Pencil Design
Create and manipulate .pen design files using Pencil MCP tools.
Workflow
1. Orientation
get_editor_state → Check active file and selection
get_guidelines → Load topic-specific rules (landing-page, design-system, table, code, tailwind)
batch_get → Read file structure or find components
2. Design (if creating from scratch)
get_style_guide_tags → Browse available visual styles
get_style_guide → Load style guide for inspiration
open_document → Create new file if needed
3. Build
batch_design → Insert, update, copy, replace, move, delete nodes (max 25 ops/call)
get_screenshot → Verify visual output after changes
snapshot_layout → Debug layout issues or find clipping problems
4. Refine
get_variables → Read design tokens and themes
set_variables → Update tokens for consistent styling
replace_all_matching_properties → Bulk property updates
Quick Reference
Element Types
| Type | Purpose | Key Properties |
|---|
frame | Container/layout | layout, gap, padding, children, reusable |
text | Typography | content, fontFamily, fontSize, fontWeight |
rectangle | Shape | width, height, fill, cornerRadius |
ref | Component instance | ref (source ID), descendants (overrides) |
icon_font | Icon | iconFontName, iconFontFamily ("lucide") |
path | Vector | geometry (SVG path data) |
Layout
| Property | Values |
|---|
layout | "none" (absolute), "horizontal", "vertical" |
justifyContent | start, center, end, space_between |
alignItems | start, center, end, stretch |
width/height | 360, "fill_container", "fill_container(360)", "fit_content" |
padding | 16, [12, 24], [8, 16, 8, 16] |
Tokens
Prefix: $--
| Category | Examples |
|---|
| Colors | $--primary, $--foreground, $--background, $--border |
| Semantic | $--color-success, $--color-warning, $--color-error |
| Typography | $--font-primary, $--font-secondary |
| Radii | $--radius-none, $--radius-m, $--radius-pill |
Operations (batch_design)
Operations use JavaScript-like syntax. Every Insert/Copy/Replace needs a binding.
| Op | Syntax | Use |
|---|
| I | btn=I(parent, {type: "frame", ...}) | Insert node |
| U | U(path, {content: "New"}) | Update properties |
| C | copy=C(sourceId, parent, {...}) | Copy node |
| R | new=R(path, {type: "text", ...}) | Replace node |
| M | M(nodeId, newParent, index?) | Move node |
| D | D(nodeId) | Delete node |
| G | G(nodeId, "stock", "office") | Apply image fill |
Component Instances
// Insert instance and override text
card=I(container, {type: "ref", ref: "CardComp"})
U(card+"/titleText", {content: "New Title"})
// Replace slot content
newContent=R(card+"/slot", {type: "text", content: "Custom"})
Critical Rules
- IDs auto-generate — never set
id in node data
- Bindings required — every I/C/R must have
name=...
- Max 25 ops — split larger designs across calls
- Copy descendants — use
descendants property, not separate U() calls
- Verify visually — call
get_screenshot after modifications
Reference Files
| File | When to Read |
|---|
| mcp-operations.md | Detailed operation syntax, examples, and edge cases |
| patterns.md | Element creation examples, styling patterns, theming |
| schema.json | Authoritative property definitions for validation |