Agent skill

Nix

Nix flakes, nix-darwin, NixOS, and home-manager development assistance

No licenceAuto-check: notes

Install Nix

skills CLI

$ npx skills add r17x/universe --skill nix -a claude-code

Project install by default; add -g for ~/.claude/skills/.

GitHub CLI

$ gh skill install r17x/universe nix --agent claude-code

Project scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).

Manual copy

$ git clone --depth 1 https://github.com/r17x/universe.git skills-src && mkdir -p .claude/skills && cp -r skills-src/.claude/skills/nix .claude/skills/nix && rm -rf skills-src

Use ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.

Claude Code skills documentation · loads skills from .claude/skills/

Paste into Claude Code

Install the "nix" agent skill from https://github.com/r17x/universe/tree/main/.claude/skills/nix into .claude/skills/nix/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "nix", then confirm the skill loads.

Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

$skill-installer

$skill-installer install https://github.com/r17x/universe/tree/main/.claude/skills/nix

Type this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.

skills CLI

$ npx skills add r17x/universe --skill nix -a codex

Project install goes to .agents/skills/; add -g for ~/.codex/skills/.

GitHub CLI

$ gh skill install r17x/universe nix --agent codex

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/r17x/universe.git skills-src && mkdir -p .agents/skills && cp -r skills-src/.claude/skills/nix .agents/skills/nix && rm -rf skills-src

Use ~/.agents/skills/ instead of .agents/skills for a personal install.

Codex skills documentation · loads skills from .agents/skills/

Paste into Codex

Install the "nix" agent skill from https://github.com/r17x/universe/tree/main/.claude/skills/nix into .agents/skills/nix/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "nix", then confirm the skill loads.

Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

skills CLI

$ npx skills add r17x/universe --skill nix -a cursor

Project install goes to .agents/skills/; add -g for ~/.cursor/skills/.

GitHub CLI

$ gh skill install r17x/universe nix --agent cursor

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/r17x/universe.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/.claude/skills/nix .cursor/skills/nix && rm -rf skills-src

Use ~/.cursor/skills/ instead of .cursor/skills for a personal install.

Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/

Paste into Cursor

Install the "nix" agent skill from https://github.com/r17x/universe/tree/main/.claude/skills/nix into .cursor/skills/nix/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "nix", then confirm the skill loads.

Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

gemini skills install

$ gemini skills install https://github.com/r17x/universe.git --path .claude/skills/nix

--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.

skills CLI

$ npx skills add r17x/universe --skill nix -a gemini-cli

Project install goes to .agents/skills/; add -g for ~/.gemini/skills/.

GitHub CLI

$ gh skill install r17x/universe nix --agent gemini-cli

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/r17x/universe.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/.claude/skills/nix .gemini/skills/nix && rm -rf skills-src

Use ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.

Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/

Paste into Gemini CLI

Install the "nix" agent skill from https://github.com/r17x/universe/tree/main/.claude/skills/nix into .gemini/skills/nix/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "nix", then confirm the skill loads.

Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

GitHub CLI

$ gh skill install r17x/universe nix

Installs for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).

skills CLI

$ npx skills add r17x/universe --skill nix -a github-copilot

Project install goes to .agents/skills/; add -g for ~/.copilot/skills/.

Manual copy

$ git clone --depth 1 https://github.com/r17x/universe.git skills-src && mkdir -p .github/skills && cp -r skills-src/.claude/skills/nix .github/skills/nix && rm -rf skills-src

Use ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.

GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/

Paste into GitHub Copilot

Install the "nix" agent skill from https://github.com/r17x/universe/tree/main/.claude/skills/nix into .github/skills/nix/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "nix", then confirm the skill loads.

GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

skills CLI

$ npx skills add r17x/universe --skill nix -a opencode

OpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.

GitHub CLI

$ gh skill install r17x/universe nix --agent opencode

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/r17x/universe.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/.claude/skills/nix .opencode/skills/nix && rm -rf skills-src

Use ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.

OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/

Paste into OpenCode

Install the "nix" agent skill from https://github.com/r17x/universe/tree/main/.claude/skills/nix into .opencode/skills/nix/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "nix", then confirm the skill loads.

OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

Facts

Skill name: nix
GitHub stars: 151
Token cost: ~829 tokens
SKILL.md length: 95 words
Files: 1
Skills in repo: 5
Repo updated: Oct 4, 2026
First seen: Oct 7, 2026
Licence: None found

At a glance

Nix flakes, nix-darwin, NixOS, and home-manager development assistance

SKILL.md covers Evaluation & Debugging, Building & Rebuilding, Service Management… and Launchd Configuration Options, plus 3 more sections
Calls nix

What it does

Nix is an agent skill from r17x/universe. Nix flakes, nix-darwin, NixOS, and home-manager development assistance

Its SKILL.md is about 830 tokens, which your agent loads only when the skill is triggered. It is a single SKILL.md file with no bundled scripts.

It works with Linux. The repository describes itself as: let universe speak itself ❄️ ƛ.

Example prompts

“/nix”

Requirements

Pre-approved tools (allowed-tools): Bash, Read, Grep, Glob, Edit, Write

What it can do on your machine

Read from SKILL.md and the folder at commit 489dbda. It shows what the files ask for, not the result of running them.

Tool permissions
Pre-approves these tools, so the agent can use them without asking each time:
- Bash
- Read
- Grep
- Glob
- Edit
- Write
From allowed-tools in the SKILL.md frontmatter.
Runs code
Shell commands in SKILL.md call:
- nix
From the folder's file list and the shell code blocks in SKILL.md.
Network
No URLs in SKILL.md.
From URLs in SKILL.md, links to its own repository left out.
Credentials
Names no API keys, tokens, secrets or passwords.
From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Nix loads about 829 tokens when it runs. Until then it costs about 19 tokens; SKILL.md has 95 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it: ~19
When it runs · the whole SKILL.md, loaded when a task matches: ~829

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Auto-check: notes

The automated check noted patterns worth knowing about, such as sudo or a known installer.

NoteRuns commands with sudoSKILL.md:58

sudo nixos-rebuild switch --flake .#<hostname>

NoteRuns commands with sudoSKILL.md:59

sudo nixos-rebuild boot --flake .#<hostname>

NotePre-approves every shell command (allowed-tools: Bash)SKILL.md
```
allowed-tools: Bash, Read, Grep, Glob, Edit, Write
```

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

Without a licence we can't republish the file, so here is its outline and opening line. It has 95 words (~829 tokens).

“For reducing CPU/IO priority in nix-darwin:”

— opening of SKILL.md by r17x

name: nix
allowed-tools: Bash, Read, Grep, Glob, Edit, Write

Read the full SKILL.md on GitHub

Files

Just SKILL.md in .claude/skills/nix of r17x/universe.

Open the folder on GitHubat commit 489dbda

Compare with similar skills

Nix next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.

Nix compared with similar skills
Skill	Stars	Used in	Tokens	Auto-check	Licence	Repo updated
Nix this skillr17x/universe	151	—	~829	Automated safety check: Notes	None	4 days ago
Configuring Horizoncoollabsio/coolify	63k	4 repos	~898	Automated safety check: Pass	MIT	yesterday
Engine Whats Newflutter/flutter	179k	—	~978	Automated safety check: Pass	BSD-3-Clause	today
Openclaw Live Updateropenclaw/openclaw	392k	—	~3.7k	Automated safety check: Pass	MIT	today
Upgrade Browserflutter/flutter	179k	—	~1.1k	Automated safety check: Pass	BSD-3-Clause	today
K8s Security PoliciesCybereason-Public/owLSM	280	12 repos	~2k	Automated safety check: Pass	GPL-2.0	yesterday

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Questions about Nix

What does Nix do?

Nix flakes, nix-darwin, NixOS, and home-manager development assistance. Nix is an agent skill from r17x/universe.

How do I install Nix in Claude Code?

Run `npx skills add r17x/universe --skill nix -a claude-code`. Or copy the skill folder (.claude/skills/nix in r17x/universe) into .claude/skills/nix in your project. Claude Code loads it when a task matches its description.

How do I install Nix in Codex?

Run `npx skills add r17x/universe --skill nix -a codex`. Or copy the skill folder (.claude/skills/nix in r17x/universe) into .agents/skills/nix in your project. Codex loads it when a task matches its description.

Can I use Nix in Cursor, Gemini CLI or GitHub Copilot?

Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add r17x/universe --skill nix -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/nix, .gemini/skills/nix, .github/skills/nix and .opencode/skills/nix in your project.

What does Nix need to run?

Going by SKILL.md and its folder, Nix needs the command-line tools its instructions call (nix). Its frontmatter pre-approves these tools: Bash, Read, Grep, Glob, Edit, Write.

Does Nix access the network?

SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.

Is Nix safe to install?

Our automated static check of SKILL.md found notes only (runs commands with sudo; pre-approves every shell command (allowed-tools: bash)), nothing it rates as a warning. It is not a guarantee. Review the folder before installing.

What licence does Nix use?

No licence was found for Nix or its repository. Without one, default copyright applies: ask the author before reusing or redistributing it.

How many tokens does Nix use?

About 829 tokens (SKILL.md is roughly 3.3k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.

What are the alternatives to Nix?

Skills that share tags, products or a category with Nix: Configuring Horizon (coollabsio/coolify, 63k stars), Engine Whats New (flutter/flutter, 179k stars), Openclaw Live Updater (openclaw/openclaw, 392k stars) and Upgrade Browser (flutter/flutter, 179k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Nix?

r17x (a GitHub user) maintains it in r17x/universe, which has 151 GitHub stars. The repository holds 5 skills in this directory. The repository was last updated on October 4, 2026.

Source: r17x/universe on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.

Nix

Install Nix

Facts

At a glance

What it does

Example prompts

Requirements

What it can do on your machine

Tool permissions

Runs code

Network

Credentials

Context cost

Safety

SKILL.md

Files

Compare with similar skills

Similar skills

Configuring Horizon

Engine Whats New

Openclaw Live Updater

Upgrade Browser

K8s Security Policies

Apple Container Test Runner

More from r17x/universe

Nix Debug

Nix Flake

Nix Module

Nix Service

Questions about Nix

Install Nix

Facts

At a glance

What it does

Example prompts

Requirements

What it can do on your machine

Tool permissions

Runs code

Network

Credentials

Context cost

Safety

SKILL.md

Files

Compare with similar skills

Similar skills

More from r17x/universe

Related

Questions about Nix