Plan to have rump in cooker (6)
I believe the answer is:
agenda
'plan' is the definition.
(I know that agenda is a type of plan)
'rump in cooker' is the wordplay.
'rump' becomes 'end' (I've seen this in another clue).
'in' indicates putting letters inside.
'cooker' becomes 'aga' (I've seen this before).
'end' inserted into 'aga' is 'AGENDA'.
'to have' is the link.
(Other definitions for agenda that I've seen before include "Item list for meeting" , "Items for discussion at committee meeting" , "Table of business" , "Items of business for committee meeting" , "Scheme" .)