A Logos process handle: %Logos.Pid{pid: pid()}. Print-only: a pid can be displayed but never appears in source text, since there is no reader syntax that produces one.

This is a genuine BEAM pid() wrapped in a tagged struct so Logos code can hold/pass/compare it as an ordinary runtime value (structs already compare structurally equal field-by-field, so two %Logos.Pid{} wrapping the same underlying pid() are =-equal for free). There is no reader syntax for this type -- Logos.Reader can never produce one; it only ever comes from evaluating spawn/spawn-link/ spawn-monitor/self (Logos.Process). Because of this, Logos.Form.t() (the type the reader can produce) excludes pid entirely -- see lib/logos/form.ex's moduledoc.