The expensive error in publishing is not a typo. It is a sentence that is plausible, confident, and not in any of the sources — the kind that survives an edit and gets quoted six months later.
Two skills make that error visible before publication: Synthesis Matrix, which keeps evidence attached while writing, and Claim Verification, which checks each sentence against the sources afterwards.
The short answer
Write from a matrix, not from memory. Then run a mechanical pass that marks every factual sentence as supported (with a quote) or unsupported (remove or re-source). Both steps are cheap; skipping either is what produces the confident, unsourceable page.
The matrix
A synthesis matrix has sources down the side and questions across the top, with quoted evidence in the cells. It is a boring artefact and it changes how a draft gets written: a sentence that has no cell to come from does not get written.
Synthesis Matrix builds one when you have five or more sources; below that the overhead exceeds the benefit and a normal notes page does the job.
The verification pass
The matrix keeps the evidence; verification checks the finished draft against it. Claim Verification scans for factual claims — numbers, dates, attributions — and matches each to a sentence in the provided sources.
Supported claims get a quote. Unsupported claims are listed for removal. A paraphrase is not a source: if the sentence is not in the material, the claim is unsupported even when it feels obviously true.
The category of claims it catches
| Claim type | Example | Why it slips through |
|---|---|---|
| Numbers | "about 40 percent of packages" | Plausible and unmemorable |
| Dates | "since the 2024 rewrite" | Nobody re-checks a date |
| Attributions | "the maintainers say" | The link goes to a repo, not a sentence |
| Formats | "returns JSON" | True of one endpoint, not the product |
| Comparisons | "faster than X" | No source states it in that form |
The table is also a writing checklist. Each row names a sentence you should not write without a quote attached.
A worked example
A draft says: "Most MCP servers are maintained by one person." Plausible, and the kind of sentence that makes a piece feel informed. Verification asks for the source sentence. If the data only shows contributor counts for a sample of packages, the claim becomes "in the 156 packages we reviewed, 71 percent had a single contributor" — narrower, sourced, and better.
That narrowing is the whole benefit. The claim becomes less quotable and more defensible, which is the correct trade for a directory that dates its entries.
Where the checks sit in the workflow
Matrix before drafting, verification after. A review in between for structure and tone, which is a human job. Running verification before the structure is settled wastes effort on paragraphs that will be cut.
Frequently asked questions
Do I need both skills? For anything with claims about third parties, yes. The matrix prevents the claim; verification catches the ones that got through.
Can verification prove a claim true? No. It proves the source says it. Whether the source is right is a different question, and often one the source itself addresses poorly.
What about quotes? Same rule — a quote must appear in the material. A reconstructed quote is the most damaging version of this error. See how we verify and AEO writing.
Last checked: 11 November 2026.
Related: research skills, writing a skill, and our methodology.
