Claude Code skills · updated 2026-10-03

Energieausweis listing skill for Claude Code — GEG 87 fields and class bands

7 Energieausweis findings in one listing page, each with file:line and the fix

On the bundled sample: 7 findings (7 errors, 0 warnings) in 1 file from 13 rules, including an expired certificate and class C printed for 182 kWh/(m2*a).

Get it on Whop - $12 onceGet it on Gumroad

Who it's for

For developers at German property portals, estate agencies and PropTech teams who render listing pages and exposés from HTML templates.

What breaks, and when

An ad that skips a GEG Sec. 87 detail or prints the wrong class misstates the certificate; a certificate is valid ten years, so one issued 12.03.2015 expired 12.03.2025.

What it printed on the bundled example

== Immobilienanzeige GEG 87 Lint — 7 findings (7 errors, 0 warnings) in 1 file · 13 rules
  ERROR listing-sample.html:18  [geg87-ausweis-typ-fehlt]
        The ad never says whether the certificate is an Energiebedarfsausweis or an Energieverbrauchsausweis.
  ERROR listing-sample.html:18  [geg87-baujahr-fehlt]
        A Wohngebaeude ad must print the Baujahr named in the certificate, and this ad does not.
  ERROR listing-sample.html:18  [geg87-ausweis-abgelaufen]
        Issued 12.03.2015, expired 12.03.2025. The issue date in the ad is more than ten years old, so the certificate behind these figures is no longer valid.
  ERROR listing-sample.html:19  [geg87-einheit-falsch]
        "182 kWh" has no per-area-per-year unit. A kWh figure is printed without the unit kWh/(m2*a), so the number does not state what the certificate states.

What you get

• SKILL.md, an offline Node scanner and the 13-rule table
• file:line, severity and the GEG duty each line misses
• Fix lines, applied only after you agree
• CI: node scripts/scan.js . exits 1 on any error

Install

Unzip into ~/.claude/skills/ (all projects) or your-repo/.claude/skills/ (one repo), then ask Claude Code: "Check our property listing pages for the Energieausweis mandatory fields. Don't edit anything yet.". Needs Node 16+.

unzip energieausweis-listing-check.zip -d ~/.claude/skills/

Ask Claude

“Check our property listing pages for the Energieausweis mandatory fields. Don't edit anything yet.”

What it does not do

It cannot see your real certificate, only what the ad prints; no network calls, no edits without your OK.

FAQ

What is a Claude Code skill?

A folder with a SKILL.md and scripts that Claude Code loads when your request matches it. You ask in plain words and Claude runs the scanner the skill carries.

How is this different from asking Claude without the skill?

The skill carries a dated rule table and a scanner that reads every file, so Claude quotes the exact date and line instead of answering from memory.

Does it send my code anywhere?

It cannot see your real certificate, only what the ad prints; no network calls, no edits without your OK.

How do I install it?

Unzip into ~/.claude/skills/ (all projects) or your-repo/.claude/skills/ (one repo), then ask Claude Code: "Check our property listing pages for the Energieausweis mandatory fields. Don't edit anything yet.". Needs Node 16+.

What do I get when I buy?

The zip. On Whop it is in your library as a download lesson with the zip attached; on Gumroad it is the product file.