Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add ariana-dot-dev/cloud-sandbox-vm-skills --skill expose-localhost-tunnelgit clone --depth 1 https://github.com/ariana-dot-dev/cloud-sandbox-vm-skillsWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/ariana-dot-dev/cloud-sandbox-vm-skills/expose-localhost-tunnel)<a href="https://agentmods.dev/skills/ariana-dot-dev/cloud-sandbox-vm-skills/expose-localhost-tunnel"><img src="https://agentmods.dev/badge/skills/ariana-dot-dev/cloud-sandbox-vm-skills/expose-localhost-tunnel/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/ariana-dot-dev/cloud-sandbox-vm-skills/expose-localhost-tunnel"><img src="https://agentmods.dev/badge/skills/ariana-dot-dev/cloud-sandbox-vm-skills/expose-localhost-tunnel.svg" alt="Reviewed on agentmods" width="80" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00094 | $0.00476 |
| Opus 5 | $0.00047 | $0.00238 |
| Sonnet 5 | $0.00019 | $0.00095 |
| Haiku 4.5 | $0.00009 | $0.00048 |
Grade C, and why
expose-localhost-tunnel scanned grade C with 2 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 9d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Downloads and executes remote codehighSupply chain
curl | sh runs whatever the server returns today, which is not necessarily what it returned when this was reviewed.
`curl -fsSL https://box.ascii.dev/install | sh`, then `box login "$BOX_API_KEY" --json`. Makes network callslowCapability
Not a fault in itself. Listed so you know the mod talks to something, and to what.
`curl -fsSL https://box.ascii.dev/install | sh`, then `box login "$BOX_API_KEY" --json`. What it actually says
Expose / tunnel localhost (Box)
Use this when a service running in a Box must be reachable from outside: sharing a dev preview, receiving webhooks, or demoing. Because the service already runs inside the VM, exposing it is one command — no ngrok-style sidecar, no extra account, no cert setup.
Recipe
box ssh "$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.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 9d ago First seen · 34 lines · 94 tokens per session scan C 093c66342847
expose-localhost-tunnel is a skill published in the GitHub repository ariana-dot-dev/cloud-sandbox-vm-skills (2 stars, last pushed 2mo ago), licensed MIT. It adds 94 tokens to every session and 476 once invoked, about $0.0005 per session on Opus 5. A static security scan graded it C with 2 findings (downloads and executes remote code, makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.
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