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.

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 CLI is available (installed before going offline, or an npm mirror is reachable): 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.

To pack a local folder, use the skill-packer CLI directly: npx skill-packer pack ./my-skill. It works fully offline.

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). Malicious or malformed skills get filtered out before you download anything. Skill Packer collects no telemetry and sends credentials only to github.com.

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.