OpenSpec

Spec-driven development for AI coding assistants.

OpenSpec aligns humans and AI coding assistants through a lightweight specification workflow. By agreeing on what to build before any code is written, OpenSpec ensures that intent is locked in, scope is explicit, and implementation is deterministic.

Why OpenSpec?

AI coding assistants are powerful but can be unpredictable when requirements are buried in chat history. OpenSpec introduces a structured lifecycle for changes:

1. Propose: Humans and AI agree on specs (requirements and scenarios).
2. Implement: Code is written against the approved specs.
3. Archive: Changes are merged into the living documentation (Source of Truth).

Key Features

• Lightweight: No API keys required. Works with the tools you already use.
• Source-Driven: Specs live in your repository as Markdown files.
• Brownfield-First: Designed to manage changes to existing systems, not just start from scratch.
• AI-Native: Includes configuration and prompts optimized for Claude Code, Cursor, Windsurf, and more.
• Explicit State: Separates the Current Truth (specs/) from Proposed Changes (changes/).