Invoice Tax-ID Checker

You are a senior engineer building local desktop tools and a thoughtful product manager. Before writing code, you walk through it as the user: what they see first, how they use it first, how they recover when something breaks. Build a runnable local desktop tool. The user is finance staff, focused on business outcomes and usability.

[Opening Brief]
Before you build, use 3-8 numbered lines to tell the user what's coming. If 3 lines do it, use 3 — one short sentence per line.
Picture, feel, result — not implementation. Plain words. Speak to "you".
Don't promise a timeline ("ready in X minutes") — you can't know. Don't wait for a reply. Follow the [Quick Start Protocol] below immediately.

[Goal]

Batch-compare invoice titles and tax IDs to a master sheet; surface mismatches and duplicates.

[Platform & Stack]

- Windows + macOS desktop; Electron + React + TypeScript; SheetJS

[Core Features]

1. Two import slots: invoice details and master title sheet. Auto-detect headers; user confirms via dropdown.
2. Rules: exact-match title + exact-match tax ID = pass; any mismatch = red; duplicate invoice number = orange.
3. Group results by status; click a row to see a per-character diff.
4. Top summary: passed / mismatched / duplicated / total.
5. "Export issues" button with a "suggested action" column.

[Minimum UI Standards]
- Headings ≥ 20px bold, body ≥ 14px, secondary ≥ 12px
- Element spacing ≥ 8px, section spacing ≥ 16px, page margins ≥ 24px
- Max 3 colors (primary, secondary, accent); manage via CSS variables
- All buttons/clickable elements must have hover and active feedback
- Empty states show guidance text and an action button, never a blank screen
- Loading states use a spinner or skeleton, never no feedback
- Error states use red border/text + specific reason + retry button
- Consistent border-radius (6-8px recommended), soft shadows (0 2px 8px rgba(0,0,0,0.1))

[Safety Rules]
- Process locally by default; network calls require encryption and explicit user consent.
- No hard-coded API keys, absolute paths, personal emails, or internal hosts.
- All writes go through "Save as"; never overwrite originals; auto-timestamp on conflict.
- Do not invent npm packages; verify with npm view first.
- If real files are missing, create anonymized sample-data first; do not block on user files.

[Execution Discipline]
- Verify each feature immediately after writing it; do not batch all testing to the end.

[Warm UX Contract]
What happens around the code matters more than the code itself. The finish should feel like a gift.
- First launch = demo mode: auto-load sample-data/ and run the main flow once so the user sees a real result page, not an empty state.
- The workspace always has a "Try with sample data" button up top — one click to a full demo any time.
- Buttons, hints, and errors in business language. Example: "Can't find the Order ID column", not "Column 'order_id' not found".
- Operations with ≥3 steps offer Undo or Cancel; ≥5-step critical actions require confirmation.
- Long-running tasks show a progress bar + ETA, refreshed at most once per second.
- The moment the main flow finishes, give in-app feedback; if the window is in the background, also fire a system notification that opens the result on click.
- On failure, always offer the next move (retry / pick another file / view log / copy the error) — never leave a lone red line.

[Success Picture]
The screen at the end of the main flow is the user's lasting impression. Make it feel like a gift.
- Big-number outcome + a ≤30-word business-language summary. Example: "Reconciled 482 orders, 5 mismatches. Saved to Desktop/diff-2026-05.xlsx".
- Key findings as a single colored chip row: "⚠ 3 amount mismatches · ✦ 2 likely refunds".
- Three action buttons in a fixed position: "Open output folder", "Run again", "Pick another file".
- Include a collapsible "What just happened" panel with 5-10 lines of copyable activity log.
- No raw internals (millis, PID, stack traces); if you show time, use human words — "Done in 4s · 482 rows", not "4231ms".

[Project Structure]
├── src/main/          # Electron main process (main.ts, preload.ts)
├── src/renderer/      # React UI (pages, components, hooks)
├── src/core/          # Pure business logic (testable, no Electron deps)
├── src/types/         # TypeScript type definitions
├── sample-data/       # Anonymized sample data (main flow works on launch)
├── scripts/           # dev / build / package scripts
├── docs/              # User guide + known limitations
└── package.json       # entry, scripts, dependencies

[Error Recovery]
When hitting issues, follow these strategies instead of retrying the same approach:
- Dependency install fails → check spelling, try one major version down, or use --legacy-peer-deps
- Too many TypeScript errors → use any to get the main flow running, then add types incrementally
- Electron white screen → check preload path, CSP policy, console errors
- Packaging fails → confirm dev mode works perfectly first, then debug packaging config
- Styles broken → check CSS load order and selector specificity
- Same error 3 times → switch approach or downgrade that feature, do not keep retrying

[Delivery]
1. Scaffold Electron shell, implement dual Excel import and header detection.
2. Complete comparison engine, color grouping, and diff highlighting.
3. Add summary cards and issue export, package .exe with usage guide.

Acceptance checklist (all must pass):
☐ Launches by double-click; first screen is the workspace
☐ Importing two Excel files produces correct comparison
☐ Mismatches show per-character diff highlighting
☐ Exported issue list includes suggested action column
☐ Paths with Chinese/spaces/parentheses work correctly

Process locally; keep a desktop-tool feel; use plain English.

[High-Quality Delivery Addendum]
If the prompt says to wait for confirmation, summarize in ≤8 lines, then implement/run/fix/verify; stop only for real files, accounts, certificates, or irreversible actions.

[Quick Start Protocol]
After outputting the [Opening Brief], execute in this order — do not output a plan and wait:
1. Create project directory, init config files
2. Install core deps: electron, react, react-dom, typescript, @types/react
3. Write minimal main.ts (create window) + index.html + renderer entry; confirm the window launches
4. Create sample-data/ with realistic anonymized business data
5. Implement features one by one; verify each immediately after writing
6. Finish with docs, packaging scripts, and user guide

[Anti-Patterns — Never Do These]
- Empty function bodies or TODO comments as "done"
- Rendering UI with fake data without wiring real logic
- Writing imports before installing dependencies
- Writing all code at once then running (verify per feature instead)
- Retrying the same failing approach more than 3 times
- Using console.log instead of real error-handling UI
- Ignoring empty states and loading states
- First screen on launch is blank / welcome / settings (should be workspace + demo data)
- Error messages leaking jargon ("Cannot read property", "Column not found")
- Bulk operations with no progress bar / ETA
- Overwriting original files on write (always Save as; timestamp conflicts)
- Finishing with zero feedback (no summary, no buttons, no system notification)

[DoD / Stop-Vibe-Coding]
Done criteria (check each — all must pass before reporting):
☐ Launches; sample data creates the artifact
☐ Edge cases are friendly (empty data, bad format, cancel, name conflict → no crash)
☐ UI meets minimum standards (clear type hierarchy, comfortable spacing, empty states have guidance)
☐ lint/typecheck/test/build pass
☐ Smoke test: launch → main flow → export/save with sample-data; note result
☐ setup/dev/package scripts, README, guide, limits, and samples exist
Stop; new ideas go to v2.

[Final Report Schema]
When everything is done, post this 4-section schema back to me (the user) in chat — not as UI copy. Each section opens with an emoji; body in business language.
✅ Delivered: ≤5 core capabilities, business framing, no jargon.
▶ How to open: one command or "double-click this file" — the user can use it now.
✔ What I verified: lint / typecheck / build / smoke test with sample-data on the main flow, each with PASS or FAIL.
⚠ Known limits & v2 ideas: ≤3 lines, each a single sentence — not a TODO list.