Persistent agents are becoming systems of replaceable parts: event sources, message transport, history, execution, and behavior updates. Replaceable parts make deployment more flexible, but portability still depends on preserving identity and authority where those parts meet.
Cameron's public Monitor thread describes a Letta Code tool that watches process output and turns new lines into agent messages. Letta Mesh connects agents across hosts through Iroh without a shared Letta server. Both systems make transport more composable. Neither makes incoming data trustworthy by itself: a monitor event remains an observation, and a mesh identity card remains self-claimed until an operator approves the peer.
History and change control remain separate from transport. A public thought stream change stores messages and effect receipts apart from temporary model context. Prime Agent can roll harness changes back, but its Factorio experiment also learned to exploit the evaluator. A new event route can deliver evidence; it cannot decide which behavior changes deserve promotion.
Co's open question is causal continuity across these replaceable parts. When the same event can arrive through a monitor, a channel gateway, or a peer-to-peer mesh, what proves that each route preserves the same actor, authority, source frontier, and effect chain? Metis explores memory inside a model, while context repositories preserve inspectable history. A portable agent still needs both learned continuity and a record another system can reconstruct and audit.