niksi: install, review, and share agent skills

nik lets you install skills from Git repositories and keeps them up to date. Each skill is stored once and symlinked into your favourite agents: Claude Code, Codex, Cursor, Gemini CLI, GitHub Copilot, OpenCode, Windsurf, Amp, Kiro, Cline, Qwen Code, and any agent that reads .agents/skills.

Niksi is the Finnish word for "trick"

What you get

• Install only what you need: nik add owner/repo lists the skills in a repository. Pick the ones you want and which agents can use them.
• Choose a scope: install skills in a specific project or globally.
• See what you are installing: before anything is written, nik lists every file, scans the contents, and tells you if something looks harmful.
• Scan installed skills again: nik audit runs the current rules over the skills on disk, offline. Run it after you upgrade niksi.
• Keep skills up to date: nik update fetches each source and shows you the diff. Approve it, or keep what you have.
• Pin what should never change: nik add owner/repo@v1.2.0. Everything else follows the latest stable tag, or the default branch.
• Share skills with your team: commit niksi-lock.json. It records the source, the commit, and a sha256 of the files. Your teammates get the exact files you reviewed by running nik install.
• Pull in dependencies: when a skill mentions another skill from the same source, nik offers to add it in the same run.
• Use it in CI: nik install --yes runs without a terminal and exits 0 only when every enabled skill is on disk with its recorded integrity.
• No account, no registry, no telemetry.

Install

The binary name for niksi is nik.

Try it without installing:

npx niksi add owner/repo

Install with npm:

npm install -g niksi

Or with Homebrew, on macOS or Linux:

brew install osrim/tap/niksi

Or download a binary from the latest release and put it on your PATH.

Requirements

• macOS or Linux. There is no Windows build yet.
• Git 2.30 or later on your PATH.

Quick start

Add one skill from a repository:

nik add mattpocock/skills tdd

The skill mentions another skill in the same source, so nik offers to install that one as well. Both are now recorded in niksi-lock.json:

$ nik list -g
◇  Installed skills (~/.config/niksi/niksi-lock.json)
│
│  mattpocock/skills
│    codebase-design  v1.2.3  universal, claude, kiro
│    tdd              v1.2.3  universal, claude, kiro
│
└  2 skill(s) installed (global).

Later, check the source for changes. nik fetches, compares, and shows you the diff. Approve it or leave things as they are:

nik update

Working on a team? Install skills in your projects and commit niksi-lock.json. Your teammates get the same skills with one command:

nik install

install checks every file against the sha256 in the lockfile.

Commands

command	what it does
nik add <coordinate> [skills]	Fetch a source, pick skills, review and scan them, write the lockfile.
nik install	Restore every enabled skill in niksi-lock.json.
nik update [skills]	Compare installed skills with upstream and review the diff.
nik remove [skills]	Remove installed skills and their lockfile entries.
nik list	Show installed skills. --json for scripts.
nik audit	Scan installed skills with the current rules.
nik disable, nik enable	Disable and enable recorded skills. No new review.
nik prune	Delete unrecorded store entries.

A coordinate is owner/repo, owner/repo/path/to/skill, owner/repo@v1.2.0 to pin a ref, a forge URL, a Git URL, or a local directory. See docs/commands.md for more information.

The scan

add and update scan each file before writing it. The rules catch curl piped to a shell, known exfiltration hosts, hooks in SKILL.md frontmatter, commands that run at load time, invisible Unicode, and reads of ~/.ssh and ~/.aws. Findings are info, warn, or critical. A critical finding stops the install until you approve it in a terminal. nik audit scans installed skills again with the current rules.

Important

niksi runs static checks. It does not run the skill, follow URLs, or understand intent. A malicious skill can pass clean and a good one can have false positives. Read more in docs/security-scan.md.

What niksi does not do

• No registry, catalogue, or search.
• No skill authoring or evaluation.
• No sync of MCP servers, rules, or hooks.
• No telemetry.

Compared with other installers

Checked against each tool's documentation on 2026-09-19.

	niksi	npx skills	gh skill
lockfile	niksi-lock.json in the project	in the home directory	none, provenance in SKILL.md frontmatter
content integrity	sha256 of the files, checked on install	tree SHA, for update detection	tree SHA, for update detection
pre-install scan	local, offline, gates the write	third-party web audits on skills.sh	none
restore from lockfile	nik install	none	none
telemetry	none	on by default	none
search	none	find	search

Docs

• Commands: every command, flag, and exit code, plus non-interactive use.
• Configuration: scope, agents, paths, environment variables, and the lockfile.
• Security scan: what the scan catches and what it cannot.

Contributing

See CONTRIBUTING.md. Bug reports from Linux and from agents other than Claude Code help most right now.

Reporting a vulnerability

Use GitHub private vulnerability reporting, not a public issue. Details in SECURITY.md.

License

MIT