Per the official site openspec.cn: 68.7k GitHub stars, MIT license, currently v1.13.0, with a new spec created roughly every 2 seconds. Works with Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, OpenCode and more.
Fill in two fields and get four OpenSpec files you can paste straight into your project.
This is a scaffold generator — it calls no AI and uploads nothing; everything runs in your browser.
Hand the output to your agent with /opsx:apply.
If you don't write down what you want, the agent guesses. Wrong guesses mean churned code and manual rollbacks.
An open spec keeps the "why we built it this way" record, so the code still makes sense three months later.
The last step of the OpenSpec workflow is /opsx:verify, which checks the implementation against the spec — not just whether tests pass.
/opsx:explore — understand the problem and the existing code before writing anything/opsx:propose — draft proposal.md, specs/, design.md and tasks.md/opsx:apply — let the agent implement the tasks/opsx:verify — check that the implementation matches the spec/opsx:archive — archive the finished changenpm install -g @fission-ai/openspec@latestOpenSpec is a lightweight, configurable open spec framework for AI coding agents. It adds a spec layer above your code: you describe what should change first, the agent implements against that description, and you verify the result before archiving the change.
People search for both spellings. "Open spec" describes the idea — a specification kept in the open, next to the code, that both humans and agents can read. OpenSpec is the open-source tool that implements that idea, maintained by Fission-AI under the MIT license.
Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI and OpenCode are supported, plus more — the official site openspec.cn lists the full set.
No. The generator runs entirely in your browser. It calls no AI model and uploads nothing — it only fills in a text template you can copy or download.
No, this page works on its own. You only install OpenSpec itself if you want to run the full workflow in your own project: npm install -g @fission-ai/openspec@latest.