Debugssy - AI-Powered Debugging for VS Code

Stop clicking through the debugger. Just tell your AI what's broken.

Debug with natural language through any AI assistant (Cursor, GitHub Copilot, Claude Desktop, etc.) using the Model Context Protocol.

💡 The Problem

Debugging is tedious:

• ❌ Manual breakpoint hunting - "Maybe line 42? No, line 58? Try 63..."
• ❌ Repetitive stepping - Click step, check variable, step again, check again...
• ❌ Context switching - Jump between code, debugger UI, and documentation
• ❌ Time wasted - 30+ minutes to find a simple null reference

✨ The Solution

Just describe the bug. Your AI does the rest.

You: "The login function returns null for admin users"

AI: Sets breakpoint → Inspects user object → Finds role check fails →
     Traces to database query → Identifies missing WHERE clause → Done! ✅

3 minutes instead of 30. That's Debugssy.

🚀 What You Get

• 🎯 AI sets breakpoints where bugs actually are (not where you guess)
• 🔍 AI inspects variables and explains what's wrong in plain English
• 📊 AI analyzes call stacks to trace execution flow
• ⚡ AI uses conditional breakpoints to catch edge cases instantly
• 🤖 Full or assisted modes - You choose the automation level

No more: Manually setting 20 breakpoints to find one bug
Instead: "Find why users can't checkout" → AI debugs it in minutes

🏁 Quick Start (2 Minutes)

Step 1: Install Extension

In VS Code: Press Ctrl+Shift+X (or Cmd+Shift+X on Mac) → Search "Debugssy" → Click Install

Or install from: VS Code Marketplace · Open VSX

Step 2: Connect Your AI (One Click!)

Choose your AI assistant:

{
  "github.copilot.chat.mcp.servers": {
    "debugssy": {
      "url": "http://localhost:3000/mcp"
    }
  }
}

{
  "mcpServers": {
    "debugssy": {
      "url": "http://localhost:3000/mcp"
    }
  }
}

{
  "mcpServers": {
    "debugssy": {
      "url": "http://localhost:3000/mcp"
    }
  }
}

Other MCP clients? Connect to http://localhost:3000/mcp

Step 3: Start Debugging!

That's it! Now just tell your AI about any bug:

💬 "Debug why users get null when logging in"
💬 "Find where cartTotal becomes 0"
💬 "Trace why this loop runs 1000x instead of 10x"

Pro tip: Type / in your AI chat to see guided debugging workflows (/debug-crash, /trace-variable, etc.)

⚙️ How It Works

Debugssy connects your AI assistant to VS Code's debugging tools via the Model Context Protocol (MCP). Your AI gets access to:

Two modes:

• Assisted (default): You control execution via VS Code UI, AI inspects & sets breakpoints
• Full automation: AI controls everything (start debugging, continue, step through)

Secure: Localhost-only, origin validation, follows MCP security standards

🎬 Real-World Examples

🐛 Crash/Exception

💬 You: "Getting 'Cannot read property id of undefined' in UserService.ts line 45"

🤖 AI: Sets breakpoint → Inspects user object (null) → Traces back through call stack
      → Finds database query missing WHERE clause → Fix identified! ⚡

🔍 Wrong Value

💬 You: "cartTotal shows $0 but should be $150"

🤖 AI: Sets breakpoints on all cartTotal assignments → Continues execution
      → Finds discount calculation multiplying by 0 instead of subtracting → Fixed! ⚡

⚡ Infinite Loop

💬 You: "Loop running 1000x instead of 10x"

🤖 AI: Sets conditional breakpoint "i > 10" → Pauses at i=11 → Inspects condition
      → Finds <= instead of < (off-by-one error) → Done! ⚡

Want guided workflows? Type / in your AI chat:

• /debug-crash - Systematic crash debugging
• /trace-variable - Track variable changes
• /inspect-function - Function behavior analysis
• /debug-loop - Loop debugging
• /auto-debug-session - Full automation (full mode)

💡 Recommended models: Claude 4.5 Haiku or Grok 4 Fast (fast, accurate, cost-effective)

⚙️ Settings

Key settings (access via File → Preferences → Settings, search "debugssy"):

All settings:

{
  "debugssy.mcp.enabled": true,
  "debugssy.mcp.port": 3000,
  "debugssy.automationLevel": "assisted", // or "full"
  "debugssy.waitForBreakpointTimeout": 5000, // ms
  "debugssy.allowStepOperations": false, // Enable step ops in full mode
  "debugssy.maxExpressionLength": 100, // Security: max expression chars
  "debugssy.expressionValidationLevel": "moderate" // Security level
}

Commands (via Ctrl+Shift+P / Cmd+Shift+P):

• Debugssy: Start Server, Stop Server, Restart Server

❓ Troubleshooting

Still stuck? Check full docs at github.com/gmaynez/debugssy

🔒 Security & Privacy

• ✅ Localhost only - No network access, binds to 127.0.0.1
• ✅ Origin validation - Prevents DNS rebinding attacks
• ✅ Expression validation - Optional safeguards against unsafe code execution
• ✅ No telemetry - Your code stays on your machine

Follows MCP Security Best Practices 2025-06-18

📋 Requirements

• VS Code 1.85.0+
• Any MCP-compatible AI assistant (Cursor, Copilot, Claude Desktop, etc.)

💝 Support This Project

If Debugssy saves you time, consider buying me a coffee! Every contribution helps maintain and improve the extension.

📚 Learn More

• GitHub Repository - Full docs, source code, contribute
• Allowlist Guide - Security configuration examples
• MCP Compliance - Security implementation details
• Model Context Protocol - Learn about MCP

📄 License

Apache License 2.0 · Copyright © 2025 Guillermo Garcia Maynez