# UML-MCP — LLM-oriented overview

Human-oriented index (install, clients, troubleshooting): docs/user-manual.md

Teaser
Improve your diagramming skills with PlantUML, Mermaid, D2 (and Kroki) by creating optimized diagrams for various purposes using Sequence, Use Case, Class, Activity, Component, State, Object, Deployment, Mermaid, D2, Graphviz, ERD, BPMN, C4.

Prompt hint
[DIAGRAM TYPE] — Sequence, Use Case, Class, Activity, Component, State, Object, Deployment, Mermaid, D2, Graphviz, ERD, BPMN, C4.
[ELEMENT TYPE] — Actors, Messages, Objects, Classes, Interfaces, Components, States, Nodes, Edges, Links, Frames, Constraints, Entities, Relationships, Tasks, Events, Modules.
[PURPOSE] — Communication, Planning, Design, Analysis, Modeling, Documentation, Implementation, Testing, Debugging.
[DIAGRAMMING TOOL] — PlantUML, Mermaid, D2 (Kroki for rendering).

Recommended: use the uml_diagram or uml_diagram_with_thinking prompt so the model plans first (diagram type, purpose, elements), then generates code and calls generate_uml.

---

UML-MCP is a diagram generation server that implements the Model Context Protocol (MCP). It lets AI assistants and other MCP clients create diagrams (UML, Mermaid, D2, Graphviz, ERD, etc.) via tools and resources.

## What it does

- Generates diagrams from code/descriptions using PlantUML, Kroki, Mermaid, D2, Graphviz backends.
- Exposes MCP tools generate_uml and validate_uml, plus resources (uml://types, uml://templates, uml://examples, uml://formats, uml://server-info, uml://workflow).
- Output formats: SVG, PNG, PDF, JPEG (and others per diagram type; see uml://formats).

## Diagram types

- UML: class, sequence, activity, use case, state, component, deployment, object.
- Other: Mermaid, D2, Graphviz, ERD, BlockDiag, BPMN, C4 (PlantUML).

## MCP tools (summary)

- generate_uml — Render a diagram. Params: diagram_type, code, output_dir (optional), output_format, theme, scale. Omit output_dir for URL/base64 only. Use uml://types for valid types.
- validate_uml — Validate inputs locally before render. Params: diagram_type, code, output_format.

Full list and parameters: docs/api/tools.md

## MCP resources

- uml://types — diagram types.
- uml://templates — diagram templates.
- uml://examples — examples.
- uml://formats — output formats.
- uml://server-info — server info.
- uml://workflow — recommended workflow: plan first (type, elements, relationships), then call generate_uml.

## Configuration

- MCP_OUTPUT_DIR / UML_MCP_OUTPUT_DIR — where to save diagrams (default: ./output).
- KROKI_SERVER, PLANTUML_SERVER — backend URLs.
- USE_LOCAL_KROKI, USE_LOCAL_PLANTUML — use local backends.
Details: docs/configuration.md

## Running

- MCP server (stdio): python server.py (from project root).
- MCP over HTTP: python server.py --transport http --host 127.0.0.1 --port 8000.
- List tools: python server.py --list-tools.

## Project layout

- server.py — MCP server entry point.
- mcp_core/ — server, config, tools, resources, prompts.
- plantuml/, kroki/, mermaid/, D2/ — diagram backends.
- config/ — example MCP client configs (Cursor, Claude Desktop).
- docs/ — documentation (this file, api/tools.md, configuration.md, installation.md, integrations/, testing.md).

## Deploy and publish

- Deploy to Vercel and publish on Smithery: docs/integrations/vercel_smithery.md
- Smithery docs index: https://smithery.ai/docs/llms.txt

## More docs

- Installation: docs/installation.md
- API / tools: docs/api/tools.md
- Configuration: docs/configuration.md
- Cursor: docs/integrations/cursor.md
- Claude Desktop: docs/integrations/claude_desktop.md
- Testing: docs/testing.md