What it is
A command-line tool that sets up a Markdown-based spec workflow inside your repo, adding slash commands so an AI coding assistant can explore ideas, write proposals, requirements, designs, and task lists, then implement and archive each change. Specs live in an openspec/ folder alongside the code, and shared stores let a team keep plans in a separate repo that spans several codebases. Developers using Claude Code, Cursor, Copilot, Codex, and more than 30 other tools rely on it to agree on and check the plan first, so coding starts only after review.