Agitation is no longer rising with appearance of tool (7)
I believe the answer is:
fretsaw
'appearance of tool' is the definition.
'fretsaw' can be an answer for 'tool' (I've seen this before). I am unsure of the 'appearance of' bit.
'agitation is no longer rising' is the wordplay.
'agitation' becomes 'fret' (fret is a kind of agitation).
'is no longer' becomes 'was' (eg if someone 'was' sad, they're no longer sad).
'rising' is a reversal indicator (going up in a down clue).
'was' backwards is 'saw'.
'fret'+'saw'='FRETSAW'
'with' is the link.
Can you help me to learn more?
(Other definitions for fretsaw that I've seen before include "Fine-toothed tool" , "Woodcutter" , "cutter" , "Tool for cutting designs in wood" , "Woodworking tool" .)