nta-corporate-number-lookup

nta-corporate-number-lookup is a skill for Claude Code from Kokai-Data/japan-business-data. It costs 108 tokens per session (791 once invoked), scanned A, original, Apache-2.0.

A lookup tool for Japan's 13-digit corporate numbers, using records from Japan's National Tax Agency. It also shows official changes such as renamed companies, relocations, mergers, dissolutions, and closures.

In plain words
What is it for?
Use it for identity checks, M&A due diligence, company research, and finding dissolved or merged companies.
Why use it?
It helps verify whether a Japanese company exists and whether its current status or history raises concerns.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the kokai-data plugin — 19 skills, 8 commands, 7 agents, 1 MCP server shipped together

Good fit Use it for identity checks, M&A due diligence, company research, and finding dissolved or merged companies.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/kokai-data/japan-business-data/nta-corporate-number-lookup
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 Kokai-Data/japan-business-data --skill nta-corporate-number-lookup
Clone the repo
git clone --depth 1 https://github.com/Kokai-Data/japan-business-data

Made for: Claude Code.

Or install kokai-data, the plugin that ships this one along with the rest of its 19 skills, 8 commands, 7 agents, 1 MCP server.

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 nta-corporate-number-lookup

README.md
[![agentmods](https://agentmods.dev/badge/skills/kokai-data/japan-business-data/nta-corporate-number-lookup/github.svg)](https://agentmods.dev/skills/kokai-data/japan-business-data/nta-corporate-number-lookup)
Your own site
<a href="https://agentmods.dev/skills/kokai-data/japan-business-data/nta-corporate-number-lookup"><img src="https://agentmods.dev/badge/skills/kokai-data/japan-business-data/nta-corporate-number-lookup/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 nta-corporate-number-lookup

Your own site · 80×15
<a href="https://agentmods.dev/skills/kokai-data/japan-business-data/nta-corporate-number-lookup"><img src="https://agentmods.dev/badge/skills/kokai-data/japan-business-data/nta-corporate-number-lookup.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 108 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 791 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 $0.00108 $0.00791
Opus 5 $0.00054 $0.00396
Sonnet 5 $0.00022 $0.00158
Haiku 4.5 $0.00011 $0.00079

Measured 12d ago against content hash ad4fdb2c4300, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

nta-corporate-number-lookup 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 12d 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.

plugins/vertical-plugins/kokai-data/skills/nta-corporate-number-lookup/SKILL.md · 60 lines

How it starts

The opening of the file, as written. The whole thing — 60 lines — stays where its author put it; the contents beside it link to each section on GitHub.

When to use

Use this skill when:

  • The user provides a 13-digit Japanese 法人番号 (corporate number).
  • You need authoritative status of the corporation: active / dissolved / merged / closed.
  • You need change history: name changes, address moves, merger events.
  • gBizINFO returned no record (small / new / non-METI-tracked entity) and you want NTA fallback.
  • M&A due diligence, KYC verification, or pre-meeting research where past 沿革 matters.

How to invoke

Call the kokai MCP server's get_nta_corporate_record tool:

{
  "name": "get_nta_corporate_record",
  "arguments": {
    "corporate_number": "<13-digit 法人番号>",
    "include_history": true
  }
}

Output structure

The response includes:

  • latest: the current authoritative record (name, address, kind, process status, assignment date)
  • history: previous records (name changes / address moves / etc., sorted by date desc)
  • is_dissolved / is_merged: boolean flags for closure status
  • process_summary: human-readable summary like "3 件の異動履歴あり (商号変更 / 国内所在地の変更 ...)"
  • process_label: 公式 process classification (01=新規 / 11=商号変更 / 12=移転 / 71=合併解散 / 81=抹消 / 99=削除)
  • source_authority: "official" (公式 cite_required layer)
  • terms_of_use: attribution + disclaimer for the 国税庁 法人番号公表サイト (cite "出典: 国税庁法人番号公表サイト" and note that the 国税庁 is the SoT for corporate-number master data)

Differentiation from gBizINFO

領域 gBizINFO (get_entity_profile) NTA (this skill)
法人番号 master 派生 source authoritative
異動履歴 (社名変更 / 移転) 大半未提示 公式 + 完全
解散 / 合併消滅 detection △ 限定的 公式 + 明確
gBizINFO 未登録法人 ❌ 取得不可 ✅ カバー
財務 / 株主 / 認定 ✅ 充実 ❌ なし

Pair this skill with the get_entity_profile tool (gBizINFO) for full coverage.

Boundary

  • Output is signal / 確認材料 / context — NOT a decision.
  • Final 申請可否 / 法的判断 requires a certified Japanese 士業 (行政書士 / 中小企業診断士 / 公認会計士 / 弁護士).
  • Cite source_url + retrieved_at + 国税庁 attribution in final output.
  • Never fictionalize. If NTA returns "no record" for a valid 法人番号, the corporation may have been recently dissolved.

Read the full file on GitHub · 60 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. 12d ago First seen · 60 lines · 0 tokens per session scan A ad4fdb2c4300

Subscribe to this mod's changes

nta-corporate-number-lookup is a skill published in the GitHub repository Kokai-Data/japan-business-data (2 stars, last pushed 2mo ago), licensed Apache-2.0. It adds 108 tokens to every session and 791 once invoked, about $0.0005 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.

Related

Other skills, from other repositories

security-compliance

Guides security professionals in implementing defense-in-depth security architectures, achieving compliance with industry frameworks (SOC2, ISO27001, GDPR, HIPAA), conducting threat modeling and risk assessments, managing security operations and incident response, and embedding security throughout the SDLC.

sangrokjung/claude-forge · 56 tokens

aenderungsvorbehalt-308

Für Änderungsvorbehalt 308: ordnet Norm, Beweislast und Gegenargument; Ergebnis: Prüfprodukt mit Risiko und nächstem Schritt.

Klotzkette/claude-fuer-deutsches-recht · 41 tokens

agb-begriff-vorformuliert-305

Für AGB Begriff Vorformuliert 305: ordnet Norm, Beweislast und Gegenargument; Ergebnis: Prüfprodukt mit Risiko und nächstem Schritt. Fachgebiet: AGB-Recht-Prüfer. Route: agb-begriff-vorformuliert-305.

Klotzkette/claude-fuer-deutsches-recht · 68 tokens

beweislast-und-zugang-309

Für Beweislast und Zugang 309: ordnet Norm, Beweislast und Gegenargument; Ergebnis: Beweislast- und Substantiierungsmatrix.

Klotzkette/claude-fuer-deutsches-recht · 43 tokens

agb-pruefung-kaltstart

Für AGB Prüfung Kaltstart: routet Rolle, Frist, Unterlagen und Fachschritt; Ergebnis: Tatbestands- oder Anspruchsmatrix.

Klotzkette/claude-fuer-deutsches-recht · 41 tokens

agb-rechtswahl-schweizer-recht-rom-i

Für AGB Rechtswahl Schweizer Recht Rom I: ordnet Norm, Beweislast und Gegenargument; Ergebnis: Prüfprodukt mit Risiko und nächstem Schritt. Fachgebiet: AGB-Recht-Prüfer. Route: agb-rechtswahl-schweizer-recht-rom-i.

Klotzkette/claude-fuer-deutsches-recht · 69 tokens