Coherent vs pen.dev

Coherent is an AI design method for building multi-page products whose pages share components and a growing design system. It generates a Next.js project using Tailwind CSS and shadcn/ui, suitable as a prototype, developer handoff, or frontend. Shared components and editable design tokens propagate changes across pages, with design-system.config.ts as the editable configuration. Users can choose from 10 prebuilt atmospheres or define their own foundation. Coherent supplies context for Cursor, Claude Code, and other AI editors through.cursorrules and CLAUDE.md files. It supports Anthropic Claude or OpenAI GPT using the user’s own API key; typical model costs are estimated at $0.01–$0.03 per page. Its MCP server can validate code, read tokens, extract a design system from a URL, or apply a DESIGN.md file. It can import DESIGN.md and export tokens as W3C DTCG JSON, CSS variables, or Tailwind configuration. Full retrofit into an existing codebase is not supported yet, and direct Figma token import is also not supported. Coherent is open source under the MIT license and available on Linux, macOS, and Windows.

pen.dev is a canvas for building software and a vector design tool integrated with development environments. Its editor works with components, variables, themes, scripts and shaders, and can import Figma files and HTML. It can export to HTML, CSS and Tailwind, as well as PNG, JPEG, WEBP and PDF. Users can work with its integrated agent or connect external agents through MCP; the available plans specify how many agents can run in parallel. Documented integrations include Claude Code, Codex, Gemini CLI, Antigravity, OpenCode, Kiro and Claude Desktop. Integrated provider options include OpenAI, Anthropic, Google Gemini, Cursor, GitHub Copilot, xAI, OpenRouter and other API-key providers. Its.pen design file is open JSON with an open schema. Tools include a Chrome extension for importing webpages, IDE extensions and an npm-installed CLI requiring Node.js 22.19 or later. The pricing page says pen.dev stays free until plans launch. The Free plan is free; Pro is $16 a month; Ultra is $48 a month.