Agent skill · software engineering · yonatangross
dev
One-command dev loop: portless HTTPS subdomain, emulate API mocks, dev server and an agent-browser session keyed to the git branch. Use when starting a branch, switching worktrees or resuming a project.
Why this skill is useful
Adds an executable script that automates the entire development loop setup with multiple tools, enhancing the AI's capability to manage development environments.
What it needs
Requires agent-browser, emulate, portless, tailscale installed locally. About 6k tokens when loaded. Last updated 2026-08-06. 215 stars on the source repository.
What this skill does
dev — Lab-Stack Boot One command boots the four moving parts of a Vercel-Labs-flavored dev loop: 1. portless → named HTTPS https://<branch>.localhost (no port collisions across worktrees) 2. emulate → stateful API emulators on the same origin via @emulators/adapter-next 3. dev server → pnpm dev / npm run dev / yarn dev (auto-detected) 4. agent-browser → pre-warmed session named after the branch State lives in .claude/state/dev-stack.json. Teardown via dev stop reads the PIDs and signals SIGTERM in reverse boot order. Paired with expect: the agent-browser session that dev warms is the same one expect (and the M125 #2 auto-trigger) attach to — no second startup latency on the first UI test. When to invoke Situation Command --- --- Start work on a new branch dev Resume after a session break dev (idempotent — skips already-live processes) Tear down before deleting branch dev stop Inspect state dev status Share preview with stakeholder dev --share (tailnet) or dev --funnel (public) Time-boxed live demo dev --live 4 (public funnel, 4-hour expiry) Resuming a backgrounded dev session (CC 2.1.144+): Sessions started via claude --bg now appear in /resume alongside interactive ones, marked bg — use /resume as the direct recovery path after a crash or session end instead of navigating the agent view. Background shell sessions (CC 2.1.154+): In claude agents, type ! <command> to run a shell command as a backgrounded session you can attach to and detach from — also available as claude --bg --exec '<command>'. Useful for long dev-loop processes (watchers, builds, servers) you want to monitor without holding a terminal. Modes (M127) Flag Wraps Reach Tailscale CLI --- --- --- --- (none) portless <slug> <pkg-mgr> run dev https://<branch>.localhost only not required --share portless --tailscale ... tailnet members on https://.ts.net required --funnel portless --funnel ... public on the internet required --live N portless --funnel ... …
How to use it
Reference it in AdaL, Claude Code, Cursor or any coding agent — nothing to install:
@skills yonatangross/dev