SCH4L3

The ledger’s source of truth is the SQLite database seeded once from src/storage/db.ts (OPENING_MONTH) and accessed via src/storage/entries.ts. No duplicate copies of the data exist elsewhere. Validation and parsing are isolated in src/domain/ledger.ts and src/domain/money.ts, and the API (src/http/api.ts) composes the view without embedding hard‑coded amounts, ensuring no shadow data. Data shaping (balance, totals, formatting) is done in domain modules and the API, keeping presentation code separate. All displayed values (balance, category totals, entry amounts) are derived directly from the database and domain logic, satisfying honesty of sourcing.

The committed implementation covers the core ledger scenarios: it seeds the six pinned March entries and computes the 3223.70 balance from integer cents (src/storage/db.ts:22-55; src/domain/ledger.ts:85-106), supports adding, in-place correction, deletion, month filtering, category totals, and validation with unchanged storage on invalid input (src/http/api.ts:40-85; src/storage/entries.ts:35-68). The browser presents balance, income, spending, entries, category totals, and edit/delete controls (src/web/index.html:18-95; src/web/app.js:39-89). The completion note accurately describes these shipped capabilities (.ololo/money-tracker-ledger-done.md:1-16), and TODO.md is marked complete for the requested scenarios (TODO.md:3-13). However, the product's declared npm test command is broken in the supplied environment because its quoted glob resolves to no files, and the TypeScript tests also cannot run directly under the available Node 20 runtime; both validation probes failed (probe:deterministic-1; probe:deterministic-2). There is also a data-honesty risk in parseAmount for very large numeric strings because Number is used internally, though ordinary cent amounts and the required 0.10 + 0.20 scenario are handled exactly (src/domain/money.ts:12-28).

The codebase shows a clear separation of concerns: pure domain logic lives in src/domain/* with no I/O, the data‑access layer is isolated in src/storage/*, the HTTP API and server are in src/http/*, and the UI lives under src/web/*. Each component has a single responsibility and a well‑defined interface (e.g., Entries class, bookView function). Dependencies flow in one direction – UI → HTTP → storage → DB – with no circular imports. The layering is proportional to the task’s requirements (persistence, validation, API, UI) and not needlessly deep for a simple ledger, earning a high score.

The implementation adds useful features beyond the required scenarios: a month selector to view entries for a specific month and a by‑category total list, both fully functional and integrated into the UI. It also provides detailed validation messages and edit/delete capabilities, improving usability. These extra touches demonstrate a genuine effort to enhance the product for real users.

The repository includes a comprehensive AGENTS.md that tells an agent what the project is, how to run it (npm start), how to verify it (npm test), and key constraints such as using integer cents for money. It also references the TODO.md plan and DECISIONS.md for guidance. Reusable automation is present via npm scripts (start, test) which the agent can invoke, but there are no custom command definitions, skill files, or scripts beyond those defaults. No automatic hooks or guardrails (e.g., pre‑commit checks, file‑watch validators) are defined, so errors must be caught manually. The amount of instruction is appropriate for the scope of a ledger project, providing enough detail without unnecessary boilerplate. Overall, the agentic setup is solid but lacks richer automation and guardrails, justifying a score of 7.0.

The code uses clear, self‑describing names (Entry, EntryDraft, ValidationError, signed, balance, categoryTotals). No dead code or obvious copy‑paste blocks. Functions are concise and each file focuses on a single concern. The only minor magic value (200‑character note limit) is still explicit in the validation logic.

Functions are short enough to read without scrolling and have limited nesting (e.g., draftFrom’s validation logic). Errors are handled centrally via ValidationError and propagated to the API layer, making it safe for newcomers to modify validation or API behaviour. Magic numbers are minimal; the note length limit could be extracted, but overall the code is easy to understand and extend.

The test suite contains concrete assertions (assert.equal, assert.ok) that verify expected values and behavior for all scenarios from the brief, including money out, correction, deletion, balance, nonsense handling, exact arithmetic, 404 handling, and month filtering. It mixes unit tests of domain logic (src/domain/ledger.ts) and integration tests exercising the storage and API layer, providing good coverage of happy paths, error paths, and boundary cases. No tests are skipped, commented out, or tautological. The only minor shortcoming is the absence of explicit tests for category totals after arbitrary modifications beyond the one correction case, but overall the suite robustly catches regressions.