MCP server

0s and 1s CIS calculators Official

uk.co.0sand1s/cis

Checked 26 Oct 2026, 08:29 UTC · Connected to it and listed its tools

Free UK CIS calculators: deductions, deadlines, late penalties, gross payment test, verification.

Website Source

At a glance

Type

MCP server

Publisher

0sand1s.co.uk (verified by the MCP Registry)

Status

Working at last check

Tools

7

Token cost

About 2,571 tokens per request

Sets up in

Claude Code, Claude Desktop, Codex, Gemini CLI, Cursor, VS Code, Antigravity, ChatGPT, OpenAI API, Grok

Last checked

26 Oct 2026, 08:29 UTC

Connect it to your agent

Add to CursorAdd to VS CodeVS Code Insiders

Opens the app, which shows the server and asks you to confirm. For other apps, copy the setup below.

Claude Code

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

Claude Desktop

Settings → Connectors → Add custom connector, and paste the URL.

Codex (config.toml)

[mcp_servers.cis]
url = "https://0sand1s.co.uk/mcp"

Gemini CLI

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

Cursor

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

VS Code

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

Antigravity

agy mcp add cis https://0sand1s.co.uk/mcp

ChatGPT

Settings → Apps & Connectors → Advanced settings: turn on Developer mode, then Create a connector and paste the URL. Which plans can do this varies.

OpenAI API (Responses tools)

{"type":"mcp","server_label":"cis","server_url":"https://0sand1s.co.uk/mcp","require_approval":"always"}

Grok (xAI API tools)

{"type":"mcp","server_label":"cis","server_url":"https://0sand1s.co.uk/mcp"}

Tools

• cis_deduction ~406 tokens
  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
• cis_gross_payment_turnover_test ~436 tokens
  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
• cis_gross_up ~324 tokens
  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
• cis_late_penalties ~450 tokens
  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 non
• cis_needs_verification ~319 tokens
  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
• cis_nil_return_check ~446 tokens
  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 sta
• cis_tax_month ~190 tokens
  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 befor

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