Debugger MCP Server

# Debugger MCP Server

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A JetBrains IDE plugin that exposes an **MCP (Model Context Protocol) server**, giving AI coding assistants full programmatic control over the debugger. Set breakpoints, step through code, inspect variables, and evaluate expressions—all driven autonomously by your AI assistant.

**Fully tested**: IntelliJ IDEA, PyCharm, WebStorm, GoLand, RustRover, Android Studio, PhpStorm
**May work** (untested): RubyMine, CLion, DataGrip

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<!-- Plugin description -->
**Debugger MCP Server** gives AI coding assistants complete control over the IDE's debugger through the Model Context Protocol (MCP). Let your AI assistant debug code autonomously—from setting breakpoints to inspecting variables to stepping through execution.

### Features

**Debug Session Management**
- **Start/Stop Sessions** - Launch any run configuration in debug mode
- **Rich Status** - Get comprehensive state in a single call (variables, stack, source context)
- **Multi-Session Support** - Manage multiple concurrent debug sessions

**Breakpoint Management**
- **Line Breakpoints** - Set breakpoints at any valid location
- **Conditional Breakpoints** - Add conditions that must be true to pause
- **Tracepoints** - Log messages without pausing execution

**Execution Control**
- **Step Over/Into/Out** - Navigate through code line by line
- **Resume & Pause** - Control execution flow
- **Run to Line** - Continue execution until a specific line

**Variable Inspection**
- **View Variables** - Inspect local variables, arguments, and object fields
- **Modify Values** - Change variable values during debugging

**Expression Evaluation**
- **Evaluate Expressions** - Run arbitrary expressions in the current context
- **Code Fragments** - Execute multi-line code snippets
- **Safety Controls** - Choose unrestricted evaluation, a default risky-operation blocklist, or conservative read-only checks with optional custom regex block rules

**Stack & Thread Navigation**
- **Stack Traces** - View the complete call stack with source locations
- **Frame Selection** - Switch context to any stack frame
- **Thread Listing** - See all threads and their states

**Companion Skill**
- **AI Debugging Guidance** - Bundled companion skill teaches AI agents optimal debugger tool usage
- **One-Click Install** - Install to `.claude/skills/` or export as `.skill`/`.zip`

### Why Use This Plugin?

Unlike manual debugging, this plugin enables:
- **Autonomous AI Debugging** - Your AI assistant can debug code without human intervention
- **Rich Context in Single Calls** - Get variables, stack, and source in one request
- **Programmatic Breakpoint Control** - Set conditional breakpoints with complex expressions
- **Cross-IDE Compatibility** - Works with any JetBrains IDE that supports XDebugger
- **22 Comprehensive Tools** - Full debugging capability through MCP
- **Configurable Server** - IDE-specific ports with customizable host binding

Perfect for AI-assisted development workflows where you want your assistant to investigate bugs, validate fixes, or explore code behavior autonomously.
<!-- Plugin description end -->

## Table of Contents

- [Installation](#installation)
- [Quick Start](#quick-start)
- [Client Configuration](#client-configuration)
- [Available Tools](#available-tools)
- [Multi-Project Support](#multi-project-support)
- [Tool Window](#tool-window)
- [Error Codes](#error-codes)
- [Settings](#settings)
- [Requirements](#requirements)
- [Contributing](#contributing)

## Installation

### Using the IDE built-in plugin system

<kbd>Settings/Preferences</kbd> > <kbd>Plugins</kbd> > <kbd>Marketplace</kbd> > <kbd>Search for "Debugger MCP Server"</kbd> > <kbd>Install</kbd>

### Using JetBrains Marketplace

Go to [JetBrains Marketplace](https://plugins.jetbrains.com/plugin/29233) and install it by clicking the <kbd>Install to ...</kbd> button.

### Manual Installation

Download the [latest release](https://github.com/hechtcarmel/jetbrains-debugger-mcp-plugin/releases/latest) and install it manually:
<kbd>Settings/Preferences</kbd> > <kbd>Plugins</kbd> > <kbd>⚙️</kbd> > <kbd>Install plugin from disk...</kbd>

## Quick Start

1. **Install the plugin** and restart your JetBrains IDE
2. **Open a project** - the MCP server starts automatically on an IDE-specific port
3. **Find your IDE port**: <kbd>Settings</kbd> > <kbd>Tools</kbd> > <kbd>Debugger MCP Server</kbd> (each IDE has a unique default port, e.g., 29190 for IntelliJ IDEA)
4. **Configure your AI assistant** with the server URL: `http://127.0.0.1:{PORT}/debugger-mcp/

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