Raincoat on, I put in a top run for pasta tubes (8)
I believe the answer is:
macaroni
'pasta tubes' is the definition.
(I've seen this before)
'raincoat on i put in a top run' is the wordplay.
'raincoat' becomes 'mac' (macintosh is a type of raincoat).
'put in' indicates putting letters inside (instruction to solver).
'top' suggests taking the first letters (in a down clue, the first letter is top).
The initial letter of 'run' is 'r'.
'mac'+'on'+'i'='maconi'
'a'+'r'='ar'
'maconi' placed around 'ar' is 'MACARONI'.
'for' is the link.
(Other definitions for macaroni that I've seen before include "being a feather in Yankee's cap?" , "Italian food" , "2 [PASTA]" , "Form of pasta" , "food at trattoria?" .)