A debugging assistant that captures everything happening in your web app during development - server logs, browser events, network requests, and automatic screenshots - organized in a timeline that AI can understand.
bun install -g dev3000 d3k
You can also install with npm or pnpm if you prefer — bun is recommended.
Select an AI agent (Claude, Codex, etc.) and start debugging. Tell your agent: "fix my app"
- Node.js >= v22.12.0
- tmux (for split-screen mode with AI agents)
d3k runs your development server and monitors it in a browser, capturing:
- Server logs and console output
- Browser console messages and errors
- Network requests and responses
- Automatic screenshots (navigation, errors, interactions)
- User interactions (clicks, form submissions)
Everything is saved to timestamped logs that AI assistants can read to understand what went wrong and suggest fixes.
d3k # Start d3k with agent selection prompt d3k --with-agent claude # Start with Claude in split-screen mode d3k --no-agent # Start d3k standalone (no agent)
d3k errors # Show recent errors (browser + server combined!) d3k errors -n 20 # Show last 20 errors d3k errors --context # Show interactions before each error (for replay) d3k errors --all # Show all errors from the session d3k logs # Show recent logs (browser + server combined) d3k logs --type browser # Show only browser logs d3k logs --type server # Show only server logs d3k logs -n 100 # Show last 100 lines d3k fix # Deep analysis of application errors d3k fix --focus build # Focus on build/compilation errors d3k fix --time 30 # Analyze last 30 minutes (default: 10) d3k crawl # Discover URLs by crawling the app d3k crawl --depth all # Exhaustive crawl (default: 1 level) d3k find-component "nav.header" # Find React component source d3k find-component "[data-testid='button']" d3k restart # Restart the development server (rarely needed)
d3k skill [name] # Get skill content or list available skills d3k upgrade # Upgrade d3k to the latest version d3k agent-browser # Run the bundled agent-browser CLI d3k cloud # Cloud-based tools using Vercel Sandbox
d3k --help # Show all options| Option | Description |
|---|---|
-p, --port <port> |
Development server port (auto-detected) |
-s, --script <script> |
Script to run (e.g. dev, main.py) |
-c, --command <command> |
Custom command (overrides auto-detection) |
--browser <path> |
Path to browser executable (Chrome, Arc, etc.) |
--profile-dir <dir> |
Chrome profile directory |
--servers-only |
Run servers only, skip browser launch |
--headless |
Run browser in headless mode (for CI) |
--debug |
Enable debug logging (disables TUI) |
-t, --tail |
Output logfile to terminal (like tail -f) |
--no-tui |
Disable TUI, use standard terminal output |
--with-agent <cmd> |
Run agent in split-screen mode (requires tmux) |
--no-agent |
Skip agent selection, run standalone |
--plugin-react-scan |
Enable react-scan performance monitoring |
--date-time <format> |
Timestamp format: 'local' or 'utc' |
- Start d3k - It detects your project type and starts the dev server
- Browser monitoring - A browser opens and monitors your app via Chrome DevTools Protocol
- Capture everything - Logs, errors, network requests, screenshots are saved
- AI reads logs - Your AI agent can read
~/.d3k/{project}/d3k.logto understand issues - Fix with context - The AI has full context to suggest accurate fixes
| What | Where |
|---|---|
| Logs | ~/.d3k/{project}/d3k.log |
| Screenshots | ~/.d3k/{project}/screenshots/ |
| Chrome profile | ~/.d3k/{project}/chrome-profile/ |
| Session info | ~/.d3k/{project}/session.json |
| Crash logs | ~/.d3k/crash.log |
d3k launches Chrome by default. Each project gets a dedicated Chrome profile that preserves login state, cookies, and local storage.
d3k --browser '/Applications/Arc.app/Contents/MacOS/Arc'# Brave d3k --browser '/Applications/Brave Browser.app/Contents/MacOS/Brave Browser' # Edge d3k --browser '/Applications/Microsoft Edge.app/Contents/MacOS/Microsoft Edge'
Skip browser monitoring entirely:
d3k --servers-only
For CI/CD environments:
d3k --headless
d3k can run alongside your AI agent in a split-screen terminal using tmux:
d3k --with-agent claude # Claude Code d3k --with-agent codex # OpenAI Codex d3k --with-agent opencode # OpenCode
Requirements:
- tmux installed (
brew install tmuxon macOS)
Controls:
Ctrl+B Left/Right- Switch focus between panesCtrl+Cin either pane - Exit both
d3k works with any web framework:
- JavaScript/TypeScript: Next.js, Vite, Create React App, Vue, Svelte, Astro
- Python: Django, Flask, FastAPI
- Ruby: Rails
- Any other web framework with a dev server
Yes! d3k works with any AI assistant that can read files. Point your AI to the log file at ~/.d3k/{project}/d3k.log.
Ctrl+C stops both d3k and your development server.
Screenshots are saved to ~/.d3k/{project}/screenshots/ with timestamps.
Check ~/.d3k/crash.log for details. Run with --debug for more verbose output.
# Install dependencies bun install # Run locally bun run dev # Build bun run build # Test bun run test # Lint bun run lint
We welcome contributions! Please see our contributing guidelines.
MIT