I won't quibble over the definition of the word "agent". If I understand you correctly, I still disagree with the point you are making.
Life is a chemical reaction. And when it comes to entropy, life doesn't "assist" the increase of entropy any more than any other chemical reaction. Things burning increase entropy just fine (with no life involved). Even natural processes that aren't chemical reactions such as ain falling, rocks eroding increase entropy. These things all happen on planets (and solar systems) where there is no life. Entropy would increase just the same whether or not there is life..
Factually the increase of entropy due to life in our Solar system is extremely small. It is not zero, but it is pretty close to zero compared to the biggest source of entropy... the burning of the our Sun.
The article is really talking about how life can be explained by thermodynamic processes.. it's not about the almost completely insignificant impact of life on the increase of entropy.