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name: accounting-uk-ltd description: Use when running the accounts of a small UK VAT-registered limited company — the full cycle of bookkeeping, bank and control-account reconciliation, VAT returns under MTD, year-end statutory accounts, CT600 corporation tax, payroll RTI, and the Companies House and HMRC deadline map. Routes to the specialist siblings and owns the engagement flow, the deadline calendar, and the current-year rates reference. Trigger on - my company accounts, VAT return, year end, CT600, corporation tax return, Companies House filing, annual accounts, bookkeeping, trial balance, payroll, HMRC deadline, small company accounts. disambiguation: The PARENT of the UK small-company accounting family and the owner of the engagement flow, deadline map and rates reference. Individual mechanics live in the siblings — bookkeeping-double-entry, uk-vat, uk-corporation-tax, uk-statutory-accounts, uk-payroll, financial-document-ingestion. Project budget-vs-actual and earned value is project-finance, not this.

Accounting — UK small VAT-registered Ltd

The operating skill for a small UK limited company that is VAT-registered: keep the books, reconcile them, file VAT, close the year, compute corporation tax, run payroll, and hit every deadline.

1. What this family cannot do — read first

These skills do not file anything, and must never imply they do.

The joint HMRC/Companies House online filing service closed on 31 March 2026. Since then:

Submission	Route
CT600 + computations + iXBRL accounts → HMRC	Commercial software effectively mandatory. Paper only with a reasonable excuse or in Welsh. Or an authorised agent.
Annual accounts → Companies House	Still flexible — CH online, third-party software, or paper by post. Software-only is coming April 2028 (deferred from 2027).
VAT return → HMRC	MTD-compatible software with an unbroken digital link.
Payroll → HMRC	RTI submissions from payroll software.

So the job here is everything up to submission: ingest the documents, keep the books, reconcile, compute, validate, produce the figures and the audit trail, and name the deadline. Then hand to recognised software or an accountant.

Say this out loud to the user when they ask you to "file" something. A skill that lets someone believe a return was submitted is worse than one that refuses.

2. THE ROUTINE — run this every time this skill is invoked

Do this before answering anything. It takes seconds and it is what makes the skill an operating system for the company rather than a reference book.

T=.accounting/tracker.json          # per-company, in the project

# 1. FIRST CONTACT ONLY — no tracker yet? Analyse the business and build one.
python3 ~/.claude/skills/accounting-uk-ltd/scripts/tracker.py \
    init --company company.json --out "$T"

# 2. EVERY invocation — what is overdue, due soon, or newly in force
python3 ~/.claude/skills/accounting-uk-ltd/scripts/tracker.py status --tracker "$T"

# 2b. EVERY invocation — what CHANGED about the business itself
python3 ~/.claude/skills/business-profile/scripts/profile.py \
    --profile .accounting/business-profile.json check

# 3. Record progress as it happens (evidence is REQUIRED to mark done)
python3 ~/.claude/skills/accounting-uk-ltd/scripts/tracker.py \
    update --tracker "$T" --id vat_return-quarter-ending-2026-09-30 \
    --status done --evidence "HMRC receipt IRmark ABC123"

# 4. Periodically — what law/rates need re-verifying
python3 ~/.claude/skills/accounting-uk-ltd/scripts/tracker.py law-check --tracker "$T"

No tracker → run init first. Establish §3's facts by asking, build the calendar, and say what was assumed. Do not answer a VAT or year-end question for a company you have not profiled: the answer depends on the scheme, the ARD and the framework, and guessing those produces a confident wrong answer.

Tracker exists → run status first, and lead your reply with anything overdue. The user asking about one thing does not make the other obligations stop running.

Run the profile check too. The tracker knows what is DUE; the profile knows what the business normally LOOKS like — who each vendor is, how they bill, what they normally cost. It answers "who is this transaction?" without rediscovering it every session, and it flags a recurring bill that stopped arriving, which no balance check can see. See business-profile.

What the routine guarantees

• Due dates are computed from the profile plus the statutory rule, and each obligation carries the rule it came from — so a date you disagree with can be argued with rather than just distrusted.
• overdue cannot be asserted away. It is derived from the due date and today, every run. You may record that something is done; nobody can record that it is not due.
• done requires evidence. A submission reference, receipt or filing id. "Done" with nothing behind it is indistinguishable from forgotten.
• init refuses to invent a profile. A missing accounting reference date is a question, not a default.

The law-watch loop, and its honest limit

law-check computes staleness and prints the sources to verify. It cannot browse. You fetch them, then record what you found:

python3 .../tracker.py law-check --tracker "$T" \
    --record-checked "CT rates unchanged; employer thresholds unchanged; Apr-2028 accounts reform confirmed"

Recording a check without actually fetching is the failure this is built to make visible. It flags when the rates reference passes its REVIEW_BY, when the check interval lapses (default 90 days), and when a watched change comes within a year of taking effect — currently the April 2027 CT600 boxes and the April 2028 accounts reform.

When something HAS changed, update references/rates-2026-27.md and its REVIEW_BY, then say which figures moved and what they affect. A rates file that silently outlives its review date is this family's worst failure mode: it produces confidently wrong tax figures that nobody can see are wrong.

3. The engagement flow

ONBOARD ─► BOOKKEEP ─► RECONCILE ─► VAT QUARTER ─► YEAR-END ─► TAX ─► HANDOFF
   │           │            │            │             │         │        │
   │           │            │            │             │         │        └─ recognised software / agent
   │           │            │            │             │         └─ uk-corporation-tax (CT600, computations)
   │           │            │            │             └─ uk-statutory-accounts (FRS 105 / 102 1A, CH accounts)
   │           │            │            └─ uk-vat (9 boxes, scheme, MTD digital link)
   │           │            └─ bookkeeping-double-entry (bank rec, control + clearing accounts, TB)
   │           └─ financial-document-ingestion (PDF statements, PDF invoices, CSV exports)
   └─ this skill (§4 facts to establish, §5 deadline map)

  uk-payroll runs on its own monthly cycle throughout, feeding wages/PAYE/NI into the books.

4. ONBOARD — establish these before doing any work

Get these wrong and everything downstream is wrong. Record each as confirmed or assumed, and treat an assumed one exactly as business-edge treats an assumed margin: it cannot carry a conclusion on its own.

Fact	Why it changes the work
Accounting reference date (ARD)	Sets year end, CH filing date, CT period. From the CH register, not from memory.
Company number + UTR + VAT number + PAYE ref	Every submission keys off these
VAT scheme — standard accrual · cash accounting · flat rate · annual · margin/retail	Changes the arithmetic of every box. Never assume standard.
VAT stagger (which quarters)	Sets four deadlines a year
Accounting framework — FRS 105 (micro) vs FRS 102 Section 1A (small)	Different statements, different disclosure, different numbers
Associated companies	Divides the CT marginal-relief limits — a classic small-company error
Payroll: employees, directors, auto-enrolment status, Employment Allowance eligibility	Single-director companies have specific EA restrictions
Period length	A short or long first period pro-rates CT limits and may need two CT600s

5. The deadline map — the highest-value thing in this file

Deadlines are the errors that cost real money, and the pairs below are the ones people conflate.

Obligation	Deadline	Common mistake
VAT return + payment	1 month + 7 days after quarter end	Filing on time, paying late — still a penalty
Corporation tax PAYMENT	9 months + 1 day after period end	Assuming it follows the filing date
CT600 FILING	12 months after period end	Assuming it matches the payment date
Companies House accounts	9 months after ARD (21 months from incorporation for a first period)	Missing that first-year periods differ
Confirmation statement	Annually, within 14 days of the review period end	Believing it is part of the accounts filing — it is separate, with its own cycle. One is due even if nothing changed. See references/confirmation-statement.md
Payroll FPS	On or before every payday	Filing after paying
PAYE/NIC payment	22nd (electronic) of the following month	19th is the postal deadline
P60 to employees	31 May	—
P11D / Class 1A	6 July / 22 July	—

Payment and filing are different obligations with different dates and separate penalties. Say which one you mean, every time.

6. Rates and thresholds

Never quote a rate from memory, and never inline one into prose. All current figures live in one place with a review date and a primary-source URL per figure:

→ references/rates-2026-27.md

Two of three secondary summaries checked while building this family were materially wrong — one reported the CT main rate as 19% (that is the small profits rate), another gave the employer secondary threshold 10× too high. That is why the rule is absolute: cite the reference, state the tax year the figure belongs to, and refuse to apply a rate to a period it does not cover.

7. Routing

Task	Skill
Read a PDF bank statement, PDF invoice, CSV export	financial-document-ingestion
Post entries, reconcile bank, clear a suspense/clearing account, build a trial balance	bookkeeping-double-entry
It does not balance / does not reconcile — diagnose and correct the error	ledger-error-diagnosis
Working inside QuickBooks — feed, rules, matching, reconcile, sync gaps	quickbooks-bookkeeping
Is this a capital asset or an expense? How do I depreciate it?	business-expenses-and-assets
Splits, processor fees, supplier credits, refunds, part-payments	bookkeeping-double-entry/references/transaction-patterns.md
Who is this vendor, how do they bill, and has anything changed?	business-profile
Gmail/Drive/Sheets from Python (invoice capture)	google-workspace-python
How long to keep records, and backing them up properly	financial-document-ingestion/references/retention-and-backup.md
Cash flow, working capital, salary vs dividend, what to watch monthly	small-business-finance
VAT scheme choice, the 9 boxes, MTD digital links, correcting an error	uk-vat
CT600, tax computation, add-backs, capital allowances, losses	uk-corporation-tax
FRS 105 / FRS 102 1A statements, Companies House accounts	uk-statutory-accounts
RTI, FPS/EPS, PAYE/NI, auto-enrolment, director payroll	uk-payroll
Confirmation statement, PSC register, SIC codes, identity verification	references/confirmation-statement.md
Full vs filleted vs abridged accounts, audit exemption, size thresholds	uk-statutory-accounts §5–§7
Pull live data from QuickBooks Online (MCP/API)	quickbooks-api
Bank / Gmail / WooCommerce / PayPal / Worldpay / Klarna feeds and their gates	references/data-feeds.md
Where received documents are stored and indexed	financial-document-ingestion §6
Spreadsheet mechanics for any of the above	ms-office-excel-python
A CSV too large to read whole	large-file-analysis

8. Standing rules

• Reconcile before you conclude. A VAT return or a set of accounts drawn from unreconciled books is a guess with a number on it. Bank, VAT control and wages control must agree first.
• Every figure traces to a document. Statement line, invoice, or payroll run. If it cannot be traced, it is a query, not an entry.
• Show the arithmetic. A tax figure without its computation cannot be checked by the user, their accountant, or HMRC.
• Round only at the end, and to the direction the relevant rule requires.
• Flag, never quietly fix. An unexplained difference is a finding. Forcing it into suspense to make the books balance hides exactly what the user needs to see.
• Work with the records that exist. Missing paperwork means a stated limitation and a best available read — not a refusal to produce anything. Say what is unresolved, what it could move, and what document would settle it.
• You are not the company's accountant of record. For anything with penalty exposure — a first CT600, a scheme change, a disclosure, an HMRC enquiry — recommend a qualified accountant reviews it before submission, and say why.

9. Anti-patterns

• Answering without running the routine (§2). Status first, overdue items led with.
• Re-deriving what the business is every session instead of consulting the profile.
• Recording a law-check that was never actually fetched.
• Marking an obligation done without evidence.
• Claiming to have filed. You cannot submit. Prepare and hand off.
• Quoting a rate from memory instead of the rates reference.
• Confusing the CT payment date with the CT filing date.
• Assuming the standard VAT scheme when the company is on flat rate or cash accounting.
• Ignoring associated companies when applying marginal relief.
• Treating the confirmation statement as part of the accounts filing.
• Balancing to suspense and calling the books reconciled.
• Giving a confident answer from unreconciled or partial records without labelling it as such.