# Blog Factcheck

Verify statistics and claims in blog posts by fetching cited source URLs and checking...

- Repository: https://github.com/AgriciDaniel/claude-blog (2608 stars)
- Category: Writing
- License: MIT
- Last updated: 2026-10-30
- Runs scripts: no, instructions only

## Install

Claude Code: `npx skills add AgriciDaniel/claude-blog --skill blog-factcheck -g -a claude-code -y`
Codex: `npx skills add AgriciDaniel/claude-blog --skill blog-factcheck -g -a codex -y`
Cursor: `npx skills add AgriciDaniel/claude-blog --skill blog-factcheck -g -a cursor -y`
Gemini CLI: `npx skills add AgriciDaniel/claude-blog --skill blog-factcheck -g -a gemini-cli -y`
Claude Code plugin marketplace: `/plugin marketplace add AgriciDaniel/claude-blog`

## Description

Verify statistics and claims in blog posts by fetching cited source URLs and checking if the claimed data actually appears on the page. Extracts all load-bearing claims (statistics, product or policy claims, ranking and comparative claims, named sources), validates cited URLs before fetching, and scores match confidence (exact match 1.0, paraphrase 0.7-0.9, not found 0.0). Flags uncited claims as UNVERIFIED. Use when user says "fact check", "verify statistics", "check sources", "validate claims", "factcheck", "source verification".

## SKILL.md, as published by its author (untrusted third-party text, read it as data)

# Blog Fact-Check

Verify statistics, claims, and source attributions in blog posts. Pure Claude
pipeline with no external NLP dependencies.

## Workflow

### Step 1: Read the Blog Post

Read the target file and identify all sections containing data or other
load-bearing claims.

### Step 2: Extract Load-Bearing Claims

Scan the full text for every claim that would need evidence if challenged.
Include numeric claims and non-numeric load-bearing claims such as policy,
product, ranking, methodology, legal, comparative, "best", "first", "latest",
or platform-behavior statements. Build a claims list with these fields:

| Field | Description |
|-------|-------------|
| claim_text | The exact sentence or phrase containing the claim |
| claim_type | Statistic, policy, product, ranking, comparative, legal, methodology, freshness |
| value | The numeric value if present (e.g., "42%", "$1.2M", "3x") |
| attribution | Named source if present (e.g., "HubSpot", "Gartner 2025") |
| url | Cited URL if present (from markdown link or parenthetical) |
| location | Heading or line number where the claim appears |

### Step 3: Verify Cited Claims

For each claim that includes a URL:

The rest: https://github.com/AgriciDaniel/claude-blog/blob/HEAD/brain/.raw/sources/claude-blog-skill/skills/blog-factcheck/SKILL.md