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 a comprehensive executable script that automates the entire development loop setup, including stateful API mocks and a pre-warmed browser session, which the AI cannot generate from knowledge alone.
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--1baa04