Copy written by agents was going out under the partners' names and reading like a machine. I called the existing voice work weak.
Stop writing style guides from adjectives. Count how I actually write, from my own texts, email, dictation and recordings, and measure the result with a blind test.
A voice you can't measure can't be checked. If the test is blind and I can still pick myself out, the work isn't done.
We counted 3,407,821 of my words. I scored 8 of 10 in the first round and 7 of 10 in the second, against a chance baseline of 5.
Style is countable. Measure it, then test it against the person.
The pair that fooled me had two f-bombs in my real message and a clean machine version. I picked the clean one as my own.