Lucas WintherandClaude Opus 5
49811f6795
AGENTS.md §1's old invariant was half wrong the moment anchored costs lost their slots: occurrenceDate is identity for calendar only. The replacement says what each schedule is and, more usefully, warns against collapsing them — that collapse is exactly the bug where paying twice in September pushed the next charge to November. §2's termination bullet now describes a defensive assert rather than a live guard, because the anchored walk steps forward from a real date and the grid walk never rebases. Also added the anchoring-change-refused-once-charged guard, which was undocumented in AGENTS.md despite having its own test suite and UI-level guard. DECISIONS.md, PRODUCT.md, ARCHITECTURE.md and TODO.md catch up to what shipped: two projection models and the three guards it deleted, a recurring cost charging more than once per cycle and being creatable from the purchase dialog, the anchored walk beside the grid walk, and schema 8 at 730 tests. The 2026-09-03 spec gets a header note pointing at the new spec and nothing else — it stays an accurate record of what was decided then. Demo data seeds two charges in one month on an anchored cost (Car insurance), so the fixed behaviour is the first thing a screenshot shows. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Budget 2.0
A personal budgeting PWA. Envelope-style monthly budgets with rollover, split purchases, finance plans, multi-currency, and JSON/ODS export. All data lives in your browser — there is no server and no account.
Development
bun install
bun run dev # dev server with hot reload, on :3000
bun test # run the test suite
bun run build # production build into dist/
Self-hosting with Docker
docker build -t budget2 .
docker run --rm -p 3000:3000 budget2
To serve from a subpath, build and run with BUN_PUBLIC_BASE_PATH:
docker build -t budget2 --build-arg BUN_PUBLIC_BASE_PATH=/budget/ .
docker run --rm -p 3000:3000 -e BUN_PUBLIC_BASE_PATH=/budget/ budget2
GitHub Pages
Pushing to main builds and deploys to Pages automatically, using
/<repository-name>/ as the base path. Enable Pages with "GitHub Actions" as
the source in the repository settings.
Your data
Everything is stored in this browser's IndexedDB. Export regularly from Settings → Your data: the JSON export is both your backup and how you move your budget to another device.
Both destructive actions there — Import, and "Reset everything" — download a backup of your current data before replacing it, and abort if that download fails. Reset puts the app back to a brand-new install: the three starter posts, the DKK/USD/EUR currency table, this month at zero income, no purchases.
Known limitations
- Data is per-browser. There is no account and no sync. If you clear this browser's site data, or move to a different browser or device, your budget is gone unless you exported it first. The JSON export is not just a nice-to-have backup — it is the only way to move a budget between devices.
- Installing and offline use are unverified. The manifest ships the SVG plus 192×192 and 512×512 PNG icons, and the service worker demonstrably installs, activates and precaches every asset — but nobody has yet confirmed that Chrome offers its "Install app" prompt, or loaded the app with the network actually cut. It works as a regular tab regardless.
Documentation
docs/ARCHITECTURE.md— layers, data flow, and why the non-obvious choices are what they are.docs/PRODUCT.md— who this is for and what must never break.AGENTS.md— the rules for changing this codebase, and the test that catches each one when broken.CLAUDE.mdandGEMINI.mdpoint at it.docs/DECISIONS.md— an index of the choices that shaped the app, and what each was chosen over.docs/TODO.md— what is still queued.docs/specs/— one design document per piece of work, each recording the alternatives that were rejected.docs/plans/— task-by-task implementation plans.