Claim Grounding Auditor is a skill that takes a draft and its source material, extracts every checkable factual claim, and returns a structured substantiation report. Each claim receives exactly one of four statuses: GROUNDED (directly supported by a strong, citable source), INFERRED (a conclusion assembled across sources rather than stated by any one of them), WEAK (supported only by an outdated, low-quality, or non-authoritative source), or UNSUPPORTED (no source found, or the source contradicts the claim).
The skill enforces a source-strength hierarchy. Primary, authoritative, and current sources rank highest. Aggregated, tertiary, or marketing content ranks lowest. A claim backed only by weak sources cannot be elevated above WEAK regardless of how confident the prose reads.
A core distinction the audit enforces is fact versus inference. When a draft combines two sourced facts into a new conclusion, that conclusion is classified as INFERRED rather than GROUNDED — even when both inputs are solid. This surfaces the most common way confident AI output smuggles in unverified conclusions.
The skill is domain-agnostic and applies to research briefs, RAG output, product copy, technical documentation, analyst reports, and any text where a wrong-but-confident sentence carries real cost. It does not fetch the open web on its own; it audits against sources the agent provides. It checks grounding and source strength, not domain correctness — a claim well-supported by a flawed source passes as GROUNDED against that source.