wanderbooks is a general MCP-first accounting application: every
business needs its accounts mapped to where they land on its income tax
return, and its CPA needs book-to-tax differences surfaced, not hidden.
- ledger_core::tax: a catalog of stable categories (gross_receipts,
commissions_fees, meals, guaranteed_payments, officer_compensation,
nondeductible, ...) with kind (income, cost of goods, deduction), the
returns each appears on (Schedule C, 1065, 1120-S, 1120), a default
deductible percent (meals 50, nondeductible 0), and guidance. Keys,
not line numbers: form lines move from year to year.
- Accounts carry tax_category and an optional deductible_percent
override, validated against the account type (and the return, at the
MCP layer), journaled as account.tax_set, replayed, projected (schema
v6).
- tax_summary(start, end, form): the P&L grouped by category, book and
deductible amounts (half away from zero to the cent), contra income
(refunds) reducing receipts, and every account still uncategorized.
- MCP: books.tax_categories (filtered to the configured return),
books.set_tax_category, a tax_summary report in every format and in
the CPA package, chart output with categories, and a fifth
tax_category column in chart CSV imports, validated before anything is
created. [company] tax_form, or derived from tax_classification.
Scope stays book basis: no tax depreciation, basis, or filing.
Tests: a hand-computed quarter (50% meals 333.33 -> 166.67, penalties at
0%, refunds as negative receipts, guaranteed payments, one uncategorized
account; book net 5,276.67 vs tax 5,483.33); overrides; category/account
/return validation; form parsing and derivation; CSV parsing; stdio:
filtered catalog, mapping, refusal, summary, all-or-nothing import.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MtYEaR6M6Ybdhm6X98BWNu
