Nice writeup on the durable state architecture for ephemeral agents. The immutable archive plus atomic pointer pattern is a clean separation of compute and state.

One part of this that deserves more attention is the identity layer. When a new worker picks up a session from the archive, it needs the same auth tokens, API keys, and resource permissions the original worker had. A session checkpoint without its credential context is half a recovery. The worker either forces the user to re-authenticate or embeds secrets in the checkpoint, which is a security risk.

A credential vault tied to the state lifecycle solves this. The checkpoint carries an opaque handle to the agent's identity bundle, and the new worker resolves it through a secure channel rather than handling raw secrets. It keeps the security boundary clean while preserving the stateless worker model. Products like CAI follow this pattern, letting ephemeral workers restore their full access context from a signed reference without ever touching the underlying credentials.