Skip to content
anlyon.devby Anlyon

S+ Money CIS Refund Calculator

uk.co.splusmoney/cis-refund-calculatorsplusmoney.co.ukstreamable-httpv1.1.0Scanned

Estimate a UK CIS construction subcontractor's tax refund for 2025-26 to 2027-28. Free, no sign-in.

2 tools: 1 do something that can't be undone and 1 only read.

Tools: 0 delete, 1 irreversible, 0 write, 1 read.
  • Reads private data · 0
  • Reads text others write · 0
  • Can send data out · 0
  • 1 finding

Anlyon alternative

1 of these tools change something. Run those as governed actions.

Declare what an action changes, and Anlyon puts it under a shared limit, binds every approval to the exact request, and grades the outcome. It works on any HTTPS API you can describe as an action.

Anlyon does not run, proxy or govern this MCP server. A tool your own code calls directly is not routed through Anlyon and is not governed by it.

Import an OpenAPI spec →
Compare with similar serversMarkdownJSONReport this listing

Tools

Grouped by what each tool does, most consequential first. Open one for its reasons and full description; descriptions are the publisher's own words.

2 tools

Can't be undone 1Claude Code: ask
  • estimate_cis_refundEstimate a UK CIS subcontractor's tax refund (or amount to pay) for tax year 2025-26, 2026-27 or 2027-28 (Budget 2026 rules for 2027-28).1 finding

    Why it is in this group

    • The name "estimate_cis_refund" says "refund": a word that usually means money moves, which cannot be taken back.
    • The server marks it read-only (readOnlyHint: true), but an annotation never lowers a class.

    Findings

    • Warn

      The server marks "estimate_cis_refund" read-only (readOnlyHint: true), and its own name, description or input give the class "irreversible".

      Matched text

      annotations: {"readOnlyHint":true,"destructiveHint":false,"idempotentHint":true,"openWorldHint":false}; The name "estimate_cis_refund" says "refund": a word that usually means money moves, which cannot be taken back.

      What this check looks for
    Description, as the server wrote it
    Estimate a UK CIS subcontractor's tax refund (or amount to pay) for tax year 2025-26, 2026-27 or 2027-28 (Budget 2026 rules for 2027-28). Takes the year's gross CIS income, the CIS deducted (the statement total, or the 20%/30% rate), allowable expenses (materials, tools, van mileage at HMRC simplified rates, parking and travel, phone, protective clothing, training and site cards, insurance, accountant) and optional other PAYE/pension income. Calculates taxable profit (or the trading allowance if better: £1,000, or £3,000 from 2027-28), income tax (England/Wales/NI or Scottish bands, Personal Allowance taper), Class 4 NIC and the Class 2 position, then compares the bill with the CIS already deducted. Returns the working line by line, payments-on-account warning, commonly missed expenses, rates used with GOV.UK sources and a result card. For self-employed sole traders under CIS, not limited companies. Read-only: stores and sends nothing. An estimate, not tax advice.

    Annotations the server declares

    • title: Estimate CIS tax refund
    • readOnlyHint: true
    • destructiveHint: false
    • idempotentHint: true
    • openWorldHint: false
Only reads 1Show 1 read-only tool
  • get_cis_tax_ratesList the UK rates a self-employed CIS subcontractor's tax bill uses for 2025-26, 2026-27 or 2027-28, each with its GOV.UK source: Personal Allowance and taper, income tax bands (En…No findings

    Why it is in this group

    • The name "get_cis_tax_rates" says "get": a word for reading.
    Description, as the server wrote it
    List the UK rates a self-employed CIS subcontractor's tax bill uses for 2025-26, 2026-27 or 2027-28, each with its GOV.UK source: Personal Allowance and taper, income tax bands (England/Wales/NI or Scotland), Class 4 NIC limits and rates, the Class 2 position (treated as paid above the Small Profits Threshold, voluntary below), HMRC simplified mileage rates, the trading allowance (£1,000; £3,000 from 2027-28), the Making Tax Digital start dates and the 20%/30% CIS deduction rates. Read-only. Not tax advice.

    Annotations the server declares

    • title: CIS subcontractor tax rates
    • readOnlyHint: true
    • destructiveHint: false
    • idempotentHint: true
    • openWorldHint: false

This is not a safety rating, and no finding is not a safety guarantee. The groups and findings come from fixed checks of the tool definitions the server returned on the date shown, not from its code or what it does when called. How the checks work.

Exfil surface

Which tools read private data, which read text someone else can write, and which can send data out. One of each is a path a prompt injection can use.

No private-data, untrusted-input, outbound path in this server alone: no tool is tagged private-data or untrusted-input or outbound.

Reads private data0
Reads files, mail, messages, databases, secrets, calendars or repositories.
Reads text others write0
Brings in text someone else can write: web pages, inbound email, messages, issues and comments.
Can send data out0
Can carry data to people or systems: it sends, posts or publishes, or takes a recipient, channel or URL.

Other servers in the same agent add their own tools to these paths. Audit your whole setup to see them together.

Findings

Matches of fixed checks, with the text they matched.

1 warn
  • Warnestimate_cis_refund

    The server marks "estimate_cis_refund" read-only (readOnlyHint: true), and its own name, description or input give the class "irreversible".

    Matched text

    annotations: {"readOnlyHint":true,"destructiveHint":false,"idempotentHint":true,"openWorldHint":false}; The name "estimate_cis_refund" says "refund": a word that usually means money moves, which cannot be taken back.

    What this check looks for

History

Changes to its tool definitions and to its remote endpoint, newest first.

No change seen yet. Its tools are rescanned every day, and a remote endpoint is looked at once a week.

All changes to this server

Install

Pinned to version 1.1.0. Values in angle brackets are yours to fill in.

claude mcp add --transport http cis-refund-calculator https://mcp.splusmoney.co.uk/mcp
claude mcp add --transport http cis-refund-calculator https://mcp.splusmoney.co.uk/mcp

Run in a terminal.

Claude Code permissions

Allow the reads, ask before a change or a way out, deny the deletes. Paste into .claude/settings.json.

.claude/settings.json
{
  "permissions": {
    "allow": [
      "mcp__cis-refund-calculator__get_cis_tax_rates"
    ],
    "ask": [
      "mcp__cis-refund-calculator__estimate_cis_refund"
    ],
    "deny": []
  }
}

Tools that only read are allowed, tools that change things ask first, tools that delete or cancel are denied. A read that can send data out (it takes a URL, say) asks first too. It assumes the server is installed as cis-refund-calculator. Review it before you use it.

Pin

Keep the decision: fail CI when the tools change, follow every change, or show a badge.

Pin in CI

Fail a build when the tools you reviewed are not the tools the server serves today.

curl -s "https://anlyon.dev/api/v1/servers/uk.co.splusmoney/cis-refund-calculator/verify?hash=88600100aca2fea959bbba0270fa8808705dafd3f3a6f6d364d5a3d54756bf41" | jq -e '.changed == false'

Pinned hash 88600100aca2, from Nov 1, 2026, 10:18 UTC.

Watch

Get told when its tools change: a new tool, a new description, a new class.

https://anlyon.dev/servers/uk.co.splusmoney/cis-refund-calculator/changes.xml

An Atom feed. Works in any feed reader or Slack's RSS app.

Badge

anlyon.dev badge for uk.co.splusmoney/cis-refund-calculator
[![anlyon.dev](https://anlyon.dev/badge/uk.co.splusmoney/cis-refund-calculator.svg)](https://anlyon.dev/servers/uk.co.splusmoney/cis-refund-calculator)

Source: MCP Registry. Synced Nov 1, 2026, 10:18 UTC.