Tone of voice forms by itself, from decisions that are not about the brand
A product's tone is set by error messages, button labels and documentation. Developers write them without thinking about the brand, and that becomes the tone.
Brand tone is usually defined at a strategy session and written down in a document. The document then sits there, and the tone forms independently of it.
It forms in places nobody thinks of as branding: error messages, button labels, documentation wording, system emails, code comments, support replies.
Why these places decide it
Because there are many of them, and because people spend more time with them than with the home page.
The home page is read once. An error message is read every time something goes wrong, which means at the moment of maximum attention and minimum patience.
The wording of an error says more about how you treat the user than any slogan. “An error occurred” and “Could not save: the file is open in another program” are two different brands, whatever the values document says.
What this means for assessing the archetype
This is why the procedure scores all twelve archetypes against quotes from the product’s real text: existing copy, documentation, interface, code.
Not against intent. Intent says what the product would like to be. The text says what it is.
The real text usually turns out to be more accurate than the authors’ idea of themselves. Tone is made of a thousand small decisions, and they reveal what the team actually considers important.
What to do about the mismatch
There almost always is one: the desired archetype and the one that follows from the texts do not match.
There are two honest options. Accept the voice that has formed and strengthen it. Or change the texts, all of them, not just the home page.
The second option costs more than it seems, and that is why the first is more often right. You cannot rewrite a hundred error messages without changing the attitude they grew out of. New ones will appear in the old tone.
A practical order
Collect quotes from the places nobody considers branding: errors, labels, documentation, system emails.
Read them in a row, without the interface. You get a fairly accurate portrait, usually a surprising one for the team.
Then score the archetypes against those quotes, not against slogans.
Why this is cheaper than a strategy session
Because the data already exists. It does not have to be invented, it does not have to be negotiated, and it does not depend on who spoke loudest in the meeting.
And because the result can be checked: you can reread the quotes and disagree with the assessment. The conclusion of a strategy session cannot be challenged. It exists as an opinion.
What this changes about working with tone
Tone stops being a section of the brand book and becomes a property of the product.
Hence a practical recommendation that sounds boring and works: a tone rule makes sense only if it can be applied to an error message. Anything you cannot test on “Could not save” does not belong in the brand book.