The fourth of the paused branches: Ledger::write_off and the bad_debts
control role, invoice.written_off with its evidence filed in the same
store call, books.write_off_invoice, the write-off on the timeline and
in Needs attention, Lean writeOff_within_bounds, rules.md B-41 and the
bookspec examples. Twenty-eight files conflicted with the S4.4, S5 and
S6 merges; resolved as plan 8.0.2 says, keeping both sides' appends with
their seams restored, and: the scope table at 125; S7's law numbered 37;
B-41 placed before B-42; the handbook's step 4 and recovery procedures
folded into the one invoices-and-bills section; S7's wire tests in their
own module with the confirm S4.4's contract needs; S7's copy of the
payment steps dropped (S6 replaced them with Ledger::settle) and its
write-off journaled through S6's journal_auto_lines; in the old-books
fixture S7's hand-written write-off moved to a second invoice, since
S6's hand-written payment settles invoice 1 in full.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HS8WZziDnyxunC23MUxrLp
The third of the paused branches: Ledger::settle with discounts and the
processor's fee (kernel::settle, Kani settle_is_exact, Lean
settle_posts_a_document_step), books.receive_payment and books.pay_bill
with applications, books.bills_due, the agings' detail and tie-out, the
aging exports and the CPA package's aging CSVs, the handlers in
tools/settlements.rs. Twelve files conflicted with the S4.4 and S5
merges, resolved as plan 8.0.2 says: both routers; both test appends
(the shared match arm in arap_standing.rs spliced into both tests; the
shared `.unwrap()` in store.rs); the scope table at 124; one
invoices-and-bills handbook (S5's send step 1 with S6's steps 2, 3, 5
and procedures) registered once; docs/mcp-interface.md with S4.4's
create docs and S6's payment docs; S5's law renumbered 35 and S6's 36
(S1's is 34); the parity rows and sections of both. S6's wire tests
create their bills as S4.4's contract now requires (confirmed, the
vendor's number, a line account, the vendor's invoice uploaded) and live
in their own module beside S4.4's tests.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HS8WZziDnyxunC23MUxrLp
AGENTS.md's formal-methods bar makes every new Ledger command a Lean
Step with a preservation proof, so `Ledger::mark_sent` gets one even
though the unit expected no Lean change (the As-built block records
that). `Documents.lean`'s `Books` gains the sends recorded, and
`Step.markSent` adds one on a document the lines carry. A send touches
no line, so every control balance, every document's sum and what is
unattached are unchanged through any day
(`Step.markSent_changes_no_figure`, no axioms), and `Reachable.tagged`
covers the new step.
`Audit.lean` lists the theorem; rules.md B-38's model now covers the
record side of a document's life as well as its figures.
One payment had to name one document and could take no discount or
processor fee, so paying several invoices from one deposit meant several
entries and the fee had nowhere to go. This adds the kernel's exact
settlement arithmetic (applications total, net deposit), a Ledger::settle
that posts one entry for a customer's or vendor's documents, and the gross
method and gross fee A-8/A-4 chose.
- kernel::settle: sum(cash)+sum(discounts)=applications, sum(cash)-fee=
deposit, None on overflow or a negative deposit. Kani settle_is_exact
plus the Decimal bridge.
- Ledger::settle / settlement_lines: one party and one kind per
settlement, one application per document, each cash+discount within
payment_room; a discount within the terms (discount_max and
discount_by) needs no reason, a larger or later one does; a bill with
an asset line is refused with D-49's remedy; a fee is a customer
payment's only and posts gross.
- Rows are payment lines in application order, then discount lines, the
fee line and the cash line, so a journaled event's line indices are
stable; replay tags exactly the line an event names and leaves an
unmatched line unattached (never refuses).
- receive_payment_with and pay_bill_with become one-application calls.
- Roles: sales_allowances (4100), purchase_discounts (6995) and
payment_processing_fees (6060), constants used on demand but not added
to control_accounts() (existing charts may use those codes for other
things).
- Lean: settle posts through Step.document, so settle_posts_a_document_step
and settle_unattached, no new constructor; both in Audit.lean.
- Core tests: bill_on_terms_with_discount, late_discount_needs_a_reason,
discount_on_an_asset_bill_is_refused_with_the_remedy,
a_fee_posts_gross_to_receivables_and_net_to_the_bank,
a_settlement_names_its_lines_and_refuses_a_document_twice, and
equipment_bill_payment_is_investing_cash in the cash-flow suite.
- Bookspec B-42 is stated, with its id BS-arap-6; the catalogue and index
now record it as CONVENTION.
just check and just prove green.
Ledger::write_off is a new command, so it is a new Step: Step.writeOff,
whose two lines are a tagged control line (the receivable falls) and an
untagged expense line (the deduction). Being a document step in shape, it
moves nothing unattached, so control_agrees and
Reachable.control_is_documents still hold with no new proof:
Step.writeOff_unattached states its half of that.
writeOff_within_bounds is the law the command's refusal enforces: a
write-off of at most what the document is owed, read over the date-sum
docSum ... through D (B-38 fixed that sum, not standing), leaves what is
owed through the write-off's day at or above zero. through_append lets
the write-off's own two lines be read separately.
Both are listed in Audit.lean; just prove holds (standard axioms only, no
sorry).
refuse hand entries (P4b S1, part A)
Plan P4b (D-45), slice S1, the engine half: rules.md B-38.
- ledger-core: every receivables or payables line carries its document
(Ledger.line_docs: DocRef, Movement, DocTag), written by the document
commands in the step that posts it, derived on replay from the existing
document events (the role's account as it stood then; payments by the
ordinal rule), copied onto a reversal's mirror. Ledger::stands_on;
doc_state / invoice_state / bill_state (total, paid, outstanding,
status Open/Partial/Paid/WrittenOff/Void, overdue days) as of any day;
ar_aging / ap_aging read them, so reversed payments and voids are right.
The control guard (add_line, add_line_fx, post_entry,
register_recurring) refuses untagged lines on receivables/payables,
exempting a reversal's mirror of a legacy line; replay never refuses.
Bounds (kernel::running_bounds, bounds_kept) on payments and reversals;
a document reversal never dated before its entry; deposit/payer accounts
must be cash-like and hold no role. New API: receive_payment_with /
pay_bill_with (PaymentDetails: instrument, reference), void_document /
check_void_document, control_check, payments_recorded,
standing_payments, replay_reverse_entry. Invoice.amount_paid/status
remain only as derived caches for the MCP layer until part B.
cashflow bill_splits reads payments from the tags.
- ledger-store: journal feature document_standing (D-39 gated) for a
payment accepted only because an earlier one was reversed;
receive_payment_with / pay_bill_with (instrument journaled as
entry.instrument_set, reference in the description), void_document;
replay uses replay_reverse_entry; schema 15 drops the projection's
amount_paid/status. Fixture p4-arap-before + golden figures written by
the version before S1, adjudicated in arap_standing.rs.
- ledger-gui: party card, cash "coming up" and company owed totals read
doc_state as of today (late from the derived state).
- Lean Documents.lean (control_agrees and friends); Kani
bounds_check_matches_definition,
bounds_kept_is_the_definition_on_books_in_bounds;
rules B-38, B-18/B-23 amended; bookspec `older = true` for legacy hand
lines; tests that hand-post to 1200/2000 post as replay or renumbered.
Review fixes (both reviews of part A):
- control_role_of guards only an account the role is assigned to or one
holding its documents' lines (a chart's own 1200 Equipment or card at
2000 is free until a document posts there); payment accounts check
other roles by holds_role (type-checked). The MCP tests that failed on
the guard (oracle_mcp, spec_projects) pass unchanged.
- standing_payments leaves out reversals (sorted, deduped); replayed
tags match the movement's side; payments_recorded counts every payment
event (tagged or not, Ledger.payment_events) and refuses overflow.
- The record caches settled (paid + discounted + written off) and owed
(Invoice/Bill.owed, never serialized): a void never reads as paid.
- assign_role: receivables/payables refuse moving onto an account with
untagged lines (RoleAccountHasHandLines) and, on their control account
holding a balance, say DocumentRoleHoldsBalance (no hand entry named);
B-23 reworded. The reversal-mirror exemption only takes a hand line
off (even chain depth); putting it back is refused.
- DocStatus Overpaid and Unattached; aging leaves out credit balances;
ControlCheck.attention lists out-of-bounds and unattached documents.
- stands_on counts a chain in order; indexes (doc_index, doc_accounts,
order_pos, reversed_by) keep the derived figures linear.
- Viewer reads a post-dated document as of its own date; one state per
row. bounds_kept's side-crossing documented as intended.
- Tests: ten new spec_documents scenarios, stronger proptests, store
proptest arap_props (live = replay = snapshot at every date, closed
months), fuzz ops void/payments with details, a GUI post-dated test;
Lean Step.assign / Step.release with unattached_zero kept; model
limits stated in docs/testing.md and B-38.
Review fixes (CPA and engineering lenses): only an assigned role's
account or one holding document lines is a control account (a chart's
own 1200 asset stays free); a role can't move onto untagged lines or off
document lines (Lean Step.assign); a void's cache never reads as paid;
no Decimal sum panics; per-document indexes keep figures linear; a
replayed tag matches its side; the feature gate counts payment events;
a payment's reversal is never listed as standing; an overpaid document
has its own status; the viewer keeps post-dated documents.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01T3gXMVt7XJPi6ens1or9Dj
The final month takes what the months before leave, spread over its days;
a disposed asset stops on its disposal day. A skipped month is caught up
in the month the run is made; a reversed run un-posts its month. New
schedules spread by day; equal-months schedules must start on the 1st.
Amounts round to the currency's own minor unit. Kani and Lean proofs; an
exhaustive search over runs, reversals and disposals.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01T3gXMVt7XJPi6ens1or9Dj
A vendor's 1099 decision is its own dated fact (files NEC or MISC, not
reportable with its reason, or undetermined), applied by each payment's
date. Payment methods are recorded; card and network payments are left
out and listed; a member's check through financing counts; a bank payment
with no method counts (D-40); $2,000 for payments after 2025. One
worksheet for the tool, the viewer and the CPA package.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01T3gXMVt7XJPi6ens1or9Dj
Each party's part of an entry is signed as its own account would show it,
with a direction and its cash and in-kind amounts; a reversal is its
original negated. Totals on a cash or all basis: for a member, all equals
the members' equity statement and cash the K-1's cash. Money is cash,
cards and the financing accounts, and a liability credit never pays its
own creditor (creditor_of), so accruals and declared distributions count
once. tin_last4 from the TIN or W-9 facts.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01T3gXMVt7XJPi6ens1or9Dj
books.rename_account; account names trimmed, bounded, refused when a
sibling's or TIN-shaped; books.show refuses what its target ignores. A
report asked for without dates covers this fiscal year so far, everywhere
(one rule for tools, descriptions and the viewer; the IIF and CPA package
keep their own dates). policy.require_tax_category warns or refuses; a
Form 4797 gain is shown apart on every return.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01T3gXMVt7XJPi6ens1or9Dj
Direct method with the operating reconciliation and noncash schedules; it
foots by construction (Lean and Kani). Every non-cash account belongs to
one section; reversals net; a member or lender paying for the company is
cash borrowed and spent (D-42, constructive receipt and disbursement);
property a member contributes stays noncash. The bookspec seed: one loader
checks every example.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01T3gXMVt7XJPi6ens1or9Dj
Members' shares of earnings are split cumulatively by largest remainder in
the closes, the members' equity statement, the K-1 worksheet and the
viewer, so a member's capital on a given day never moves by a cent when its
month is later closed. Old closes replay as they were; the first P3 close
carries any true-up. Feature members_cumulative. Kani and Lean proofs of
the bounded drift; bookspec examples.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01T3gXMVt7XJPi6ens1or9Dj
Settings, conventions (posting templates, approval rules, policies,
close steps, calendar, mappings, notes), decisions, open items and
entry approvals are journal events (journal format 2). Books that keep
their settings never read wanderbooks.toml or config.json; the server
and the viewer take the vault key from --vault-key-file instead.
books.import_settings moves a settings file in once, exactly as the
server reads it. Approval rules, when enforced, gate every posting
path. Replay refuses what it can't read as newer, never as corrupt.
Lean: a record changes no figure. Mutation on the whole diff: every
survivor killed by a test but two equivalent (docs/testing.md). The
Company page says a late open item is overdue in words, not colour
alone.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01T3gXMVt7XJPi6ens1or9Dj
The ranks of n parts are a permutation of 0..n-1 (being ahead is a strict
total order; pigeonhole by hand, core Lean has no subperm), so exactly
u parts get a unit and one gets the fraction. apportion_sum and
apportion_sum_of_shortfall; the audit shows only the standard axioms.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01GWVo7x3UHw5kwCUaWxiejX
Each close into members' capital rounded on its own, ties to the
earlier member, so twelve monthly 50/50 closes of odd-cent income could
leave one member several cents ahead of half the year (docs/testing.md
#12, found with the members' equity fix).
- CloseTo::Members now splits cumulatively over a run (closes back to
back with the same members and shares): each close gives a member
allocate(run total so far) - allocate(run total before). Periods
record their close order and a cumulative close's members and net
(Period::close_seq, member_close) so the next close continues the run
and replay recomputes it exactly. A close to anything else, or other
shares, ends the run.
- Journaled "rounding": "cumulative". The per-close rule is kept as
CloseTo::MembersPerClose for closes journaled "largest_remainder";
older closes still replay with the last member absorbing it.
- Lean: runPart_telescopes (a member's total from a run is their
allocation of the run's total) and closePart_total (each close hands
out exactly its net), audited to the standard axioms.
- Tests: hand-computed three one-cent months (per close A 0.03 / B 0;
cumulative A 0.02 / B 0.01), a run ending, a property that each member
stays within a cent of their share (fails on the per-close rule), and
a store contract that each rule journals and replays as itself.
The first company's books have no closes yet, so all of theirs use the new rule.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01GWVo7x3UHw5kwCUaWxiejX
The money arithmetic every invariant rests on now lives in one kernel,
ledger-core/src/kernel.rs: signing a line, totals, net, per-account
movements, reversal, normal balances, trial-balance columns, closing
lines, and the rounding plug for member splits. It is generic over a
checked `Amount` trait. The engine runs it on Decimal (validate,
movements, reverse_entry, account_balance, close_period_to, allocate,
trial_balance): there is one copy of the arithmetic, and it is the one
under proof.
Three layers, docs/verification.md maps every law to its proofs:
- Kani (src/proofs.rs): 17 harnesses prove the kernel at i64 for every
input up to 4 lines over 3 accounts. An entry is accepted exactly
when it is two or more positive, in-range lines whose debits equal
credits; accepted entries net to zero; grouping by account loses
nothing; a reversal mirrors and cancels its original; trial-balance
columns balance iff the books net to zero; closing lines zero their
accounts and a close balances however the net is split; the plug
makes parts sum to the whole. No panics, no overflow. kani::cover!
shows the proofs are not vacuous.
- Lean 4 (verify/lean): 24 headline theorems for books of any size. The
ledger is a state machine (add account, draft, post, reverse, open,
close), and in every reachable state the books net to zero, the trial
balance balances (as of any date), and the accounting equation holds.
Posting only appends ("posted is forever"), closed periods are
frozen, a close zeroes revenue and expenses and credits exactly the net
income, and period statements add up. Audit.lean shows standard axioms
only, no sorry.
- Bridge (tests/kernel_bridge.rs): the Decimal and i64 kernels agree.
What the proofs found (each one missed by every test, fuzzer, and
mutant):
- The engine accepted negative line amounts; only MCP refused them. Now
NegativeAmountLine: direction is the side's job.
- Summing lines near Decimal::MAX panicked. Lines are now capped at one
quadrillion and ten decimal places (AmountOutOfRange), which keeps
every realistic sum exact, and the kernel's sums are checked.
- FX conversion (foreign_amount * fx_rate) could panic the same way; it
is now a checked multiply.
- Kani itself: 0.68 mis-models symbolic-length copy_from_slice
(model-checking/kani#4904) and reported a reversal that doesn't net to
zero. The counterexample, replayed natively, passes, and a 15-line
standalone crate reproduces the bug. Harnesses avoid bulk copies, and
a should_panic canary will flag the upstream fix.
`just prove` runs it all (Kani memory- and time-capped, fails on an
unsatisfiable cover or a non-standard Lean axiom). AGENTS.md now makes
formal coverage part of every core change.
Also, docs: GnuCash is *an* oracle, never *the* oracle (the owner). The
spec is accounting principles, proved. Golden files are recomputed from
principles. External implementations (GnuCash, the old Sheet, QBO/Xero)
are cross-checks whose disagreements get adjudicated, never obeyed.
docs/oracle.md gains "Who is right"; AGENTS, README, architecture,
roadmap, parity, and STATUS are reworded to match.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01GWVo7x3UHw5kwCUaWxiejX
swaitsandClaude Fable 5.1