Reusable SDK facilities for one Agent loop. Applications retain resource ownership, permissions and child scheduling.
Loop
Structured messages and linked tool results; parallel tool calls by default with serial hooks.
Identified steering/follow-up queues and lifecycle events on the existing Agent.
Lifecycle
Cancellation and aclose settle the owned producer; effects are not rolled back or replayed.
dump/restore retain conversation, skill and compaction data; hosts reinject live resources.
One built-in policy; generic Agent compaction is off unless explicitly configured.
Composition
ToolRepo supplies actual default bash/filesystem/current_time tools; submit_result is opt-in.
McpRegistry owns MCP connections and proxies; Agent consumes it separately from ordinary tools.
CapabilityAssembly combines explicitly opened host bindings and selected skills, without another runtime.
Workers contribute hooks, commands, UI and providers, not model tools.
Handles and delegation contracts; Coding/Claw own child execution runtimes and authority.