vercel-labs/dev3000/d3k

d3k

Own the project's dev server and monitored browser through a small background runtime. No global d3k installation is needed. Evidence stays in bounded memory; browser authentication stays in the project Chrome profile.

Use node <skill-directory>/scripts/runtime.mjs as runtime below, from the target project root. In a development checkout the helper runs the source with Bun; installed skills use the JavaScript package through pnpm dlx (Node.js 24+ and pnpm required). Package acquisition runs in an isolated temporary directory so the target app’s pnpm workspace settings do not affect it; runtime commands still run against the target project. To try unreleased source from another project, set D3K_RUNTIME_ROOT to the dev3000 checkout. Do not use a previously published package to test unreleased changes.

Prepare

1. Run runtime portless status. Canonical HTTPS must be ready (canonical: true, serviceInstalled: true, setupRequired: false) before starting the app or browser. If needed run runtime portless setup, wait for the one-time administrator authorization, then check again. Stop if setup is unavailable; never silently substitute direct localhost.
2. Run runtime status. Reuse a ready runtime for this project. If it is starting, wait for readiness. Do not start another dev server. A legacy d3k session must be stopped before switching runtimes.
3. Start runtime start in a retained background tool session. Keep its process handle. The runtime detects the package manager and dev script; use --command '<dev command>' when needed. Poll runtime status until ready: true and browserConnected: true with a port-free https://...localhost URL. Inspect runtime events if startup fails while the runtime is still alive, and the retained process output if it exits.

Reproduce and inspect

• For “let me test,” give the user the app URL and leave the browser running while they reproduce the issue.
• For autonomous debugging, drive the same browser with runtime browser snapshot -i, runtime browser click @e2, and other agent-browser commands. The runtime supplies the CDP connection; never open a separate browser or profile.
• Before a reproduction, read runtime status and keep its sessionId and cursor.
• After the interaction, read runtime events --session <id> --after <cursor>. Server output, console messages, exceptions, network requests, and navigation share sequence numbers. Requests and responses carry CDP request IDs; adjacent server lines are chronological context, not proof of causation.
• Continue from the returned cursor while hasMore is true. Use --limit 1..500, --source server|browser|runtime, or --level error for focused reads. For error context, read the unfiltered interval as well. Filters advance the cursor through examined events; retain the original cursor if you need another view of the same interval.
• reset: true means the runtime restarted. dropped reports evicted events. Never claim complete evidence across either gap. Replay the interaction if necessary.
• Fix the code and repeat the same interaction, then inspect the new interval. Keep the runtime alive across edits.

Lifecycle

Keep the runtime's project-stable profile for sign-in state. Use --headless for CI or when requested; --servers-only deliberately omits the browser. Automatic screenshots and persistent log files are off; request a screenshot through runtime browser screenshot <absolute-path> when visual evidence is needed.

Stop with runtime stop or the retained process handle when asked. Leaving the browser open for user testing means leaving the runtime alive. Events are lost when it exits; only profile and session discovery data persist. Console/server text may contain application secrets; inspect selectively and avoid copying sensitive values into reports.