fission-ai/openspec

OpenSpec is a tool that brings structured planning to AI-assisted coding by introducing a lightweight specification layer between "having an idea" and "writing code." The core problem it addresses is that AI coding assistants, like Claude Code, GitHub Copilot, or Cursor, tend to produce unpredictable or poorly scoped results when given vague instructions in chat. OpenSpec makes you and your AI agree on what to build before any code is written. The workflow works through slash commands. You describe a feature by typing something like /opsx:propose add-dark-mode and the AI creates a folder for that change containing a set of structured files: a proposal explaining the rationale, a specifications file defining requirements and edge cases, a design document covering the technical approach, and a tasks checklist breaking down the implementation steps. Only after this planning structure exists do you invoke /opsx:apply to have the AI work through the implementation tasks in order, ticking them off one by one. When the feature is done, /opsx:archive moves the folder into a dated archive so the project history remains readable. This approach gives you predictability without ceremony. If requirements evolve mid-feature, you can update the spec files at any time, there are no rigid phase gates that block progress. The tool is designed to work with existing projects (not just new ones from scratch) and supports over 20 AI assistants and editors via the slash command mechanism. A developer would use OpenSpec when building non-trivial features with AI assistance and finding that the AI keeps going off in wrong directions, missing scope, or needing to be re-briefed repeatedly. It essentially turns informal chat conversations into structured collaborative planning documents. The tech stack is TypeScript and Node.js, distributed as an npm package via the CLI.