Crossword Genius

How is worker producing effects? (9)

Ross

I believe the answer is:

operative

I'm a little stuck... Click here to teach me more about this clue!

'effects?' is the definition.
Although both the answer and definition are singular nouns, I can't understand how they can define each other.

'how is worker' is the wordplay.
I cannot quite understand how this works, but
'worker' could be 'rat' (rat is a kind of worker) and 'rat' is found in the answer.
This explanation may well be incorrect...

'producing' acts as a link.

Can you help me to learn more?

(Other definitions for operative that I've seen before include "Having force - skilled worker" , "Significant" , "American detective" , "Functioning; worker" , "desired effect" .)

I've seen this clue in the Sydney Morning Herald.
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