glebis/sketch

Sketch - Collaborative SVG Canvas

Description

Opens a Fabric.js-based SVG editor in the browser for collaborative visual prototyping. Claude can write and read SVG through MCP tools while the user edits interactively. Changes sync in real-time via WebSocket.

Tools Available (via sketch-mcp-server)

• sketch_open_canvas - Open a named canvas (creates if new), launches browser editor
• sketch_get_svg - Read current SVG from a canvas
• sketch_set_svg - Replace entire canvas with new SVG
• sketch_add_element - Add SVG elements without clearing existing content
• sketch_add_textbox - Add a fixed-width text area (Textbox) with word wrapping
• sketch_lock_objects - Lock all current objects (non-selectable, non-movable)
• sketch_unlock_objects - Unlock all objects
• sketch_save_template - Save canvas as reusable JSON template (preserves Textbox widths + lock state)
• sketch_load_template - Load a saved JSON template into a canvas
• sketch_list_templates - List all saved templates
• sketch_clear_canvas - Clear canvas to blank state (use before streaming)
• sketch_focus_canvas - Bring canvas window to foreground
• sketch_list_canvases - List all active canvases
• sketch_close_canvas - Close a canvas and its browser tab

Usage Patterns

Quick sketch

1. sketch_open_canvas with a name
2. sketch_set_svg or sketch_add_element to draw
3. User edits in browser
4. sketch_get_svg to see changes

Streaming (real-time build-up)

1. sketch_open_canvas with a name
2. sketch_focus_canvas to bring window to front
3. sketch_clear_canvas to start fresh
4. Call sketch_add_element multiple times -- each fragment appears instantly
5. User watches the UI build up in real-time

Multiple canvases

Each canvas opens in its own browser tab. Use different names for different drawings.

SVG tips

• Use standard SVG elements: <rect>, <circle>, <ellipse>, <line>, <path>, <text>, <polygon>, <polyline>
• Include xmlns="http://www.w3.org/2000/svg" on the root <svg> element
• Set width and height on the root SVG (default: 1200x800)
• Colors: use hex colors (#ff0000) -- avoid rgba() as Fabric.js SVG parser may not handle it
• Text: <text x="100" y="100" font-size="24">Hello</text>
• Images: <image href="data:image/png;base64,..." width="200" height="200"/>
• Avoid <defs>, <linearGradient>, <filter> -- Fabric.js has limited support for these