Duck Tax MCP server

• Registry namecom.ducktax/ducktaxverified in the MCP registry

The registry name sits under ducktax.com. The registry only lets a publisher use that namespace after proving control of the domain through DNS or HTTP.

• Stateanswerschecked 2026-10-24
• Tools20
• Server calls itselfducktax
• Server version0.1.0
• Protocol version2025-06-18

On 2026-10-24 the server answered initialize and tools/list without a sign-in. First answer in 110 ms.

• Its tools do every use case we checked: fill micro entity accounts from a bank statement or CSV; catch filing deadlines and estimate late penalties.
• Checked on 4 of the 7 days it takes to judge reliability.

Said by rules from the measurements above. The likely first call is a model's pick from the tool list; read its description before relying on it.

• INITE MCP scoreafter a weeka score needs 7 daily checks: 4 so far
• What an agent can do with it2 of 2 use cases
• Answeredmeasuring4 of the 7 daily checks it takes to print a share
• Median first answer153 ms
• Space in an agent's context≈ 6,099 tokensthe definitions of all its tools (20), which an agent carries on every turn
• Tool definitionsA · 99 of 100
• Typed results0 of 20 toolsdeclared outputSchema: results come typed, read once

• Parameters without a description: in 1 of 20

A program checks the server once a day: initialize and tools/list, no model. Tokens are the definitions' length at about four characters a token. The grade averages six checks of every tool's name, description, schema and annotations; it says how well the tools are described, not whether they work. The score weighs what was measured and nothing else: answering (25%), doing the product's job (25%), definitions (20%), context (10%), use (10%) and how readily a client connects (10%). A part that was not measured is left out, and a hidden instruction caps the score at 40. The state of vendors' MCP servers: method and numbers →

• check_accounts

  Derive 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…

• dormant_figures

  The 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…

• totals_to_figures

  Turn 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…

• late_filing_penalty

  What 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…

• list_jurisdictions

  The 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…

• sample_accounts

  A 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_company

  Look 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…

• search_companies

  Find 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_figures

  Read 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…

• explain_accounts

  A 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…

• categorise_transactions

  Categorise 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…

• check_filing_extension

  Whether 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…

• draft_extension_reason

  Turn 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…

• list_saved_filings

  The 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_filing

  Save 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…

• delete_filing

  Delete one saved filing by id, permanently. Confirm with the person before calling this; there is no undo and no trash.

• track_company_deadlines

  Watch 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…

• list_tracked_companies

  Every 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_deadlines

  Stop 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…

• server_status

  What 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…