FacTool is an AI application designed to detect factual accuracy within generative AI models. It operates as an open-source initiative hosted on GitHub under the GAIR-NLP organization, facilitating the assessment of factual consistency in AI-generated outputs. Users can actively contribute to its enhancement by registering on GitHub and engaging with the project's development. Integrated within the GitHub ecosystem, FacTool offers diverse functionalities including workflow automation, package hosting, vulnerability management, rapid development environments, and AI-powered code assistance via Copilot.