OpenSpec

OpenSpec is an open-source framework for spec-driven development (SDD) with AI coding assistants. Instead of asking an agent to “just build it” and hoping for the best, OpenSpec has you agree on a written specification first — then lets the AI implement against it. The project has earned more than 72,000 stars on GitHub and is actively developed, with its latest updates in 2026.

Overview

The workflow is deliberately lightweight. You describe a change, and OpenSpec generates a proposal with requirements, scenarios and a task list in plain markdown files inside your repository. You review and edit those specs like any other code, then ask your coding assistant to work through the tasks. When the change ships, the specs are archived as living documentation of what the system does and why. Because everything lives in the repo as files, specs survive across tools, teammates and model generations — no proprietary platform required.

Key Features

• Spec-first workflow: proposal, requirements, scenarios and tasks
• Plain markdown artifacts stored in your repository, fully versioned
• Works with popular AI coding assistants through a simple CLI
• Change folders keep related specs and tasks organized together
• Archive flow turns completed changes into durable documentation
• No lock-in: specs remain useful even without the tooling

💳 Pricing

OpenSpec is free and open source under the MIT license. Install the CLI, run it in any repository and use it with the AI coding assistant and model you already pay for — OpenSpec itself charges nothing.

Who Is It For

OpenSpec is for developers and teams who use AI coding agents daily and want fewer surprises: clearer intent up front, reviewable plans, and a written record of what was built that outlives any single chat session. It is especially valuable on brownfield projects, where an agent misunderstanding the existing system is the most expensive failure mode.