Stitch MCP Server

upload_design_md

Destructive

Upload DESIGN.md content to a Stitch project so that a design system can be generated from the file's specifications.

Instructions

Uploads DESIGN.md to a Stitch project. Use this tool when the user wants to create a design system from a DESIGN.md file.

Instructions for Tool Call:

Call create_design_system_from_design_md tool immediately after this tool to create the design system from the uploaded DESIGN.md, and display the design system in the UI.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`projectId`	Yes	Required. The project ID to upload the DESIGN.md to, example: '4044680601076201931', without the `projects/` prefix.
`designMdBase64`	Yes	Required. The base64-encoded DESIGN.md content. The decoded content must be valid UTF-8; uploads with invalid UTF-8 bytes will be rejected. Run `base64 -w 0 ` to get the base64-encoded string.

Output Schema

TableJSON Schema

Name	Required	Description
`x`	No	Optional. The x position of the screen.
`y`	No	Optional. The y position of the screen.
`id`	No	Optional. The screen instance id.
`type`	No	Optional. The type of screen instance.
`label`	No	Optional. The screen label.
`width`	No	Optional. The screen width.
`height`	No	Optional. The screen height.
`hidden`	No	Optional. User driven action hiding screen from the canvas.
`groupId`	No	Optional. Group identifier for Genie Agent output grouping. Screens with the same groupId are rendered and interact as a group.
`groupName`	No	Optional. Human-readable name for the group (e.g., "Warm Minimalism", "Ethereal Glow").
`isResized`	No	Optional. Whether this screen has been resized by the user.
`isFavourite`	No	Optional. Whether this screen is marked as a favourite by the user.
`needsLayout`	No	Optional. Whether this screen instance needs frontend layout positioning. Set by the PostProcessor when auto-linking screens that the agent generated but the frontend has not yet positioned on the canvas.
`sourceAsset`	No	Optional. The resource name of the source asset. Format: assets/{asset}
`textContent`	No	Optional. Text content for TEXT_INSTANCE nodes.
`sourceScreen`	No	Optional. The resource name of the source screen. Format: projects/{project}/screens/{screen}
`variantScreenInstance`	No	Optional. The variant Screen Instance.

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.0.0Sep 14, 2026

TDQS

A4.3/5.0

Behavior3/5

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

Annotations already declare destructiveHint=true and readOnlyHint=false, so the write/destructive nature is known. The description reinforces the upload action but does not disclose additional behavioral traits such as overwrite behavior, prerequisites, or side effects beyond the workflow instruction. Since annotations cover the core safety profile, the description adds only modest context.

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 two sentences plus one bullet point. It front-loads the core action, then provides usage context and a required follow-up instruction. Every sentence earns its place with no redundant or fluffy text.

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?

This is a simple upload tool with clear purpose, an output schema exists, and annotations cover the destructive hint. The description includes a critical workflow instruction (calling create_design_system_from_design_md immediately after), making the overall interaction complete for an agent. No return-value explanation is needed due to the output schema.

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?

The input schema has 100% description coverage for both parameters. The description adds a practical hint for the base64 parameter ('Run `base64 -w 0 `') and reminds about the projectId format ('without the `projects/` prefix'), which slightly elevates it above the schema-only baseline.

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 the action: 'Uploads DESIGN.md to a Stitch project.' It uses a specific verb and resource, and distinguishes from siblings by emphasizing the upload step, while explicitly naming the follow-up sibling tool create_design_system_from_design_md. No tautology.

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 states when to use the tool: 'Use this tool when the user wants to create a design system from a DESIGN.md file.' It also provides a required sequencing instruction to call create_design_system_from_design_md immediately after, which is valuable. However, it does not mention when not to use the tool or name alternative tools, so it lacks full exclusions.

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

Deploy Server