A .skill file is a ZIP archive containing everything a skill needs: the SKILL.md file plus its scripts and assets. Skill Packer turns GitHub skills into these portable files. You can copy it to another machine, archive it, or hand it to a teammate. Install it with npx skill-packer add my-skill.skill; no network access required. Since a .skill is a standard ZIP, any zip tool can open and manage it, which helps with manual archiving.

skill-packer is the open-source CLI behind this website (MIT licensed, on GitHub). No install needed — run it with npx:

Pack skills into .skill files

• npx skill-packer pack ./my-skill — pack a local directory
• npx skill-packer pack anthropics/skills -s skill-creator — pack one skill from a GitHub repo
• npx skill-packer pack https://github.com/anthropics/skills --all — pack every skill in a repo
• npx skill-packer pack ./my-skill -o ./dist -f — choose the output directory and overwrite

Sources can be local paths, owner/repo shorthand, or any GitHub, GitLab, or generic Git URL. Without --skill or --all it lists the discovered skills and asks for confirmation.

Install a .skill file (add, aliases: install, unpack)

• npx skill-packer add ./my-skill.skill — install to ./.agents/skills (project scope)
• npx skill-packer add ./my-skill.skill --global — install to ~/.agents/skills
• npx skill-packer add my-skill — bare name: resolved from the current directory, then from $SKILL_PACKER_REPO_DIR

Discover and validate

• npx skill-packer list vercel-labs/agent-skills — list skills in a repo or directory
• npx skill-packer check ./my-skill --strict — validate a skill against the format rules

Packing needs internet: the server clones the skill's repository from GitHub to build the .skill file. Installing does not. Download .skill files on a machine with internet access and copy them to the offline machine (USB drive, internal network, any medium). Then install one of these ways:

• If the NPMJS is available: run npx skill-packer install my-skill.skill --global; it installs to ~/.agents/skills. Run it inside a project to install to ./.agents/skills.
• If not, use any zip tool: .skill is a standard ZIP. The one-click copy command on the download page, unzip my-skill.skill -d ~/.agents/skills/, works wherever unzip exists. GUI archive managers work too; no CLI needed.

npx skills installs directly from a live repository and needs network access to pull the current state. Skill Packer produces a standalone .skill file you can carry, archive, and install anywhere, including machines without internet. It is a packaging tool, the skill equivalent of a .deb or .gem package; npx skills is a live installer.

Skill Packer accepts repositories up to 100 MB. Each packing job times out after 5 minutes, and you can queue up to 10 jobs at a time. Downloaded files are tied to your browser session; finish downloads before closing the tab.

Skill Packer validates every skill before packing: it checks archives for path traversal, requires a root SKILL.md, and enforces size limits on actual decompressed bytes (zip-bomb protection). Skill Packer is open-source software, and its source code is available on GitHub.

Any tool that follows the SKILL.md convention: Claude Code, OpenCode, Cursor, and other agents that read skills from .agents/skills-style directories. The format follows the community standard from agentskills.io. The skill-packer CLI installs into 28+ agent directories automatically.