Duck Tax
Check micro-entity company accounts: raw figures in, validated balance sheet and deadlines out.
Connect it
Settings → Connectors → Add custom connector
URL: https://ducktax.com/api/mcpSettings → Apps & Connectors → Advanced → Developer mode
Create connector with URL: https://ducktax.com/api/mcp{
"mcpServers": {
"ducktax": {
"url": "https://ducktax.com/api/mcp"
}
}
}claude mcp add --transport http ducktax https://ducktax.com/api/mcp{
"servers": {
"ducktax": {
"type": "http",
"url": "https://ducktax.com/api/mcp"
}
}
}20 tools, pulled live
check_accountsread-onlyDerive a small-company balance sheet (micro-entity, in UK terms) from raw figures and validate it. Returns the derived sheet for the current and prior year, the figures the authority would reject (negatives where it wants a positive, share capital left at nil), and whether they are complete enough to hand to a filing product. It does NOT check that the sheet balances and cannot: retained earnings
dormant_figuresread-onlyThe complete set of figures for a dormant company: share capital, the matching cash, and zeros everywhere else. The register says when the last accounts were filed dormant, and for those companies this collapses the whole form to one call. Amounts in major units.
totals_to_figuresread-onlyTurn categorised bank-statement totals into balance sheet figures, applying the rules that stop an import lying: only income categories reach turnover, only expense categories reach operating costs, and the owner topping up the account is never sales. Totals are signed major units per category code; get codes from categorise_transactions.
late_filing_penaltyread-onlyWhat missing a Companies House accounts deadline costs. Given the due date, returns days remaining or overdue, the penalty band already incurred, and what the next band costs, the number that makes someone act today. UK private companies only.
list_jurisdictionsread-onlyThe countries this server knows about and what it can actually do in each: which have a real accounts engine, which registers can be searched or looked up, the currency, and the identifiers each jurisdiction files under. Call this first when unsure.
sample_accountsread-onlyA real worked example: nil turnover, a director loan, a near-empty bank account, the simplest accounts the UK regime permits. Use it to demonstrate check_accounts or as a template for a first-year company. Amounts in major units.
lookup_companyread-onlyLook a company up on its public register (Companies House for GB, ABN Lookup for AU) by its registered number. Returns the full public record: name, status, registered office, officers, SIC codes, accounting period, plus both filing deadlines with days remaining and the late-filing penalty already incurred if overdue. Rate limited and quota-charged; cached results are free. Find the number first w
search_companiesread-onlyFind a company by name on its public register and get back its registered number, status and address. This is how you reach lookup_company when the person only knows the name. Free of the daily quota; lightly rate limited.
get_prior_year_figuresread-onlyRead last year's figures out of the company's last filed accounts at Companies House, ready to drop into the *Prior fields of check_accounts or save_filing. Saves typing seven numbers from a PDF and gets the comparatives exactly as filed. GB only, and only when the last accounts were filed digitally. Quota-charged; cached results are free.
explain_accountsread-onlyA plain-English reading of a set of figures, written for a director who is not an accountant: what the derived balance sheet says about the company and anything that needs attention before filing. Only the derived sheet is sent to the model, no company name or number. Quota-charged; identical figures are answered from cache free.
categorise_transactionsread-onlyCategorise bank-statement transaction descriptions into the fixed vocabulary this product maps to balance sheet lines (sales, software, owner-in, …). Send description strings only, never amounts or dates. Sum the amounts per returned category yourself, then call totals_to_figures. One statement import is one quota unit; previously seen descriptions are answered from a shared cache free.
check_filing_extensionread-onlyWhether a company can still apply to its registrar for more time to file, how many days are left to apply, and what being late costs if that window is missed. This is usually the most useful thing to tell somebody who has just found a deadline: applying is free, takes about 15 minutes, and has to be done BEFORE the deadline it extends, so the option expires on the same day the penalty starts. Retu
draft_extension_reasonread-onlyTurn a short factual account of what went wrong into the reason text for an application for more time to file accounts, framed in the terms the registrar actually applies. It uses only the facts you give it: it will not invent circumstances, and where something is missing it leaves a bracketed placeholder rather than filling it in. The person must check every sentence before using it, because they
list_saved_filingsread-onlyThe user's saved filings, most recently touched first, with every figure in major units. This is the same list the website dashboard shows. Start here when asked about "my accounts" or "my company".
save_filingSave a set of figures to the user's account, or update a saved one by passing its id from list_saved_filings. Figures in major units. The filing is saved even when validation finds problems, because a work in progress is worth keeping, and the problems come back in the response so you can raise them.
delete_filingcan modifyDelete one saved filing by id, permanently. Confirm with the person before calling this; there is no undo and no trash.
track_company_deadlinesWatch a company by its register number and get reminded before its filing deadlines. Which channels are actually available depends on the server: the reply reports what will really be sent, and it can be nothing at all, so read it rather than assuming. No saved filing is needed: this is for the deadline itself, which matters months before any figures exist. Reminders go out on a ladder of days bef
list_tracked_companiesread-onlyEvery company this user gets deadline reminders about, including the ones implied by their saved filings. Shows the next accounts deadline and days remaining where a register record is already cached. Free: this never contacts a register.
untrack_company_deadlinescan modifyStop sending deadline reminders about a company. This mutes rather than forgets, which is the only thing that holds: a company implied by a saved filing would otherwise be re-added by the next scan. track_company_deadlines un-mutes it again.
server_statusread-onlyWhat this deployment can actually do right now: which integrations are configured, whether your token is valid, and how much of each daily quota you have left. Call it when a tool refuses and you want to know whether the feature is off or used up.
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