William doesn't start from scratch. It arrives with UK VAT rules built in from HMRC, and the moment you connect your ledger it keeps learning — your chart of accounts, your historical documents, how your firm codes transactions. Every correction sharpens it further.
But patterns have limits. Some things in your firm are policy, not pattern — a supplier that's always VAT exempt, Uber always coded to Travel. Rules like these shouldn't be inferred; they should be set. That's what Teach William is for.
Two ways to teach William
There are two layers — one for certainty, one for flexibility.
Fixed rules — for decisions with no room for interpretation. Set a category, tax rate, due date, or currency once, and William never deviates.
Guidance — plain-language instruction for anything more nuanced. Write it the way you'd explain a quirk to a new team member: "Amazon orders vary — always check the line items. Office supplies → 520, IT equipment → 740."
Fixed rules always take priority over guidance. If a fixed rule and a guidance line both apply to a document, William follows the fixed rule.
What you can teach William about
Guidance isn't limited by scope. Write in plain language how William should treat the documents — the way you'd explain it to a new team member.
To point guidance at a specific supplier, category, tax rate, or tracking category, type @ and select the value:
“@Uber always coded to @Travel”
“Assign @Project X tracking category for all receipts from @Cardiff”
Guidance isn't limited to coding, either. Write it for fields, line items, and publishing too:
Fields — "Add the invoice number in the description"
Line items — "@Amazon orders vary — split by line item. Office supplies → 520, IT equipment → 740"
Publishing — "Auto-publish everything from @Uber", "Never auto-publish anything over £5,000"
Company-wide — "For CIS invoices, use the pre-deduction total as the total", or narrow it: "For CIS invoices from @Cardiff, use the pre-deduction total as the total"
The Guidance page shows every piece of guidance you've set up for a company in one place.
Two limits worth knowing:
Splitting and merging documents — guidance can't drive these. Do it directly on the document instead.
Auto-publish stays conservative. Guidance telling William to publish is a signal, not an override. If confidence on the other checks is low, or a document fails one of them, William holds it for review anyway.
William can suggest rules
William tirelessly watches where it gets things wrong — every gap in what it knows about this company — and surfaces them as suggested rules in Teach William.
Each suggestion shows:
A proposed rule, or an open question. For example: "Everything from Uber goes to Travel", or "What category applies to Vodafone?". Accept the suggestion, reject it, or add more detail to turn it into new guidance
The documents the suggestion is based on.
Every suggestion you act on closes a knowledge gap for good. William carries that lesson into every future document — and never forgets.
What's next
Teaching William sets the rules and guidance it follows. Tracking William's decisions shows you those rules at work — every call explained in plain language, for any document.
That's how you stay in control: you've set what William follows, and you can verify every decision yourself — not take it on faith.
Track William's decisions and the reasoning behind them — read William's reasoning for any document, and turn corrections into a permanent rule.
Meet William, your AI bookkeeping agent — back to the overview if you want to revisit what William does end-to-end.