- actor/<id>/ holds actor.wasm, actor.json, source/, public/, data/, versions/ - the broker boots by scanning actor/; a changed actor.wasm is an upgrade, a rejected one stays in versions/ with a reason and the files come back - /actor hides every data/ folder - subscriptions live in the subscriber's actor.json - cargo installs the SDK and points sausage-actor at it; no build limits - PROTOCOL.md