PlantUML Diagrams is a diagram generation service that creates PlantUML diagrams with automatic syntax validation and auto-fix suggestions. Key features of PlantUML Diagrams: - Generate embeddable SVG/PNG image URLs for valid diagrams - Provide structured feedback to resolve syntax issues - Encode or decode PlantUML code for easy URL sharing - Save diagrams locally with secure path restrictions - Support for sequence diagrams, class diagrams, architecture diagrams, and C4 diagrams - Advanced features like `!include` directives and external libraries - Works with any PlantUML server (default: plantuml.com/plantuml)

PlantUML MCP Server

[](https://smithery.ai/server/@infobip/plantuml-mcp-server)

A Model Context Protocol (MCP) server that provides PlantUML diagram generation capabilities for Claude Desktop and Claude Code.

Available Tools

1. generate_plantuml_diagram - Generate diagrams and get embeddable URLs (SVG/PNG), optionally save locally 2. encode_plantuml - Encode PlantUML code for URL sharing 3. decode_plantuml - Decode PlantUML from encoded strings

Available Prompts

1. plantuml_error_handling - Guidelines for handling PlantUML syntax errors and implementing auto-fix workflows

This prompt provides Claude instances with comprehensive instructions on how to:

The prompt enables Claude to automatically detect and fix common PlantUML errors like missing tags, invalid arrow syntax, typos in keywords, and missing quotes, making PlantUML diagram generation more reliable and user-friendly.

Quick Setup

For Claude Code

# Using default PlantUML server
claude mcp add plantuml --scope user --env PLANTUML_SERVER_URL=https://www.plantuml.com/plantuml -- npx plantuml-mcp-server

For Claude Desktop

Add this to your Claude Desktop MCP configuration (~/Library/Application Support/Claude/claude_desktop_config.json on macOS):

{
  "mcpServers": {
    "plantuml": {
      "command": "npx",
      "args": ["plantuml-mcp-server"],
      "env": {
        "PLANTUML_SERVER_URL": "https://www.plantuml.com/plantuml"
      }
    }
  }
}

To use your own PlantUML server, change the PLANTUML_SERVER_URL environment variable.

Then restart Claude Desktop/Code to activate the MCP server.

What You Can Do

After setup, you can ask Claude to:

Saving Diagrams Locally

The generate_plantuml_diagram tool supports saving diagrams to local files via the output_path parameter.

Security: By default, files can only be saved within the current working directory. Only .svg and .png extensions are allowed.

To allow additional directories, set the PLANTUML_ALLOWED_DIRS environment variable:

# Allow specific directories (colon-separated)
PLANTUML_ALLOWED_DIRS=/home/user/diagrams:/tmp/output
Allow any directory (use with caution)
PLANTUML_ALLOWED_DIRS=*

---

Examples

C4 diagram for plantuml-mcp-server

> add c4 diagram for this project in readme 'C4 diagram for plantuml-mcp-server' section

Sequence diagram for plantuml-mcp-server

> add sequence diagram in readme in architecture section

![PlantUML MCP Server Architecture](https://www.plantuml.com/plantuml/png/XLHDZzem4BtxLups50wKGwiU8b4j0aehmIhYwuI4J3m4guwTscDMjEf_hnoJyB5BUujddcVUUpFnioDkoPUAaII5a2ckQJMRmcoOmGBj4IrqOM3pWoJCoLk4hygyCiPpCXQULWxj4t07uODLt9BCPSKrmTDGSIyGHkX-aAbgK0pTmjxfM6Ddm-nzu8VSb3MY2J3MxpTSlsj9aYlvYvCq6lfzTgRH_H8gfh08UgzwRNJYI4W3PBbsbR7KOI7RuDk226ICSkb6Tw50ZPOJRgj0mPTgAoGlB2z34dLkn2KLGW9lGZNXKRm1arWhi0tE1ih1oq0WKazXZZyzEheCvzpjNjj3MaaR23nk1KQwJUca1coqTr8Na7j7femGgOlcNWDEuTjocS5alDpeNjEYvuv5xtUiAlwmbdCxWFMauG-24s-ANiIIjngmtA4GVASGLlFfbT9WJWeZwIh5JwqJmT7ncUP37sl0rOw7qxs7TzFxbtE3gbAdIxN6fVIo19y_9PrmubM5MdpSdGXTZ9ppEqb9vv43qK9mP8Ftzmui3kQrnLXqNb7SA_