0s and 1s CIS calculators

What you can do with it

We have not written a plain-language summary for this one yet. Below are the facts we read from the registry.

• Connection: Runs in the cloud
• Transport: Streamable HTTP
• Category: Online shops & payments

Install

Pick the AI app you use, then copy the settings.

You need

• Runs in the cloudNothing to install; it connects over the internet

Which app do you use?

https://0sand1s.co.uk/mcp

claude mcp add --transport http cis https://0sand1s.co.uk/mcp

{
  "mcpServers": {
    "cis": {
      "url": "https://0sand1s.co.uk/mcp"
    }
  }
}

{
  "servers": {
    "cis": {
      "type": "http",
      "url": "https://0sand1s.co.uk/mcp"
    }
  }
}

https://0sand1s.co.uk/mcp

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These settings are generated from the maker’s registry entry. If the README says otherwise, follow the README.

What it can do

Tool names and descriptions exactly as the server reported them on Nov 7, 2026. The maker wrote them, not us; we show them as plain text.

• cis_deduction

  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

• cis_gross_up

  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

• cis_tax_month

  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 t

• cis_late_penalties

  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, th

• cis_gross_payment_turnover_test

  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,

• cis_needs_verification

  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 pa

• cis_nil_return_check

  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

Basic checksi

We check information anyone can see; we have not read the code. Checks that do not apply are left out of the count. · Checked Nov 8, 2026

• ✓ Pass

  Maker matches the repo

  The registry name was verified against the domain 0sand1s.co.uk (the registry checks domain ownership)

• … Not checked yet

  Still maintained

  We have not read this repo from GitHub yet

• … Not checked yet

  Has a licence

  We have not read this repo from GitHub yet

• ✓ Pass

  Endpoint responds

  Responded in 937 ms (HTTP 200)

• – Not applicable

  Sign-in with OAuth

  No sign-in needed

• ✓ Pass

  No hidden instructions in tool descriptions

  Read 7 tool descriptions and found no hidden instructions to the AI

Compared with others in Online shops & paymentsi

• More stars than 0% of the other 2550 servers in this category
• Published to the registry more recently than 60% of the other 2550 servers in this category
• Basic checks equal to or better than 100% of the other 2550 servers in this category

Compared with every active server in this category in the registry. Stars count only when the publisher owns the repo.

Alternatives

Servers in the same category from other makers, sorted by stars.

Reading a card:★ GitHub starsiThree pillars: reviews · checks · usageiUpdated = latest version published to the registryi

README from the maker

claude mcp add --transport http 0sand1s https://0sand1s.co.uk/mcp

{ "mcpServers": { "0sand1s": { "url": "https://0sand1s.co.uk/mcp" } } }

{ "servers": { "0sand1s": { "type": "http", "url": "https://0sand1s.co.uk/mcp" } } }

curl "https://0sand1s.co.uk/api/v1/deduction?gross=1200&vat=200&materials=300&rate=20"