Agent skill

CLI

Headless CLI mode for NullPlayer. An agent skill from ad-repo/nullplayer.

Custom licenceAuto-check passed

Install CLI

skills CLI

$ npx skills add ad-repo/nullplayer --skill cli -a claude-code

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

GitHub CLI

$ gh skill install ad-repo/nullplayer cli --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/ad-repo/nullplayer.git skills-src && mkdir -p .claude/skills && cp -r skills-src/skills/cli .claude/skills/cli && 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 "cli" agent skill from https://github.com/ad-repo/nullplayer/tree/main/skills/cli into .claude/skills/cli/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "cli", 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/ad-repo/nullplayer/tree/main/skills/cli

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 ad-repo/nullplayer --skill cli -a codex

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

GitHub CLI

$ gh skill install ad-repo/nullplayer cli --agent codex

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

Manual copy

$ git clone --depth 1 https://github.com/ad-repo/nullplayer.git skills-src && mkdir -p .agents/skills && cp -r skills-src/skills/cli .agents/skills/cli && 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 "cli" agent skill from https://github.com/ad-repo/nullplayer/tree/main/skills/cli into .agents/skills/cli/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "cli", 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 ad-repo/nullplayer --skill cli -a cursor

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

GitHub CLI

$ gh skill install ad-repo/nullplayer cli --agent cursor

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

Manual copy

$ git clone --depth 1 https://github.com/ad-repo/nullplayer.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/skills/cli .cursor/skills/cli && 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 "cli" agent skill from https://github.com/ad-repo/nullplayer/tree/main/skills/cli into .cursor/skills/cli/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "cli", 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/ad-repo/nullplayer.git --path skills/cli

--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 ad-repo/nullplayer --skill cli -a gemini-cli

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

GitHub CLI

$ gh skill install ad-repo/nullplayer cli --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/ad-repo/nullplayer.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/skills/cli .gemini/skills/cli && 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 "cli" agent skill from https://github.com/ad-repo/nullplayer/tree/main/skills/cli into .gemini/skills/cli/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "cli", 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 ad-repo/nullplayer cli

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 ad-repo/nullplayer --skill cli -a github-copilot

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

Manual copy

$ git clone --depth 1 https://github.com/ad-repo/nullplayer.git skills-src && mkdir -p .github/skills && cp -r skills-src/skills/cli .github/skills/cli && 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 "cli" agent skill from https://github.com/ad-repo/nullplayer/tree/main/skills/cli into .github/skills/cli/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "cli", 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 ad-repo/nullplayer --skill cli -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 ad-repo/nullplayer cli --agent opencode

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

Manual copy

$ git clone --depth 1 https://github.com/ad-repo/nullplayer.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/skills/cli .opencode/skills/cli && 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 "cli" agent skill from https://github.com/ad-repo/nullplayer/tree/main/skills/cli into .opencode/skills/cli/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "cli", 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: cli
GitHub stars: 157
Token cost: ~8k tokens
SKILL.md length: 3,393 words
Files: 1
Skills in repo: 39
Repo updated: Oct 8, 2026
First seen: Oct 7, 2026
Licence: Custom licence

At a glance

Headless CLI mode for NullPlayer. An agent skill from ad-repo/nullplayer.

Works in 2 steps: Source selection → Playback routing
Working on CLI features
SKILL.md covers Positioning, Launching, Automation Use Cases and Architecture, plus 18 more sections
Calls swift

What it does

CLI is an agent skill from ad-repo/nullplayer. Headless CLI mode for NullPlayer. Use when working on CLI features, arguments, playback control, query commands, source resolution, or terminal display. Covers architecture, all flags, keyboard controls, and source APIs.

Its SKILL.md is about 8k tokens, which your agent loads only when the skill is triggered. It is a single SKILL.md file with no bundled scripts.

The repository describes itself as: nullPlayer is a free open source macOS media player with some unique features.

When your agent uses it

Working on CLI features
Playback control
Source resolution
Terminal display

Example prompts

“/cli”

Workflow steps

2 steps, taken from the first numbered list in SKILL.md.

Source selection
Playback routing

What it can do on your machine

Read from SKILL.md and the folder at commit 9281472. It shows what the files ask for, not the result of running them.

Tool permissions
Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.
From allowed-tools in the SKILL.md frontmatter.
Runs code
Shell commands in SKILL.md call:
- swift
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

CLI loads about 8k tokens when it runs. Until then it costs about 56 tokens; SKILL.md has 3,393 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it: ~56
When it runs · the whole SKILL.md, loaded when a task matches: ~8k

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 passed

The automated check found no risky patterns in SKILL.md.

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

Its licence (Custom licence) doesn't allow us to republish the file, so here is its outline and opening line. It has 3,393 words (~7,979 tokens).

“NullPlayer supports a --cli flag that launches a headless mode for browsing, searching, playing, and routing media from all configured sources via the terminal. Treat this as a first-class command surface, not a debug-only mode. The process stays alive during…”

— opening of SKILL.md by ad-repo, Custom licence

name: cli

Outline of SKILL.md

NullPlayer CLI Mode
Positioning
Launching
Automation Use Cases
Architecture
New Files (Sources/NullPlayer/CLI/)
Modified Files
Arguments
Boolean Flags
Query Commands (print and exit)
String/Int Parameters
Multi-Source / Multi-Output Framing
Query vs Control Behavior
--library Flag
Implicit music-library selection (Plex, Jellyfin, Emby)
Radio Modes (--radio )
RadioFolderKind Mapping
Keyboard Controls (during playback)
Thread Safety
Album Art Rendering
Log Suppression
Casting Keep-Alive
Exit Codes
AudioEngine.isHeadless Pattern
resolvedAudioEngine Pattern
currentMetadataTitle
Connection State Checks
LibraryFilter Usage
Testing
Test Files

Read the full SKILL.md on GitHub

Files

Just SKILL.md in skills/cli of ad-repo/nullplayer.

Open the folder on GitHubat commit 9281472

Compare with similar skills

CLI 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.

CLI compared with similar skills
Skill	Stars	Used in	Tokens	Auto-check	Licence	Repo updated
CLI this skillad-repo/nullplayer	157	—	~8k	Automated safety check: Pass	Custom licence	today
Review Arguments Dslruby-git/ruby-git	1.8k	—	~2.9k	Automated safety check: Pass	MIT	6 days ago
Jetson Headless ModeNVIDIA/skills	3.5k	1 repos	~1.9k	Automated safety check: Pass	Apache-2.0	today
Shopify Storefront Headlessjeremylongshore/tons-of-skills-marketplace	2.8k	—	~1.3k	Automated safety check: Pass	MIT	today
Matlab Validate Function Argumentsmatlab/matlab-agentic-toolkit	1.1k	—	~5.6k	Automated safety check: Pass	Custom licence	today
Oral Argumentlawve-ai/awesome-legal-skills	836	1 repos	~2.2k	Automated safety check: Pass	Custom licence	5 days ago

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Questions about CLI

What does CLI do?

Headless CLI mode for NullPlayer. An agent skill from ad-repo/nullplayer. CLI is an agent skill from ad-repo/nullplayer. Headless CLI mode for NullPlayer.

When should I use CLI?

CLI fits situations like: working on CLI features; playback control; source resolution; terminal display.

How do I install CLI in Claude Code?

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

How do I install CLI in Codex?

Run `npx skills add ad-repo/nullplayer --skill cli -a codex`. Or copy the skill folder (skills/cli in ad-repo/nullplayer) into .agents/skills/cli in your project. Codex loads it when a task matches its description.

Can I use CLI 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 ad-repo/nullplayer --skill cli -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/cli, .gemini/skills/cli, .github/skills/cli and .opencode/skills/cli in your project.

What does CLI need to run?

Going by SKILL.md and its folder, CLI needs the command-line tools its instructions call (swift).

Does CLI 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 CLI safe to install?

Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.

What licence does CLI use?

CLI has a licence file (the repository's licence) that doesn't match a standard licence. Read it on GitHub before reusing the skill.

How many tokens does CLI use?

About 8k tokens (SKILL.md is roughly 32k 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 CLI?

Skills that share tags, products or a category with CLI: Review Arguments Dsl (ruby-git/ruby-git, 1.8k stars), Jetson Headless Mode (NVIDIA/skills, 3.5k stars), Shopify Storefront Headless (jeremylongshore/tons-of-skills-marketplace, 2.8k stars) and Matlab Validate Function Arguments (matlab/matlab-agentic-toolkit, 1.1k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains CLI?

ad-repo (a GitHub user) maintains it in ad-repo/nullplayer, which has 157 GitHub stars. The repository holds 39 skills in this directory. The repository was last updated on October 8, 2026.

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

CLI

Install CLI

Facts

At a glance

What it does

When your agent uses it

Example prompts

Workflow steps

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

Review Arguments Dsl

Jetson Headless Mode

Shopify Storefront Headless

Matlab Validate Function Arguments

Oral Argument

Argument Strength Evaluation

More from ad-repo/nullplayer

Skin Screenshots

Vis Classic Guide

App Control

Chromecast Casting

Emby Integration

Live UI Testing

Questions about CLI