dJEB_mcp_server

This MCP server bridges Claude Desktop with the JEB Decompiler to enable AI-assisted reverse engineering workflows for Android APK analysis. Once configured, Claude can issue natural language prompts that leverage a suite of tools exposed by the JEB MCP server, such as decompiling methods or classes, listing and filtering classes, retrieving AndroidManifest.xml and resources, performing batch renames, and extracting cross-references. The server sits between Claude Desktop and JEB (via a bridge script) and communicates over a local port (default 8851). Available tools let you decompile targets to Java source, inspect class hierarchies, search resources, and perform batch operations that would be tedious manually. This enables a streamlined workflow where you can ask for code-style refactoring, API endpoint discovery, or cross-reference analysis, and have results returned in a developer-friendly format.

Key capabilities include:

• Decompile: decompile methods or entire classes to Java source.
• Navigation: list classes, search resources, and explore cross-references.
• Batch operations: rename classes/methods/fields and batch-rename local variables.
• Resource access: retrieve and inspect AndroidManifest.xml and resource files.
• Cross-references: locate all references to methods, fields, or strings.
• Class hierarchy: view implementations and inheritance.

To use it, configure Claude Desktop to connect to the local MCP server, ensure JEB is running and the bridge script is loaded in JEB, and then start Claude with prompts that request specific actions using the available tools.

Prerequisites

• JEB Decompiler (licensed) installed on your machine
• Claude Desktop installed
• Python 3.x installed on the machine where Claude Desktop runs

Setup steps

1. Clone the MCP server repository (or your project folder):

   git clone https://github.com/yourusername/jeb-mcp-server.git
   cd jeb-mcp-server
   

2. Prepare Claude Desktop configuration

   • Find Claude Desktop MCP configuration file:
     • macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
     • Windows: %APPDATA%/Claude/claude_desktop_config.json
   • Add or update the MCP server entry to point to the bridge script:

     {
       "mcpServers": {
         "dJEB_mcp_server": {
           "command": "python3",
           "args": ["/absolute/path/to/jeb_mcp_bridge.py"]
         }
       }
     }
     

3. Run the JEB bridge and server script

   • In JEB, load your APK and run the MCP bridge script (jeb_mcp_bridge.py) through the provided workflow. The JEB server (dJEB_mcp_server.py) will listen on port 8851.
   • Start Claude Desktop and ensure the MCP server configuration is loaded (you may need to restart Claude Desktop after configuration changes).

4. Validate the connection

   • Use a simple prompt in Claude to request a basic operation (e.g., list_classes) and verify results appear without errors.

Notes

• Ensure Python 3 is accessible to Claude Desktop and that the jeb_mcp_bridge.py path is absolute.
• The MCP server expects the JEB environment to be active and licensed; without JEB running, the bridge will not connect.

Tips and common issues:

• Port conflicts: The MCP bridge defaults to port 8851. If you already have a process using this port, update the bridge or server to a free port and reflect the change in Claude Desktop configuration.
• Environment variables: Some setups may need additional variables for JEB or Python paths. You can define them under the env section in mcp_config as needed.
• Long prompts: For large analysis tasks, break prompts into smaller steps (e.g., first decompile a set of classes, then retrieve cross-references) to improve reliability.
• Data handling: When renaming identifiers, start with non-critical elements to validate mappings before applying bulk changes.
• Logging: Enable verbose logs if available to troubleshoot bridge connectivity between Claude Desktop, the bridge, and JEB.
• Compatibility: This setup assumes JEB is accessed via a Jython (2.7) compatible environment; ensure scripts are compatible with that runtime.