Skip to content
Get packs

OpenSpec

Plain-text specs that your AI coding assistant and you agree on before any code is written.

GitHub Download v1.16.0
Stars
73.7k
Forks
5k
Licence
MIT
Language
TypeScript
Last update
4 days ago
Type
Dev tool

What it is

OpenSpec is a command-line tool that adds a lightweight specification layer to AI coding assistants. Before the assistant writes code, you and the AI create a proposal, requirement specs, a design, and a task list in an openspec/ folder inside your project. You review that plan, then the AI implements it and archives the change when done.

  • Turn a rough idea into a proposal, specs, design and tasks with /opsx:explore and /opsx:propose
  • Have an AI apply a checklist of implementation tasks step by step with /opsx:apply
  • Archive a finished change so its specs update the project's current specs with /opsx:archive
  • Keep requirements as readable Markdown files with concrete WHEN/THEN scenarios in the repo

Great for

  • Developers who use AI coding assistants and want to agree on requirements before code is written
  • Teams working on existing (brownfield) codebases, which the README names as a design goal
  • Solo developers who want their AI to stay on a defined plan within one repo
  • Teams that want to share specs across several repositories (Stores, in beta)

Not ideal for

  • People who want a rigid, phase-gated process: the README positions OpenSpec as fluid and iterative, not waterfall
  • Projects that do not use an AI coding assistant, since the workflow is built around slash commands in those tools
  • Anyone needing a stable cross-repo feature, because Stores are described as beta
Step-by-step guide: how to use OpenSpecInstall, first run, examples, tips and FAQs
OpenSpec vs Spec KitOpenSpec vs planning-with-files

How to get it

  1. 1

    Install with a package manager

    You'll need: Node.js 20.19.0 or higher (only if using the npm install route) · On Alpine Linux: libstdc++ and libgcc packages for the binary install

    Install with npm (requires Node.js 20.19.0+)

    npm install -g @fission-ai/openspec@latest

    Install with Homebrew

    brew install openspec

    Initialize in your project

    cd your-project && openspec init
  2. 2

    Run it

    • Install the CLI using one of the methods in the README
    • Run openspec init inside your project directory
    • In your AI assistant, run /opsx:explore if you are unsure what to build, or /opsx:propose <name> if you know
    • Review the generated proposal, specs, design and tasks, then run /opsx:apply
  3. 3

    Get the most out of it

    • Use /opsx:explore first to shape a plan before proposing code changes
    • Select the expanded workflow with openspec config profile, then apply it with openspec update, to get commands like /opsx:verify and /opsx:bulk-archive
    • Read the project customization docs for profiles, project config and schemas
    • Check the community schemas catalog for third-party workflow bundles

Downloads

Source code (.zip)main branch · straight from GitHubRelease v1.16.08 files incl. openspec-darwin-x64.tar.gzOfficial website & docsopenspec.dev/

Strengths

  • Plain Markdown specs with no special syntax to learn
  • Works with 30+ AI assistants via slash commands, according to the README
  • Ships as a single binary install that the README says needs no Node.js

Trade-offs

  • Stores, the cross-repo feature, are labeled beta in the README
  • Slash command names vary by tool (for example /opsx-propose in Cursor and GitHub Copilot), which adds some setup confusion
  • Value depends on your AI assistant following the spec files reliably, which the README does not measure

How it compares

ProjectStarsTypeLevelUpdatedBest for
OpenSpec (this)73.7kDev toolbeginner4 days agoDevelopers who use AI coding assistants and want to agree on requirements before code is written
spec-kit145kDev toolintermediate6 days agoDevelopers who use an AI coding agent and want more predictable results from it
get-shit-done64.2kDev toolintermediate5 months agoDevelopers who already use Claude Code and want to find the current GSD project
planning-with-files27.8kDev toolbeginner6 days agoDevelopers running long multi-step tasks in Claude Code or Codex CLI
gsd-core11.1kFrameworkintermediate4 days agoDevelopers already using Claude Code, Codex, Cursor, or another supported AI coding runtime
Trail-Code11kDev toolbeginner4 days agoDevelopers who use Claude Code, Cursor, Codex or similar agents on a medium or large repository

Stats synced from GitHub. The assessment above was drafted with AI from the project's README on 2026-10-29 and may miss recent changes — check the README before relying on a command. MIT licence: free to use, modify and distribute, including commercially, as long as you keep the copyright notice.