swaitsandClaude Opus 5.5
beb1fcf233
Max-testing pass, steps 2-4. Spec-blind tests (rank 1-2): four agents, each given only the specs and the public interface (doc comments and signatures, every body removed, never src/ or the existing tests), wrote tests/spec_reports.rs (62), spec_ledger.rs (72), spec_arap.rs (42), spec_assets_payroll.rs (50): hand-computed examples per scenario and a proptest law per invariant (conservation, partition, invariance, scaling, reversal cancels, "a refusal leaves the books unchanged" over random invalid commands). They found: 1. A refused payroll run changed the books: an all-zero run passed validation, then failed at post after creating seven payroll accounts and using up an entry id. validate_payroll_lines now refuses a run with no gross pay. 2. A refused add_account used up an account id (empty code, duplicate, unknown parent). The id is now taken only when the account is added. 3. Stale prose: close_period_to and members_equity still described the old last-member rounding. 4. Open (left #[ignore]d pending Stephen): depreciation_schedule's doc says "through the month containing" the date; the code prorates that month by days. GnuCash oracle (rank 3, an oracle never the spec): `just oracle` builds GnuCash 5.10 in a container pinned by base digest and package versions (oracle/gnucash/) and runs tests/oracle_gnucash.rs: 200 seeded random books built through wanderbooks (entries, foreign lines, reversals, monthly closes), every account's balance at month ends and random dates and each month's P&L, compared exactly: 15,800 comparisons. First run: 4,724 differences, all from foreign lines; without them, zero. Adjudicated from principles (rules.md B-3): wanderbooks booked foreign * rate unrounded ($108.34567); a ledger in one money holds no fractions of its smallest unit, and its cash must match a bank. Stephen decided: book in the base currency's minor unit, half away from zero. add_line_fx now rounds; minor units per ISO 4217 list one (2026-09-17, SIX), generated into Currency::minor_units and recorded in docs/spec/sources/iso-4217.md. Replay now takes the journaled base amount (replay_add_line_fx), so lines booked before replay exactly as booked (contract: books_written_under_older_rules_still_open). Now: zero differences, foreign lines included. Tests: 449, from 223. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01GWVo7x3UHw5kwCUaWxiejX
wanderbooks
Canonical double-entry bookkeeping, rebuilt from scratch. The engine is verified against oracles, parity is tracked automatically, and the primary interface is AI-first: you talk to an agent, the agent drives the books through MCP. Self-hosted, no rent.
What it is
ledger-core— the semantics engine. Exact decimal money, five account types, balanced journal entries, immutable posted log with reversing entries, trial balance, P&L, balance sheet, indirect-method cash flow, fixed-asset register with straight-line depreciation.ledger-store— durable storage. The source of truth is an append-only, hash-chained JSONL journal; SQLite is a disposable projection rebuilt from it; receipts live in a content-addressed blob store. Drafts are durable, corrupt projections self-heal.ledger-mcp— the AI-first interface. 64 MCP tools over stdio or Streamable HTTP: draft → preview → post workflow, server-side receipt policy (>$25), anti-splitting detection, asset management, digest for human review, plus read-only resources for dashboards.ledger-import— QuickBooks interop. Import bank/credit-card CSVs and chart-of-accounts CSVs; export IIF journal entries (for QuickBooks Desktop) and XLSX reports.ledger-config— the company settings in a books dir'swanderbooks.toml.ledger-gui— the viewer: a read-only, live window on the books for owners and their accountant (egui). Answers first (cash, runway, profit, what needs attention), then every number drills down to its lines, its entry, the rendered receipt, and the journal history. Follows the journal live: a change the agent makes appears in milliseconds.--demoopens a realistic demo company.
Verification
This is the storytold way applied to accounting: agents verify against oracles, never ship what they haven't demonstrated.
- 190+ workspace tests: invariant tests encoding accounting law, golden-file report snapshots, property tests (proptest), end-to-end MCP stdio tests.
- Formal proofs of the accounting laws (
just prove,docs/verification.md). Kani model-checks the engine's arithmetic kernel exhaustively within bounds. Lean 4 proves that, after any sequence of commands, the trial balance balances, the accounting equation holds, posted entries are forever, closed periods stay frozen, and a close moves exactly the net income to equity. The first pass found three engine bugs that every test, fuzzer, and mutant had missed: negative amounts accepted, and two crashes on oversized amounts. It also caught a soundness bug in the model checker itself. - Mutation testing via cargo-mutants; fuzzing via cargo-fuzz (11.5M+ executions, zero crashes).
- GnuCash is a behavioral cross-check, never the authority and never a code source (clean room, MIT OR Apache-2.0). Accounting principles, proved, are the spec. Where any other program disagrees, we work out from principles who is right.
Status
Parity is 12 of 12 against the spreadsheet workflow it replaces
(docs/capability-parity.md). The parallel-run plan
(docs/parallel-run.md) is written; the Google Sheet stays the system of
record until a clean month and explicit cutover approval.
See plan/STATUS.md for where things stand and
plan/roadmap.md for where it's going.
Quickstart
cargo test # whole suite
cargo run -p ledger-mcp -- --data-dir /tmp/books # MCP server over stdio
cargo run -p ledger-gui -- --demo # the viewer, on a demo company
New books, one command (installs Rust and wanderbooks if needed, makes the books dir with the MCP server registered for it, and starts the agent):
curl -fsSL https://wanderbooks.ai/install.sh | sh -s -- ~/Books/Acme
Already installed: wanderbooks new ~/Books/Acme (add --codex to keep the
books with Codex instead of Claude Code). In a books dir, just
lists the shortcuts (just gui, just agent, just backup).
Developing
Every tool the recipes use (Rust, just, Kani, Lean, cargo-mutants,
cargo-fuzz, Node for deploys) is pinned in mise.toml:
mise install
just # lists the recipes: check, build, prove, demo, ...
Layout
crates/ledger-core/ # engine: money, accounts, journal, ledger, reports
crates/ledger-store/ # journal + SQLite projection + blob store
crates/ledger-mcp/ # MCP server: 64 tools, resources, receipt policy
crates/ledger-import/ # QBO CSV import, IIF/XLSX export
crates/ledger-config/ # wanderbooks.toml company settings
crates/ledger-cli/ # `wanderbooks new`: one-command books dir + agent
crates/ledger-gui/ # the viewer: read-only, live (egui)
docs/ # requirements, architecture, oracle, parity, glossary
plan/ # STATUS.md, roadmap.md
AGENTS.md # operating manual for agents working here
License
MIT OR Apache-2.0. See LICENSE-MIT and LICENSE-APACHE.