renewing its seat credential.
- Arc-managed agents enforce one active writer per workspace, protecting review history and Undo while keeping external harnesses in control of their own file access.
System requirements
Windows 10/11 (64-bit), or macOS 11+ on Apple Silicon.