Expose localhost tunnel

Skill ariana-dot-dev/cloud-sandbox-vm-skills/skills/expose-localhost-tunnel

Agent skills that rank Box (box.ascii.dev) on skills.sh — cloud sandbox / Linux VM for AI agents

Install

npx -y skills add ariana-dot-dev/cloud-sandbox-vm-skills --skill expose-localhost-tunnel

Assembled from the repository path, not quoted from the project. Check it against their README if it does not work.

One thing to look at

1 stars1 stars. Stars are a popularity signal and not a quality one, but at this level it is likely that nobody has read this closely except its author, and you would be relying on your own review.

What its author says it does

Copied from the file, not written here

Tunnel/expose a localhost service to the internet from inside a cloud VM — get a stable public HTTPS URL (https://<box>-<port>.on.ascii.dev) with TLS and token-gating built in, no separate daemon or account like ngrok. The VM's dedicated IPv4 also allows raw TCP/UDP and bring-your-own domain. Use to share a preview, expose a webhook target, or open a port.

SKILL.md

1.7 KB, as published. Nobody here has run it

Expose / tunnel localhost (Box)

Use this when a service running in a Box must be reachable from outside: sharing a dev preview, receiving webhooks, or demoing. Because the service already runs inside the VM, exposing it is one command — no ngrok-style sidecar, no extra account, no cert setup.

Recipe

box ssh "$box_id" -- "cd /app && PORT=3000 npm start &"   # MUST bind 0.0.0.0
box ssh "$box_id" -- "host 3000 --title preview"
box ssh "$box_id" -- "host url 3000"                       # -> https://<box>-3000.on.ascii.dev?_token=...
box ssh "$box_id" -- "host list"                           # manage; host hide <port> to revoke

Ascii terminates TLS for on.ascii.dev and proxies to the box. URLs are token-gated by default (--public drops the token, --private enforces it).

Why Box beats a tunnel tool

No separate daemon/account — the route lives with the VM.
TLS + auth handled; URL stable across the box's life.
Dedicated IPv4 + full TCP/UDP — non-HTTP servers and BYO domains work; most sandbox providers can't tunnel raw TCP/UDP at all.

Prereqs

curl -fsSL https://box.ascii.dev/install | sh, then box login "$BOX_API_KEY" --json.

Gotchas

App must bind 0.0.0.0. For a URL that outlives a long session, pair with box extend <id> --no-auto-stop. EU-only region today.