hms

hms is a skill for Claude Code, Codex from jokull/icelandic-data. It costs 36 tokens per session (2,263 once invoked), scanned A, original, MIT.

A collection of Icelandic property-registry data from HMS, the Housing and Construction Authority. It covers property purchases since 2006 and land parcels with geographic shapes.

In plain words
What is it for?
Use it to analyse property prices and valuations, map transactions, study municipalities and work with land parcels. The data is available as downloadable CSV files and geocoded records.
Why use it?
It provides a structured way to work with property transactions, valuations, addresses and locations instead of collecting records manually. The purchase registry is updated daily.

Skill for Claude CodeCodex

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.

agentmods
npx agentmods add skills/jokull/icelandic-data/hms
Any agent
npx skills add jokull/icelandic-data --skill hms
Clone the repo
git clone --depth 1 https://github.com/jokull/icelandic-data

Made for: Claude Code, Codex.

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 hms

README.md
[![agentmods](https://agentmods.dev/badge/skills/jokull/icelandic-data/hms.svg)](https://agentmods.dev/skills/jokull/icelandic-data/hms)
Your own site
<a href="https://agentmods.dev/skills/jokull/icelandic-data/hms"><img src="https://agentmods.dev/badge/skills/jokull/icelandic-data/hms.svg" alt="Measured on agentmods" height="20"></a>
Per session 36 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,263 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. Scan, not verified.
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 $0.00036 $0.02263
Opus 5 $0.00018 $0.01131
Sonnet 5 $0.00007 $0.00453
Haiku 4.5 $0.00004 $0.00226

Measured 4d ago against content hash 8da240dba3f6, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

hms scanned grade A with 1 finding 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 4d 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.

Makes network callslowCapability

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

- `hms.is` is fronted by Vercel with an anti-bot checkpoint. `curl` and `httpx` get the "Vercel Security Checkpoint" HTML. Use Playwright (headless Chromium) to bypass.
.agents/skills/hms/SKILL.md · 156 lines

How it starts

The opening of the file, as written. The whole thing — 156 lines — stays where its author put it; the contents beside it link to each section on GitHub.

HMS - Húsnæðis- og mannvirkjastofnun

Property registry and housing market data from Iceland's Housing and Construction Authority.

Data Sources

Kaupskrá fasteigna (Property Purchase Registry)

URL: https://frs3o1zldvgn.objectstorage.eu-frankfurt-1.oci.customer-oci.com/n/frs3o1zldvgn/b/public_data_for_download/o/kaupskra.csv

Format: CSV (semicolon delimited, ISO-8859-1 encoded)

Update frequency: Daily

Coverage: 2006-present, ~222k transactions

Key Fields
Field Type Description
faerslunumer int Unique transaction ID
fastnum str Property number
heimilisfang str Address
postnr int Postal code
heinum int Location ID (7-digit, different from iceaddr hnitnum)
svfn str Municipality code
sveitarfelag str Municipality name
utgdag date Purchase agreement date
thinglystdags timestamp Registration date
kaupverd int Purchase price (in thousands of ISK)
fasteignamat int Property valuation at sale (thousands)
fasteignamat_gildandi int Current property valuation (thousands)
brunabotamat_gildandi int Fire insurance value (thousands)
byggar int Year built
einflm float Unit area (m²)
lod_flm float Lot area
fjherb int Number of rooms
tegund str Property type: Sérbýli, Fjölbýli, Sumarhús, Atvinnuhúsnæði, etc
fullbuid bool Whether property is complete
onothaefur_samningur bool Unusable for analysis (related party, multiple properties, etc)
Caveats
  • Prices in thousands: kaupverd=57000 means 57,000,000 ISK
  • heinum ≠ hnitnum: Cannot join directly to iceaddr, use address+postnr instead
  • onothaefur_samningur: Filter these for market analysis (related party sales, partial transfers)

Geocoding with iceaddr

The heinum field does NOT match iceaddr's hnitnum. Join on parsed address components:

-- Parse address from kaupskra
TRIM(regexp_extract(HEIMILISFANG, '^([^0-9]+)', 1)) as street_name,
TRY_CAST(regexp_extract(HEIMILISFANG, '([0-9]+)', 1) AS INTEGER) as house_num,
upper(regexp_extract(HEIMILISFANG, '[0-9]+([a-zA-Z]?)$', 1)) as house_letter

-- Join to iceaddr.stadfong
ON lower(street_name) = lower(heiti_nf)
AND house_num = husnr
AND postnr = postnr
AND house_letter = COALESCE(upper(bokst), '')

Read the full file on GitHub · 156 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. 4d ago First seen · 156 lines · 36 tokens per session scan A 8da240dba3f6

Subscribe to this mod's changes

hms is a skill published in the GitHub repository jokull/icelandic-data (52 stars, last pushed yesterday), licensed MIT. It adds 36 tokens to every session and 2,263 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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