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Glossary
Plain definitions of the terms this site uses: Cast & Rule's own words first, then the MTD for Income Tax and AI terms a practice needs to judge any AI tool. Where a term describes a part of Cast & Rule, its status is given.
Terms
Cast & Rule's own words
- The Clerk
- The product's assistant (a working name). The Clerk prepares; a partner rules. Any action that sends, files or posts outside the practice needs a partner's ruling. How it works
- Cast
- To add up a column of figures. In Cast & Rule, the machine preparing the work.
- Rule off
- To draw a single line over a total and a double line under it, so the figure is final. In Cast & Rule, the partner's decision.
- Prepared
- Machine work that is finished and checked, waiting for a decision. Shown in grey, never in the partner colour.
- Ruled
- Kept for a partner's recorded decision, which carries a name, a qualification and a time.
- Awaiting partner
- The state of any prepared work that hasn't yet been ruled on. It stays visible until a partner acts.
- The Desk
- The partner's home: work needing a ruling, deadlines and recent activity.
- Workpapers
- Working-paper templates the Clerk drafts from.
- Schedules
- Jobs that run to a timetable, such as an MTD tracker for each client.
- Sources
- Connections to the client's records. See Connections for the status of each one. Connections
- The Strongroom
- Keeps each client's records in its own encrypted compartment, on local hardware the practice controls. Security overview
- Rules
- The firm's AI-use policy, applied as permissions on each task, with controls on each connection.
- Ruling
- The partner sign-off queue. How it works
- The Ledger
- The practice's record of what the AI did. It records the kind, size and a fingerprint of each action, never the content. Each entry is locked to the one before it (a hash chain), so a later change to an entry our service has checked shows up. Security questions
AI and UK accountancy terms
- Governed MCP
- The way the Clerk reads a connected system such as Xero: read-only first, one client per connection, a fixed set of named things it can do, and every call recorded in the Ledger. (MCP is the technical standard the connection uses.) Any write needs a partner's ruling on that exact action. Connections
- Shadow AI
- AI tools used in a practice without anyone reviewing or approving them. Usually taken up with good intentions by staff trying to work faster, not through carelessness. See the shadow-AI checklist. Shadow-AI checklist
- AI-use policy
- A practice's own written rules for which AI tools are approved, what must never be typed into one, and who signs off AI-assisted work before it reaches a client. See the policy template. AI-use policy template
- MTD for Income Tax
- Making Tax Digital for Income Tax: HMRC's programme, brought in in stages, that requires compatible software, digital records and quarterly updates from qualifying sole traders and landlords, from April 2026 for the first income band. HMRC: before you use MTD for Income Tax
- Quarterly update
- Under MTD for Income Tax, a running summary of income and expenses for the tax year so far, sent to HMRC from compatible software. With standard periods the updates cover 6 April to 5 July, 6 April to 5 October, 6 April to 5 January and 6 April to 5 April, each due by the 7th of the following month (7 August, 7 November, 7 February, 7 May). A quarterly update isn't a tax return; the year still ends with a final declaration. HMRC: send quarterly updates
- Qualifying income
- The gross income from self-employment and property, before expenses, that decides whether MTD for Income Tax applies. It applies from 6 April 2026 above £50,000, from April 2027 above £30,000 and from April 2028 above £20,000, each measured on an earlier tax year's return, with some exemptions. Check HMRC's guidance for each client. HMRC: before you use MTD for Income Tax
- Local processing
- Running the AI model and handling client files on a machine the practice controls. It says where processing happens. On its own it doesn't prove confidentiality, lawful processing, safe updates or that clients' records are kept apart. Cast & Rule processes on local hardware in the practice. Security architecture
- Human review
- A competent person, with enough information and the authority to change the result, checks AI-assisted work before anyone relies on it. A quick click-through isn't review. In Cast & Rule, that's the partner's ruling. AI-use policy template, section 4
- Client separation
- Keeping one client's records out of work on another. A connection limited to one client helps, but it isn't separation on its own. In Cast & Rule, each client has its own encrypted store. Security architecture
- Source provenance
- The link from each figure or statement back to the record it came from, with its date, so a reviewer can check it rather than take it on trust. Product tour: a cast workpaper
- Tamper evidence
- What the Ledger gives, because each entry is locked to the one before it: a later change to an entry already checked shows up. It doesn't stop tampering, and it can't prove that every action was recorded. Security questions
Questions partners ask
Frequently asked questions
Why does Cast & Rule use its own vocabulary at all?
It borrows from the paper ledger a practice already knows: cast, ruled off, a strongroom. That way the product's behaviour matches something familiar rather than generic software terms.
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