D3k Agent Skill

Use when the user asks to use d3k, run/dev/test/debug a web project with d3k, or reproduce a browser issue. Own the runtime: reuse or background-start d3k non-interactively, wait for readiness, use its project-stable managed Chrome profile, and inspect unified browser/server evidence.

2k tokens

context cost

the whole folder, loaded on every use

files

instructions only

copies elsewhere

how many repositories repackaged it

1561

stars on the repo

on the repository, not the skill itself

Install

one command, takes just this skill from the repository

npx skills add https://github.com/vercel-labs/dev3000 --skill d3k

What comes with it

1 303 bytes besides the instruction

PUBLISH.md

agents/openai.yaml

The instruction itself

8 sections, as written by the author

d3k Agent Runtime

d3k is the local web runtime for this task. It starts the dev server behind a stable Portless URL, owns a project-stable Chrome profile, and records server logs, browser console output, network activity, interactions, and screenshots in one timeline.

When this skill triggers, operate d3k. Do not merely tell the user how to run it.

Interpret the Request

"Let me test/dev my project with d3k": prepare the runtime and headed browser, confirm it is ready, then hand control to the user. Wait for them to reproduce the issue before inspecting evidence.
"Test/debug/fix this with d3k": prepare the runtime, then drive the managed browser and investigate autonomously.
If ambiguous, start the runtime and browser first. That action is safe and useful for either path.

Start or Reuse d3k

Run from the project root.

Check for an existing project runtime:

d3k status --json

If it reports "running": true, reuse it. Do not start a second dev server or browser.

If d3k is not installed, install it:

bun install -g dev3000

Use npm install -g dev3000 only when Bun is unavailable.

Start d3k with the agent's shell/process tool as a retained background or yielded session:

d3k --no-agent --no-tui -t

Do not wait for this long-running command to exit. Keep its process/session handle so you can monitor or stop it later. Prefer the execution tool's background/session support over shelling with &.

If the target URL is already known, pass it so the managed browser opens there:

d3k --no-agent --no-tui -t --app-url "<url>"

Let d3k auto-detect the package manager, dev command, and port. Add --command, --script, or --port only when detection is wrong or the user specified them.

Poll until the runtime is ready:

d3k status --json

A successful status response is the readiness boundary. Prefer the reported Portless appUrl; the underlying app port may change between runs. If startup fails, inspect the retained process output and d3k logs --type server; do not launch a separate dev server.

User-Driven Testing

When the user says "let me test":

Confirm the status response includes the app URL and "browserConnected": true.
Tell the user the monitored browser is ready.
Keep the d3k process running and wait for the user to reproduce the behavior.
When they report that it happened, begin with:

d3k errors --context
d3k logs -n 200

Do not replace the headed browser with automation while the user is testing.

Agent-Driven Testing

Drive the exact browser d3k is monitoring:

d3k agent-browser snapshot -i
d3k agent-browser click @e2
d3k agent-browser fill @e3 "text"
d3k errors --context

Use --require-d3k-browser when opening a URL so failure cannot silently create another browser:

d3k agent-browser --require-d3k-browser open "<url>"

After every reproduction or code change, replay the relevant interaction and check d3k errors --context again.

Evidence Commands

Prefer these over ad-hoc log scraping:

d3k status --json
d3k errors --context
d3k logs -n 200
d3k logs --type browser
d3k logs --type server

Artifacts live under ~/.d3k/<project>/, including session.json, logs, screenshots, and the Chrome profile.

Browser and Auth Safety

d3k must own browser startup by default. Its per-project Chrome profile preserves login state, cookies, and local storage.

For Google OAuth, Supabase auth, and other auth-sensitive flows, never substitute raw Chrome, Playwright, a browser MCP session, manual CDP attachment, or agent-browser --profile. Those paths use a different browser/profile and can trigger "This browser or app may not be secure."

If the managed browser is unavailable, stop or interrupt the retained d3k process and restart d3k cleanly. Do not work around it by creating another browser.

Use --headless only for CI or when explicitly requested. Use --servers-only only when browser monitoring is intentionally unwanted.

Operating Rules

Do not run npm run dev, bun run dev, or another dev server alongside d3k.
Do not start a second d3k when d3k status --json reports an active one.
Keep d3k alive across edits and retests.
Preserve the project-stable Chrome profile unless the user explicitly asks for a fresh profile.
Leave the runtime running when handing a headed browser to the user; stop it only when asked or when the task requires a clean restart.
Portless routing is the default. Use --no-portless or PORTLESS=0 only when direct localhost routing is explicitly required.

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32k tokens

Open Source

by browser-use

> Documentation reference for writing Python code using the browser-use open-source library. Use this skill whenever the user needs help with Agent, Browser, or Tools configuration, is writing code that imports from browser_use, asks about @sandbox deployment, supported LLM models, Actor API, custom tools, lifecycle hooks, MCP server setup, or monitoring/observability with Laminar or OpenLIT. Also trigger for questions about browser-use installation, prompting strategies, or sensitive data handling. Do NOT use this for Cloud API/SDK usage or pricing — use the cloud skill instead. Do NOT use this for directly automating a browser via CLI commands — use the browser-use skill instead.

Use the browse CLI for Browserbase browser automation, Browserbase cloud APIs, Browserbase Functions, templates, web fetch/search, diagnostics, and Browse.sh skill discovery/installation. Use when the user asks to navigate pages, inspect browser state, run local or remote browser sessions, manage Browserbase resources, call Browserbase Functions, browse or scaffold Browserbase templates, fetch or search web content, diagnose browse setup, find or install a skill for a website task, discover site-specific Browse.sh skills, or install/refresh this browse skill.

Development workflows for the playwright-cli repository. Use when the user asks about rolling dependencies, releasing, or other repo maintenance tasks.

Turn a website's observable HTTP traffic into a best-effort OpenAPI 3.1 spec by analyzing a `browser-trace` capture. Use when the user wants to discover/extract API endpoints from a browser session, build an OpenAPI doc from network traffic, or document a third-party site's XHR/fetch surface for client integration.

26k tokens scripts

How to use it

Copy the folder

Take vercel-labs/d3k from the repository into ~/.claude/skills for personal use, or into .claude/skills inside a project.

Check the name does not clash

The agent identifies a skill by the name field in its header. Two skills with the same name cannot sit side by side — one of them will be ignored.

Install what it needs

The instructions reference npm. Without those the skill loads but fails at the first command.