Stitch MCP Server

update_design_system

Destructive

Update a project's design system to change its visual theme, branding, colors, typography, shape, and appearance. Apply consistent design tokens across all screens.

Instructions

Updates a design system for a project. Use this tool when the user wants to change the overall visual theme, style, or branding of the application. This includes configuring:

Color Palette: Presets, custom primary colors, and saturation levels.
Typography: Font families (e.g., Inter, Roboto, etc.).
Shape: Corner roundness for UI elements.
Appearance: Light and dark mode background colors.
Design MD: Free-form design instructions in markdown. This tool establishes the foundational design tokens that apply across all screens in the project.

Input Schema

TableJSON Schema

Name	Required	Description
`name`	Yes	Required. Identifier. The resource name of the design system to update. Format: `assets/{asset_id}` Example: `assets/15996705518239280238`
`projectId`	Yes	Required. The project ID to update design system for, example: '4044680601076201931', without the `projects/` prefix.
`designSystem`	Yes	Required. The design system to update.

Output Schema

TableJSON Schema

Name	Required	Description
`name`	No	Identifier. The resource name of the asset. Format: assets/{asset}
`version`	No	Output only. The version of this asset. 0 indicates unversioned (legacy data). Incremented when the asset content changes.
`copiedFrom`	No	Optional. The resource name of the asset this was copied from, if any. Format: assets/{asset} Tracks the fork history of assets.
`designSystem`	No	Optional. The design system.

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.0.0Sep 14, 2026

TDQS

A4.5/5.0

Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare destructiveHint=true, so the destructive nature is known. The description adds that the tool 'establishes the foundational design tokens that apply across all screens in the project,' explaining the broad scope of the change. It does not detail overwrite semantics, but the annotation covers the destructive aspect, and the added context about cross-screen impact is valuable.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is well-structured with a clear opening sentence, a 'Use this tool when...' statement, and a concise bullet list of features. Every sentence adds useful context without fluff or redundancy, making it efficient and easy to scan.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the tool's complexity (nested designSystem object) and the presence of an output schema, the description covers the core 'what', 'when', and 'scope' (applies across all screens). It includes the key configurable categories, and the schema fills in the detailed parameter definitions. The description is complete enough for an agent to decide when to invoke the tool and what to include.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so parameters are already well-documented. The description adds high-level conceptual categories (Color Palette, Typography, Shape, Appearance, Design MD) that help an agent map user intent to the relevant fields in the nested designSystem object, going beyond the raw schema by grouping related parameters into thematic areas.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states 'Updates a design system for a project' and specifies the exact use case: 'when the user wants to change the overall visual theme, style, or branding of the application.' It enumerates the configurable aspects (color, typography, shape, appearance, design MD), making the tool's purpose unambiguous and distinct from creation or other operations.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description explicitly says 'Use this tool when the user wants to change the overall visual theme, style, or branding,' which is clear when-to-use guidance. It does not explicitly mention when not to use or name alternative sibling tools like create_design_system, so it lacks explicit exclusions or alternatives, but the context is sufficient.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Deploy Server