tax-advisor

tax-advisor is a skill for Claude Code from kazukinagata/shinkoku. It costs 248 tokens per session (3,088 once invoked), scanned A, original, MIT.

A Japanese tax-advice skill based on 2025 tax rules. It answers tax-filing and tax-saving questions using documents in a reference folder rather than general guesses.

In plain words
What is it for?
Use it for Japanese questions about income tax, deductions, tax returns, donations, pensions, housing-loan credits, and consumption tax.
Why use it?
It gives answers a defined evidence source and requires important calculations, legal references, warnings, and a disclaimer.

Skill for Claude Code

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

Part of the shinkoku plugin — 24 skills shipped together

Good fit Use it for Japanese questions about income tax, deductions, tax returns, donations, pensions, housing-loan credits, and consumption tax.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/kazukinagata/shinkoku/tax-advisor
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 kazukinagata/shinkoku --skill tax-advisor
Clone the repo
git clone --depth 1 https://github.com/kazukinagata/shinkoku

Made for: Claude Code.

Or install shinkoku, the plugin that ships this one along with the rest of its 24 skills.

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 tax-advisor

README.md
[![agentmods](https://agentmods.dev/badge/skills/kazukinagata/shinkoku/tax-advisor/github.svg)](https://agentmods.dev/skills/kazukinagata/shinkoku/tax-advisor)
Your own site
<a href="https://agentmods.dev/skills/kazukinagata/shinkoku/tax-advisor"><img src="https://agentmods.dev/badge/skills/kazukinagata/shinkoku/tax-advisor/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 tax-advisor

Your own site · 80×15
<a href="https://agentmods.dev/skills/kazukinagata/shinkoku/tax-advisor"><img src="https://agentmods.dev/badge/skills/kazukinagata/shinkoku/tax-advisor.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 248 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,088 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. Third-party audits
  • Socket pass 18 Sept 2026
  • Snyk pass 18 Sept 2026
How audits are shown
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 $0.00248 $0.03088
Opus 5.5 $0.00099 $0.01235
Sonnet 5.5 $0.00050 $0.00618
Haiku 4.5 $0.00025 $0.00309

Measured 1mo ago against content hash 81dba543a133, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

tax-advisor 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 1mo 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/tax-advisor/SKILL.md · 227 lines

How it starts

The opening of the file, as written. The whole thing — 227 lines — stays where its author put it; the contents beside it link to each section on GitHub.

税務アドバイザー(Tax Advisor)

税理士・ライフプランナー相当の専門知識で、ユーザーの税務相談に回答するスキル。 令和7年分(2025年課税年度)の税制に基づく。

設定の読み込み(最初に実行)

  1. shinkoku.config.yaml を Read ツールで読み込む
  2. ファイルが存在しない場合は /setup スキルの実行を案内して終了する
  3. 設定値を把握し、相対パスは CWD を基準に絶対パスに変換する:
    • db_path: MCP ツールの db_path 引数に使用
    • output_dir: 進捗ファイル等の出力先ベースディレクトリ
    • 各ディレクトリ: ファイル参照時に使用

回答の基本方針

1. 正確性の担保

  • 回答は必ず reference/ ディレクトリ内のファイルを根拠とする
  • 一般知識や推測で回答しない。根拠が見つからない場合はその旨を明示する
  • 金額・税率・要件は reference ファイルの数値を引用する
  • 条文・通達の参照を回答に含める(例: 所得税法第89条、所基通36-1)

2. 回答の構造

以下の構造で回答を組み立てる:

  1. 結論を先に: 質問に対する端的な回答
  2. 根拠の提示: 該当する条文・制度の説明
  3. 具体的な計算例: ユーザーの状況に合わせた試算(可能な場合)
  4. 注意点・落とし穴: reference/common-mistakes.md の関連項目
  5. 免責事項: 回答の末尾に必ず disclaimer を付記

3. 収入と所得の変換

ユーザーは「収入」で質問するが、税制上の判定は「所得」で行う。以下のルールを適用する:

  • ユーザーが「年収」「収入」と言った場合 → 「所得」に変換して計算する
  • 変換過程をユーザーに明示する(例: 「給与収入500万円 → 給与所得控除後の所得356万円」)
  • 変換には reference/glossary.md の変換表を使用する
  • 給与所得控除額は reference/income-tax.md の速算表を使用する

4. 令和7年分改正への対応

令和7年分(2025年)の税制改正を正確に反映する:

  • reference/tax-reform/2025.md の改正内容を常に考慮する
  • 前年以前の情報と混同しない(特に基礎控除額、給与所得控除額)
  • 経過措置(reference/tax-reform/transition.md)の適用期限に注意する
  • 翌年以降の予定改正(reference/tax-reform/upcoming.md)は参考情報として提示する

リファレンスファイルの参照ガイド

質問のカテゴリに応じて、以下のファイルを参照する:

所得・税額に関する質問

質問カテゴリ 参照ファイル
所得税の仕組み・税率 reference/income-tax.md
住民税の仕組み・税率 reference/resident-tax.md
消費税・インボイス reference/consumption-tax.md
源泉徴収・年末調整 reference/withholding-tax.md

控除に関する質問

質問カテゴリ 参照ファイル
所得控除の一覧・概要 reference/income-deductions.md
税額控除の一覧・概要 reference/tax-credits.md
医療費控除 reference/medical-expenses.md
配偶者控除・特別控除 reference/spouse.md
扶養控除 reference/dependents.md
住宅ローン控除 /tax-housing-loan-context を実行する
控除の最適化・組み合わせ reference/deduction-optimizer.md
控除シミュレーションの手順 reference/deduction-simulation-guide.md

事業・経費に関する質問

質問カテゴリ 参照ファイル
青色申告 reference/blue-return.md
事業経費・家事按分 reference/business-expenses.md
副業の事業所得vs雑所得判定 reference/side-business-classification.md
電子帳簿保存法 /tax-ebookkeeping-context を実行する
経費算入の可否判定(品目別) reference/expense-deductibility-guide.md
業種別の経費ガイド reference/industry-expense-guide.md

Read the full file on GitHub · 227 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. 1mo ago First seen · 227 lines · 248 tokens per session scan A 81dba543a133

Subscribe to this mod's changes

tax-advisor is a skill published in the GitHub repository kazukinagata/shinkoku (366 stars, last pushed 1mo ago), licensed MIT. It adds 248 tokens to every session and 3,088 once invoked, about $0.0010 per session on Opus 5.5. 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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