This skill should be used when the user asks to "add a cask to homebrew", "create a homebrew cask", "add an app to homebrew", "new cask for", "homebrew cask for", "package an app for homebrew", "submit to homebrew-cask", "make a cask", "contribute a cask", or wants to package a macOS application for Homebrew.
apm install @malob/new-cask[](https://apm-p1ls2dz87-atlamors-projects.vercel.app/packages/@malob/new-cask)---
name: new-cask
argument-hint: "<url>"
description: >-
This skill should be used when the user asks to "add a cask to homebrew",
"create a homebrew cask", "add an app to homebrew", "new cask for",
"homebrew cask for", "package an app for homebrew", "submit to homebrew-cask",
"make a cask", "contribute a cask", or wants to package a macOS application
for Homebrew.
allowed-tools: >-
Read,
Grep,
Glob,
WebFetch,
WebSearch,
Bash(brew *),
Bash(gh *),
Bash(curl *),
Bash(hdiutil *),
Bash(defaults read *),
Bash(shasum *),
Bash(git *),
Bash(plutil *),
Bash(file *),
Bash(lipo *),
Bash(ls *),
Bash(find *),
Bash(strings *),
Bash(unzip *),
Bash(open *),
Bash(${CLAUDE_PLUGIN_ROOT}/scripts/*)
---
# 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.
**Use the suggested token** from app-inspector for subsequent steps. This token comes from Homebrew's tooling and handles naming conventions and collision detection.
**Note on versioned URLs:** If the download URL is unversioned (e.g., `App.dmg`), the livecheck-advisor may find a versioned URL in an appcast, release feed, or other source. If so, you'll need to re-download using the versioned URL to get the correct SHA256.
### Step 3: Livecheck Strategy
Determine how to check for updates:
```
Use the Task tool:
- subagent_type: homebrew:livecheck-advisor
- prompt: Recommend a livecheck strategy for <app-name>.
Download URL: <url>
Homepage: <homepage>
Update URL: <appcast-or-feed-url-if-found>
Current version: <version>
```
Get the recommended livecheck block.
### Step 4: Write the Cask
Synthesize everything into a cask file:
```
Use the Task tool:
- subagent_type: homebrew:cask-writer
- prompt: Write a cask for <app-name> with this metadata:
Token: <token>
Version: <version>
URL: <download-url>
SHA256: <checksum> (or :no_check if unversioned URL)
(If separate binaries per architecture, provide URL and SHA256 for each)
Name: <display-name>
Description: <one-line-desc>
Homepage: <homepage>
Bundle ID: <bundle-id>
App bundle: <app-name>.app
Min macOS: <min-version>
Auto-updates: <yes/no>
Livecheck: <livecheck-block>
Architecture: <arm64/intel/universal, only if not universal>
```
**Note:** The zap stanza is added later after running createzap during testing.
### Step 5: Testing
#### Automated Tests
Run the validation script:
```bash
${CLAUDE_PLUGIN_ROOT}/scripts/test-cask.sh "<token>"
```
If tests fail, review the output, fix the cask (often `brew style --fix` handles style issues), and re-run.
**For unversioned URLs:** Use `--skip-livecheck` flag.
#### Install and Validate
1. **Install:**
```bash
HOMEBREW_NO_INSTALL_FROM_API=1 brew install --cask <token>
```
2. **Launch:**
```bash
open -a "<App Name>"
```
3. **User verification:** Ask the user to sign in or set up the app if needed, then confirm when done.
#### Zap Discovery
4. **Run createzap** (try both app name and bundle ID):
```bash
brew tap nrlquaker/createzap 2>/dev/null || true
brew createzap "<App Name>"
brew createzap "<bundle-id>"
```
5. **Update the cask** - Add the discovered zap paths using the Edit tool. For simple additions you can edit directly; for significant changes, re-invoke the cask-writer agent.
6. **Uninstall:**
```bash
brew uninstall --cask <token>
```
7. **Re-run automated tests** if zap stanza was added.
### Step 6: Submit PR
When ready to submit:
```
Use the Task tool:
- subagent_type: homebrew:pr-submitter
- prompt: Submit a PR for the <token> cask.
Version: <version>
Cask path: <path-to-cask-file>
All tests passed: yes
```
## Error Recovery
If any step fails:
- The task list shows which steps completed
- You can resume from the failed step
- Agent outputs are preserved in conversation history
## Reference Documentation
For detailed guidance, agents can read these docs (at `/opt/homebrew/docs/`):
- `Acceptable-Casks.md` - What's allowed
- `Cask-Cookbook.md` - Stanza reference
- `Brew-Livecheck.md` - Livecheck strategies
- `Adding-Software-to-Homebrew.md` - Contribution process
## Scripts Location
Scripts are at `${CLAUDE_PLUGIN_ROOT}/scripts/`:
- `download-checksum.sh <url> [filename]` - Download and SHA256
- `test-cask.sh <token> [--skip-livecheck]` - Run audit/style/livecheck