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.
npx skills add bartosz-kuc/skanfirmy-mcp --skill skillgit clone --depth 1 https://github.com/bartosz-kuc/skanfirmy-mcpWrote 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.
[](https://agentmods.dev/skills/bartosz-kuc/skanfirmy-mcp/skill)<a href="https://agentmods.dev/skills/bartosz-kuc/skanfirmy-mcp/skill"><img src="https://agentmods.dev/badge/skills/bartosz-kuc/skanfirmy-mcp/skill/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.
<a href="https://agentmods.dev/skills/bartosz-kuc/skanfirmy-mcp/skill"><img src="https://agentmods.dev/badge/skills/bartosz-kuc/skanfirmy-mcp/skill.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00140 | $0.01579 |
| Opus 5 | $0.00070 | $0.00790 |
| Sonnet 5 | $0.00028 | $0.00316 |
| Haiku 4.5 | $0.00014 | $0.00158 |
Grade A, and why
verify-polish-company 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 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.
Makes network callslowCapability
Not a fault in itself. Listed so you know the mod talks to something, and to what.
Call these with any HTTP client (`curl`, `fetch`, `requests`, a web-fetch How it starts
The opening of the file, as written. The whole thing — 120 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Verify a Polish company (skanfirmy.pl)
This skill verifies Polish businesses straight from official government
registers (Ministry of Finance, Ministry of Justice / KRS, Statistics Poland /
GUS, and the European Commission / VIES) through skanfirmy.pl, a free public
API. Every endpoint is a plain GET that returns JSON when you add
?format=json. No API key, no account, no daily quota. Be reasonable:
issue user-driven single lookups, not mass scraping.
When to use it
Reach for this skill when the user asks to:
- check whether a Polish company is an active VAT payer or is VAT-exempt;
- verify that a bank account belongs to a contractor on the White List (needed for Polish "due diligence" on payments over 15 000 PLN);
- pull a company's KRS registry data (legal form, PKD, share capital, address, representation) by NIP or KRS number;
- look up REGON and official name/address by NIP — including sole traders (JDG) that are not in the KRS;
- validate an EU VAT number (any member state) via VIES;
- check many NIPs at once.
NIP = 10-digit Polish tax ID. KRS = court-register number. REGON =
statistical register number. VAT-UE/VIES numbers are prefixed by a 2-letter
country code (e.g. DE, IE, FR).
REST endpoints (GET, keyless)
Call these with any HTTP client (curl, fetch, requests, a web-fetch
tool). Append ?format=json for machine-readable JSON; without it you get
crawlable HTML with embedded JSON-LD.
| Endpoint | What it returns |
|---|---|
GET https://skanfirmy.pl/nip/{nip} |
VAT status + White List (accounts) + KRS data + REGON, combined in one response |
GET https://skanfirmy.pl/nips/{list} |
The same for up to 30 comma-separated NIPs in one call (no KRS join) |
GET https://skanfirmy.pl/regon/{nip} |
REGON registry data: REGON number, official name, legal form, address; covers sole traders (JDG) |
GET https://skanfirmy.pl/vies/{country}/{number} |
Whether an EU VAT number is valid, plus the registered name/address |
What ships with it
2 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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.
- 10d ago First seen · 120 lines · 140 tokens per session scan A 26ae6486e828
verify-polish-company is a skill published in the GitHub repository bartosz-kuc/skanfirmy-mcp (0 stars, last pushed 9d ago), licensed MIT. It adds 140 tokens to every session and 1,579 once invoked, about $0.0007 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 2026-08-31.
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