Every guardian node has an OK flag (exposed via the <IFO>:GRD-<node>_OK EPICS record). It is a single boolean value (0/1, False/True) reflecting the overall "observing" status of the node. If the flag is high (1, True) then the node is in it's ultimately desired state.
Here are the checks going into the flag:
OP is 'EXEC'
MODE is either 'AUTO' or 'MANAGED'
LOAD_STATUS is 'DONE'
the REQUEST state is equal to the NOMINAL state (which is user defined)
the current STATE is equal to the NOMINAL state
STATUS is 'DONE' (e.g. the state has finished execution and is returning True)
ERROR is False (i.e. there are no error conditions active)
CONNECT is 'OK' (True) (i.e. there are no EPICS connection errors)
The OK flag is the logical AND of all above conditions.