Annotations

Four annotations drive everything. All are runtime annotations on methods of a Node subclass, bound when the node is registered with orchestrator.registerNode(name, node).

Annotation	Repeatable	Method signature	Binds to
@SubscribedTo	yes	0 or 1 parameter, any return	topic subscription (callback pool)
@RunPeriodically	yes	no parameters, any body	scheduler pool (or hardware thread)
@RunnableAction	no	no parameters, returns void	action pool, fired by name
@OnHardwareThread	no	— (modifier on @SubscribedTo methods)	re-routes the subscriber to the hardware thread

Rules that apply to all four

• Write the full attribute. @SubscribedTo(topic = "..."), not @SubscribedTo("...") — the annotation has no shorthand value. @RunnableAction("name") is the exception; its only attribute is the value.
• Methods must not be static. The binder invokes them reflectively on the node instance.
• Errors in bound methods never crash the robot. They are logged through the orchestrator’s sink and the next invocation proceeds.
• Structural violations throw at registerNode time, not at runtime — a wrong parameter count or return type fails the OpMode during init, where it is visible on the Driver Station.

Next steps

Each annotation’s page covers its attributes, runtime behavior, and gotchas.