Spies sat about gathering in information (6)
I believe the answer is:
agents
'spies' is the definition.
(secret agents)
'sat about gathering in information' is the wordplay.
'about' indicates an anagram.
'gathering' is an insertion indicator (gather can mean to acquire or bring in).
'in information' becomes 'gen' (I can't justify this - if you can you should give a lot more credence to this answer).
'sat' with letters rearranged gives 'ats'.
'ats' enclosing 'gen' is 'AGENTS'.
Can you help me to learn more?
(Other definitions for agents that I've seen before include "Sales reps" , "They operate on behalf of others" , "They act for others" , "Spies" , "travelling salesmen" .)