brreg

brreg is a skill for Claude Code, Codex from nordio-ai/brreg-mcp-server. It costs 51 tokens per session (1,798 once invoked), scanned A, original, MIT.

A set of instructions for researching Norwegian companies through Brønnøysundregistrene, Norway's official business register. It explains how to use the register's company lookup, search, roles, and accounts functions safely.

In plain words
What is it for?
Use it when looking up companies, searching by industry or municipality, checking roles or annual accounts, interpreting register fields, or testing the Brreg connection offline.
Why use it?
The register can return plausible-looking numbers even when a query is wrong, so the instructions add checks for interpreting results correctly.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: mentions Claude Code.

Good fit Use it when looking up companies, searching by industry or municipality, checking roles or annual accounts, interpreting register fields, or testing the Brreg connection offline.

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Install with agentmods
npx agentmods add skills/nordio-ai/brreg-mcp-server/brreg
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 nordio-ai/brreg-mcp-server --skill brreg
Clone the repo
git clone --depth 1 https://github.com/nordio-ai/brreg-mcp-server

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 brreg

README.md
[![agentmods](https://agentmods.dev/badge/skills/nordio-ai/brreg-mcp-server/brreg/github.svg)](https://agentmods.dev/skills/nordio-ai/brreg-mcp-server/brreg)
Your own site
<a href="https://agentmods.dev/skills/nordio-ai/brreg-mcp-server/brreg"><img src="https://agentmods.dev/badge/skills/nordio-ai/brreg-mcp-server/brreg/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for brreg

Your own site · 80×15
<a href="https://agentmods.dev/skills/nordio-ai/brreg-mcp-server/brreg"><img src="https://agentmods.dev/badge/skills/nordio-ai/brreg-mcp-server/brreg.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 51 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,798 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.
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 $0.00051 $0.01798
Opus 5 $0.00026 $0.00899
Sonnet 5 $0.00010 $0.00360
Haiku 4.5 $0.00005 $0.00180

Measured 10d ago against content hash db38b1042e5a, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

brreg 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 10d 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/brreg/SKILL.md · 123 lines

How it starts

The opening of the file, as written. The whole thing — 123 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Brønnøysundregistrene — reading the register without being lied to

The API is open, keyless and unauthenticated. Fetching is not the problem. The problem is that every trap below returns a plausible number with HTTP 200 instead of an error, so a wrong answer looks exactly like a right one.

This skill is for the agent driving brreg-mcp-server (or its CLI). The tools carry these guards and fire them automatically — this file is why they exist and what to do when one speaks.

Surfaces

You are Use
Claude Desktop the .mcpb — four tools, guards always on
Claude Code / a script brreg <verb> — the same handlers over argv
brreg get_units --orgnrs 923609016
brreg search_units --nace 96.210 --kommune 0301 --employees-min 1 --employees-max 4
brreg get_financials --orgnrs 918035443
brreg reference          # field glossary with statutory sources, retired NACE, role codes
brreg self-test --mock   # proves the install works offline

Always parse the JSON. stdout is one object per invocation (elapsed_sec included); diagnostics go to stderr; usage errors exit 2. Everything reproduces offline with --mock — the mock swaps the socket, not the code path, and its dataset is the trap set.

The rule that matters most

Never conclude from a zero, an absence, or a null without reading hints first.

The tools return hints precisely when the register is being quiet in a misleading way. A total: 0 with a retired_nace hint means "the code moved", not "no such businesses". If you report the zero, you have reported the trap's output as a finding.

What each silence actually means

You see It does NOT mean It means
total: 0 "none exist" possibly a retired NACE code — SN2007 expired 2025-01-01, brreg serves SN2025. Read hints.
driftsinntekter: null + filed_no_revenue_line zero revenue a holding company — accounts filed, income sits in subsidiaries as financial income.
status: not_applicable dormant / a red flag an ENK (sole proprietorship). They never file. ~74% of the register.
antallAnsatte: null headcount unknown withheld — brreg never shows a value below 5 but holds the number.
gone (410) not found removed on legal grounds — brreg asks that caches drop it too.
deleted + slettedato an error dissolved — arrives as HTTP 200 with a reduced payload, straight into your success branch.

Read the full file on GitHub · 123 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. 10d ago First seen · 123 lines · 51 tokens per session scan A db38b1042e5a

Subscribe to this mod's changes

brreg is a skill published in the GitHub repository nordio-ai/brreg-mcp-server (0 stars, last pushed 17d ago), licensed MIT. It adds 51 tokens to every session and 1,798 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 2026-08-31.

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