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mfraunhofermfraunhofer/claude-skills/check-domain/SKILL.md

check-domain

Skill0 starsChanged 3 months agoMITView on GitHub

Check domain availability with a whois lookup against the official registrars (DENIC for .de, EURid for .eu, Verisign for .com/.net, PIR for .org). Use when checking if a domain is available, during brand/naming research, or before registering a new domain.

  • Installs packages

The file

We split this skill into the rules it gives an agent

7 rules. About 0 are common, 4 are distinctive, and 3 are very specific to this project.

  • ≈0

    Common · estimate

    Many files like this have a rule of this kind.

  • ≈4

    Distinctive · estimate

    This author's own choices. Worth a look.

  • 3

    Very specific

    Tied to their project's names, files or tools. Probably skip.

  • Common
  • Distinctive
  • Very specific
  1. Very specific:

    Check whether domain names are available for registration.

    line 8
  2. Distinctive:

    Before registering a new domain

    line 13
  3. Distinctive:

    Check a single domain:

    line 22
  4. Distinctive:

    Check one name across all major TLDs (.de .com .eu .org .net):

    line 32
  5. Very specific:

    Do NOT use the python-whois pip package for .de domains: its error text can contain Status: free even when the domain IS registered, and it …

    line 54
  6. Distinctive:

    Do NOT use third-party WHOIS sites (who.is, whois.com): they cache results and can be wrong.

    line 55
  7. Very specific:

    Always use the system whois command, which queries the official registrars directly.

    line 56

≈ “Common” is an estimate: at least 1 in 5 of the 350,495 skill files we read have a rule of the same kind, not the same words. “Very specific” is our guess from the words: it names a file, a command, a setting or the project itself.

Keep what fits and drop the rest. Your version, ready for your agents.
Files
SKILL.md

Check Domain Availability

Check whether domain names are available for registration. Uses the system whois command directly against official registrars for reliable results, no third-party libraries or lookup sites.

When to use

  • Checking if a domain is available
  • Brand/naming research where domain availability matters
  • Before registering a new domain

Requirements

The system whois command. No API keys.

  • macOS: brew install whois (or preinstalled)
  • Debian/Ubuntu: apt install whois

Usage

Check a single domain:

python3 ~/.claude/skills/check-domain/scripts/check_domain.py example.de

Check multiple domains:

python3 ~/.claude/skills/check-domain/scripts/check_domain.py example.de example.com example.eu example.org

Check one name across all major TLDs (.de .com .eu .org .net):

python3 ~/.claude/skills/check-domain/scripts/check_domain.py --all mybrand

Output:

mybrand.de         FREE
mybrand.com        TAKEN  (registered: 2019-06-28, expires: 2026-06-28)
mybrand.eu         FREE

How it works

  • Calls the whois CLI directly (not the python-whois library, which is unreliable for .de domains)
  • Parses the raw WHOIS response per TLD:
    • .de (DENIC): Status: free = available
    • .com/.net (Verisign): No match for = available
    • .eu (EURid): Status: AVAILABLE = available
    • .org (PIR): NOT FOUND = available
  • Returns registration dates where the registrar exposes them

Notes

  • Do NOT use the python-whois pip package for .de domains: its error text can contain Status: free even when the domain IS registered, and it sometimes reports registered domains as free.
  • Do NOT use third-party WHOIS sites (who.is, whois.com): they cache results and can be wrong.
  • Always use the system whois command, which queries the official registrars directly. For .de, DENIC (whois.denic.de) is the only authoritative source; for .eu, EURid.

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