What is cast?

Cast is an open-source, self-hosted framework for running AI agents built on Anthropic's Claude, designed for teams or households who want to share the same agent setup. The main problem it addresses is that most agent tools assume one developer talking to one agent. As soon as more people need to use the same setup, questions about identity and access control become difficult to answer. Cast handles that by putting access rules in configuration files rather than in the model's instructions. Because the model never sees those rules directly, it cannot accidentally reveal them or be talked out of enforcing them. Agents in Cast are defined as folders of files, not written code. You can create and modify them in two ways: through a chat-based dashboard builder called Design, where you describe what you want in plain English and it scaffolds the files for you, or through Claude Code using three custom skills that integrate the building process into a coding session. Both approaches edit the same files, so you can mix and match. Once an agent is running, each person you invite gets their own private conversation with it over Slack, Telegram, or a web interface. Getting Cast running requires a container runtime (Apple Container on macOS or Docker on Linux), Node 20 or later, and either an Anthropic API key or a Claude.ai account token. Running "pnpm start" from the cloned repository installs dependencies, builds the agent container image, and starts the server. The dashboard opens at a local web address and starts empty, walking you through creating your first agent. The project is in developer alpha. The core pieces, including agent isolation, identity management, routing, and access control between agents, are the most settled parts. The in-browser build console is newer and described by the author as less stable. The license is MIT.