Permission cards in Scala

The carrier is golem.schema.GuestPermissionCardHandle. Because the handle is opaque, choose its schema explicitly with GuestPermissionCardHandle.intoSchema(PermissionCardSpec(...)):

import golem.schema.{GuestPermissionCardHandle, IntoSchema, PermissionCardSpec}
 
given IntoSchema[GuestPermissionCardHandle] =
  GuestPermissionCardHandle.intoSchema(PermissionCardSpec(polymorphic = false))

Use the handle in an agent or tool input/output only where that IntoSchema is in scope. Decoding uses the SDK’s provided FromSchema. Guest code cannot construct or re-wrap a raw card through the public Scala API; it receives one from the runtime or another call. Encoding transfers ownership, so never serialize, persist, duplicate, or reuse a transferred handle.