diff --git a/README.md b/README.md
index 0d36835..f1b760c 100644
--- a/README.md
+++ b/README.md
@@ -79,9 +79,10 @@ listed first; rules.md B-13). An example that closes to the members
 declares `largest-remainder`, the rule a members close splits by.
 
 Required everywhere: the top-level keys, `[setup]` with its four keys and
-its accounts, the events, and at least one `[[expect]]` with values: a
-figure query's are exact decimal strings (`"2340.00"`, `"-12.50"`; never a
-float), a format query's are text (below). Amounts on lines are positive;
+its accounts, the events (`events = []`, before `[setup]`, when nothing is
+posted), and at least one `[[expect]]` with values: a figure query's are
+exact decimal strings (`"2340.00"`, `"-12.50"`; never a float), a format
+query's are text (below). Amounts on lines are positive;
 the side gives the direction.
 
 ### Optional keys, for the rules that need them
@@ -99,26 +100,55 @@ the side gives the direction.
 - `today` (in `[setup]`): the day the books are asked on, `YYYY-MM-DD`,
   in the company's time zone: what an omitted date means (B-30). A query
   that omits a date needs it.
-- `cash_accounts`, `financing_accounts`, `investing_accounts`: arrays of
-  account codes, the statement of cash flows' account roles (ASC
-  230-10-45-10 to 45-15). The cash and financing accounts are also what a
-  payee is paid from, for `vendor_1099_paid` (a payment card is neither:
-  its charges go on Form 1099-K; rules.md B-19), and the cash accounts
-  are an IIF file's bank accounts (B-34).
+- `cash_accounts`, `financing_accounts`, `investing_accounts` (in
+  `[setup]`): arrays of account codes, the statement of cash flows'
+  account roles (ASC 230-10-45-10 to 45-15). The cash and financing
+  accounts are also what a payee is paid from, for `vendor_1099_paid` (a
+  payment card is neither: its charges go on Form 1099-K; rules.md B-19);
+  with the cards, what party money is, for
+  `party_part` and `party_totals` (B-35 item 5: no `cash_accounts`, every
+  asset account but receivables); the cash accounts are what the K-1
+  worksheet reads as money (`k1`) and an IIF file's bank accounts (B-34).
 - `[[setup.fixed_assets]]` `{ cost_account, accumulated_account,
   expense_account }`: accounts that hold property and equipment (their
   cost and accumulated depreciation are investing; ASC 230-10-45-12(c),
   45-13(c)).
-- `[[setup.members]]` `{ name, capital_account, share? }`: the members of
-  a multi-member LLC. `share` is the member's share of income, an exact
-  decimal fraction (`"0.5"`, `"0.3333"`); every member has one or none
-  does, and the shares sum to 1. A close to the members and
-  `members_equity` need them.
+- `[[setup.parties]]` `{ name, roles, creditor_of?, tin_last4?,
+  w9_tin_last4?, tin_purged? }`: the company's directory (B-26). `roles`
+  are role keys (`member`, `vendor`, `customer`, `contractor`,
+  `landlord`, `employee`, `financial_institution`, `payout_platform`,
+  `tax_agency`, `government_agency`); `vendor` or `customer` (one at
+  most) gives the party its record. `creditor_of`: the liabilities, by
+  code, the company owes the party itself (a card's issuer, a lender,
+  each member for what the members advanced: B-35 item 6). `tin_last4`:
+  its TIN facts' last four (an SSN's); `w9_tin_last4`: its W-9's (a 1099
+  role's); `tin_purged = true`: the vault's copy purged, the facts kept.
+  Never a full TIN. Each name once.
+- `[[setup.members]]` `{ name, capital_account, share?,
+  distributions_account? }`: the members of a multi-member LLC. `share`
+  is the member's share of income, an exact decimal fraction (`"0.5"`,
+  `"0.3333"`); every member has one or none does, and the shares sum to
+  1. A close to the members, `members_equity` and `k1` need them.
+  `distributions_account`: the member's distributions account (B-13). A
+  member whose `name` is a party's in `setup.parties` with the `member`
+  role is that party, as the company's settings name them: an entry's
+  parties' shares resolve with those members (B-35), and so does the
+  1099 worksheet.
 - `[[setup.payees]]` `{ name, form }`: a payee marked for an information
-  return, `form` `"1099-NEC"` or `"1099-MISC"`; each name once.
+  return from the beginning, `form` `"1099-NEC"` or `"1099-MISC"`; each
+  name once. A payee in `setup.parties` with the `vendor` role is that
+  party's vendor record; any other is a vendor record of its own.
 - `payee` on an event: the payee (by name, one of `setup.payees`) the
   entry paid. Not on a reversal, which takes its original's, nor on a
   close.
+- `parties = [{ party, amount? }, { party, percent? }, ...]` on an event:
+  the parties (by name, in `setup.parties`) the entry is with, each with
+  its share: an `amount` (an exact decimal string), a `percent`, or
+  neither (derived from the entry: all of it for one party, the members'
+  capital lines or income shares for several: B-35). An entry naming a
+  party with a vendor record is tagged with that payee too; with
+  `payee` as well, the payee's party is one of the parties.
+  Not on a reversal, which takes its original's.
 - `close = { start, to, rounding? }` as an event: closes the period from
   `start` through the event's `date` (rules.md B-11, B-13), `to`
   `"members"` (split by share, in the order listed) or
@@ -150,8 +180,9 @@ A query over a period takes `from` and `to`; a query as of a day takes
 `as_of`; the other is refused. A date left out is resolved by the one
 rule (rules.md B-30) on `setup.today`: an omitted `to` is today, an
 omitted `from` the first day of the fiscal year that holds `to`, an
-omitted `as_of` today (`vendor_1099_paid` and the format queries give
-theirs). A query no crate answers is refused, never skipped.
+omitted `as_of` today (`vendor_1099_paid`, `party_totals` and the
+format queries give theirs). A query no crate
+answers is refused, never skipped.
 
 | query | dates | values | checked by |
 |---|---|---|---|
@@ -161,7 +192,11 @@ theirs). A query no crate answers is refused, never skipped.
 | `entry` | `entry = N`, no dates | entry N's lines, `"<code>.debit"` and `"<code>.credit"` each the sum of that account's lines on that side, every line of the entry named | `ledger-core` `tests/bookspec.rs` |
 | `balances` | `as_of` | each account named by code, its balance on its normal side (a member's capital after a loss is negative); the example names the accounts it shows | `ledger-core` `tests/bookspec.rs` |
 | `members_equity` | `from`, `to` | the statement of changes in members' equity (rules.md B-13): `"<member>.beginning"`, `.contributions`, `.net_income`, `.distributions`, `.other`, `.ending`; the example names the figures it shows | `ledger-core` `tests/bookspec.rs` |
-| `vendor_1099_paid` | `from` (January 1 of `to`'s year), `to` | each payee's payments by name, out of the cash and financing accounts (`cash_accounts` required), every payee listed | `ledger-core` `tests/bookspec.rs` |
+| `k1` | `from`, `to` | the K-1 worksheet (B-13; Schedule K-1 Item L): `"<member>.beginning"`, `.contributions_cash`, `.contributions_property`, `.net_income`, `.distributions`, `.other`, `.ending`; the example names the figures it shows (`cash_accounts` required) | `ledger-core` `tests/bookspec.rs` |
+| `vendor_1099_paid` | `from` (January 1 of `to`'s year), `to` | each payee's payments that count toward its 1099, by name: out of the cash and financing accounts (`cash_accounts` required), a card's or payment network's left out (B-19), every payee listed | `ledger-core` `tests/bookspec.rs` |
+| `party_part` | `entry = N`, `party`, no dates | entry N's part for the party (B-35): `resolved`, signed as a line on the party's own account would be (paid or given positive, received negative), the entry's `direction` (`paid`, `received` or `neither`), and what of it moved as money (`cash`) and as property (`in_kind`), every one given | `ledger-core` `tests/bookspec.rs` |
+| `party_totals` | `party`, `basis` (`cash` or `all`), `from`, `to` | what was `paid` to the party and `received` from it over the period (B-35 item 4: basis `cash` money, `all` money and property in kind; each entry on its first original's side), both given | `ledger-core` `tests/bookspec.rs` |
+| `party_tin_last4` | `party`, no dates | `tin_last4`: the party's TIN facts' last four, else its W-9's, `""` for none (B-26) | `ledger-core` `tests/bookspec.rs` |
 | `period` | `from`, `to`, either or both left out | the dates a period report asked with those dates covers, by the one rule (B-30): `from`, `to` (`YYYY-MM-DD`); or `refused` | `ledger-core` `tests/bookspec.rs` |
 | `day` | `as_of`, or left out | the day a report as of a day is made as of: `as_of` | `ledger-core` `tests/bookspec.rs` |
 | `calendar_year` | none | the year a calendar-year count (1099s, party totals) asked without one counts: `year` | `ledger-core` `tests/bookspec.rs` |
@@ -172,8 +207,9 @@ theirs). A query no crate answers is refused, never skipped.
 
 A figure query is a table (`[expect.values]`, or `values = { ... }`); a
 format query, and `uncategorized_accounts`, an array (`values = [ ...
-]`). `period`, `day` and `calendar_year` give dates and a year, and
-`account_names` names, not figures.
+]`). `period`, `day` and `calendar_year` give dates and a year,
+`account_names` names, `party_part`'s `direction` and
+`party_tin_last4` words, not figures.
 
 A command is tried on a copy of the books, as the books' own command
 does it, and changes nothing checked after it. It shows no values: it is
diff --git a/examples/p3-party-accrual-counts-once.toml b/examples/p3-party-accrual-counts-once.toml
new file mode 100644
index 0000000..8d8d099
--- /dev/null
+++ b/examples/p3-party-accrual-counts-once.toml
@@ -0,0 +1,134 @@
+# P3 defect 24 (found in design; wanderbooks plan/served.md P3 "Settled in
+# design"): party totals treated every liability but payables and payroll
+# as money, so an accrual through another liability counted when it was
+# booked and again when it was settled. Regression test: ledger-core
+# tests/spec_party_totals.rs
+# defect24_an_accrual_through_another_liability_counts_once. The shape:
+# bookspec/README.md.
+
+id = "p3-party-accrual-counts-once"
+title = "An accrual through a liability that isn't money counts once, when it is settled"
+rule = """
+Money is cash, the company's cards, the members' financing and loans.
+Every other liability (accrued expenses, deferred revenue) is a promise:
+an entry through it moves nothing with the party until it is settled in
+money.
+"""
+status = "CHOICE"
+sources = [
+  "Helvering v. Price, 309 U.S. 409, 412-413 (1940): a promise to pay is not payment (wanderbooks docs/spec/sources/helvering-v-price-1940.md)",
+  "DECISION (owner, 2026-10-20): money is cash, cards, the members' financing and loans (wanderbooks rules.md B-35 item 5)",
+]
+tags = ["parties", "accruals", "deferred-revenue", "money"]
+
+[setup]
+currency = "USD"
+fiscal_year_start = "01-01"
+basis = "accrual"
+rounding = "half-even"
+cash_accounts = ["1000"]
+financing_accounts = ["2100"]
+
+[[setup.accounts]]
+code = "1000"
+name = "Checking"
+type = "asset"
+
+[[setup.accounts]]
+code = "2100"
+name = "Due to Members"
+type = "liability"
+
+[[setup.accounts]]
+code = "2200"
+name = "Accrued Expenses"
+type = "liability"
+
+[[setup.accounts]]
+code = "2400"
+name = "Deferred Revenue"
+type = "liability"
+
+[[setup.accounts]]
+code = "4000"
+name = "Revenue"
+type = "revenue"
+
+[[setup.accounts]]
+code = "6050"
+name = "Domain & Hosting"
+type = "expense"
+
+[[setup.parties]]
+name = "Northwind Filings"
+roles = ["vendor"]
+
+[[setup.parties]]
+name = "Riley Chen"
+roles = ["customer"]
+
+[[events]]
+date = "2026-03-31"
+description = "Hosting accrued"
+parties = [{ party = "Northwind Filings" }]
+lines = [
+  { account = "6050", side = "debit", amount = "300.00" },
+  { account = "2200", side = "credit", amount = "300.00" },
+]
+
+[[events]]
+date = "2026-04-15"
+description = "Hosting paid"
+parties = [{ party = "Northwind Filings" }]
+lines = [
+  { account = "2200", side = "debit", amount = "300.00" },
+  { account = "1000", side = "credit", amount = "300.00" },
+]
+
+[[events]]
+date = "2026-01-02"
+description = "A year paid ahead"
+parties = [{ party = "Riley Chen" }]
+lines = [
+  { account = "1000", side = "debit", amount = "1200.00" },
+  { account = "2400", side = "credit", amount = "1200.00" },
+]
+
+[[events]]
+date = "2026-01-31"
+description = "January earned"
+parties = [{ party = "Riley Chen" }]
+lines = [
+  { account = "2400", side = "debit", amount = "100.00" },
+  { account = "4000", side = "credit", amount = "100.00" },
+]
+
+[[expect]]
+query = "party_part"
+entry = 1
+party = "Northwind Filings"
+values = { resolved = "300.00", direction = "neither", cash = "0.00", in_kind = "0.00" }
+
+# Before P3: 600.00.
+[[expect]]
+query = "party_totals"
+party = "Northwind Filings"
+basis = "all"
+from = "2026-01-01"
+to = "2026-12-31"
+values = { paid = "300.00", received = "0.00" }
+
+[[expect]]
+query = "party_part"
+entry = 4
+party = "Riley Chen"
+values = { resolved = "100.00", direction = "neither", cash = "0.00", in_kind = "0.00" }
+
+# Before P3: 1,300.00.
+[[expect]]
+query = "party_totals"
+party = "Riley Chen"
+basis = "all"
+from = "2026-01-01"
+to = "2026-12-31"
+values = { paid = "0.00", received = "1200.00" }
diff --git a/examples/p3-party-distribution-still-owed.toml b/examples/p3-party-distribution-still-owed.toml
new file mode 100644
index 0000000..68b868b
--- /dev/null
+++ b/examples/p3-party-distribution-still-owed.toml
@@ -0,0 +1,200 @@
+# P3 defect 24 in a member's entry (found in review, 2026-10-21): a
+# distribution declared to a liability that isn't money counted as paid
+# when declared and again when paid. A distribution's cash is the money it
+# paid, its in kind the property it gave; the rest is still owed. Regression
+# tests: ledger-core tests/spec_party_totals.rs
+# defect24_a_distribution_declared_to_a_payable_counts_once_when_paid and
+# a_distribution_of_money_and_depreciated_property_splits_by_what_moved.
+# The shape: bookspec/README.md.
+
+id = "p3-party-distribution-still-owed"
+title = "A distribution counts the money it paid and the property it gave; what is still owed counts when paid"
+rule = """
+An entry naming only members that moves their capital counts what moved
+it. Of a distribution, the cash is the money it paid (through the cash
+accounts, a card, the members' financing or a loan), the in kind the
+property it gave up (at what the books carried it), and the rest, credited
+to a liability that isn't money for the entry (distributions payable, or
+what the members are owed when they are named its creditors), is a
+promise: it counts nothing until it is paid, then once, as paid. The
+statement of members' equity counts a distribution when it is declared,
+so party totals catch up with it when it is paid.
+"""
+status = "AUTHORITY"
+sources = [
+  "Helvering v. Price, 309 U.S. 409, 412-413 (1940): a promise to pay is not payment (wanderbooks docs/spec/sources/helvering-v-price-1940.md)",
+  "Treas. Reg. §1.704-1(b)(2)(iv)(b)(4)-(5): a partner's capital account falls by the money and the property distributed (docs/spec/sources/irs-capital-accounts.md)",
+  "DECISION (owner, 2026-10-20): a member's entry counts what moved their capital; money is cash, cards, the members' financing and loans (rules.md B-35)",
+]
+tags = ["parties", "members", "distributions", "promises", "in-kind", "money"]
+
+[setup]
+currency = "USD"
+fiscal_year_start = "01-01"
+basis = "accrual"
+rounding = "half-even"
+cash_accounts = ["1000"]
+
+[[setup.accounts]]
+code = "1000"
+name = "Checking"
+type = "asset"
+
+[[setup.accounts]]
+code = "1500"
+name = "Equipment"
+type = "asset"
+
+[[setup.accounts]]
+code = "1510"
+name = "Accumulated Depreciation — Equipment"
+type = "asset"
+
+[[setup.accounts]]
+code = "2150"
+name = "Distributions Payable"
+type = "liability"
+
+[[setup.accounts]]
+code = "3000"
+name = "Capital — Tobin Harlow"
+type = "equity"
+
+[[setup.accounts]]
+code = "3001"
+name = "Capital — Morgan Ellis"
+type = "equity"
+
+[[setup.accounts]]
+code = "3100"
+name = "Distributions — Tobin Harlow"
+type = "equity"
+
+[[setup.parties]]
+name = "Tobin Harlow"
+roles = ["member"]
+
+[[setup.parties]]
+name = "Morgan Ellis"
+roles = ["member"]
+
+[[setup.members]]
+name = "Tobin Harlow"
+share = "0.5"
+capital_account = "3000"
+distributions_account = "3100"
+
+[[setup.members]]
+name = "Morgan Ellis"
+share = "0.5"
+capital_account = "3001"
+
+# 1. A distribution declared to Tobin: still owed, counts nothing.
+[[events]]
+date = "2026-06-30"
+description = "Distribution declared"
+parties = [{ party = "Tobin Harlow" }]
+lines = [
+  { account = "3100", side = "debit", amount = "200.00" },
+  { account = "2150", side = "credit", amount = "200.00" },
+]
+
+# 2. It is paid: paid, money, once.
+[[events]]
+date = "2026-07-15"
+description = "Distribution paid"
+parties = [{ party = "Tobin Harlow" }]
+lines = [
+  { account = "2150", side = "debit", amount = "200.00" },
+  { account = "1000", side = "credit", amount = "200.00" },
+]
+
+# 3. Declared and partly paid at once: the money now, the rest when paid.
+[[events]]
+date = "2026-08-31"
+description = "Distribution, part paid"
+parties = [{ party = "Tobin Harlow" }]
+lines = [
+  { account = "3100", side = "debit", amount = "300.00" },
+  { account = "1000", side = "credit", amount = "100.00" },
+  { account = "2150", side = "credit", amount = "200.00" },
+]
+
+# 4. Equipment carried at 1,000.00 less 300.00 depreciated, with 100.00 in
+# cash, distributed to Morgan: 100.00 cash, 700.00 in kind.
+[[events]]
+date = "2026-09-01"
+description = "Equipment and cash distributed"
+parties = [{ party = "Morgan Ellis" }]
+lines = [
+  { account = "3001", side = "debit", amount = "800.00" },
+  { account = "1510", side = "debit", amount = "300.00" },
+  { account = "1500", side = "credit", amount = "1000.00" },
+  { account = "1000", side = "credit", amount = "100.00" },
+]
+
+[[expect]]
+query = "party_part"
+entry = 1
+party = "Tobin Harlow"
+values = { resolved = "200.00", direction = "neither", cash = "0.00", in_kind = "0.00" }
+
+[[expect]]
+query = "party_part"
+entry = 3
+party = "Tobin Harlow"
+values = { resolved = "300.00", direction = "paid", cash = "100.00", in_kind = "0.00" }
+
+[[expect]]
+query = "party_part"
+entry = 4
+party = "Morgan Ellis"
+values = { resolved = "800.00", direction = "paid", cash = "100.00", in_kind = "700.00" }
+
+# Before the review: 700.00 (event 1's 200.00 and the 200.00 still owed
+# on event 3 counted as paid, and event 2 paid the first again).
+[[expect]]
+query = "party_totals"
+party = "Tobin Harlow"
+basis = "cash"
+from = "2026-01-01"
+to = "2026-12-31"
+values = { paid = "300.00", received = "0.00" }
+
+# Through June: declared, not yet paid. The statement counts it already.
+[[expect]]
+query = "party_totals"
+party = "Tobin Harlow"
+basis = "all"
+from = "2026-01-01"
+to = "2026-06-30"
+values = { paid = "0.00", received = "0.00" }
+
+[[expect]]
+query = "members_equity"
+from = "2026-01-01"
+to = "2026-06-30"
+values = { "Tobin Harlow.contributions" = "0.00", "Tobin Harlow.distributions" = "200.00" }
+
+# Before the review: 0.00 cash, 800.00 in kind.
+[[expect]]
+query = "party_totals"
+party = "Morgan Ellis"
+basis = "cash"
+from = "2026-01-01"
+to = "2026-12-31"
+values = { paid = "100.00", received = "0.00" }
+
+[[expect]]
+query = "party_totals"
+party = "Morgan Ellis"
+basis = "all"
+from = "2026-01-01"
+to = "2026-12-31"
+values = { paid = "800.00", received = "0.00" }
+
+[[expect]]
+query = "members_equity"
+from = "2026-01-01"
+to = "2026-12-31"
+values = { "Morgan Ellis.contributions" = "0.00", "Morgan Ellis.distributions" = "800.00" }
diff --git a/examples/p3-party-gift-card-is-a-promise.toml b/examples/p3-party-gift-card-is-a-promise.toml
new file mode 100644
index 0000000..852eaab
--- /dev/null
+++ b/examples/p3-party-gift-card-is-a-promise.toml
@@ -0,0 +1,92 @@
+# P3 defect 24 and the card rule (found in review, 2026-10-21): the
+# company's cards are the liabilities whose names say "card", so a gift
+# card the company sold (deferred revenue) read as money: received when
+# sold and again when redeemed. Regression
+# test: ledger-core tests/spec_party_totals.rs
+# defect24_a_gift_card_sold_is_received_once.
+# The shape: bookspec/README.md.
+
+id = "p3-party-gift-card-is-a-promise"
+title = "A gift card the company sold is a promise, not a card it pays with"
+rule = """
+The company's cards are liability accounts whose names say "card", but not
+"gift card": gift cards the company sold are revenue it owes its customers
+in service (deferred revenue), a promise. Selling one is money received
+from the buyer; redeeming it moves no money and counts nothing.
+"""
+status = "CONVENTION"
+sources = [
+  "DECISION (owner, 2026-10-20): money is cash, cards, the members' financing and loans; every other liability is a promise, counted when settled (wanderbooks rules.md B-35 item 5)",
+  "Helvering v. Price, 309 U.S. 409, 412-413 (1940): a promise to pay is not payment (docs/spec/sources/helvering-v-price-1940.md)",
+]
+tags = ["parties", "cards", "deferred-revenue", "money"]
+
+[setup]
+currency = "USD"
+fiscal_year_start = "01-01"
+basis = "accrual"
+rounding = "half-even"
+cash_accounts = ["1000"]
+
+[[setup.accounts]]
+code = "1000"
+name = "Checking"
+type = "asset"
+
+[[setup.accounts]]
+code = "2050"
+name = "Business Card"
+type = "liability"
+
+[[setup.accounts]]
+code = "2410"
+name = "Gift Card Liability"
+type = "liability"
+
+[[setup.accounts]]
+code = "4000"
+name = "Revenue"
+type = "revenue"
+
+[[setup.parties]]
+name = "Riley Chen"
+roles = ["customer"]
+
+[[events]]
+date = "2026-03-01"
+description = "Gift card sold"
+parties = [{ party = "Riley Chen" }]
+lines = [
+  { account = "1000", side = "debit", amount = "100.00" },
+  { account = "2410", side = "credit", amount = "100.00" },
+]
+
+[[events]]
+date = "2026-03-05"
+description = "Gift card redeemed"
+parties = [{ party = "Riley Chen" }]
+lines = [
+  { account = "2410", side = "debit", amount = "100.00" },
+  { account = "4000", side = "credit", amount = "100.00" },
+]
+
+[[expect]]
+query = "party_part"
+entry = 1
+party = "Riley Chen"
+values = { resolved = "-100.00", direction = "received", cash = "-100.00", in_kind = "0.00" }
+
+[[expect]]
+query = "party_part"
+entry = 2
+party = "Riley Chen"
+values = { resolved = "100.00", direction = "neither", cash = "0.00", in_kind = "0.00" }
+
+# Before the review: 200.00.
+[[expect]]
+query = "party_totals"
+party = "Riley Chen"
+basis = "all"
+from = "2026-01-01"
+to = "2026-12-31"
+values = { paid = "0.00", received = "100.00" }
diff --git a/examples/p3-party-members-equity-and-k1.toml b/examples/p3-party-members-equity-and-k1.toml
new file mode 100644
index 0000000..f9b20ee
--- /dev/null
+++ b/examples/p3-party-members-equity-and-k1.toml
@@ -0,0 +1,219 @@
+# P3 defect 14, settled in design (wanderbooks plan/served.md P3): party
+# totals count a member's entry by what moved their capital, so basis all
+# is the statement of members' equity and basis cash means what it means
+# on the K-1 worksheet. Regression tests: ledger-core
+# tests/spec_party_totals.rs a_members_mixed_entry_splits_as_the_k1_does,
+# basis_all_is_the_members_equity_statement_and_cash_the_k1s, and the
+# property member_totals_are_the_members_equity_statement. The shape:
+# bookspec/README.md.
+
+id = "p3-party-members-equity-and-k1"
+title = "A member's totals are their capital account: basis all the statement of members' equity, basis cash the K-1's cash"
+rule = """
+An entry naming only members that moves their equity counts what moved
+their capital: a contribution received, a distribution paid. The
+property in it (asset accounts that are neither cash nor receivables) is
+in kind, shared among the members in proportion to their parts, to the
+cent, leftover cents by largest remainder, ties to the member listed
+first; the rest is cash, as the K-1 worksheet counts it: money, or what a
+member paid for the company (an expense booked straight to capital, a
+debt to them converted to capital).
+"""
+status = "CHOICE"
+sources = [
+  "Treas. Reg. §1.704-1(b)(2)(iv)(b)(1)-(2), (c)(1): money and property contributed; a partnership liability a partner pays is money contributed (wanderbooks docs/spec/sources/irs-capital-accounts.md)",
+  "Partner's Instructions for Schedule K-1 (Form 1065), Item L: the capital contributed during the year (docs/spec/sources/irs-capital-accounts.md)",
+  "DECISION (owner, 2026-10-15): what a member paid for the company is cash on the K-1 (wanderbooks ledger-core k1 INVARIANT 3); DECISION (owner, 2026-10-20): a member's entry counts what moved their capital (rules.md B-35)",
+]
+tags = ["parties", "members", "k1", "members-equity", "in-kind", "rounding"]
+
+[setup]
+currency = "USD"
+fiscal_year_start = "01-01"
+basis = "accrual"
+rounding = "largest-remainder"
+cash_accounts = ["1000"]
+financing_accounts = ["2100"]
+
+[[setup.accounts]]
+code = "1000"
+name = "Checking"
+type = "asset"
+
+[[setup.accounts]]
+code = "1500"
+name = "Equipment"
+type = "asset"
+
+[[setup.accounts]]
+code = "2100"
+name = "Due to Members"
+type = "liability"
+
+[[setup.accounts]]
+code = "3000"
+name = "Capital — Tobin Harlow"
+type = "equity"
+
+[[setup.accounts]]
+code = "3001"
+name = "Capital — Morgan Ellis"
+type = "equity"
+
+[[setup.accounts]]
+code = "6050"
+name = "Domain & Hosting"
+type = "expense"
+
+[[setup.parties]]
+name = "Tobin Harlow"
+roles = ["member"]
+
+[[setup.parties]]
+name = "Morgan Ellis"
+roles = ["member"]
+
+[[setup.members]]
+name = "Tobin Harlow"
+share = "0.5"
+capital_account = "3000"
+
+[[setup.members]]
+name = "Morgan Ellis"
+share = "0.5"
+capital_account = "3001"
+
+# 1. A joint contribution of cash and property (the K-1 worksheet's
+# SCENARIO 3): 500.00 each, of it 300.00 cash and 200.00 in kind.
+[[events]]
+date = "2026-02-01"
+description = "Joint contribution, cash and equipment"
+parties = [{ party = "Morgan Ellis" }, { party = "Tobin Harlow" }]
+lines = [
+  { account = "1000", side = "debit", amount = "600.00" },
+  { account = "1500", side = "debit", amount = "400.00" },
+  { account = "3000", side = "credit", amount = "500.00" },
+  { account = "3001", side = "credit", amount = "500.00" },
+]
+
+# 2. One cent of property shared by two equal parts: the cent goes to the
+# member listed first in the company's members (Tobin), whatever the
+# order the entry names them in.
+[[events]]
+date = "2026-02-02"
+description = "A cent of property"
+parties = [{ party = "Morgan Ellis" }, { party = "Tobin Harlow" }]
+lines = [
+  { account = "1000", side = "debit", amount = "0.99" },
+  { account = "1500", side = "debit", amount = "0.01" },
+  { account = "3000", side = "credit", amount = "0.50" },
+  { account = "3001", side = "credit", amount = "0.50" },
+]
+
+# 3. An expense Morgan paid, booked straight to capital: cash.
+[[events]]
+date = "2026-02-03"
+description = "Hosting Morgan paid"
+parties = [{ party = "Morgan Ellis" }]
+lines = [
+  { account = "6050", side = "debit", amount = "50.00" },
+  { account = "3001", side = "credit", amount = "50.00" },
+]
+
+# 4. What the company owed Tobin, converted to capital: cash.
+[[events]]
+date = "2026-02-04"
+description = "Advance converted"
+parties = [{ party = "Tobin Harlow" }]
+lines = [
+  { account = "2100", side = "debit", amount = "70.00" },
+  { account = "3000", side = "credit", amount = "70.00" },
+]
+
+[[expect]]
+query = "party_part"
+entry = 1
+party = "Tobin Harlow"
+values = { resolved = "-500.00", direction = "received", cash = "-300.00", in_kind = "-200.00" }
+
+[[expect]]
+query = "party_part"
+entry = 2
+party = "Tobin Harlow"
+values = { resolved = "-0.50", direction = "received", cash = "-0.49", in_kind = "-0.01" }
+
+[[expect]]
+query = "party_part"
+entry = 2
+party = "Morgan Ellis"
+values = { resolved = "-0.50", direction = "received", cash = "-0.50", in_kind = "0.00" }
+
+[[expect]]
+query = "party_part"
+entry = 3
+party = "Morgan Ellis"
+values = { resolved = "-50.00", direction = "received", cash = "-50.00", in_kind = "0.00" }
+
+[[expect]]
+query = "party_part"
+entry = 4
+party = "Tobin Harlow"
+values = { resolved = "-70.00", direction = "received", cash = "-70.00", in_kind = "0.00" }
+
+# Tobin: cash 300.00 + 0.49 + 70.00; in kind 200.00 + 0.01.
+[[expect]]
+query = "party_totals"
+party = "Tobin Harlow"
+basis = "cash"
+from = "2026-01-01"
+to = "2026-12-31"
+values = { paid = "0.00", received = "370.49" }
+
+[[expect]]
+query = "party_totals"
+party = "Tobin Harlow"
+basis = "all"
+from = "2026-01-01"
+to = "2026-12-31"
+values = { paid = "0.00", received = "570.50" }
+
+# Morgan: cash 300.00 + 0.50 + 50.00; in kind 200.00.
+[[expect]]
+query = "party_totals"
+party = "Morgan Ellis"
+basis = "cash"
+from = "2026-01-01"
+to = "2026-12-31"
+values = { paid = "0.00", received = "350.50" }
+
+[[expect]]
+query = "party_totals"
+party = "Morgan Ellis"
+basis = "all"
+from = "2026-01-01"
+to = "2026-12-31"
+values = { paid = "0.00", received = "550.50" }
+
+[[expect]]
+query = "members_equity"
+from = "2026-01-01"
+to = "2026-12-31"
+values = { "Tobin Harlow.contributions" = "570.50", "Tobin Harlow.distributions" = "0.00" }
+
+[[expect]]
+query = "members_equity"
+from = "2026-01-01"
+to = "2026-12-31"
+values = { "Morgan Ellis.contributions" = "550.50", "Morgan Ellis.distributions" = "0.00" }
+
+[[expect]]
+query = "k1"
+from = "2026-01-01"
+to = "2026-12-31"
+values = { "Tobin Harlow.contributions_cash" = "370.49", "Tobin Harlow.contributions_property" = "200.01" }
+
+[[expect]]
+query = "k1"
+from = "2026-01-01"
+to = "2026-12-31"
+values = { "Morgan Ellis.contributions_cash" = "350.50", "Morgan Ellis.contributions_property" = "200.00" }
diff --git a/examples/p3-party-own-liability-never-pays.toml b/examples/p3-party-own-liability-never-pays.toml
new file mode 100644
index 0000000..15f5b1b
--- /dev/null
+++ b/examples/p3-party-own-liability-never-pays.toml
@@ -0,0 +1,240 @@
+# P3 defect 24 and wanderbooks rules.md B-35 item 6: a credit to a
+# liability the company owes a party itself never counts as paying that
+# party. Regression test: ledger-core tests/spec_party_totals.rs
+# defect24_a_credit_to_a_partys_own_liability_never_pays_it. The shape:
+# bookspec/README.md.
+
+id = "p3-party-own-liability-never-pays"
+title = "A credit to what the company owes a party itself never pays it"
+rule = """
+A party may be named the creditor of the liabilities the company owes it
+itself: a card's issuer, a loan's lender, each member for what the
+members advanced. For an entry naming it, a credit to one is a promise,
+not a payment: a fee on the issuer's own card, equipment bought on the
+seller's own note, a distribution credited to what the members are owed.
+It counts when it is paid. Property a member contributes subject to a
+loan counts at its value net of the loan, in kind.
+"""
+status = "AUTHORITY"
+sources = [
+  "Helvering v. Price, 309 U.S. 409, 412-413 (1940): a promise to pay, even a secured one, is not payment (wanderbooks docs/spec/sources/helvering-v-price-1940.md)",
+  "Treas. Reg. §1.704-1(b)(2)(iv)(b)(2): property contributed, net of liabilities the partnership takes it subject to (docs/spec/sources/irs-capital-accounts.md)",
+  "DECISION (owner, 2026-10-20): a liability credit never counts as paying that liability's own creditor (rules.md B-35)",
+]
+tags = ["parties", "creditors", "cards", "notes", "distributions", "members"]
+
+[setup]
+currency = "USD"
+fiscal_year_start = "01-01"
+basis = "accrual"
+rounding = "half-even"
+cash_accounts = ["1000"]
+financing_accounts = ["2100", "2500"]
+
+[[setup.accounts]]
+code = "1000"
+name = "Checking"
+type = "asset"
+
+[[setup.accounts]]
+code = "1500"
+name = "Equipment"
+type = "asset"
+
+[[setup.accounts]]
+code = "2050"
+name = "Business Card"
+type = "liability"
+
+[[setup.accounts]]
+code = "2100"
+name = "Due to Members"
+type = "liability"
+
+[[setup.accounts]]
+code = "2500"
+name = "Note Payable"
+type = "liability"
+
+[[setup.accounts]]
+code = "3000"
+name = "Capital — Tobin Harlow"
+type = "equity"
+
+[[setup.accounts]]
+code = "3001"
+name = "Capital — Morgan Ellis"
+type = "equity"
+
+[[setup.accounts]]
+code = "6400"
+name = "Bank Fees"
+type = "expense"
+
+[[setup.parties]]
+name = "Harbor Bank"
+roles = ["financial_institution"]
+creditor_of = ["2050"]
+
+[[setup.parties]]
+name = "Lakeside Supply"
+roles = []
+creditor_of = ["2500"]
+
+[[setup.parties]]
+name = "Tobin Harlow"
+roles = ["member"]
+creditor_of = ["2100"]
+
+[[setup.parties]]
+name = "Morgan Ellis"
+roles = ["member"]
+creditor_of = ["2100"]
+
+[[setup.members]]
+name = "Tobin Harlow"
+share = "0.5"
+capital_account = "3000"
+
+[[setup.members]]
+name = "Morgan Ellis"
+share = "0.5"
+capital_account = "3001"
+
+# 1. The issuer's fee on its own card: neither.
+[[events]]
+date = "2026-05-01"
+description = "Card fee"
+parties = [{ party = "Harbor Bank" }]
+lines = [
+  { account = "6400", side = "debit", amount = "25.00" },
+  { account = "2050", side = "credit", amount = "25.00" },
+]
+
+# 2. The card paid off: paid to the issuer.
+[[events]]
+date = "2026-05-20"
+description = "Card payment"
+parties = [{ party = "Harbor Bank" }]
+lines = [
+  { account = "2050", side = "debit", amount = "125.00" },
+  { account = "1000", side = "credit", amount = "125.00" },
+]
+
+# 3. A distribution to Tobin credited to what the members are owed:
+# still owed, counts as nothing.
+[[events]]
+date = "2026-06-30"
+description = "Distribution declared"
+parties = [{ party = "Tobin Harlow" }]
+lines = [
+  { account = "3000", side = "debit", amount = "200.00" },
+  { account = "2100", side = "credit", amount = "200.00" },
+]
+
+# 4. It is paid: paid, money.
+[[events]]
+date = "2026-07-15"
+description = "Distribution paid"
+parties = [{ party = "Tobin Harlow" }]
+lines = [
+  { account = "2100", side = "debit", amount = "200.00" },
+  { account = "1000", side = "credit", amount = "200.00" },
+]
+
+# 5. Equipment on the seller's own note: neither.
+[[events]]
+date = "2026-08-01"
+description = "Equipment on a note"
+parties = [{ party = "Lakeside Supply" }]
+lines = [
+  { account = "1500", side = "debit", amount = "900.00" },
+  { account = "2500", side = "credit", amount = "900.00" },
+]
+
+# 6. A payment on the note: paid.
+[[events]]
+date = "2026-09-01"
+description = "Note payment"
+parties = [{ party = "Lakeside Supply" }]
+lines = [
+  { account = "2500", side = "debit", amount = "300.00" },
+  { account = "1000", side = "credit", amount = "300.00" },
+]
+
+# 7. Equipment worth 1,000.00 Morgan contributes subject to 200.00 owed
+# on the note: 800.00 received, in kind (before P3: "paid 200.00").
+[[events]]
+date = "2026-09-15"
+description = "Equipment contributed with its loan"
+parties = [{ party = "Morgan Ellis" }]
+lines = [
+  { account = "1500", side = "debit", amount = "1000.00" },
+  { account = "2500", side = "credit", amount = "200.00" },
+  { account = "3001", side = "credit", amount = "800.00" },
+]
+
+[[expect]]
+query = "party_part"
+entry = 1
+party = "Harbor Bank"
+values = { resolved = "-25.00", direction = "neither", cash = "0.00", in_kind = "0.00" }
+
+# Before naming the issuer the card's creditor: 150.00.
+[[expect]]
+query = "party_totals"
+party = "Harbor Bank"
+basis = "all"
+from = "2026-01-01"
+to = "2026-12-31"
+values = { paid = "125.00", received = "0.00" }
+
+[[expect]]
+query = "party_part"
+entry = 3
+party = "Tobin Harlow"
+values = { resolved = "200.00", direction = "neither", cash = "0.00", in_kind = "0.00" }
+
+[[expect]]
+query = "party_totals"
+party = "Tobin Harlow"
+basis = "all"
+from = "2026-01-01"
+to = "2026-12-31"
+values = { paid = "200.00", received = "0.00" }
+
+[[expect]]
+query = "party_part"
+entry = 5
+party = "Lakeside Supply"
+values = { resolved = "-900.00", direction = "neither", cash = "0.00", in_kind = "0.00" }
+
+[[expect]]
+query = "party_totals"
+party = "Lakeside Supply"
+basis = "all"
+from = "2026-01-01"
+to = "2026-12-31"
+values = { paid = "300.00", received = "0.00" }
+
+[[expect]]
+query = "party_part"
+entry = 7
+party = "Morgan Ellis"
+values = { resolved = "-800.00", direction = "received", cash = "0.00", in_kind = "-800.00" }
+
+[[expect]]
+query = "party_totals"
+party = "Morgan Ellis"
+basis = "cash"
+from = "2026-01-01"
+to = "2026-12-31"
+values = { paid = "0.00", received = "0.00" }
+
+[[expect]]
+query = "party_totals"
+party = "Morgan Ellis"
+basis = "all"
+from = "2026-01-01"
+to = "2026-12-31"
+values = { paid = "0.00", received = "800.00" }
diff --git a/examples/p3-party-reversed-card-payment.toml b/examples/p3-party-reversed-card-payment.toml
new file mode 100644
index 0000000..4c39c96
--- /dev/null
+++ b/examples/p3-party-reversed-card-payment.toml
@@ -0,0 +1,99 @@
+# P3 defect 14, the second bug found in design (wanderbooks P3 brief
+# §1.4): a member pays the card from their own funds; reversing it read
+# as a second payment. Regression test: ledger-core
+# tests/spec_party_totals.rs
+# defect14_a_reversed_member_card_payment_nets_to_zero. The shape:
+# bookspec/README.md (`after = N` asks a query after event N).
+
+id = "p3-party-reversed-card-payment"
+title = "A reversed payment of one liability by another nets to zero"
+rule = """
+A reversal's part for each party is its original's negated, never read
+from the reversal's own lines. A member paying the company's card from
+their own funds (Dr card / Cr due to members), tagged with the card's
+issuer, is paid to the issuer; its reversal takes that back, so the pair
+nets to zero; reversing the reversal pays it again.
+"""
+status = "AUTHORITY"
+sources = [
+  "Pacioli, Summa (1494), Geijsbeek tr.: a mistake is corrected by the opposite entry (wanderbooks docs/spec/sources/pacioli-1494.md, rules.md B-9)",
+]
+tags = ["parties", "reversals", "liabilities"]
+
+[setup]
+currency = "USD"
+fiscal_year_start = "01-01"
+basis = "accrual"
+rounding = "half-even"
+cash_accounts = ["1000"]
+financing_accounts = ["2100"]
+
+[[setup.accounts]]
+code = "1000"
+name = "Checking"
+type = "asset"
+
+[[setup.accounts]]
+code = "2050"
+name = "Business Card"
+type = "liability"
+
+[[setup.accounts]]
+code = "2100"
+name = "Due to Members"
+type = "liability"
+
+[[setup.parties]]
+name = "Harbor Bank"
+roles = ["financial_institution"]
+
+[[events]]
+date = "2026-06-01"
+description = "A member pays the card from their own funds"
+parties = [{ party = "Harbor Bank" }]
+lines = [
+  { account = "2050", side = "debit", amount = "100.00" },
+  { account = "2100", side = "credit", amount = "100.00" },
+]
+
+[[events]]
+date = "2026-06-02"
+description = "Reversed"
+reverses = 1
+
+[[events]]
+date = "2026-06-03"
+description = "The reversal reversed"
+reverses = 2
+
+[[expect]]
+query = "party_part"
+entry = 1
+party = "Harbor Bank"
+values = { resolved = "100.00", direction = "paid", cash = "100.00", in_kind = "0.00" }
+
+[[expect]]
+query = "party_part"
+entry = 2
+party = "Harbor Bank"
+values = { resolved = "-100.00", direction = "received", cash = "-100.00", in_kind = "0.00" }
+
+# After the reversal: nothing paid (before P3: 200.00, the reversal read
+# as a second payment).
+[[expect]]
+query = "party_totals"
+after = 2
+party = "Harbor Bank"
+basis = "cash"
+from = "2026-01-01"
+to = "2026-12-31"
+values = { paid = "0.00", received = "0.00" }
+
+[[expect]]
+query = "party_totals"
+after = 3
+party = "Harbor Bank"
+basis = "cash"
+from = "2026-01-01"
+to = "2026-12-31"
+values = { paid = "100.00", received = "0.00" }
diff --git a/examples/p3-party-signs-and-reversals.toml b/examples/p3-party-signs-and-reversals.toml
new file mode 100644
index 0000000..85fc5c3
--- /dev/null
+++ b/examples/p3-party-signs-and-reversals.toml
@@ -0,0 +1,289 @@
+# P3 defect 14 (wanderbooks plan/served.md P3; audit findings F36, F37):
+# a party's part of an entry is signed as a line on the party's own
+# account, with its direction and what of it was money or property; a
+# reversal is the exact opposite of what it reverses; party totals take a
+# basis. Regression test: ledger-core tests/spec_party_totals.rs
+# defect14_shares_take_the_partys_side_and_reversals_flip. The shape:
+# bookspec/README.md.
+
+id = "p3-party-signs-and-reversals"
+title = "A party's part of an entry is signed as its own account would show it, and a reversal is the exact opposite"
+rule = """
+A party's part of an entry is debit-positive, as a line on the party's own
+account would be: positive when the company paid it or gave it value,
+negative when the company received from it. Each part has a direction
+(paid, received, neither) and a cash and an in-kind amount. An entry
+naming only members that moves equity counts what moved their capital,
+the property in it in kind. A reversal's part is exactly its original's
+negated. A bill or invoice moves nothing with the party yet (neither).
+Party totals on basis cash count the cash parts, on basis all the cash
+and in-kind parts, each on its root original's side.
+"""
+status = "CONVENTION"
+sources = [
+  "Pacioli, Summa (1494), Geijsbeek tr., ch. 36: debit is what owes, credit what is owed (wanderbooks docs/spec/sources/pacioli-1494.md)",
+  "Treas. Reg. §1.704-1(b)(2)(iv)(b)(1)-(2), (4)-(5): a partner's capital account rises by money and property contributed, falls by money and property distributed (docs/spec/sources/irs-capital-accounts.md)",
+  "Helvering v. Price, 309 U.S. 409, 412-413 (1940): a promise to pay is not payment (docs/spec/sources/helvering-v-price-1940.md)",
+  "DECISION (owner, 2026-10-20): a member's entry counts what moved their capital (wanderbooks rules.md B-35)",
+]
+tags = ["parties", "signs", "reversals", "members", "in-kind", "basis"]
+
+[setup]
+currency = "USD"
+fiscal_year_start = "01-01"
+basis = "accrual"
+rounding = "half-even"
+cash_accounts = ["1000"]
+financing_accounts = ["2100"]
+
+[[setup.accounts]]
+code = "1000"
+name = "Checking"
+type = "asset"
+
+[[setup.accounts]]
+code = "1200"
+name = "Accounts Receivable"
+type = "asset"
+
+[[setup.accounts]]
+code = "1500"
+name = "Equipment"
+type = "asset"
+
+[[setup.accounts]]
+code = "2000"
+name = "Accounts Payable"
+type = "liability"
+
+[[setup.accounts]]
+code = "2100"
+name = "Due to Members"
+type = "liability"
+
+[[setup.accounts]]
+code = "3000"
+name = "Capital — Tobin Harlow"
+type = "equity"
+
+[[setup.accounts]]
+code = "3001"
+name = "Capital — Morgan Ellis"
+type = "equity"
+
+[[setup.accounts]]
+code = "3999"
+name = "Retained Earnings"
+type = "equity"
+
+[[setup.accounts]]
+code = "4000"
+name = "Revenue"
+type = "revenue"
+
+[[setup.accounts]]
+code = "6000"
+name = "Organizational Costs"
+type = "expense"
+
+[[setup.parties]]
+name = "Tobin Harlow"
+roles = ["member"]
+
+[[setup.parties]]
+name = "Morgan Ellis"
+roles = ["member"]
+
+[[setup.parties]]
+name = "Northwind Filings"
+roles = ["vendor"]
+
+[[setup.parties]]
+name = "Riley Chen"
+roles = ["customer"]
+
+[[setup.members]]
+name = "Tobin Harlow"
+share = "0.5"
+capital_account = "3000"
+
+[[setup.members]]
+name = "Morgan Ellis"
+share = "0.5"
+capital_account = "3001"
+
+# 1. Tobin pays the filing fee for the company (through the members'
+# financing account), tagged with the vendor: paid to the vendor, money.
+[[events]]
+date = "2026-10-04"
+description = "Filing fee, paid by Tobin"
+parties = [{ party = "Northwind Filings" }]
+lines = [
+  { account = "6000", side = "debit", amount = "64.00" },
+  { account = "2100", side = "credit", amount = "64.00" },
+]
+
+# 2. Tobin's cash contribution: received, money.
+[[events]]
+date = "2026-10-05"
+description = "Tobin's contribution"
+parties = [{ party = "Tobin Harlow" }]
+lines = [
+  { account = "1000", side = "debit", amount = "400.00" },
+  { account = "3000", side = "credit", amount = "400.00" },
+]
+
+# 3. Reimbursing Tobin for the fee: paid, money (cash paying down what
+# the company owed him).
+[[events]]
+date = "2026-10-08"
+description = "Reimbursement"
+parties = [{ party = "Tobin Harlow" }]
+lines = [
+  { account = "2100", side = "debit", amount = "64.00" },
+  { account = "1000", side = "credit", amount = "64.00" },
+]
+
+# 4. A laptop Tobin contributes: received, in kind.
+[[events]]
+date = "2026-10-12"
+description = "Laptop contributed"
+parties = [{ party = "Tobin Harlow" }]
+lines = [
+  { account = "1500", side = "debit", amount = "1480.00" },
+  { account = "3000", side = "credit", amount = "1480.00" },
+]
+
+# 5. Its reversal: the exact opposite, paid, in kind.
+[[events]]
+date = "2026-10-13"
+description = "Laptop contribution reversed"
+reverses = 4
+
+# 6. The laptop again, half each, by amount.
+[[events]]
+date = "2026-10-14"
+description = "Laptop contributed jointly"
+parties = [{ party = "Tobin Harlow", amount = "740.00" }, { party = "Morgan Ellis", amount = "740.00" }]
+lines = [
+  { account = "1500", side = "debit", amount = "1480.00" },
+  { account = "3000", side = "credit", amount = "740.00" },
+  { account = "3001", side = "credit", amount = "740.00" },
+]
+
+# 7. A bill from the vendor (credit to payables, its own account): neither.
+[[events]]
+date = "2026-10-20"
+description = "Bill"
+parties = [{ party = "Northwind Filings" }]
+lines = [
+  { account = "6000", side = "debit", amount = "80.00" },
+  { account = "2000", side = "credit", amount = "80.00" },
+]
+
+# 8. The bill reversed: the exact opposite, still neither.
+[[events]]
+date = "2026-10-21"
+description = "Bill reversed"
+reverses = 7
+
+# 9. An invoice to the customer (a debit to receivables): neither.
+[[events]]
+date = "2026-10-20"
+description = "Invoice"
+parties = [{ party = "Riley Chen" }]
+lines = [
+  { account = "1200", side = "debit", amount = "120.00" },
+  { account = "4000", side = "credit", amount = "120.00" },
+]
+
+[[expect]]
+query = "party_part"
+entry = 1
+party = "Northwind Filings"
+values = { resolved = "64.00", direction = "paid", cash = "64.00", in_kind = "0.00" }
+
+[[expect]]
+query = "party_part"
+entry = 2
+party = "Tobin Harlow"
+values = { resolved = "-400.00", direction = "received", cash = "-400.00", in_kind = "0.00" }
+
+[[expect]]
+query = "party_part"
+entry = 3
+party = "Tobin Harlow"
+values = { resolved = "64.00", direction = "paid", cash = "64.00", in_kind = "0.00" }
+
+[[expect]]
+query = "party_part"
+entry = 4
+party = "Tobin Harlow"
+values = { resolved = "-1480.00", direction = "received", cash = "0.00", in_kind = "-1480.00" }
+
+[[expect]]
+query = "party_part"
+entry = 5
+party = "Tobin Harlow"
+values = { resolved = "1480.00", direction = "paid", cash = "0.00", in_kind = "1480.00" }
+
+[[expect]]
+query = "party_part"
+entry = 6
+party = "Morgan Ellis"
+values = { resolved = "-740.00", direction = "received", cash = "0.00", in_kind = "-740.00" }
+
+[[expect]]
+query = "party_part"
+entry = 7
+party = "Northwind Filings"
+values = { resolved = "-80.00", direction = "neither", cash = "0.00", in_kind = "0.00" }
+
+[[expect]]
+query = "party_part"
+entry = 8
+party = "Northwind Filings"
+values = { resolved = "80.00", direction = "neither", cash = "0.00", in_kind = "0.00" }
+
+[[expect]]
+query = "party_part"
+entry = 9
+party = "Riley Chen"
+values = { resolved = "120.00", direction = "neither", cash = "0.00", in_kind = "0.00" }
+
+# Tobin: cash in 400.00 (event 2), paid back 64.00 (event 3); in kind
+# 1,480.00 − 1,480.00 (events 4 and 5 net) + 740.00 (event 6).
+[[expect]]
+query = "party_totals"
+party = "Tobin Harlow"
+basis = "cash"
+from = "2026-01-01"
+to = "2026-12-31"
+values = { paid = "64.00", received = "400.00" }
+
+[[expect]]
+query = "party_totals"
+party = "Tobin Harlow"
+basis = "all"
+from = "2026-01-01"
+to = "2026-12-31"
+values = { paid = "64.00", received = "1140.00" }
+
+# The vendor: the fee a member paid for the company; the bill and its
+# reversal count nothing.
+[[expect]]
+query = "party_totals"
+party = "Northwind Filings"
+basis = "all"
+from = "2026-01-01"
+to = "2026-12-31"
+values = { paid = "64.00", received = "0.00" }
+
+# Basis all over Tobin's equity entries is the statement of members'
+# equity: contributions 400.00 + 740.00 (events 4 and 5 cancel).
+[[expect]]
+query = "members_equity"
+from = "2026-01-01"
+to = "2026-12-31"
+values = { "Tobin Harlow.contributions" = "1140.00", "Tobin Harlow.distributions" = "0.00" }
+
diff --git a/examples/p3-party-tin-last4.toml b/examples/p3-party-tin-last4.toml
new file mode 100644
index 0000000..6bffe0d
--- /dev/null
+++ b/examples/p3-party-tin-last4.toml
@@ -0,0 +1,86 @@
+# P3 defect 11 (audit finding F28): the directory showed a member's TIN as
+# missing because it read W-9 facts only. Regression tests: ledger-core
+# tests/spec_party_totals.rs
+# defect11_a_partys_tin_last4_is_its_tin_facts_else_its_w9s; ledger-mcp
+# tests/spec_vault.rs defect11_the_directory_shows_a_members_tin_last4.
+# The shape: bookspec/README.md.
+
+id = "p3-party-tin-last4"
+title = "A party's TIN last four is its TIN facts', else its W-9's"
+rule = """
+The books keep a taxpayer identification number truncated to its last
+four digits. A party's last four is its TIN facts' (a member's SSN for
+the K-1), else its W-9 facts'; the two never disagree. A TIN purged from
+the vault keeps its last four in the books. A party with neither has
+none.
+"""
+status = "AUTHORITY"
+sources = [
+  "Treas. Reg. §301.6109-4(a): a truncated TIN shows the last four digits (wanderbooks docs/spec/sources/irs-truncated-tin.md)",
+  "DECISION (owner, 2026-10-15): a party's TIN facts and W-9 facts never disagree (wanderbooks ledger-core parties INVARIANT 2a)",
+]
+tags = ["parties", "tin", "w9", "k1"]
+# Nothing is posted: the facts are the directory's.
+events = []
+
+[setup]
+currency = "USD"
+fiscal_year_start = "01-01"
+basis = "accrual"
+rounding = "half-even"
+
+[[setup.accounts]]
+code = "1000"
+name = "Checking"
+type = "asset"
+
+[[setup.parties]]
+name = "Tobin Harlow"
+roles = ["member"]
+tin_last4 = "4321"
+
+[[setup.parties]]
+name = "Riley Chen"
+roles = ["contractor"]
+w9_tin_last4 = "8765"
+
+[[setup.parties]]
+name = "Morgan Ellis"
+roles = ["member", "contractor"]
+tin_last4 = "1111"
+w9_tin_last4 = "1111"
+
+[[setup.parties]]
+name = "Lakeside Supply"
+roles = []
+
+[[setup.parties]]
+name = "Avery Quinn"
+roles = ["member"]
+tin_last4 = "2468"
+tin_purged = true
+
+[[expect]]
+query = "party_tin_last4"
+party = "Tobin Harlow"
+values = { tin_last4 = "4321" }
+
+[[expect]]
+query = "party_tin_last4"
+party = "Riley Chen"
+values = { tin_last4 = "8765" }
+
+[[expect]]
+query = "party_tin_last4"
+party = "Morgan Ellis"
+values = { tin_last4 = "1111" }
+
+[[expect]]
+query = "party_tin_last4"
+party = "Lakeside Supply"
+values = { tin_last4 = "" }
+
+[[expect]]
+query = "party_tin_last4"
+party = "Avery Quinn"
+values = { tin_last4 = "2468" }