Maven Decoder MCP Server

A comprehensive Model Context Protocol (MCP) server for analyzing Maven jar files in your local repository (~/.m2). This server provides powerful tools for agentic coding assistance in Java projects, enabling AI agents to understand dependencies, analyze bytecode, extract source code, and navigate the Maven ecosystem.

🚀 Features

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- Jar File Analysis: Deep inspection of jar files including metadata, manifests, and structure
- Dependency Resolution: Complete dependency tree analysis with transitive dependencies
- Source Code Extraction: Extract source code from source jars or decompile bytecode
- Class Information: Detailed class signatures, methods, fields, and annotations
- Search Capabilities: Find classes, methods, and dependencies across all artifacts
- Version Management: Compare versions, find dependents, and track version conflicts

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- Decompilation Support: Integrated support for multiple Java decompilers (CFR, Fernflower, Procyon)
- Conflict Analysis: Detect and analyze dependency version conflicts
- Repository Navigation: Browse and explore the local Maven repository structure
- Metadata Parsing: Extract and parse Maven POM files and metadata
- Service Discovery: Find and analyze Java services and SPI implementations
- Response Management: Intelligent pagination and summarization for large responses
- Method Extraction: Extract specific methods from large Java classes

📦 Installation

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- Java 8+ (for decompilation features)
- Maven local repository (~/.m2/repository)
- One of: Python 3.8+, Node.js 14+, or Docker

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#### One-Line Install (Recommended)
``bash
curl -fsSL https://raw.githubusercontent.com/salitaba/maven-decoder-mcp/main/install.sh | bash
`

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#### Method 1: uvx (Recommended)
`bash


Install uv (if not installed)

curl -Ls https://astral.sh/uv/install.sh | sh

Ensure your shell PATH is updated (restart shell or eval as printed by installer)

Run the server via uvx (isolated, fast, no venv needed)

uvx maven-decoder-mcp

Optional: pick a specific Python

uvx --python 3.12 maven-decoder-mcp

`

#### Method 2: Node.js/npm
`bash


Install globally

npm install -g maven-decoder-mcp

Or install locally

npm install maven-decoder-mcp

Run the server

maven-decoder-mcp

or if installed locally: npx maven-decoder-mcp

`

#### Method 3: Docker
`bash


Pull and run


docker run --rm -it \
-v ~/.m2:/home/mcpuser/.m2 \
-v $(pwd):/workspace \
ali79taba/maven-decoder-mcp:latest
`

#### Method 4: From Source (Development)
`bash


Clone repository

git clone https://github.com/salitaba/maven-decoder-mcp.git
cd maven-decoder-mcp

Option A: Using Virtual Environment

python3 -m venv .venv
source .venv/bin/activate # On Windows: .venv\Scripts\activate
pip install -r requirements.txt
pip install "git+https://github.com/modelcontextprotocol/python-sdk.git"
./setup_decompilers.sh

Option B: System-wide Installation (not recommended)

./setup_decompilers.sh
`

🔧 Configuration

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Add to your ~/.cursor/mcp_servers.json:

`json
{
"maven-decoder": {
"command": "uvx",
"args": ["maven-decoder-mcp"]
}
}
`

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The server runs as a standard MCP server and can be integrated with any MCP-compatible client.

🛠️ Available Tools

| Tool | Description |
|------|-------------|
| list_artifacts | List artifacts in Maven repository with filtering |
| analyze_jar | Analyze jar file structure and contents |
| extract_class_info | Get detailed information about Java classes |
| get_dependencies | Retrieve Maven dependencies from POM files |
| search_classes | Search for classes across all jars |
| extract_source_code | Decompile and extract Java source code |
| compare_versions | Compare different versions of artifacts |
| find_usage_examples | Find usage examples in test code |
| get_dependency_tree | Get complete dependency tree |
| find_dependents | Find artifacts that depend on a specific artifact |
| get_version_info | Get all available versions of an artifact |
| analyze_jar_structure | Analyze overall jar structure and metadata |
| extract_method_info | Extract specific method information from Java classes |

💡 Usage Examples

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`
"Show me all dependencies of org.springframework:spring-core:5.3.21"
`

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`
"Decompile the class com.example.MyService from my Maven repository"
`

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`
"Find all version conflicts in my Maven repository"
`

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`
"Show me all public methods in the Jackson ObjectMapper class"
`

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`
"List all Spring classes with pagination (page 2, 10 items per page)"
"Extract source code for a large class with summarization"
"Get method information for specific patterns in a class"
`

🔄 Response Management

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The server automatically handles large responses through intelligent pagination:

- Automatic Detection: Responses exceeding 50KB are automatically paginated
- Configurable Page Size: Default 20 items per page, customizable per request
- Pagination Metadata: Each response includes pagination information
- Supported Tools: list_artifacts, extract_class_info, search_classes, get_dependencies, find_dependents, get_version_info

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Large text content is automatically summarized to improve readability:

- Smart Summarization: Preserves important parts (package declarations, method signatures, closing braces)
- Configurable Limits: Default 10KB text limit, customizable
- Java-Specific: Optimized for Java source code structure
- Metadata Preservation: Original structure and metadata are maintained

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New tool for targeted access to specific methods:

- Pattern Matching: Use regex patterns to find specific methods
- Limited Results: Control the number of methods returned
- Full Context: Includes method signatures, bodies, and line numbers
- Efficient Processing: Only extracts requested methods, not entire classes

🏗️ Architecture

The server is built with a modular architecture:

- MavenDecoderServer: Main MCP server implementation
- ResponseManager: Handles pagination and summarization
- JavaDecompiler: Handles multiple decompilation strategies
- MavenDependencyAnalyzer: Analyzes Maven dependencies and metadata
- Decompilers: CFR, Procyon, Fernflower, and javap integration

🧪 Development

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`bash

Install development dependencies

pip install -e ".[dev]"

Run tests

pytest

Run specific test

python test_startup.py
`

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`bash

Build distribution

python setup.py sdist bdist_wheel

Install locally

pip install dist/maven_decoder_mcp-*.whl
`

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`bash

Build Docker image

docker build -t maven-decoder-mcp .

Run container

docker run --rm -it maven-decoder-mcp
`

📝 Configuration Options

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- MAVEN_HOME: Custom Maven repository location (default: ~/.m2/repository)
- MCP_LOG_LEVEL: Logging level (DEBUG, INFO, WARNING, ERROR)
- MCP_MAX_RESPONSE_SIZE: Maximum response size in bytes (default: 50000)
- MCP_MAX_ITEMS_PER_PAGE: Default items per page (default: 20)
- MCP_MAX_TEXT_LENGTH: Maximum text length before summarization (default: 10000)
- MCP_MAX_LINES: Maximum lines before summarization (default: 500)

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The server automatically detects and configures:
- Maven repository location
- Available Java decompilers
- System capabilities

🔍 Troubleshooting

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Server won't start
`bash


Check Python installation

python --version

Check Maven repository

ls ~/.m2/repository

Check logs

maven-decoder-mcp --debug
`

Decompilation fails
`bash


Check Java installation

java -version

Setup decompilers manually

maven-decoder-setup decompilers
`

No artifacts found
`bash


Verify Maven repository location

ls ~/.m2/repository

Run a Maven build to populate repository

mvn dependency:resolve
`

🤝 Contributing

1. Fork the repository
2. Create a feature branch (git checkout -b feature/amazing-feature)
3. Commit your changes (git commit -m 'Add amazing feature')
4. Push to the branch (git push origin feature/amazing-feature`)
5. Open a Pull Request

📄 License

This project is licensed under the MIT License - see the LICENSE file for details.

🙏 Acknowledgments

- Model Context Protocol - The protocol that powers this server
- CFR - Java decompiler
- Procyon - Java decompiler
- Maven - Dependency management

📊 Stats

!GitHub Stars
!PyPI Downloads
!Docker Pulls

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Made with ❤️ for the Java development community