Tax Classifier

Tax Classifier

Classify Japanese business transactions into standard accounting categories (kanjou-kamoku / 勘定科目) using a 3-stage pipeline that minimizes API costs and maximizes accuracy.

When to use

Invoke this skill whenever the user provides a transaction description (e.g. "スタバ 渋谷店 ¥580") and needs:

• A 勘定科目 classification
• A 税区分 (consumption-tax treatment) assignment
• A confidence score

Pipeline overview

Stage 0 — Exclusion check (7 rules)

Before any classification attempt, run check_exclusion to filter out non-classifiable items. The standard rules exclude:

1. Transfer-to-self (振替) entries
2. Opening / closing balance lines
3. Duplicate reversed entries (赤伝)
4. Summary / subtotal rows
5. Tax-payment lines handled separately
6. Payroll deduction detail lines
7. Memo-only entries with zero amount

If an item is excluded, return the exclusion reason without proceeding.

Stage 1 — Memory recall + keyword dictionary (14 categories)

Query recall_memory first. If the exact vendor or pattern has been corrected before, use the memorized classification immediately.

If no memory hit, match against the 14-category keyword dictionary:

Category	Examples
会議費	cafe, meeting room
交際費	dinner with client, gift
旅費交通費	train, taxi, hotel
通信費	phone, internet, postage
消耗品費	office supplies, toner
地代家賃	rent, parking
水道光熱費	electricity, gas, water
支払手数料	bank fee, service charge
広告宣伝費	ads, marketing
外注費	subcontractor, freelancer
福利厚生費	employee meal, health check
保険料	insurance premium
租税公課	stamp duty, property tax
雑費	miscellaneous (last resort)

Stage 2 — Claude AI fallback

When keyword matching fails or confidence is below threshold, call classify_transaction which uses Claude to analyze the description with full context from the firm's CLAUDE.md configuration.

Consumption tax handling

Always assign a tax treatment. Be careful with the rates:

• 10% — standard rate (標準税率)
• 8% reduced — food/beverage for takeout, newspaper subscriptions (軽減税率)
• Exempt (非課税) — land rent, insurance, interest
• Non-taxable (不課税) — donations, damages, foreign transactions

When uncertain between 10% and 8%, flag as "confirmation needed" rather than guessing. A wrong tax rate causes real compliance risk.

Important guidelines

• The tax accountant's judgment is always final. This tool assists; it does not replace professional judgment.
• Items with confidence below 70% should be surfaced as "要確認" (confirmation needed) with the top-2 candidate categories shown.
• Never silently auto-classify ambiguous items at high volume. Surface uncertainty clearly.

MCP tools used

• classify_transaction — full AI classification
• check_exclusion — Stage 0 exclusion filter
• recall_memory — check correction history