tunnel-doctor

tunnel-doctor is a skill for Claude Code from daymade/claude-code-skills. It costs 226 tokens per session (20,384 once invoked), scanned D, original, MIT.

A troubleshooting guide for network paths involving Tailscale, proxies, VPNs, SSH, virtual machines, containers, and WSL, the Linux environment that runs inside Windows.

In plain words
What is it for?
It is for diagnosing routing, DNS, proxy bypass, TUN forwarding, SSH tunnelling, and proxy-chain performance problems on macOS and Windows/WSL.
Why use it?
It helps find which networking layer is causing a connection to fail, slow down, or stall instead of relying on guesswork.

Skill for Claude Code

Written for Claude Code: allowed-tools in frontmatter. Also seen: mentions Claude Code.

Good fit It is for diagnosing routing, DNS, proxy bypass, TUN forwarding, SSH tunnelling, and proxy-chain performance problems on macOS and Windows/WSL.

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Install with agentmods
npx agentmods add skills/daymade/claude-code-skills/tunnel-doctor
About the project

Claude Code Skills Marketplace is a collection and marketplace of skills, plugins, agents, and instructions that extend Claude Code with specialized development workflows. It is for developers who want to install existing workflows or create, validate, and package their own Claude Code skills.

daymade/claude-code-skills · 1,385 stars · on GitHub

Install

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.

Any agent
npx skills add daymade/claude-code-skills --skill tunnel-doctor
Clone the repo
git clone --depth 1 https://github.com/daymade/claude-code-skills

Made for: Claude Code.

Its marketplace also offers this one on its own, as the plugin tunnel-doctor/plugin install tunnel-doctor after adding the marketplace above.

Wrote 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.

agentmods badge for tunnel-doctor

README.md
[![agentmods](https://agentmods.dev/badge/skills/daymade/claude-code-skills/tunnel-doctor/github.svg)](https://agentmods.dev/skills/daymade/claude-code-skills/tunnel-doctor)
Your own site
<a href="https://agentmods.dev/skills/daymade/claude-code-skills/tunnel-doctor"><img src="https://agentmods.dev/badge/skills/daymade/claude-code-skills/tunnel-doctor/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.

agentmods 80×15 button for tunnel-doctor

Your own site · 80×15
<a href="https://agentmods.dev/skills/daymade/claude-code-skills/tunnel-doctor"><img src="https://agentmods.dev/badge/skills/daymade/claude-code-skills/tunnel-doctor.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 226 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 20,384 The whole file, excluding the scripts and references it only reads on demand.
Security scan D 3 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • Socket pass 23 Mar 2026
  • Snyk warn 23 Mar 2026
How audits are shown
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00226 $0.20384
Opus 5 $0.00113 $0.10192
Sonnet 5 $0.00045 $0.04077
Haiku 4.5 $0.00023 $0.02038

Measured today against content hash ad59feb7ad00, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade D, and why

tunnel-doctor scanned grade D with 3 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 today.

The scan reads SKILL.md. This mod also ships 1 executable file (scripts/quick_diagnose.py), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

Asks for rootmediumPrivilege escalation

A mod that escalates privileges can change anything on the machine, not only the project.

**Why "restart the app" beats "flush DNS cache"**: `sudo dscacheutil -flushcache; sudo killall -HUP mDNSResponder` flushes cached results, but the resolver chain in `scutil --dns` is rebuilt from network configuration, n

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://tailscale.com/install.sh | sh

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

SSH/HTTP fails, browser returns 503 while curl works, Git SSH closes through the
tunnel-doctor/SKILL.md · 1,291 lines

How it starts

The opening of the file, as written. The whole thing — 1,291 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Tunnel Doctor

Diagnose and fix conflicts when Tailscale coexists with proxy/VPN tools on macOS, with specific guidance for SSH access to WSL instances.

Methodology base: the general diagnostic discipline this skill builds on — evidence over assumption, falsification over confirmation, layered isolation, counter-review — lives in the debugging-network-issues skill. This skill is the macOS Tailscale⨯proxy domain layer on top of it; reach for the base skill when the symptom is not a known Tailscale/proxy conflict.

Ownership boundary: this skill owns concrete local network-path operations: Tailscale, route/DNS/proxy interception, VM/WSL propagation, TUN forwarding planes, and proxy node/exit/chain capacity. Use debugging-network-issues as the general method when the boundary is still unknown or the symptom belongs to SSE/CDN/application protocol behavior. This keeps one concrete operator instead of forcing the user to choose between two overlapping proxy doctors.

Target and task scope

Before remote probes or changes, establish whether the target is a designated test machine, an explicitly requested colleague's working computer, or unknown. Use the owner's existing machine-purpose ledger and current task; do not log into a colleague's machine to classify it. Saved SSH access and previous successful tests do not grant ongoing use. Use designated test machines for routine testing; their unavailability does not authorize another person's computer.

Keep an explicitly requested one-off test on a colleague's computer within its stated result and necessary verification. Stop there on completion, cancellation, or a need for an unapproved environment change. Move later performance, migration, and regression tests to designated test machines. A test failure does not authorize disabling that person's proxy/VPN, quitting apps, changing routes, or installing a background task. Proceed with disruptive repair there only when the user has explicitly requested that repair and its interruption. Existing authorization for owner test-machine maintenance remains valid; do not ask again for its routine steps.

Read the full file on GitHub · 1,291 lines

Files

What ships with it

6 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

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.

  1. today Changed · +30 lines ad59feb7ad00
  2. 6d ago First seen · 1,261 lines · 226 tokens per session scan D 702087cc5904

Subscribe to this mod's changes

tunnel-doctor is a skill published in the GitHub repository daymade/claude-code-skills (1,385 stars, last pushed today), licensed MIT. It adds 226 tokens to every session and 20,384 once invoked, about $0.0011 per session on Opus 5. A static security scan graded it D with 3 findings (asks for root, downloads and executes remote code, makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.

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