uml-mcp

UML-MCP: Diagram Generation via MCP

Generate UML and other diagrams through the Model Context Protocol.

At a glance

Topic	What you get
Diagrams	30+ types: UML (Class, Sequence, Activity, Use Case, State, Component, Deployment, Object), Mermaid, D2, Graphviz, TikZ, ERD, BlockDiag, BPMN, C4, and more via Kroki
MCP tools	generate_uml, validate_uml, list_diagram_types, generate_uml_batch
Outputs	SVG, PNG, PDF, JPEG, base64 (availability varies by diagram type)
Pipeline	Kroki first, then PlantUML or Mermaid.ink
Deployment	Local stdio, local HTTP, Docker, Vercel, Smithery

Source	URL
Live MCP (HTTP)	https://uml-mcp.vercel.app/mcp
Smithery catalog	Add via Smithery

Quick Start

Choose your mode

• Remote (recommended): Fast setup over HTTP MCP with Vercel serverless runtime
• Local: stdio process for file output and local debugging

Remote quick start (Vercel HTTP MCP)

Configuration for the public Vercel deployment:

"uml-mcp": {
  "transport": "http",
  "url": "https://uml-mcp.vercel.app/mcp"
}

Local quick start (stdio MCP)

git clone https://github.com/antoinebou12/uml-mcp.git && cd uml-mcp
uv sync
uv run python server.py

Example client configs:

• config/cursor_config.json
• config/claude_desktop_config.json
• config/README.md for exact config file locations
• Claude Code: install the bundled plugin from the repo marketplace (see below) or read docs/integrations/claude_code.md

Claude Code plugin

Adds the hosted HTTP MCP server plus a diagram skill (no settings.json paste). In Claude Code:

/plugin marketplace add https://github.com/antoinebou12/uml-mcp
/plugin install uml-mcp@uml-mcp-plugins

Use a local path instead of the GitHub URL if you already cloned this repo. Custom endpoints and validation: docs/integrations/claude_code.md.

Remote vs Local

• Transport: Remote uses HTTP MCP, local uses stdio by default
• Runtime: Remote runs on Vercel, local runs in your Python environment
• File writes: Remote is read-only (no output_dir), local supports output_dir
• Returned data: Both return URL + base64; local can also save files
• Environment variables: Remote is managed server-side; local reads your env config

MCP clients must call /mcp, not the site root.

Supported Diagram Types

Category	Examples
UML (PlantUML)	Class, Sequence, Activity, Use Case, State, Component, Deployment, Object
General	Mermaid, D2, Graphviz, ERD, BlockDiag, BPMN, C4
Specialized	TikZ, Excalidraw, Nomnoml, Pikchr, Structurizr, SVGBob, WaveDrom, WireViz, …

Full list with supported formats: run python server.py --list-tools or query uml://types and uml://formats.

MCP Tools and Resources

Tools

Tool	Purpose
generate_uml	Render a diagram; omit output_dir for URL/base64 only
validate_uml	Structural validation before render; strict enables extra Mermaid/D2 checks
list_diagram_types	Same metadata as uml://types when resources are awkward
generate_uml_batch	Multiple diagrams in one call (cap: MCP_BATCH_MAX_ITEMS)

Resources (uml://)