GitUML — Java / Spring Boot UML Generator + MCP Server

Generate UML class diagrams, sequence diagrams, flowcharts, and component diagrams from any Java or Spring Boot repository — via CLI or directly inside Claude Desktop as an MCP server.

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Features

• 5 MCP tools exposed to Claude Desktop: analyze_repo, generate_class_diagram, generate_sequence_diagram, generate_flowchart, generate_component_diagram
• Works with GitHub/GitLab URLs (shallow clone) or local paths
• Detects project type: pure_java, spring_boot, spring_mvc
• Detects build system: maven, gradle, none
• Annotation-aware Spring layer detection (Controller → Service → Repository → Model → Config → Messaging)
• Output in Mermaid, PlantUML, or both
• Test directories excluded by default

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Project Structure

gituml/
├── server.py              ← MCP server (FastMCP, STDIO transport)
├── main.py                ← CLI entry point (argparse)
├── test_server.py         ← Quick smoke-test for server tools
├── requirements.txt
├── core/
│   ├── models.py          ← Data models: ClassMeta, MethodMeta, RepoMetadata, …
│   └── java_parser.py     ← javalang-based Java AST parser
└── diagrams/
    ├── class_diagram.py
    ├── sequence_diagram.py
    ├── flowchart.py
    └── component_diagram.py

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Requirements

• Python 3.10+
• Git installed and available on PATH (needed for cloning remote repos)

pip install -r requirements.txt

requirements.txt installs:

Package	Purpose
javalang	Java AST parsing
gitpython	Shallow-clone remote repositories
mcp[cli]	FastMCP server / STDIO transport

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Usage — CLI

# From a GitHub URL
python main.py --repo https://github.com/spring-projects/spring-petclinic

# From a local path
python main.py --repo /path/to/my-spring-app

# With sequence diagram entry point
python main.py --repo /path/to/my-app \
               --entry-class UserController \
               --entry-method createUser

# With method-level flowchart
python main.py --repo /path/to/my-app \
               --flow-class OrderService \
               --flow-method processOrder

# Custom output directory, Mermaid only
python main.py --repo /path/to/my-app --output-dir ./diagrams --format mermaid

# Include test directories
python main.py --repo /path/to/my-app --include-tests

# Limit class diagram to 30 classes
python main.py --repo /path/to/my-app --max-classes 30

CLI Arguments

Argument	Short	Default	Description
--repo	-r	(required)	GitHub URL or local path
--output-dir	-o	./output	Directory for output .md files
--entry-class	-ec	None	Class for sequence diagram entry point
--entry-method	-em	None	Method to trace in sequence diagram
--flow-class	-fc	None	Class for method-level flowchart
--flow-method	-fm	None	Method for method-level flowchart
--format		both	mermaid | plantuml | both
--max-classes		60	Max classes in class diagram
--include-tests		False	Include test source directories

Output Files

All written to ./output/ by default:

output/
├── class_diagram.md
├── component_diagram.md
├── sequence_diagram.md
└── flowchart.md

Preview .md files in VS Code with the Markdown Preview Enhanced extension (Ctrl+Shift+V / Cmd+Shift+V).

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Usage — MCP Server (Claude Desktop)

Step 1 — Install Claude Desktop

Download from https://claude.ai/download

Step 2 — Locate the config file

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

Step 3 — Register GitUML

Open the config file and add the gituml entry:

Windows

{
  "mcpServers": {
    "gituml": {
      "command": "python",
      "args": ["C:\\Users\\YourName\\projects\\gituml\\server.py"]
    }
  }
}

macOS / Linux

{
  "mcpServers": {
    "gituml": {
      "command": "python3",
      "args": ["/home/yourname/projects/gituml/server.py"]
    }
  }
}

Windows note: Use double backslashes \\ in paths inside JSON.

Step 4 — Restart Claude Desktop

After saving the config, fully quit and relaunch Claude Desktop.

in the chat input bar — Ask for available tools and it should return the following:

• analyze_repo
• generate_class_diagram
• generate_sequence_diagram
• generate_flowchart
• generate_component_diagram
• generate_all

Step 5 — Talk to Claude

Analyse this repo: https://github.com/spring-projects/spring-petclinic

Generate a class diagram for C:/projects/my-spring-app

Show me the sequence diagram for UserController.createUser

Generate a flowchart for the processOrder method in OrderService

Show the component architecture of https://github.com/myorg/myrepo

Generate all diagrams for https://github.com/user/repo and save to ./output

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MCP Tools Reference

analyze_repo

Returns a structured summary of the repository — no diagrams generated.

Parameter	Type	Required	Description
repo	str	✅	GitHub URL or local path

Returns: Project type, build system, package list, layer breakdown, dependency graph.

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generate_class_diagram

Generates a UML class diagram showing classes, fields, methods, inheritance, and Spring layers.

Parameter	Type	Default	Description
repo	str	(required)	GitHub URL or local path
output_dir	str	""	Write to file if provided, else return as string
format	str	"both"	mermaid | plantuml | both
package_filter	str	None	Filter to classes in this package prefix
max_classes	int	60	Max classes to include

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generate_sequence_diagram

Traces the call chain from an entry point across Spring layers.

Parameter	Type	Default	Description
repo	str	(required)	GitHub URL or local path
output_dir	str	""	Write to file if provided
format	str	"both"	Output format
entry_class	str	None	Starting class (e.g. UserController)
entry_method	str	None	Starting method (e.g. createUser)

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generate_flowchart

Generates a control-flow diagram for a specific method, or a high-level architecture flowchart.

Parameter	Type	Default	Description
repo	str	(required)	GitHub URL or local path
output_dir	str	""	Write to file if provided
format	str	"both"	Output format
target_class	str	None	Class containing the target method
target_method	str	None	Method to flowchart

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generate_component_diagram

High-level architecture view — components grouped by Spring layer or package.

Parameter	Type	Default	Description
repo	str	(required)	GitHub URL or local path
output_dir	str	""	Write to file if provided
format	str	"both"	Output format

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generate_all

Generates all 4 diagrams and writes them to disk — equivalent to running main.py from the CLI.

Parameter	Type	Default	Description
repo	str	(required)	GitHub URL or local path
output_dir	str	"output"	Directory to write all 4 .md files
format	str	"both"	Output format
entry_class	str	""	Sequence diagram entry class
entry_method	str	""	Sequence diagram entry method
flow_class	str	""	Flowchart target class
flow_method	str	""	Flowchart target method
include_tests	bool	False	Include test source directories
max_classes	int	60	Max classes in class diagram

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Supported

Category	Detail
Languages	Java (via javalang AST parser)
Frameworks	Plain Java, Spring Boot, Spring MVC
Build tools	Maven (pom.xml), Gradle (build.gradle)
Sources	GitHub URLs, GitLab URLs, local paths
Output	Mermaid, PlantUML, or both
Spring layers	controller, service, repository, model, config, messaging, scheduler

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Troubleshooting

No Java classes found — Confirm the path points to a Java project root. Check that .java files exist under src/.

Failed to clone repo — Verify git is on your PATH and the URL is accessible. Private repos require SSH key or credential setup.

gitpython not installed — Run pip install gitpython.

Claude Desktop tools not appearing — Check the JSON config for syntax errors (trailing commas, wrong path separators on Windows). Fully quit and relaunch Claude Desktop.

MCP server not starting — Test the server directly: python server.py — it should block silently (waiting on STDIO). Any Python import errors will surface here.

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