Pencil is an agent-driven design canvas that lives directly inside your IDE, allowing developers to design and code in the same environment without handoffs. It uses an open file format stored in your repository, enabling version control, branching, and merging like standard code. With AI agents, users can generate full screens or components through prompts and collaborate in parallel. It supports Figma imports, editable CSS, built-in design kits, and production-ready HTML, CSS, and React output. The platform also integrates with external tools, APIs, and data sources while giving full read and write control over design files.