fuel

fuel is a skill for Claude Code, Codex from jokull/icelandic-data. It costs 34 tokens per session (957 once invoked), scanned A, original, MIT.

A skill for analysing fuel prices in Iceland, including major retailers and their parent companies. It uses Gasvaktin, a dataset of Icelandic fuel prices collected over time.

In plain words
What is it for?
Use it to process daily fuel-price data, calculate market averages, compare retailers, and examine historical monthly or company-level trends.
Why use it?
It brings station prices and company ownership into one analysis, including the distinction between retail brands and consolidated parent-company finances.

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/fuel
Any agent
npx skills add jokull/icelandic-data --skill fuel
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 fuel

README.md
[![agentmods](https://agentmods.dev/badge/skills/jokull/icelandic-data/fuel.svg)](https://agentmods.dev/skills/jokull/icelandic-data/fuel)
Your own site
<a href="https://agentmods.dev/skills/jokull/icelandic-data/fuel"><img src="https://agentmods.dev/badge/skills/jokull/icelandic-data/fuel.svg" alt="Measured on agentmods" height="20"></a>
Per session 34 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 957 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. 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 $0.00034 $0.00957
Opus 5 $0.00017 $0.00478
Sonnet 5 $0.00007 $0.00191
Haiku 4.5 $0.00003 $0.00096

Measured 5d ago against content hash d61483ffe0a6, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

fuel 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 5d 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.

.agents/skills/fuel/SKILL.md · 70 lines

How it starts

The opening of the file, as written. The whole thing — 70 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Fuel — Icelandic Fuel Market

Companies

Retailer Kennitala Parent Parent kt Stations
N1 ehf. 4110033370 Festi hf. 5402062010 ~100
Olís ehf. 5002693249 Hagar hf. 6702032120 ~65
Orkan IS ehf. 6803190730 Styrkás/SKEL 6309212010 ~75
Atlantsolía ehf. 5906023610 Private ~30

Use parent kennitalas for consolidated financials — fuel is a segment within diversified conglomerates.

Skeljungur ehf. (6309212010) is the wholesale fuel company under Styrkás — separate from Orkan retail but same ownership.

Data Sources

Gasvaktin — Daily retail prices

  • Repo: github.com/gasvaktin/gasvaktin
  • Location: data/raw/gasvaktin/vaktin/trends.json
  • Company codes: n1=N1, ol=Olís, or=Orkan, ox=Orkan X, ao=Atlantsolía, co=Costco, dn=Dælan, ob=ÓB, sk=Skeljungur
  • Data since April 2016, ~weekly observations per company

Processing

uv run python scripts/fuel.py

Outputs:

  • data/processed/fuel_prices_daily.csv — all observations
  • data/processed/fuel_market_daily.csv — market averages (major 4 retailers)
  • data/processed/fuel_prices_monthly.csv — monthly by company
  • data/processed/fuel_price_spread.csv — price spread between retailers

Annual reports (skatturinn.is)

uv run python scripts/skatturinn.py download 5402062010 --year 2024  # Festi (N1 parent)
uv run python scripts/skatturinn.py download 6702032120 --year 2024  # Hagar (Olís parent)
uv run python scripts/skatturinn.py download 6309212010 --year 2024  # Skeljungur (Orkan wholesale)

Note: Festi has two reports per year (parent + consolidated). The download script picks typeid=1 first. For segment data, you may need the consolidated report (typeid=2).

Hagar fiscal year

Hagar uses Feb-Jan fiscal year (e.g., "2024" = Feb 2023 – Jan 2024).

Other data sources

  • IEA End-Use Prices — cross-country fuel price comparison with tax breakdown
  • Samkeppniseftirlitið — competition authority reports (2015 fuel market study, 2024 Festi fine)
  • Crude oil prices — Brent ICE for margin computation

Read the full file on GitHub · 70 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. 5d ago First seen · 70 lines · 34 tokens per session scan A d61483ffe0a6

Subscribe to this mod's changes

fuel is a skill published in the GitHub repository jokull/icelandic-data (52 stars, last pushed yesterday), licensed MIT. It adds 34 tokens to every session and 957 once invoked, about $0.0002 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.

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