# Rsr Fact Check > Verify one specific claim against primary sources and return a verdict with evidence. - Skill: `matrixx0070/rsr-fact-check` (Agent Skill) - Install (CLI): `npx skillmds@latest add matrixx0070/rsr-fact-check` - Raw SKILL.md: https://api.skillmd.com/api/skills/matrixx0070/rsr-fact-check/raw - Safety review: pending (external: skill-scanner PASS, skillspector PASS) - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: Coding & Dev Tools - Author: Matrixx0070 (https://skillmd.com/u/matrixx0070) - Updated: 2026-09-08 - Page: https://skillmd.com/skills/matrixx0070/rsr-fact-check --- # Fact Check ## When to use Reach for this when there's a single discrete claim on the table and you need to know if it's true — a statistic, a quote, an attribution, a date, a "study shows" assertion. Output is a verdict backed by the primary source, or an honest "unverifiable." **Not for:** answering an open question (use rsr-deep-dive); rating a source overall (use rsr-source-eval); reconciling many sources into a narrative (use rsr-synthesis). This targets exactly one claim. ## Method 1. **Isolate the claim.** Restate it as a single checkable proposition. Split compound claims — "sales doubled and profits rose" is two checks. *Decision:* if it's a matter of opinion or prediction, stop and label it non-factual. 2. **Identify what would confirm or refute it.** What primary evidence would settle it — the original study, the filing, the transcript, the dataset? 3. **Trace to the primary.** Follow citations upstream past the article to the original source. *Decision:* if you can only find restatements and never the primary, that itself is a finding (verdict: unverified). 4. **Compare against the primary.** Does the primary actually say this? Watch for numbers stripped of context, quotes trimmed to flip meaning, and correlation reported as cause. 5. **Check currency.** Was it true once but since superseded? 6. **Rule.** Assign True / Misleading / False / Unverifiable, quote the decisive evidence, and cite the primary. ## Example Claim: "A Harvard study found coffee cuts heart-disease risk by 50%." Isolate: single stat, attributed. Trace: the article cites a news piece citing an observational study. Primary: the study reports a ~15% *association* in the highest-consumption group, not causation, not 50%. Verdict: **False** — the 50% figure and the causal framing are unsupported; the real finding is a modest correlation. Evidence quoted from the study abstract, cited. ## Pitfalls - Stopping at a secondary source that "confirms" it without reaching the primary — you've verified an echo. - Missing that a real number was quoted stripped of its qualifier (per-year vs. lifetime, relative vs. absolute). - Calling a claim False when it's merely unverifiable — absence of evidence is its own verdict. - Fact-checking an opinion or forecast as if it had a truth value. ## Output format ``` Claim: Verdict: Primary source: — <date> <link> Decisive evidence: "<quote from primary>" What the claim got wrong (if any): <e.g. dropped qualifier, correlation→cause> As of: <date checked> ```