Pencil Design

Pencil Design Agent

ABSOLUTE RULE — NO EXCEPTIONS

The main agent (you) must NEVER directly call any mcp__pencil__* tool. Not even once. Not even to "quickly check" something. Not even get_editor_state. Every single Pencil MCP interaction goes through a subagent via the Agent tool. This is non-negotiable — Pencil MCP outputs are enormous and will destroy the main conversation's context window.

If you find yourself about to call mcp__pencil__* directly: STOP. Spawn a subagent instead.

How It Works

When the user requests any .pen file work, you MUST:

1. Spawn an Agent (subagent) with a clear, detailed prompt describing the design task
2. The subagent has access to all Pencil MCP tools and will do the actual work
3. The subagent returns a concise summary of what it did (under 300 words)
4. You relay that summary to the user — this is all that enters the main context

Subagent Prompt Template

When spawning the subagent, include ALL of the following in the prompt:

You are a Pencil design specialist working with .pen files via the Pencil MCP server.

## Your Task
{describe the user's request in detail}

## Available Pencil MCP Tools
You have access to these tools (use ToolSearch to load them first):
- mcp__pencil__get_editor_state - Check current editor state (start here)
- mcp__pencil__open_document - Open a .pen file or create new one
- mcp__pencil__get_guidelines - Get design guidelines for a topic
- mcp__pencil__get_style_guide_tags - Get available style guide tags
- mcp__pencil__get_style_guide - Get a style guide by tags or name
- mcp__pencil__batch_get - Read nodes by pattern or ID
- mcp__pencil__batch_design - Insert/copy/update/replace/move/delete nodes
- mcp__pencil__snapshot_layout - Check computed layout rectangles
- mcp__pencil__get_screenshot - Take a screenshot of a node
- mcp__pencil__get_variables - Get current variables and themes
- mcp__pencil__set_variables - Add or update variables
- mcp__pencil__find_empty_space_on_canvas - Find empty space for new content
- mcp__pencil__search_all_unique_properties - Search unique properties in node tree
- mcp__pencil__replace_all_matching_properties - Replace matching properties in node tree

## Critical Rules
1. ALWAYS start by calling get_editor_state to understand current context
2. Use ToolSearch with "select:mcp__pencil__<tool_name>" to load each tool before first use
3. Contents of .pen files are encrypted - ONLY use Pencil MCP tools, never Read/Grep
4. When designing, use get_guidelines and get_style_guide for best results
5. Use get_screenshot periodically to validate your design visually
6. Keep batch_design operations to max 25 per call
7. After completing work, use get_screenshot to capture the final result

## Response Format
Return a concise summary (under 300 words) containing:
- What you did (actions taken)
- Current state of the design
- Any issues or decisions that need user input
- If you took screenshots, mention what they show

When to Use This Skill

This skill MUST be triggered for ANY of these scenarios:

• User mentions .pen files
• User asks to create, edit, or view a design in Pencil
• User asks to open the Pencil editor
• User wants to update variables, styles, or nodes in a .pen file
• User asks for a screenshot or layout check of a .pen design
• Any task that would require calling mcp__pencil__* tools

Important Notes

• Never call Pencil MCP tools directly from the main conversation - always delegate to a subagent
• If the task is complex (multiple screens, full app design), break it into multiple subagent calls
• The subagent should use get_screenshot at the end so the user can see the result
• If the subagent needs user input (e.g., design choices), relay the question back to the user and spawn a new subagent (or resume the previous one) with their answer
• You can resume a previous subagent using its agent ID if follow-up work is needed on the same design