Agents

The catalog comes from the host you pick — this machine, Cloud, or a paired gateway.

Desktop

First launch asks you to pick preferred agents from the public ACP registry. Installed agents show up in the composer and on New session. Manage agents installs more, uninstalls, or adds a custom harness (command, args, env).

API keys come from your shell environment. If you launch Spellbook from a dock or start menu, PATH may not include opencode or uvx — start it from a terminal, or add a custom agent with an absolute path.

Cloud

Hosted Cloud advertises one catalog row per agent profile you chose at onboarding (Coding, Finance). Change the set on Account; it applies the next time the sandbox wakes. See Cloud.

Paired host

Web and phone show whatever spellbook gateway advertises: registry agents on the host PATH, plus pins in ~/.spellbook/config.json. Install agents on the host; the catalog on the client updates.

New session

Every first-run path ends here. The setup bar above the composer picks the agent (and a folder, when the host is this machine). Send a message to begin.