Most vendor contracts protect the vendor. Ours has a clause that protects the buyer from us.
It is short. It is in the standard master agreement, not buried in a schedule. It reads, roughly: every artifact we deliver — proposal, plan, dashboard tile, report, receipt — carries a visible evidence class on the claim it makes; if any deliverable arrives with a claim tagged U (unverified) and we have not flagged that U inline before you opened the artifact, you may refuse delivery and we will not invoice the work that produced it. (Class C)
That second half is the part that does the work. The first half is a documentation rule. The second half puts money behind it.
A quick reminder of the alphabet we are using on the page. We tag claims with a letter so the reader knows what kind of evidence stands behind each one. A is empirical, observed in the session you are reading. B is code or inspection — the source exists, you can read it. C is configuration or integration — the wiring is in place and you can verify the wiring. E is an outside expert citation — Popper, a peer-reviewed paper, a named author. F means a falsifier is attached: the claim names the observation that would force us to give it up. U is the fail-safe: unverified, opinion, in-progress, not yet supported. (Class C) We wrote about the letters themselves in /what-an-evidence-class-actually-means; the clause here is what happens when we forget to use them honestly.
The reason the clause exists is that disclosure rules without consequences are decorative. A standard you only enforce on yourself when you remember to is, again, a hope. The clause makes the omission cost us. If a claim is U and we do not say so, the buyer is not arguing about a footnote — they are exercising a contractual right to send the artifact back and to drop the cost off the invoice. The incentive runs the right way: the cheapest path for us is to label honestly, including labeling our own uncertainty as U up front. A U-tagged claim, surfaced cleanly, is fine. A U-tagged claim disguised as a B or a C is the breach.
Three concrete things the clause changes about a working week.
One: the editorial pass on every artifact has a new specific question. Not "does this read well." Not "is the tone right." It is, "for each claim on this page, what is the evidence class, and is the tag visible to the reader." When the answer is "I am not sure," the tag becomes U until someone does the work to move it. (Class C)
Two: scope conversations early in a project get blunter. If a prospect asks for a forecast we cannot honestly tag above U — say, performance on data we have not seen yet — we say that, and the proposal carries the U on its face. The prospect can decide whether a U-tagged forecast is useful to them. Some say yes; some say no. Both are reasonable. What is not reasonable is presenting that same forecast as a C and counting on the prospect not to ask.
Three: the corrections page has a clear trigger. If a buyer invokes the refusal right, the artifact and the reason get a public entry. Not the buyer's name and not the sensitive content — the structural fact that a U-class claim slipped through without its tag, and what we changed about the template so the same slip is harder next time. The point is that the rule has teeth on the inside of the agency, not only at the contract boundary. (Class C)
There is a limit worth naming. The clause forces disclosure of class. It does not, on its own, force the class to be high. A page full of honestly-labeled U claims is still a page of U claims, and a buyer who expected mostly C and F is entitled to walk. We treat that as a feature, not a bug — the clause makes the conversation about the mix happen at the table rather than after the work is paid for. The deeper rule, in /partnership-vs-vendor-contract, is that the buyer is allowed to see what they are buying before they buy it. Disclosure of class is one of the ways we hold to that. (Class E, after Popper, 1934 — a claim that cannot be checked is not yet a claim worth paying for.)
If you are reading vendor contracts this quarter, a cheap test: look for a clause that costs the vendor something when they over-claim. If there isn't one, the disclosure language elsewhere in the document is decorative.
- /partnership-vs-vendor-contract — the broader contract posture this clause lives inside.
- /what-an-evidence-class-actually-means — the letters, in plain language, with examples.
- /workshop — bring a real artifact you are evaluating; we will read it with you and mark the claims, class by class, before any money moves.