Expense Category Analyser

People look at individual transactions and call them fine. £4.99. £12.99/month. A £30 dinner. Each one defensible in isolation, none of them visible in aggregate. The skill makes the aggregate visible — categorises every line, totals it monthly and annualised, ranks by impact, and runs a forensic scan for the seven specific leak patterns that quietly drain a current account.

The leak detection is the part most spreadsheets miss. Subscription zombies — services where the user is still paying but the engagement evidence has gone cold, plus the duplicates (three cloud storage services, two streaming bundles with overlapping content). The drip leak — £3.50 a day on coffee reads as £77/month or £924/year, and only the yearly number tends to change behaviour. The convenience tax — the ratio between dining out and groceries, with takeaways routinely costing 3-4x the ingredient cost. The bank fee bleed — overdraft, FX, ATM, late payment — all pure waste, all fixable by switching account or setting alerts.

The skill is opinionated about ranking by impact, not by category type. If dining out is the second-biggest line, that's where the attention goes — not the £6 you spent on stamps. The fixes get an effort-vs-impact table: cancelling zombies is 10 minutes and saves £40/month, switching banks is an hour and saves £14/month, halving takeaway orders is a habit change worth £170/month. The user picks; the skill stops them treating all fixes as equivalent.

It doesn't moralise. £340 on takeaway is a fact. Whether it's too much is the user's call. The job is to make the number visible, annualise it, compare it to what £340/month could otherwise buy, and let the user decide what to change. Bank exports get parsed even when descriptions are cryptic — "POS 12345" gets a best-guess category with a flag, and uncategorisable transactions get grouped for confirmation rather than silently dropped.

This is categorisation and pattern-finding, not financial or tax advice. If the analysis surfaces something that changes your tax position, your debt strategy, or any decision with real financial consequence, an accountant or financial adviser should review it before you act.