0s and 1s CIS calculators

Install

Works with Claude Code, VS Code, Cursor, Windsurf. Read the repository before you give any tool access to your data.

npx agentmarket install connector/0sand1s-co-uk-cis

About

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Permissions

What this server can do and what it asks for, from its tool list and install config. Checked Oct 25, 2026.

Tools

7 read · 0 write · 0 deleteRead-only

Secrets

None asked for

Install scripts

Nothing to install (hosted)

Runs as

Hosted (remote endpoint)

Tools (7)

As the server listed them on Oct 25, 2026. Descriptions are the server’s own words; hidden characters are shown as [U+…].

• cis_deductionCIS deduction, gross to netread-only

  Works out the CIS deduction on a payment to a subcontractor, from the gross bill to the net payment. Takes the gross including VAT, the VAT, the subcontractor's materials and the rate (0, 20 or 30). VAT is never taxed under CIS and materials come off before the rate applies; the deduction is rounded down to the penny. Returns each step of the working, money in pence and pounds. Does not cover retentions, or decide which rate applies (verify the subcontractor with HMRC for that).

• cis_gross_payment_turnover_testCIS gross payment status turnover testread-only

  Checks the turnover test for CIS gross payment status (Finance Act 2004 Schedule 11, SI 2005/2045 reg 28): £30,000 net construction turnover for a sole trader; for a partnership or company, the lower of £30,000 for each partner or relevant person and £100,000. In a close company, shareholders count as well as directors. Returns the figure needed by each route, which one applies, and how far short. Covers the turnover test only, not the business test or the compliance test.

• cis_gross_upCIS gross up, net to grossread-only

  Finds the gross amount (excluding VAT) that leaves a given net payment after the CIS deduction, for a subcontractor quoted a take-home figure. Takes the net, the subcontractor's materials and the rate (0, 20 or 30). Where rounding lets two grosses give the same net, the larger is returned so CIS is never under-deducted. Returns the forward working on that gross, money in pence and pounds. VAT is not included; add it on top if the subcontractor charges it.

• cis_late_penaltiesCIS late filing penaltiesread-only

  Works out the late filing penalties on one monthly CIS return under Finance Act 2009 Schedule 55: £100 the day after the 19th, £200 at 2 months, then the greater of £300 and 5% of the deductions at 6 and at 12 months (5% alone for a first return). Takes the tax year and month, the filing date or none, today's date, the deductions and whether a return had been filed before. Returns each penalty with its date and whether it is charged, avoided or still to come. Does not cover deliberate withholding, interest on late payment, or appeals.

• cis_needs_verificationDoes a CIS subcontractor need verifying?read-only

  Says whether a contractor must verify a subcontractor with HMRC before paying them (SI 2005/2045 reg 6): not needed if the subcontractor was on one of this contractor's CIS returns, or was verified by this contractor, in the tax year of the payment or the two before. Takes the payment date, the tax years the subcontractor was on a return and the last verification date, all supplied by the caller. Does not contact HMRC or verify anyone, and does not cover group companies or business transfers.

• cis_nil_return_checkIs a CIS nil return due?read-only

  Says whether a contractor must file a CIS nil return for a tax month (SI 2005/2045 reg 4(9A) and (9B), inserted by SI 2026/289 from 6 April 2026): due when a mainstream contractor that has paid subcontractors before pays none that month, unless it told HMRC no later than 14 days before the month started. Takes the tax year and month and yes or no answers. Returns whether a nil return is due, why, and the date it is due. Does not file anything.

• cis_tax_monthCIS tax month and deadlinesread-only

  For a date, gives the CIS tax month it falls in (the 6th to the 5th), the tax year, the date the monthly return (CIS300) is due (the 19th, also the date for paying HMRC by any means other than electronically), and the date for paying HMRC electronically (the 22nd, moved back to the banking day before when the 22nd is a weekend or an England and Wales bank holiday). Bank holidays are known to bank_holidays_known_until; after that only weekends move the date.

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Last commit

Oct 18, 2026 (11 days ago)

Last release

Oct 18, 2026 (11 days ago)

From GitHub (fetched Oct 24, 2026).

Details

Registry name

uk.co.0sand1s/cis

Version

1.0.1

Auth

Auth not stated

License

MIT

Repository

github.com/0sand1s-uk/cis-mcp

Website

0sand1s.co.uk/developers

First seen

Oct 24, 2026

Last checked

Oct 25, 2026

Source

Official MCP Registrygithub-graphql