Voice as a Lint Rule

I was sitting across from the founders of Kintsu, a new medspa, talking about how their brand should sound. Not adjectives. Sentences a real person would actually say to a guest at the door. We argued over a few words. One of them was "journey". They had heard it in every medspa pitch they had ever sat through. By the time we got up from the table, we had five voice pillars and a stack of SAY THIS / NOT THIS pairs. "Journey" was on the wrong side of the line.

Then I went back to the repo and made the voice executable. The pillars and pairs landed in the brand voice and imagery guidelines. A compressed version landed in a 71-line AI_DESIGN_GUIDELINES.md that the AI agents read at the start of every session. The next time an agent reached for "journey" in a draft, the rule caught it. The word never shipped.

That is the thesis. A banned-words list is to brand voice what a typecheck is to code. It will not catch every problem. It catches the dumb ones you cannot afford to ship, and it runs every time without getting tired.

The voice document had no teeth

For a long time, a brand voice lived in a Google Doc or a Figma PDF. A designer opened it the first week of onboarding. A senior skimmed it before a launch. The rest of the time it sat on a shelf, and the brand drifted toward whatever felt fine on a Wednesday afternoon.

Nothing in the workflow forced anyone to consult the doc. Nothing in review flagged a regression. Voice drift was a slow leak you noticed at the end of a quarter, when the homepage suddenly read like every other medspa on the internet. The drift is not loud. It is boring. That is the part people miss.

The team is no longer just humans

Half the copy on a modern project is drafted by a designer with Claude open, an engineer using Cursor, or a contractor with ChatGPT in another tab. The agents are fast and capable. They are also untrained on your brand. So the voice has to live where the agents read.

For Kintsu, the in-person voice walk became code in the same repo. The five pillars and SAY THIS / NOT THIS pairs in the Voice and Imagery Guidelines, compressed into the 71-line AI_DESIGN_GUIDELINES.md the AI loads on every session. The site itself was built largely by AI agents under that contract. Of the 214 commits on the Kintsu-Site repo, I authored 209. The voice held because the rule held.

For Nibbble, the code repo carries CLAUDE.md and AGENTS.md. The parallel vault carries CLAUDE.md, AGENTS.md, and GEMINI.md. Whichever AI a contributor opens, the contract is on the table.

For this portfolio, the discipline is the same. content/facts.yaml is the canonical claims registry. The prompt rules say: if a number or date is not omit it. Do not guess. That is the only reason this essay does not have an invented number in it.

Voice walked with the client. Voice committed to the repo. Voice enforced at PR time.

The cheapest possible voice gate

The Kintsu prohibited-words list bans "journey", "holistic", "glow up", "self-care", "state-of-the-art", and "we believe". The point is not pedantry. The point is that a one-line check runs in code review and never gives the writer the benefit of the doubt at 4:55pm on a Friday. It does not care whether the writer is junior, senior, human, or a model. The line is the line.

This is not a new idea. Engineers have encoded judgment into lint rules and CI for two decades. The new move is to put brand judgment into the same machinery, before the team can ship around it.

The deliverable changed

Six long-form Kintsu strategy documents, around 2,745 lines, now live in the repo. Positioning. Voice. Imagery. Naming. Tone for in-app moments. The deliverable used to be a deck. Now it is a set of files the team and the agents both read, in the place where the work happens.

That changes what a senior brand or design hire is asked to do. The job is no longer to write the guide and hand it off. It is to encode the taste so the system enforces it.

What this means for a design org

Voice review stops being a copy review job. It becomes a contract a director writes once and the team enforces in code review, the same way they enforce a typecheck. A junior can hold the line because the line is in the file, not in their head.

Taste still gets set in a room, in person if it can be. What changes is what happens after the room. The taste gets translated into rules a system can run. Banned words. SAY THIS / NOT THIS. A canonical facts file. A short markdown contract at the top of the repo.

What the job actually is now

Set the voice in person. Codify it. Put it where the agents read. Enforce it at PR time, alongside engineers enforcing types and security enforcing scopes.

Skip that last step and the voice document goes back on the shelf, and the brand drifts. I have watched it happen. The rule in the repo is the thing that stops it.