Review and validate claims using counter-hypothesis testing. Use when verifying technical content, checking references, validating API endpoints, or performing quality assurance on deliverables.
Install
npx skills add github/gh-aw --skill fact-checkingnpx skills add github/gh-aw --skill fact-checking -a claude-code -gnpx skills add github/gh-aw --skill fact-checking -a codex -ggemini skills install https://github.com/github/gh-aw.git --path .squad/templates/skills/fact-checkinggh skill install github/gh-aw fact-checkinggit clone --depth 1 https://github.com/github/gh-aw /tmp/github__gh-aw
mkdir -p ~/.claude/skills ~/.agents/skills
cp -R /tmp/github__gh-aw/.squad/templates/skills/fact-checking ~/.claude/skills/fact-checking # Claude Code
cp -R /tmp/github__gh-aw/.squad/templates/skills/fact-checking ~/.agents/skills/fact-checking # Codex, Cursor, Gemini CLI, Copilot, OpenCode