jadx-mcp-plugin

⚙️ Jadx MCP Plugin — Decompiler Access for Claude via MCP

This project provides a Jadx plugin written in Java, which exposes the Jadx API over HTTP — enabling live interaction through MCP clients like Claude via the Model Context Protocol (MCP). A lightweight FastMCP adapter in Python acts as a bridge between Claude and the plugin. This enables intelligent navigation and automation of reverse engineering workflows, ideal for AI-assisted security analysis of Android apps.

🧰 Setup Instructions

# Clone this repository
git clone https://github.com/mobilehackinglab/jadx-mcp-plugin.git
cd jadx-mcp-plugin

# Create and activate a virtual environment
python3 -m venv venv

# Activate:
source venv/bin/activate      # Linux/Mac
.\venv\Scripts\activate       # Windows

Install Python dependencies

pip install -r requirements.txt

🧠 Setup Claude MCP CLient Integration

To use this adapter in Claude Desktop, go to `File` -> `Settings` -> `Developer` -> `Edit Config` -> `claude_desktop_config.json` and add an MCP server pointing to the Python executable in the venv (to prevent depedency issues) and the full adapter path following below examples:

Windows:

{
  "mcpServers": {
    "Jadx MCP Server": {
      "command": "C:\\Workset\\jadx-mcp-plugin\\venv\\Scripts\\python.exe",
      "args": ["C:\\Workset\\jadx-mcp-plugin\\fastmcp_adapter.py"]
    }
  }
}

MacOS / Linux:

{
  "mcpServers": {
    "Jadx MCP Server": {
      "command": "/Users/yourname/jadx-mcp-plugin/venv/bin/python",
      "args": ["/Users/yourname/jadx-mcp-plugin/fastmcp_adapter.py"]
    }
  }
}

Make sure to restart (Quit) Claude after editing the config.

After restart it should look like this:

✅ Usage Flow

1. Open Jadx with the latest plugin JAR from the releases placed in its `plugins/` folder or load it via `Plugins` -> `install plugin`.

2. Load an APK or DEX file

3. (Optional) You can specify the HTTP interface address by launching Jadx with:

jadx-gui -Pjadx-mcp.http-interface=http://localhost:8085

This is useful if you want to change the default host/port (`http://localhost:8085`).

> Note: If you change the interface address here, make sure to also update the corresponding URL in `fastmcp_adapter.py` to match.

4. Claude will detect and activate the Jadx MCP Server tools.

5. You can now list classes, fetch source, inspect methods/fields, and extract code live.

🧪 Tools Provided

🛠 Development

☕ Java Plugin

The Java plugin is located at:

plugin/src/main/java/com/mobilehackinglab/jadxplugin/McpPlugin.java

It uses the `JadxPlugin` API (`jadx.api.*`) to:

• Load decompiled classes and methods
• Serve structured data via an embedded HTTP server
• Respond to `/invoke` and `/tools` endpoints

🚀 Automated Installation with Gradle Tasks

You can use the following Gradle task to build and install the plugin in one step:

./gradlew installPlugin

> This uses the `jadx plugins` CLI. Make sure Jadx is installed and available in your `PATH`.

For other plugin-related tasks (uninstall, enable/disable), see the task definitions in `plugin/build.gradle`.

🔧 Manual Installation

To build the plugin:

./gradlew build
# Output: plugin/build/libs/jadx-mcp-plugin-.jar

Install the plugin JAR using the `jadx plugins` CLI:

jadx plugins --install-jar path/to/jadx-mcp-plugin-.jar

Alternatively, place the built `.jar` file into your Jadx `plugins/` folder, typically located at: `~/.jadx/plugins/`

If you place the JAR manually, you’ll also need to enable the plugin through the Jadx GUI or by running:

jadx plugins --enable jadx-mcp

Python FastMCP Adapter

The adapter file is:

fastmcp_adapter.py

It translates Claude’s MCP tool calls into HTTP POSTs to the running Jadx plugin server. Make sure Jadx is open before starting Claude.

🤝 Contributing

PRs, feature requests, and tool extensions are welcome!

This project is maintained by Mobile Hacking Lab.

🧩 Credits

• Jadx
• FastMCP
• Claude by Anthropic