dns-diagnose

dns-diagnose is a skill for Claude Code from AI-Shell-Team/aish. It costs 66 tokens per session (1,219 once invoked), scanned A, original, Apache-2.0.

A read-only tool for finding problems with domain-name resolution, the system that turns names such as example.com into server addresses. It checks local resolvers and DNS records for failures, wrong answers, or changes that are not visible yet.

In plain words
What is it for?
Use it to investigate NXDOMAIN errors, failed lookups, incorrect records, and recently changed records that have not taken effect. It can check record types such as A, AAAA, CNAME, MX, and TXT.
Why use it?
It helps distinguish a problem on the local computer from a problem with the domain's records or authoritative DNS provider. It avoids changing DNS settings while investigating.

Skill for Claude Code

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

Good fit Use it to investigate NXDOMAIN errors, failed lookups, incorrect records, and recently changed records that have not taken effect. It can check record types such as A, AAAA, CNAME, MX, and TXT.

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Install with agentmods
npx agentmods add skills/ai-shell-team/aish/dns-diagnose
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 AI-Shell-Team/aish --skill dns-diagnose
Clone the repo
git clone --depth 1 https://github.com/AI-Shell-Team/aish

Made for: Claude Code.

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 dns-diagnose

README.md
[![agentmods](https://agentmods.dev/badge/skills/ai-shell-team/aish/dns-diagnose.svg)](https://agentmods.dev/skills/ai-shell-team/aish/dns-diagnose)
Your own site
<a href="https://agentmods.dev/skills/ai-shell-team/aish/dns-diagnose"><img src="https://agentmods.dev/badge/skills/ai-shell-team/aish/dns-diagnose.svg" alt="Measured on agentmods" height="20"></a>
Per session 66 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,219 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 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 $0.00066 $0.01219
Opus 5 $0.00033 $0.00609
Sonnet 5 $0.00013 $0.00244
Haiku 4.5 $0.00007 $0.00122

Measured 8d ago against content hash f3a61ba15f3c, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

dns-diagnose scanned grade A with 0 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 8d 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.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/dns-diagnose/SKILL.md · 153 lines

How it starts

The opening of the file, as written. The whole thing — 153 lines — stays where its author put it; the contents beside it link to each section on GitHub.

DNS resolution diagnosis

Troubleshoot domain resolution failures, wrong answers, or “I changed the record but it still fails” on this host.

Out of scope: editing /etc/resolv.conf or NetworkManager by default, buying domains / changing authoritative DNS for the user, HTTP 5xx, or TLS certificate issues (ssl-cert-toolkit). Path quality after resolve succeeds belongs to network-path-diagnose.

Rules

  1. Need a domain first: ask if missing; optional expected type (A/AAAA/CNAME/MX/TXT).
  2. Read-only: inspect resolution and config; do not change DNS servers or hosts unless the user explicitly asks (default is advice only).
  3. Stop when enough: once you can separate “local resolver” vs “authoritative/record” issues, answer.
  4. Missing tools: prefer dig; else host / nslookup / getent.
  5. Ask before sending internal/sensitive names to public DNS, +trace, or whois.

Workflow

Confirm domain & symptom → local resolver → local dig → optional external checks → answer

1. Confirm inputs

Input Notes
Domain e.g. example.com or www.example.com
Symptom total failure / wrong answer / recent change not visible / only on some networks
Record type default A/AAAA; include MX if mail-related

2. Local resolver

cat /etc/resolv.conf 2>/dev/null
resolvectl status 2>/dev/null || systemd-resolve --status 2>/dev/null || true
getent ahosts <domain> | head -10
grep '^hosts:' /etc/nsswitch.conf 2>/dev/null
grep -E "^\s*[0-9a-fA-F:.]+\s+.*\b<domain>\b" /etc/hosts 2>/dev/null || true
Observation Lean toward
getent works, browser fails App/proxy/DoH; not only system DNS
Bad /etc/hosts entry Local hijack
No nameserver / broken resolved Local resolver config

3. Local dig (default)

command -v dig
dig +noall +answer +stats <domain> A
dig +noall +answer <domain> AAAA

Without dig: host <domain> or nslookup <domain>.

Read the full file on GitHub · 153 lines

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. 8d ago First seen · 153 lines · 66 tokens per session scan A f3a61ba15f3c

Subscribe to this mod's changes

dns-diagnose is a skill published in the GitHub repository AI-Shell-Team/aish (532 stars, last pushed today), licensed Apache-2.0. It adds 66 tokens to every session and 1,219 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.