# Openpencil Skill

> LLM skill for designing with OpenPencil via the op CLI and MCP tools

- **Type:** MCP server
- **Install:** `agentstack add mcp-zseven-w-openpencil-skill`
- **Verified:** Yes — security-reviewed for prompt injection and unsafe behavior
- **Seller:** [ZSeven-W](https://agentstack.voostack.com/s/zseven-w)
- **Installs:** 0
- **Category:** [AI & ML](https://agentstack.voostack.com/c/ai-and-ml)
- **Latest version:** 0.1.0
- **License:** MIT
- **Upstream author:** [ZSeven-W](https://github.com/ZSeven-W)
- **Source:** https://github.com/ZSeven-W/openpencil-skill

## Install

```sh
agentstack add mcp-zseven-w-openpencil-skill
```

Requires the [AgentStack CLI](https://agentstack.voostack.com/docs/cli). Works with Claude Code, Cursor, and any MCP-compatible agent.

## About

# OpenPencil Skill

  English · 简体中文 · 繁體中文 · 日本語 · 한국어 · Français · Español · Deutsch · Português · Русский

LLM skill for designing with [OpenPencil](https://github.com/ZSeven-W/openpencil) — teaches AI agents to use the `op` CLI, batch design DSL, MCP tools, and design best practices.

Follows the [agentskills.io](https://agentskills.io/specification) specification.

## Prerequisites

Install the `op` CLI before using this skill:

```bash
npm install -g @zseven-w/openpencil
```

Ensure a running OpenPencil instance (desktop app or web server) for `op` to connect to.

## Installation

> **Note:** Installation differs by platform. Claude Code and Cursor have built-in plugin systems. Codex and OpenCode require manual setup.

### Claude Code (Plugin Marketplace)

Register the marketplace, then install the plugin:

```
/plugin marketplace add zseven-w/openpencil-skill
/plugin install openpencil-skill@openpencil-skill
```

### Cursor

In Cursor Agent chat:

```
/add-plugin openpencil-skill
```

Or search for "openpencil" in the plugin marketplace.

### Codex

Tell Codex:

```
Fetch and follow instructions from https://raw.githubusercontent.com/zseven-w/openpencil-skill/main/.codex/INSTALL.md
```

### OpenCode

Tell OpenCode:

```
Fetch and follow instructions from https://raw.githubusercontent.com/zseven-w/openpencil-skill/main/.opencode/INSTALL.md
```

### Gemini CLI

```bash
gemini extensions install https://github.com/zseven-w/openpencil-skill
```

To update:

```bash
gemini extensions update openpencil-skill
```

## Verify Installation

Start a new session and ask to design something with OpenPencil (e.g., "design a landing page using op CLI"). The agent should automatically use the skill to generate PenNode JSON via the `op` CLI or MCP tools.

## What's Included

- `op` CLI command reference (app control, document ops, nodes, import, layout, pages, variables, codegen)
- Batch Design DSL syntax with full landing page example
- PenNode schema — all node types (frame, rectangle, ellipse, polygon, text, path, image, icon_font, ref, line, group), properties, fills
- 40+ semantic roles with smart defaults
- Design principles — typography, color, spacing, shadows
- Layout engine rules and sizing decisions
- Layered MCP workflow (skeleton → content → refine)
- Codegen pipeline (plan → submit → assemble → clean)
- Import support (SVG, Figma .fig files)
- Common patterns — navbar, hero, cards, forms, footer
- Common mistakes table

## License

MIT

## Source & license

This open-source MCP server is cataloged on AgentStack and links to its original source — we do not rehost the code.

- **Author:** [ZSeven-W](https://github.com/ZSeven-W)
- **Source:** [ZSeven-W/openpencil-skill](https://github.com/ZSeven-W/openpencil-skill)
- **License:** MIT

Install and usage instructions live in the source repository linked above.

## Pricing

- **Free** — Free

## Security capabilities

Automated source analysis of v0.1.0 — what this tool can access:

- **Network access:** no
- **Filesystem access:** no
- **Shell / process execution:** no
- **Environment & secrets:** no
- **Dynamic code execution:** no

*"Yes" means the capability is present in the source — more access means more to trust, not that it is unsafe.*


## Versions

- **0.1.0** — security scan: passed — Imported from the upstream source.

## Links

- Listing page: https://agentstack.voostack.com/l/mcp-zseven-w-openpencil-skill
- Seller: https://agentstack.voostack.com/s/zseven-w
- Browse the marketplace: https://agentstack.voostack.com/browse

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Listed on AgentStack — the marketplace for AI agent skills and MCP servers. Every listing is security-reviewed. Creators keep 70%.