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Fact Checker

Verifies factual claims in your documents against official sources and applies corrections only after you approve them.

Content & WritingBeginner★ 1,323⑂ 212AI score 9/10Last updated: Aug 8, 2026

What it does

  • Scans a document for verifiable claims — specs, version numbers, release dates, statistics, benchmark scores, pricing — while skipping opinions, prose, and tutorial steps.
  • Searches authoritative sources for each claim: official product pages, API docs, release notes, GitHub releases, and package registries (npm, PyPI, crates.io).
  • Produces a comparison table and fact-check report with statuses (✅ accurate, ❌ incorrect, ⚠️ outdated, ❓ unverifiable), including line locations, current text, proposed fix, source link, and rationale.
  • Never edits silently: it waits for explicit approval, then applies edits, verifies them, and reminds you to commit.
  • Adds good hygiene: temporal qualifiers ("as of January 2026"), numeric precision matched to the source, and inline citations.

Who it's for

  • Technical writers, bloggers, and book authors whose docs contain fast-moving facts (AI model specs, library versions).
  • Engineering teams refreshing stale wikis, READMEs, or onboarding guides.
  • Analysts and marketers who want sourced numbers before a report or proposal goes out.

Examples

  1. Model spec refresh: "Fact-check the context windows in section 2.1" → outdated model names and token counts are tabled against current official docs, then fixed on approval.
  2. Benchmark verification: "Verify the benchmark scores in chapter 5" → each number compared to the official publication, with only the mismatches flagged and linked.
  3. Dependency audit: "Are the library versions in the README still current?" → registry lookups surface outdated pins with changelog references for the update.

· · · Install guide · · ·

Install in the Claude app (no terminal)
  1. Download the ZIP with the button below.
  2. In Claude, open Settings → Capabilities and turn on 'Code execution and file creation'. (one time)
  3. Go to Customize → Skills → + → 'Upload a skill' and upload the ZIP.
↓ Download ZIP
Install in Claude Code

Let Claude do it — paste this into Claude Code

Install the skill I found on Claude Skill Mart.
Copy the fact-checker folder from the GitHub repo daymade/claude-code-skills into my ~/.claude/skills/fact-checker/.
When it's done, tell me in one line what this skill can do.

Install with a command instead

git clone https://github.com/daymade/claude-code-skills.git && mkdir -p ~/.claude/skills && cp -r claude-code-skills/fact-checker ~/.claude/skills/

⚠ This is a third-party skill. Check the source repository before installing.

  1. Open a terminal (Terminal on macOS/Linux, Git Bash or WSL on Windows).
  2. Clone the skills repository: 
    git clone https://github.com/daymade/claude-code-skills.git
  3. Make sure the Claude Code skills directory exists: 
    mkdir -p ~/.claude/skills
  4. Copy just this skill into place: 
    cp -r claude-code-skills/fact-checker ~/.claude/skills/
  5. Confirm the install: ls ~/.claude/skills/fact-checker should show SKILL.md.
  6. Restart Claude Code and allow web tools (WebSearch/WebFetch) — the skill depends on live source lookups.
  7. Open the file you want checked and ask: "Fact-check this document" or "Verify the numbers in docs/guide.md".
  8. Review the report; the skill only rewrites your file after you say "apply the corrections". Commit to git first for a safe rollback.
View source on GitHub ↗License: MIT