Use this skill during code reviews to proactively investigate the codebase for duplicated functionality, reinvented wheels, or failure to reuse existing project best practices and shared utilities.
Install
npx skills add google-gemini/gemini-cli --skill review-duplicationnpx skills add google-gemini/gemini-cli --skill review-duplication -a claude-code -gnpx skills add google-gemini/gemini-cli --skill review-duplication -a codex -ggemini skills install https://github.com/google-gemini/gemini-cli.git --path .gemini/skills/review-duplicationgh skill install google-gemini/gemini-cli review-duplicationgit clone --depth 1 https://github.com/google-gemini/gemini-cli /tmp/google-gemini__gemini-cli
mkdir -p ~/.claude/skills ~/.agents/skills
cp -R /tmp/google-gemini__gemini-cli/.gemini/skills/review-duplication ~/.claude/skills/review-duplication # Claude Code
cp -R /tmp/google-gemini__gemini-cli/.gemini/skills/review-duplication ~/.agents/skills/review-duplication # Codex, Cursor, Gemini CLI, Copilot, OpenCode