wanderbooks/docs/spec

Specification sources

wanderbooks' rules come from documents, not from anyone's memory. This directory holds the authorities the engine's specs cite (docs/spec/rules.md is the rule catalog), and every spec block in the code carries a SOURCE: line pointing into it.

The authority stack

There is no single "bible" of US bookkeeping. Authority is layered, and the layers differ in what they cover and in whether we may copy them:

Layer	What it governs	Copyright	Here
Pacioli (1494), Geijsbeek translation (1914)	The mechanics of double entry: debits equal credits, the trial balance, one money, writing only forward, correcting by opposite entry, closing into capital. No modern standard restates these; they predate every regulator.	Public domain	Vendored verbatim: sources/pacioli-1494.md
IRS: Internal Revenue Code, Treasury Regulations, publications, form instructions	Records and supporting documents, retention, accounting periods and methods, information returns (1099), capitalization (de minimis, 12-month rule), partners' capital, payroll taxes, rounding on returns, return line items for tax categories (sources/irs-tax-lines.md)	Public domain (17 U.S.C. §105; IRS.gov's content policy)	Vendored verbatim: sources/irs-*.md, sources/us-public-domain-status.md
File formats: Intuit (QuickBooks Online bank CSV, QuickBooks Desktop IIF), ECMA-376 Office Open XML, Microsoft Excel limits	What ledger-import reads and writes: bank/card CSV layouts and signs, IIF journal entries, how XLSX stores numbers and Excel's 15-digit precision	© Intuit Inc.; © Ecma International; © Microsoft	Cited with short quotes, URLs, and hashes: sources/intuit-bank-csv.md, sources/intuit-iif.md, sources/xlsx-numbers.md
FASB Accounting Standards Codification (ASC)	Authoritative US GAAP: cash flows (ASC 230), revenue and principal vs agent (ASC 606), foreign currency (ASC 830), credit losses and aging (ASC 326), property and depreciation (ASC 360)	© Financial Accounting Foundation	Cited by paragraph with short quotes only (in rules.md)
FASB Concepts Statement No. 8, Chapter 4 (2021)	Definitions of the five elements (it replaced Concepts Statement 6)	© Financial Accounting Foundation; non-authoritative	Cited with short quotes only
Textbooks (OpenStax Principles of Accounting, Vol. 1)	Conventions no standard states: normal balances, closing-entry mechanics, straight-line depreciation arithmetic	CC BY-NC-SA 4.0 (incompatible with this repo's license)	Cited with short quotes and attribution only
Convention or decision	Where no authority speaks: aging bucket edges, cent rounding among members, closed-period locks	—	Stated as CONVENTION or DECISION, with who decided and when

How to read a SOURCE line

SOURCE: Pacioli ch. 36 (sources/pacioli-1494.md); IRS Pub. 583 (sources/irs-records.md)
SOURCE: ASC 830-20-30-1 (cited, rules.md B-3)
SOURCE: DECISION (Stephen, 2026-10-13)
SOURCE: CONVENTION (QuickBooks aging); nearest authority ASC 326-20-55-38 (illustrative)

A rule whose only source is CONVENTION or DECISION is a candidate for a human to confirm or overturn; nothing else is.

Rules added later never lock out older books

When a rule is tightened (a check added to a command), books written before it must still open. Journal replay and the SQLite cross-check read history through the engine's replay_* commands, which skip checks added later; new commands go through the checked ones. Pinned by books_written_under_older_rules_still_open (ledger-store).

Vendoring rules

• Public-domain texts are copied verbatim (whitespace normalized), each with its URL, retrieval date, and the SHA-256 of the retrieved file, so anyone can check the excerpt against the original.
• Copyrighted sources are cited by paragraph, quoted briefly, never copied.
• When an authority changes (the IRS revises a publication; a statute is amended), add the new text beside the old with its effective date. Rules that depend on dates (1099 thresholds) must say which text applies when.
• Rules that change with the law are registered in crates/ledger-core/src/rules.rs with the years they are known for and a review date. Past what it knows, the engine refuses rather than guesses; from the review date, the MCP digest and the viewer flag the rule. Whoever updates one (human or agent) vendors the new official text here, extends the rule, and sends the change upstream: a pull request at https://github.com/swaits/wanderbooks (best), or an issue.

Open: sources we could not verify

Read on 2026-10-13 through Deloitte's free DART roadmaps, which reproduce ASC text: ASC 230-10-45-16 and -28, 326-20-55-37/38, 606-10-25-23, 45-2, 55-37/38, 830-20-30-1. Read directly in the ASC basic view on 2026-10-14 (sources/fasb-asc.md): 360-10-35-4, 340-10-05-2/4/5, 210-10-45-1/2/5, 230-10-45-7/10/12/13/14/15, 606-10-55-36 through 55-38. None left open.