new-cask

new-cask is a skill for Claude Code from malob/nix-config. It costs 93 tokens per session (1,698 once invoked), scanned A, original, MIT.

A workflow for packaging a macOS application as a Homebrew cask, the package description Homebrew uses to install graphical Mac apps.

In plain words
What is it for?
Use it to create and test a cask from an app name, download URL, or product homepage, then prepare a pull request.
Why use it?
It organizes the checks, download inspection, cask writing, testing, and submission steps needed to contribute a cask to Homebrew-Cask.

Skill for Claude Code

Written for Claude Code: allowed-tools in frontmatter.

Runs only inside its plugin — its command needs a path that Claude Code sets for a plugin’s own hooks and for nothing else. Install the plugin, not this.

Part of the homebrew plugin — 1 skill, 5 agents shipped together

Good fit Use it to create and test a cask from an app name, download URL, or product homepage, then prepare a pull request.

Compare 6 skills from other repositories ↓
Install

Getting it into your agent

This one installs as part of its plugin. Adding the marketplace and installing the plugin brings it with everything else the plugin ships.

Claude Code
/plugin marketplace add malob/nix-config
Claude Code
/plugin install homebrew

Made for: Claude Code.

Or install homebrew, the plugin that ships this one along with the rest of its 1 skill, 5 agents.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for new-cask

README.md
[![agentmods](https://agentmods.dev/badge/skills/malob/nix-config/new-cask.svg)](https://agentmods.dev/skills/malob/nix-config/new-cask)
Your own site
<a href="https://agentmods.dev/skills/malob/nix-config/new-cask"><img src="https://agentmods.dev/badge/skills/malob/nix-config/new-cask.svg" alt="Measured on agentmods" height="20"></a>
Per session 93 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,698 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00093 $0.01698
Opus 5 $0.00046 $0.00849
Sonnet 5 $0.00019 $0.00340
Haiku 4.5 $0.00009 $0.00170

Measured 8d ago against content hash 263e99bf17a3, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, from the pricing page.

Security

Grade A, and why

new-cask scanned grade A with 1 finding against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 8d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

Bash(curl *),
configs/claude/plugins/homebrew/skills/new-cask/SKILL.md · 222 lines

How it starts

The opening of the file, as written. The whole thing — 222 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Creating a New Homebrew Cask

You are orchestrating the creation of a new Homebrew cask. This skill coordinates multiple specialist agents and scripts to complete the workflow.

IMPORTANT: This skill runs in the main conversation context. You will use the Task tool to spawn agents for specialized work.

Input

URL provided: $ARGUMENTS

If no URL was provided, ask the user for:

  1. The app name, OR
  2. A download URL (direct link to DMG/ZIP), OR
  3. The product homepage (you'll find the download link)

Workflow Overview

1. Pre-flight checks    → Agent: pre-flight-checker
2. Download & inspect   → Agent: app-inspector
3. Livecheck strategy   → Agent: livecheck-advisor
4. Write cask file      → Agent: cask-writer
5. Testing              → Automated tests, install, createzap, uninstall
6. Submit PR            → Agent: pr-submitter

Create a task list to track progress through these steps.

Step-by-Step Execution

Step 1: Pre-flight Checks

Before investing time, verify the app is suitable:

Use the Task tool:
- subagent_type: homebrew:pre-flight-checker
- prompt: Check if this app is suitable for homebrew-cask submission.
  <include whatever info you have: URL, app name, homepage>

The agent will derive any missing info (app name from URL, homepage via search, etc.) and include it in the output.

Capture from output: App name, homepage, download URL, description - you'll need these for later steps.

Decision point: If the agent returns REJECT, stop and explain why to the user. If CAUTION, inform the user and ask if they want to proceed.

Step 2: Download and Inspect

Download and inspect the app in one step:

Use the Task tool:
- subagent_type: homebrew:app-inspector
- prompt: Download and inspect the app.
  Download URL: <url>
  Homepage: <homepage>

The agent will download the file, compute the SHA256, extract all metadata, and run Homebrew's generate_cask_token tool to get the canonical token.

Capture from output: Suggested token, SHA256, version, bundle ID, app name, min macOS, auto-update info (framework, appcast URL if found), architecture.

Read the full file on GitHub · 222 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 8d ago First seen · 222 lines · 93 tokens per session scan A 263e99bf17a3

Subscribe to this mod's changes

new-cask is a skill published in the GitHub repository malob/nix-config (462 stars, last pushed yesterday), licensed MIT. It adds 93 tokens to every session and 1,698 once invoked, about $0.0005 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.