PLAIN is a structured markdown format that turns product ideas into machine-readable specs. It bridges the gap between product teams and AI tools like Claude, Gemini, Cursor, v0, Figma Make, Bolt, and Lovable, enabling them to generate UI, code, and documentation directly from your vision.
Unlike traditional specs scattered across tools and documents, a PLAIN file consolidates your product's design vision, technical foundation, and user experience into a single, AI-friendly document.
- Structures your product vision: Define your idea, core purpose, and target audience, giving both humans and AI a shared understanding of what you're building.
- Captures your design direction: Specify your color palette, typography, icons, and layout preferences so AI generates UIs that match your vision.
- Documents requirements systematically: Prioritize features using MoSCoW (Must/Should/Could/Won't) while User Stories capture the human context behind each requirement.
- Specifies technical architecture: Define your tech stack, data models, page routes, and component inventory in dedicated sections.
- Empowers AI-assisted decisions: Write "Let AI decide for me" in any section you're unsure about and AI will choose modern, compatible options that fit your stack.
- Serves as living documentation: Keep your spec in version control alongside your code. Update it as your product evolves, fork it for new features.
PLAIN is for Product Managers who want to quickly test whether their ideas actually work, Designers who want to bring creative ideas to life faster, and Developers who want to build great-looking apps without getting lost in design decisions.
It's also for Solo Founders and Small Teams who lack expertise in certain areas and can use "Let AI decide for me!" to get intelligent recommendations. And for AI tools like Claude, Cursor, v0, Bolt, and Lovable that need structured input to generate production-ready code and components.
In short, PLAIN is for anyone who loves to design and code.
Follow these three steps to turn your product idea into a working application.
Download the PLAIN.md and add it to the root level of your project folder. Rename it to {project-name}-plain.md to avoid confusion as your project grows.
Start with the project metadata in the HTML comment at the top (title, description, author, date, etc.). Then review the "Instructions for AI Coding Assistants" section and customize it if needed.
Work through each section from Project Overview to Additional Notes. The template includes examples and explanations for guidance. Once you've filled in your content, delete the examples and explanations to keep your spec clean.
📚 Feeling stuck? If you're experiencing blank page syndrome, finding the technical choices overwhelming, or simply want to explore your options, visit the glossary folder. It contains comprehensive guides for every technical decision—from frameworks to databases—with real-world examples and clear recommendations to help you make informed choices.
Still unsure? For any section where you're uncertain, simply write Let AI decide for me.
Your spec is ready. Feed it to your favorite AI tool with the following command and let it build your application.
Example Prompt:
Read the
{project-name}-plain.mdfile in my project. Start with the "Instructions for AI Coding Assistants" section to understand the core principles, then work through each section from Project Overview to Additional Notes. Generate a complete application that follows every specification precisely.
Bonus Tip: Keep your PLAIN document in version control alongside your code. It serves as living documentation that evolves with your product.
Plainify is a guided web application designed to help you create PLAIN specifications without staring at a blank page. Instead of manually filling out the template from scratch, Plainify provides a structured, section-by-section workflow that shows you relevant options and examples for each part of your specification.
How it works:
- Guided Section-by-Section Interface: Work through each PLAIN section with curated options and examples, eliminating the blank page problem
- Context-Aware Options: See relevant choices for Design Style, Color Palettes, Tech Stack, UI Libraries, and more
- AI-Enhanced Generation: When you click Generate, Claude LLM processes your selections and creates a
{project-name}-plain.mdfile - Intelligent Context Layer: The LLM interprets your choices and adds contextual details that help AI code assistants better understand your requirements
- Ready-to-Use Output: Receive a complete, well-formed PLAIN markdown file ready to be added to your project repository
Plainify bridges the gap between knowing what a PLAIN specification should contain and actually creating one. It's perfect for teams who want to leverage PLAIN without spending hours learning the format's nuances.
AI tools can process various formats like PDF, DOCX, or images, but Markdown stands out as the ideal choice for PLAIN specifications. It's plain text that AI can easily read, parse, and regenerate without special processing. It's also human-readable in any text editor, no special tools required.
More importantly, Markdown files fit naturally into your development workflow. They integrate seamlessly with Git repositories, making it easy to track changes to your specs over time. They're lightweight, portable, and stay in sync with your codebase. In short, Markdown gives you the best of both worlds: effortless human collaboration and seamless AI integration.
Found a way to make PLAIN even plainer? We'd love to hear it! Every great tool starts as a simple idea. PLAIN started as one, and with your help, it'll grow into something even better.
Whether it's a typo fix, a new section idea, or a complete overhaul, we welcome it all. You can also share your filled-out PLAIN files with the community! If you've created a {project-name}-plain.md for your project, submit it with a live demo or design link in it to inspire others.
Read the Contribution Guidelines and join the crew!
This project is licensed under the MIT License. See the LICENSE file for details.