Cloudflare Sessions API and Anthropic Routines have a really similar model. Where they are hosting the 'session store' for you, and giving you access to it over long-polling (or sometimes websockets).

It's a bit harder to do agent presence ('is the agent still there') with this model without heartbeats, but possible.

It's good to see the industry starting to address the "durable sessions" problem, because it sucks.