Productivity

0sand1s.co.uk

An MCP server providing UK Construction Industry Scheme tax calculations, including CIS deductions, gross-up, tax month deadlines, late filing penalties, and gross payment turnover tests.

1 endpoint7 known toolsFirst detected October 19, 2026Last detected October 19, 2026

ENDPOINT 1

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

No auth detected

MCP server metadata

Name: 0s and 1s
Version: 1.0.1

Capabilities

tools.listChanged

Server instructions

Calculators for the UK Construction Industry Scheme (CIS), for contractors who pay subcontractors. Money in is pounds ("1,200.00" or 1200); money out is { pence, pounds }. Dates are YYYY-MM-DD; pass today's date where a tool asks for it. Each answer lists its GOV.UK and legislation.gov.uk sources. Answers follow the published rules; they are not tax advice and do not come from HMRC.

Known tools 7

cis_deduction

Works out the CIS deduction on a payment to a subcontractor, from the gross bill to the net payment.

Potential side effects

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.

Potential side effects

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 the banking day before when the 22nd is a weekend or an England and Wales bank holiday).

Inferred read-only

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).

Inferred read-only

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.

Potential side effects

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.

Potential side effects

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 before the month started.

Inferred read-only

CONNECT WITH APPROVAL

Client installation

Review this server and its permissions before adding it. Secret placeholders must be set locally.

Codex

~/.codex/config.toml

[mcp_servers.0s-and-1s]
url = "https://0sand1s.co.uk/mcp"
enabled = true

Claude Code

.mcp.json

{
  "mcpServers": {
    "0s-and-1s": {
      "type": "http",
      "url": "https://0sand1s.co.uk/mcp"
    }
  }
}

Claude Desktop

Settings → Connectors → Add custom connector

Name: 0s-and-1s
Remote MCP URL: https://0sand1s.co.uk/mcp

Add this remote URL as a custom connector in Claude Desktop. Availability depends on the user plan and workspace policy.

Cursor

.cursor/mcp.json

{
  "mcpServers": {
    "0s-and-1s": {
      "url": "https://0sand1s.co.uk/mcp"
    }
  }
}

Visual Studio Code

.vscode/mcp.json

Add to Visual Studio Code

{
  "servers": {
    "0s-and-1s": {
      "type": "http",
      "url": "https://0sand1s.co.uk/mcp"
    }
  }
}

Generic MCP

Client-specific MCP configuration

{
  "name": "0s-and-1s",
  "transport": "streamable-http",
  "url": "https://0sand1s.co.uk/mcp"
}

MCP Inspector

Run the official MCP Inspector locally and enter the indexed Streamable HTTP endpoint.

TRUST AND VERIFICATION EVIDENCE

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Checking the associated registrable domain. The BuiltWith key remains server-side.

Indexed

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