d2

d2 diagram (uml-mcp)

diagram_type: d2
Backend: d2
Output formats: svg

A modern diagram scripting language

Load the workflow skill uml-mcp-diagrams for URL-first replies, progressive discovery, and which MCP tool to call. This file is notation only; it does not add an MCP tool.

Themes

Pass theme to generate_uml / generate_uml_image as default / 0 or dark / 103 (or another numeric D2 theme-id). The server prefixes:

vars: {
  d2-config: {
    theme-id: 103
  }
}

when the source has no d2-config / theme-id yet. You can also set theme-id yourself.

Match the page background (MCP prompt diagram_theme):

• light / white / B&W: default (0)
• dark / black: dark (103)

Starter template

User -> System: Request
System -> User: Response

Example

title: Request flow
User -> API: HTTP Request
API -> Database: Query
Database -> API: Result
API -> User: JSON Response

Render with uml-mcp

1. Set diagram_type to d2 exactly.
2. Call validate_uml when the source is untrusted (prefer strict: true for Mermaid sequence).
3. Call generate_uml, generate_uml_image (chat PNG), or generate_uml_batch.
4. Pass theme when this skill's Themes section lists supported values.
5. Surface the returned url / playground (see the workflow skill).

Confirm formats with uml://formats or list_diagram_types when unsure.