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's wanderbooks.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. --demo opens a realistic demo company.

Verification

This is the storytold way applied to accounting: agents verify against oracles, never ship what they haven't demonstrated.

• 70 workspace tests: invariant tests encoding accounting law, golden-file report snapshots, property tests (proptest), end-to-end MCP stdio tests.
• Mutation testing via cargo-mutants; fuzzing via cargo-fuzz (11.5M+ executions, zero crashes).
• GnuCash is the behavioral oracle (never a code source — clean room, MIT OR Apache-2.0).

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).

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.