Hallmark Development Setup: A Complete Guide to Building AI-Assisted Design Skills

To set up Hallmark for development, clone the repository, optionally install Node.js for the preview server, and run npm run serve to view the static demo site locally.

Hallmark is a self-contained design skill for Claude Code, Cursor, and Codex developed by Nutlope. The entire setup process requires zero runtime dependencies—only a modern Node.js environment (≥14) if you want the convenience of the built-in preview server. This guide walks through the complete Hallmark development setup, from initial clone to validation and distribution.

Understanding the Hallmark Repository Structure

Before diving into setup commands, it helps to understand how the repository is organized. Hallmark consists of three distinct sections:

Section	Purpose	Key Files
Skill definition	Core skill manifest and design references loaded by AI assistants	skills/hallmark/SKILL.md (entry point), skills/hallmark/references/ (design assets)
Static demo site	Browsable showcase of generated pages and test fixtures	site/index.html, site/_tests/ (test pages)
Package metadata	Skill installation metadata and convenience scripts	package.json (declares entry point and serve script)

All design logic lives in markdown and static assets. The skill is consumed directly from the file system—no build step, no compilation, no secret configuration.

Step-by-Step Hallmark Development Setup

1. Clone the Repository

Start by obtaining a local copy of the source code:

git clone https://github.com/Nutlope/hallmark.git
cd hallmark

2. Optional: Install Node.js Dependencies

Node.js is only required for the npm run serve convenience script. The skill itself functions without any npm packages:

npm install

This creates a package-lock.json for the serve script. If you skip this step, you can still use any static file server (see alternatives below).

3. Start the Local Preview Server

Run the built-in development server to browse the demo site:

npm run serve

# → Serves site/ folder at http://localhost:4173

This script is defined in package.json and provides instant feedback as you edit skill files.

Alternative without Node.js:

python3 -m http.server --directory site 4173

Both approaches serve the site/ directory for browser-based validation.

4. Edit the Skill Definition

The development workflow centers on two locations:

• skills/hallmark/SKILL.md — The main skill manifest read by Claude Code, Cursor, and Codex
• skills/hallmark/references/ — The complete design library including macrostructures, color palettes, copy guidelines, and component cookbooks

Modify these files to change how AI assistants interpret and apply Hallmark's design language.

5. Validate Changes in the Browser

After editing, verify your changes by opening the corresponding example page:

# Example: view the "Cobalt" theme after modifications

open http://localhost:4173/examples/cobalt-01/

For systematic validation, check the built-in tests under site/_tests/ which verify skill output against slop-test gates.

6. Distribute the Updated Skill

Once satisfied with your changes, deploy the skill using either method:

• Registry method: npx skills add nutlope/hallmark
• Direct copy method: Copy SKILL.md plus the references/ folder into your target AI assistant's skill directory

The direct copy method is preferred during active development for rapid iteration.

Key Files for Hallmark Development

File	Role	Location
package.json	Declares skill entry point and serve script	Repository root
skills/hallmark/SKILL.md	Main skill manifest consumed by AI assistants	skills/hallmark/
skills/hallmark/references/	Complete design library (macrostructures, themes, copy, components)	skills/hallmark/references/
site/_tests/	Test fixtures for validation	site/_tests/
site/index.html	Demo site landing and navigation	site/
site/js/main.js	Minimal client-side interactivity	site/js/

Environment Requirements

• Node.js: ≥14 (optional, only for npm run serve)
• No API keys, environment variables, or external services required
• Pure file-level operations throughout the entire workflow

Summary

• Hallmark development setup requires only a git clone and optional Node.js installation—no complex toolchain or dependencies
• The repository structure separates skill definition (skills/hallmark/), demo site (site/), and metadata (package.json) for clear organization
• Run npm run serve (or Python's built-in server) to preview changes locally at localhost:4173
• Edit SKILL.md and references/ files to modify design behavior; validate via browser examples and site/_tests/
• Deploy using npx skills add or direct file copy—no build process required

Frequently Asked Questions

Does Hallmark require Node.js to function as a skill?

No. According to the Nutlope/hallmark source code, the skill itself has zero runtime dependencies. Node.js ≥14 is only needed if you want to use the npm run serve convenience script for local preview. The AI assistants consume SKILL.md and the references/ folder directly from the file system without any npm packages.

Where is the main skill entry point located?

The primary skill manifest is at skills/hallmark/SKILL.md. This file is read by Claude Code, Cursor, and Codex when the skill is loaded. All design references are organized under skills/hallmark/references/ including macrostructures, color palettes, and component documentation.

How do I test specific design changes in Hallmark?

After editing skill files, start the preview server with npm run serve and navigate to the corresponding example page. For instance, changes to the Cobalt theme can be viewed at http://localhost:4173/examples/cobalt-01/. Systematic validation is available through the test fixtures in site/_tests/.

Can I develop with Hallmark without using npm at all?

Yes. The repository includes no required npm dependencies. You can serve the site/ folder using any static file server—Python's http.server, npx serve, or even a simple python3 -m http.server --directory site 4173 command works identically to npm run serve.

{
  "mcpServers": {
    "instagit": {
      "command": "npx",
      "args": ["-y", "instagit@latest"]
    }
  }
}