Shrinking Algorithm MCP Server

Disclaimer: This setup assumes you are using Claude Desktop as your MCP client.

This MCP server exposes a single tool — shrink_diagram_by_kruskal — that accepts the text content of a PlantUML (.puml) file and returns a shrunken version of the diagram using Kruskal's algorithm. The intended workflow is:

Paste your .puml file content into Claude Desktop
Claude calls shrink_diagram_by_kruskal with the content
The MCP server processes it and returns the shrunken diagram
Claude presents the result back to you

Prerequisites

Docker Desktop installed and running
Claude Desktop installed

Step 1 — Build the Docker Image

⚠️ The build command must be run from the repository root, not from inside mcp_server/.

macOS / Linux:

docker build -f mcp_server/Dockerfile -t shrinking-algorithm-mcp .

Windows (Command Prompt):

docker build -f mcp_server\Dockerfile -t shrinking-algorithm-mcp .

Windows (PowerShell):

docker build -f mcp_server\Dockerfile -t shrinking-algorithm-mcp .

To verify the image was built successfully:

docker images | grep shrinking-algorithm-mcp

Step 2 — Create the Docker MCP Catalog

2a — Create the catalog YAML file

Create the following file at ~/.docker/mcp/catalogs/shrinking-algorithm.yaml:

macOS / Linux:

mkdir -p ~/.docker/mcp/catalogs

Then create the file ~/.docker/mcp/catalogs/shrinking-algorithm.yaml with this content:

tools:
  shrinking-algorithm:
    image: shrinking-algorithm-mcp:latest
    description: Shrinks PlantUML diagrams using Kruskal's algorithm.

Windows — create the file at %USERPROFILE%\.docker\mcp\catalogs\shrinking-algorithm.yaml with the same content.

2b — Register the catalog in the Docker MCP registry

Open (or create) ~/.docker/mcp/registry.yaml and add the following entry under the top-level servers key:

servers:
  shrinking-algorithm:
    ref: ""

If the file already has other entries, just append the shrinking-algorithm block under servers.

Windows — the file is at %USERPROFILE%\.docker\mcp\registry.yaml.

Step 3 — Configure Claude Desktop

Locate your Claude Desktop config file:

| Platform | Path | |----------|------| | macOS | ~/Library/Application Support/Claude/claude_desktop_config.json | | Windows | %APPDATA%\Claude\claude_desktop_config.json | | Linux | ~/.config/Claude/claude_desktop_config.json |

The contents of /mcp_server/claude_desktop_config.json in this repository show the server entry you need. Open your Claude Desktop config and merge in the shrinking-algorithm block under mcpServers:

{
  "mcpServers": {
    "shrinking-algorithm": {
      "command": "docker",
      "args": [
        "run",
        "--rm",
        "-i",
        "shrinking-algorithm-mcp"
      ]
    }
  }
}

If you already have other servers in mcpServers, just add the shrinking-algorithm entry alongside them.

Step 4 — Restart Claude Desktop

Fully quit and reopen Claude Desktop:

macOS: Cmd+Q, then reopen
Windows / Linux: Close from the system tray, then reopen

After restarting, click the 🔧 tools icon in the chat input area — you should see shrink_diagram_by_kruskal listed.

Usage

Paste the contents of a .puml file into the chat and prompt Claude:

"Use the shrink_diagram_by_kruskal tool on this diagram."

Claude will extract the text, call the tool, and return the shrunken diagram directly in the conversation.

Troubleshooting

Tool not appearing in Claude Desktop:

Make sure Docker Desktop is running
Verify the image exists: docker images | grep shrinking-algorithm-mcp
Check for JSON syntax errors in claude_desktop_config.json

Checking live logs:

# macOS / Linux
tail -f ~/Library/Logs/Claude/mcp-server-shrinking-algorithm.log

Testing the container directly:

docker run --rm -i shrinking-algorithm-mcp

MCP Servers