Scanty contribution to welcome agreement (6)
I believe the answer is:
meagre
'scanty' is the definition.
(similar in meaning)
'contribution to welcome agreement' is the wordplay.
'contribution to' indicates the answer is hidden within the clue.
'MEAGRE' is hidden within 'welcome agreement'.
(Other definitions for meagre that I've seen before include "Polite form of address" , "Lean and scanty" , "Scant" , "Paltry" , "miserly" .)