- Node.js 20.19.0 or higher — Check your version:
node --version
npm install -g @fission-ai/openspec@latestpnpm add -g @fission-ai/openspec@latestyarn global add @fission-ai/openspec@latestBun can install OpenSpec globally, but OpenSpec currently runs on Node.js.
You still need Node.js 20.19.0 or higher available on PATH.
bun add -g @fission-ai/openspec@latestRun OpenSpec directly without installation:
nix run github:Fission-AI/OpenSpec -- initOr install to your profile:
nix profile install github:Fission-AI/OpenSpecOr add to your development environment in flake.nix:
{
inputs = {
nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
openspec.url = "github:Fission-AI/OpenSpec";
};
outputs = { nixpkgs, openspec, ... }: {
devShells.x86_64-linux.default = nixpkgs.legacyPackages.x86_64-linux.mkShell {
buildInputs = [ openspec.packages.x86_64-linux.default ];
};
};
}openspec --versionUpgrade the package, then refresh each project's generated files:
npm install -g @fission-ai/openspec@latest # or pnpm/yarn/bun equivalent
openspec update # run inside each projectopenspec update regenerates the skill and command files for the tools you've configured, so your slash commands stay current with the installed version.
There's no openspec uninstall command, because OpenSpec is just a global package plus some files in your project. Removing it is a few manual steps, and nothing here touches your source code.
1. Remove the global package:
npm uninstall -g @fission-ai/openspec # or: pnpm rm -g / yarn global remove / bun rm -g2. Remove OpenSpec from a project (optional). Delete the openspec/ directory if you no longer want its specs and changes:
rm -rf openspec/Think before you do this: openspec/specs/ and openspec/changes/archive/ are your record of how the system behaves and why it changed. If you might want that history, keep the folder (or keep it in git) even after uninstalling.
3. Remove generated AI tool files (optional). OpenSpec writes skill and command files into per-tool directories like .claude/skills/openspec-*/, .cursor/commands/opsx-*, and so on. Delete the openspec-* skills and opsx-* commands for whichever tools you configured. The exact paths per tool are listed in Supported Tools.
If you also have OpenSpec marker blocks in files like CLAUDE.md or AGENTS.md, remove those blocks by hand; your own content in those files is yours to keep.
After installing, initialize OpenSpec in your project:
cd your-project
openspec initSee Getting Started for a full walkthrough.