fact-checker

Installation
SKILL.md

Fact Checker

Verify factual claims in marketing content and return an accuracy score with source citations.

What to Verify

Claim Type Example Verification Method
Statistics "85% of marketers use AI" WebSearch for source
Metrics "Saves 10 hours/week" Look for case studies
Quotes "As Forbes reported..." Verify quote exists
Comparisons "Fastest in the industry" Check competitor data
Awards/Recognition "Award-winning platform" Verify award exists
Dates/Events "Founded in 2015" Cross-reference sources

What NOT to Verify

  • Opinions ("We believe...")
  • Subjective claims ("Beautiful design")
  • Future projections ("Will transform...")
  • Internal metrics without external validation

Process

  1. Extract Claims

    • Parse content for factual statements
    • Identify statistics, percentages, quotes, comparisons
    • Flag superlatives ("best", "fastest", "only")
  2. Categorize

    • Verifiable: Has a specific, checkable assertion
    • Opinion: Subjective, not fact-checkable
    • Vague: Could be verified if made specific
  3. Verify via WebSearch

    • Search for authoritative sources
    • Prioritize: official reports, academic sources, reputable publications
    • Check recency of data
  4. Score Each Claim

    • Verified: Found supporting source
    • Unverified: No source found, but not contradicted
    • Contradicted: Found conflicting information
    • Outdated: Data exists but is stale
    • Opinion: Not fact-checkable
  5. Calculate Overall Score

    • Score = (Verified + 0.5 x Unverified) / Total Verifiable Claims x 10

Output Format

## Fact Check Report: [Content Title/Description]

**Overall Accuracy Score:** X/10
**Claims Analyzed:** X total (X verifiable, X opinions)

### Claim Analysis

| # | Claim | Type | Status | Source | Action |
|---|-------|------|--------|--------|--------|
| 1 | "85% of marketers..." | Stat | Verified | [HubSpot 2024] | Add citation |
| 2 | "Best solution..." | Opinion | N/A | - | OK as-is |
| 3 | "Saves 10 hours" | Metric | Unverified | - | Add case study |
| 4 | "Founded 2015" | Fact | Contradicted | Was 2016 | Correct date |

### High-Risk Claims

Claims that need immediate attention:

1. **[Claim]** - [Why it's risky] - [Recommended fix]

### Recommendations

**To improve accuracy score:**
1. Add citations for unverified statistics
2. Soften absolute claims ("best" -> "leading")
3. Update outdated data points
4. Remove or rephrase contradicted claims

**Legal/Compliance Notes:**
- [Any claims that could trigger FTC/advertising concerns]

Scoring Rubric

Score Meaning
9-10 Excellent - All major claims verified with sources
7-8 Good - Most claims verified, minor gaps
5-6 Fair - Mix of verified and unverified claims
3-4 Poor - Many unverified or contradicted claims
1-2 Critical - Major factual issues found

Source Quality Hierarchy

Prefer sources in this order:

  1. Primary sources - Original research, official reports
  2. Authoritative publications - Industry reports, academic papers
  3. Reputable media - Major publications (Forbes, WSJ, NYT)
  4. Industry sources - Trade publications, analyst reports
  5. Company sources - Press releases, official statements

Avoid: blogs, forums, Wikipedia (use as starting point only)

Special Attention

FTC/Advertising Compliance:

  • Testimonials must be genuine and typical
  • "Free" claims must have no hidden costs
  • Comparisons must be substantiated
  • Health/financial claims need strong evidence

Common Marketing Claim Patterns:

  • "Studies show..." -> Which studies? Link them
  • "Experts agree..." -> Which experts? Quote them
  • "Industry-leading..." -> By what measure?
  • "#1 rated..." -> By whom? When?
Weekly Installs
8
GitHub Stars
37
First Seen
Mar 24, 2026