Clever getting a page in message (7)
I believe the answer is:
capable
'clever' is the definition.
(thesaurus)
'a page in message' is the wordplay.
'page' becomes 'p'.
'in' means one lot of letters goes inside another.
'message' becomes 'cable' (cable is a kind of message).
'a'+'p'='ap'
'ap' placed inside 'cable' is 'CAPABLE'.
'getting' is the link.
(Other definitions for capable that I've seen before include "qualified" , "Competent, having a certain ability" , "accomplished" , "'Clever, able (7)'" , "Of a person, competent" .)