Join in as craftsman took a meal (9)
I believe the answer is:
cooperate
'join in' is the definition.
(thesaurus)
'craftsman took a meal' is the wordplay.
'craftsman' becomes 'cooper' (cooper is a kind of craftsman).
'took a meal' becomes 'ate'.
'cooper'+'ate'='COOPERATE'
'as' acts as a link.
(Other definitions for cooperate that I've seen before include "Work together on a common enterprise" , "Work to the same end" , "Play ball with" , "Work constructively with others" , "band together" .)