Run into agent that's able to move supply (4)
I believe the answer is:
spry
'able to move supply' is the definition.
I can't judge whether this definition defines the answer.
'run into agent' is the wordplay.
'run' becomes 'r' (cricket abbreviation).
'into' means one lot of letters goes inside another.
'agent' becomes 'spy' (spy is a kind of agent).
'r' going within 'spy' is 'SPRY'.
'that's' acts as a link.
Can you help me to learn more?
(Other definitions for spry that I've seen before include "Still able to move lightly and fast" , "'Agile, nimble (4)'" , "Lively (especially of an older person)" , "Alert" , "'Active and lively, nimble (4)'" .)