Pencil MCP Set Variables

Tools

This skill is designed to call the Pencil MCP tool:

• set_variables

If your client namespaces MCP tools, it may appear as mcp__pencil__set_variables.

When to use this skill

Intent Recognition (CRITICAL)

Even if a trigger phrase matches, you must verify the user's intent:

1. Is the user explicitly asking to use "Pencil"?
2. Is the current conversation context clearly about "Pencil" design tasks?

If the answer is NO, do NOT use this skill. (e.g., "Set variables" might refer to .env files).

CRITICAL PREREQUISITE: You must ONLY use this skill when the user EXPLICITLY mentions "Pencil".

ALWAYS use this skill when:

• You are initializing a Design System (e.g., "Init uView Pro colors") in Pencil.
• You need to update the theme (e.g., "Apply Dark Mode") in Pencil.
• You want to define new Design Tokens.

Trigger phrases include:

• "Set Pencil variables" (设置 Pencil 变量)
• "Update Pencil tokens" (更新 Pencil 令牌)
• "Change Pencil theme" (修改 Pencil 主题)
• "Define Pencil colors" (定义 Pencil 颜色)

Input Parameters

• filePath (string, optional): Path to .pen file.
• variables (object, required): The variable definitions matching the .pen schema.
• replace (boolean, optional):
  • true: Completely replace all existing variables.
  • false (default): Merge/Update existing variables.

How to use this skill

1. Define Schema: Construct the variable objects (Name, Type, Value, Theme Modes).
2. Call Tool: set_variables(variables={...}).
3. Verify: Optionally call get_variables to confirm changes.

Examples

1. Simple: Add a Color

Register a single new color variable.

{
  "variables": [
    {
      "name": "brand/primary",
      "value": "#0066FF",
      "type": "color"
    }
  ]
}

2. Medium: Update Theme Tokens

Update multiple variables for a specific theme (e.g., Dark Mode) by merging.

{
  "replace": false,
  "variables": [
    { "name": "bg/default", "value": "#121212", "type": "color" },
    { "name": "text/primary", "value": "#FFFFFF", "type": "color" }
  ]
}

3. Complex: Full System Replacement

Completely replace the existing variable system with a new set of tokens.

{
  "replace": true,
  "variables": [
    { "name": "spacing/small", "value": 8, "type": "float" },
    { "name": "spacing/medium", "value": 16, "type": "float" },
    { "name": "font/base", "value": "Inter", "type": "string" }
  ]
}

Keywords

English keywords: set variables, update tokens, define theme, design system init, color definition, style dictionary

Chinese keywords (中文关键词): 设置变量, 更新令牌, 定义主题, 设计系统初始化, 颜色定义, 样式字典

能力边界

✅ 适用场景

• 当你需要使用此技能对应的技术栈时
• 当项目需要遵循最佳实践时
• 当需要快速上手或深入理解核心概念时

⚠️ 需要注意

• 复杂业务逻辑需要结合具体场景调整
• 性能优化需要根据实际数据量评估

❌ 不适用场景

• 不相关的技术栈或框架
• 需要完全自定义的特殊场景

常见陷阱 (Gotchas)

1. 版本兼容性：注意框架版本与依赖库的兼容性，不同版本 API 可能有差异
2. 配置文件格式：配置文件格式错误是最常见的问题，建议使用编辑器的语法检查
3. 环境变量：确保所有必要的环境变量已正确设置，敏感信息不要硬编码
4. 依赖冲突：多版本共存时注意依赖冲突，使用 lock 文件锁定版本
5. 性能陷阱：大数据量场景下注意性能优化，避免 N+1 查询等常见问题

使用流程

Step 1: 环境准备

确保开发环境已安装必要的依赖和工具。

Step 2: 配置初始化

根据项目需求进行基础配置。

Step 3: 核心功能使用

按照示例代码实现核心功能。

Step 4: 测试验证

运行测试确保功能正常。

Step 5: 部署上线

完成开发后进行部署和监控。