OpenSpec: Make AI Coding Assistants Follow a Spec, Not Just Guess

Originally published at recca0120.github.io The most common problem with AI coding assistants isn't that they can't write code — it's that they write something different from what you had in mind. You say "add dark mode" and it rewrites CSS variables, adds a toggle button, and refactors the layout — when all you wanted was to change color tokens. Next conversation, context is gone, and it guesses your intent from scratch. OpenSpec solves this: before AI starts writing code, it produces a spec document. Both sides align on "what to do" and "how to do it", then implement according to the spec. Core Concept OpenSpec is a Spec-Driven Development (SDD) framework: Propose — Describe what you want to change, AI produces proposal, specs, design, tasks Apply — AI implements step by step following the task checklist Archive — Archive completed changes with a record Spec files live in your codebase, managed with Git. Context doesn't disappear between conversations. Install Requires Node.js 20.19.