# K1 chat-thread session actor public contract 0.3.16
## Constructors
The five existing constructors retain their names, arguments and composition, from the base actor through the full Social, SetLaunchNode, RustCode and WebCode actor.
The actor retains its ordered event loop, durable state, inference and model-usage lifecycle, restart generation, session view, and snapshots. `StageRuntime` owns provider-stage coordination, code lanes, WebSearch correlation, mailbox flushes, and acknowledgement order.
`PreparePreflight` atomically persists the ordered preflight through Durable State, then launches every concrete synchronous Ktool outside actor and persistence locks. `ResumePreflight` rebinds trusted authority and relaunches only unresolved calls after recovery. Terminal completions return through the actor channel as ordinary correlated Tool Results.
A prepared chat starts provider inference only after one User Message is durable and all blocking preflight calls are terminal. Non-blocking calls never hold that gate; a result arriving during inference reuses Stage Runtime's existing mailbox-flush path. Snapshots remain Running while unresolved preflight work exists.
This package owns no persistence format, provider prompt, HTTP implementation, retry, timeout, migration, daemon composition, deployment, or live-behavior proof.