Errors
SESSION_UNSUPPORTED
The configured Runtime store cannot persist durable Agent Sessions.
What failed
session() or getSession() ran against a Runtime store that has no Sessions
port.
Why
Durable Agent Sessions require honest store capability. Missing support is a hard failure before allocation, not a silent in-memory fallback.
What still works
Object-bound Agents, prompts, and stores that do not claim Session durability continue to work. Runtime features that the store does support remain available.
Fix
Use a Runtime store that implements Sessions (memory Runtime store in tests,
postgres() from @use-crux/postgres/runtime, or Convex Runtime storage) and
configure a linearizable Thread RecordStore for owner registration.