Stitch MCP — Apply Design System

Applies a previously created Stitch Design System to one or more screens. This updates the screen's visual theme (colors, font, roundness) to match the design system, ensuring visual consistency across a project.

Critical prerequisite

Only use this skill when the user explicitly mentions "Stitch".

You must have:

1. A projectId (numeric)
2. One or more screenId values (numeric)
3. An assetId from a design system (from list_design_systems or create_design_system)

When to use

• After creating a design system and wanting to apply it to screens
• User says "make all screens match this theme" or "apply the design system"
• The orchestrator's Step 5b stores an assetId and offers to apply it
• Ensuring visual consistency across a multi-screen project

Call the MCP tool

{
  "name": "apply_design_system",
  "arguments": {
    "projectId": "3780309359108792857",
    "selectedScreenIds": ["88805abc123def456", "99906xyz789ghi012"],
    "assetId": "ds_abc123"
  }
}

Parameter reference

projectId — numeric ID only, no prefix

✅ "3780309359108792857"
❌ "projects/3780309359108792857"

selectedScreenIds — array of numeric screen IDs

✅ ["88805abc123def456"]
❌ ["projects/123/screens/88805abc123def456"]

All selected screens will have the design system applied.

assetId — the design system identifier

The name field from a design system asset, or just the ID portion:

✅ "ds_abc123"

Get this from:

• stitch-mcp-list-design-systems → extract from the name field of each asset
• stitch-mcp-create-design-system → returned in the response name field

Output

Returns updated screen data reflecting the applied design system.

After applying

1. Re-fetch affected screens: stitch-mcp-get-screen for each screenId
2. Show updated screenshots to the user
3. Offer:
   • "Edit the updated screens?" → stitch-mcp-edit-screens
   • "Convert to code?" → framework conversion
   • "Apply to more screens?" → another apply_design_system call