Debugging Strategies

Transform debugging from frustrating guesswork into systematic problem-solving with proven strategies, powerful tools, and methodical approaches.

When to Use This Skill

• Tracking down elusive bugs
• Investigating performance issues
• Understanding unfamiliar codebases
• Debugging production issues
• Analyzing crash dumps and stack traces
• Profiling application performance
• Investigating memory leaks
• Debugging distributed systems

Core Principles

1. The Scientific Method

1. Observe: What's the actual behavior? 2. Hypothesize: What could be causing it? 3. Experiment: Test your hypothesis 4. Analyze: Did it prove/disprove your theory? 5. Repeat: Until you find the root cause

2. Debugging Mindset

Don't Assume:

• "It can't be X" - Yes it can
• "I didn't change Y" - Check anyway
• "It works on my machine" - Find out why

Do:

• Reproduce consistently
• Isolate the problem
• Keep detailed notes
• Question everything
• Take breaks when stuck

3. Rubber Duck Debugging

Explain your code and problem out loud (to a rubber duck, colleague, or yourself). Often reveals the issue.

Systematic Debugging Process

Phase 1: Reproduce

## Reproduction Checklist

1. **Can you reproduce it?**
   - Always? Sometimes? Randomly?
   - Specific conditions needed?
   - Can others reproduce it?

2. **Create minimal reproduction**
   - Simplify to smallest example
   - Remove unrelated code
   - Isolate the problem

3. **Document steps**
   - Write down exact steps
   - Note environment details
   - Capture error messages

Phase 2: Gather Information

## Information Collection

1. **Error Messages**
   - Full stack trace
   - Error codes
   - Console/log output

2. **Environment**
   - OS version
   - Language/runtime version
   - Dependencies versions
   - Environment variables

3. **Recent Changes**
   - Git history
   - Deployment timeline
   - Configuration changes

4. **Scope**
   - Affects all users or specific ones?
   - All browsers or specific ones?
   - Production only or also dev?

Phase 3: Form Hypothesis

## Hypothesis Formation

Based on gathered info, ask:

1. **What changed?**
   - Recent code changes
   - Dependency updates
   - Infrastructure changes

2. **What's different?**
   - Working vs broken environment
   - Working vs broken user
   - Before vs after

3. **Where could this fail?**
   - Input validation
   - Business logic
   - Data layer
   - External services

Phase 4: Test & Verify

## Testing Strategies

1. **Binary Search**
   - Comment out half the code
   - Narrow down problematic section
   - Repeat until found

2. **Add Logging**
   - Strategic console.log/print
   - Track variable values
   - Trace execution flow

3. **Isolate Components**
   - Test each piece separately
   - Mock dependencies
   - Remove complexity

4. **Compare Working vs Broken**
   - Diff configurations
   - Diff environments
   - Diff data

Debugging Tools

JavaScript/TypeScript Debugging

// Chrome DevTools Debugger
function processOrder(order: Order) {
  debugger; // Execution pauses here

  const total = calculateTotal(order);
  console.log("Total:", total);

  // Conditional breakpoint
  if (order.items.length > 10) {
    debugger; // Only breaks if condition true
  }

  return total;
}

// Console debugging techniques
console.log("Value:", value); // Basic
console.table(arrayOfObjects); // Table format
console.time("operation");
/* code */ console.timeEnd("operation"); // Timing
console.trace(); // Stack trace
console.assert(value > 0, "Value must be positive"); // Assertion

// Performance profiling
performance.mark("start-operation");
// ... operation code
performance.mark("end-operation");
performance.measure("operation", "start-operation", "end-operation");
console.log(performance.getEntriesByType("measure"));

VS Code Debugger Configuration:

// .vscode/launch.json
{
  "version": "0.2.0",
  "configurations": [
    {
      "type": "node",
      "request": "launch",
      "name": "Debug Program",
      "program": "${workspaceFolder}/src/index.ts",
      "preLaunchTask": "tsc: build - tsconfig.json",
      "outFiles": ["${workspaceFolder}/dist/**/*.js"],
      "skipFiles": ["<node_internals>/**"]
    },
    {
      "type": "node",
      "request": "launch",
      "name": "Debug Tests",
      "program": "${workspaceFolder}/node_modules/jest/bin/jest",
      "args": ["--runInBand", "--no-cache"],
      "console": "integratedTerminal"
    }
  ]
}

Python Debugging

# Built-in debugger (pdb)
import pdb

def calculate_total(items):
    total = 0
    pdb.set_trace()  # Debugger starts here

    for item in items:
        total += item.price * item.quantity

    return total

# Breakpoint (Python 3.7+)
def process_order(order):
    breakpoint()  # More convenient than pdb.set_trace()
    # ... code

# Post-mortem debugging
how to use debugging-strategies
CursorClaude CodeClineCodexWindsurfGooseGitHub CopilotVS CodeGemini CLIKiloOpencodeKimi CLIRoo ClineAiderContinueZedBolt.newLovablev0Replit AgentSweepSmol DeveloperDevinCavemanAmpAntigravity
How to use debugging-strategies on Cursor
AI-first code editor with Composer
1
Prerequisites
Before installing skills in Cursor, ensure your development environment meets these requirements:
›Cursor installed and configured on your development machine
›Node.js version 16.0+ with npm package manager (verify with node --version)
›Active project directory or workspace where you want to add debugging-strategies
2
Execute installation command
Execute the skills CLI command in your project's root directory to begin installation:
$npx skills add https://github.com/wshobson/agents --skill debugging-strategiescopy
The skills CLI fetches debugging-strategies from GitHub repository wshobson/agents and configures it for Cursor.
3
Select Cursor when prompted
The CLI will show a list of available agents. Use arrow keys to navigate and space to select Cursor:
◆ Which agents do you want to install to?
│
│ ── Universal (.agents/skills) ── always included ────
│   • Amp
│   • Antigravity
│   • Cline
│   • Codex
│ ●Cursor(selected)
│   • Cursor
│   • Windsurf
4
Verify installation
Confirm successful installation by checking the skill directory location:
.cursor/skills/debugging-strategies
Reload or restart Cursor to activate debugging-strategies. Access the skill through slash commands (e.g., /debugging-strategies) or your agent's skill management interface.
⚠
Security & Verification Notice
We perform automated surface-level scans (Gen AI Scanner, Socket, Snyk) during installation. These checks detect common vulnerabilities but do not guarantee complete security. Always review skill source code and verify the publisher's reputation before production use.
Skills execute code in your development environment. Always verify the publisher's identity, review recent commits, and test in isolated environments before production deployment.
Additional Resources
›View source code on GitHub›Skills CLI documentation›Learn more about Cursor›What are agent skills?