Everyday agent tools

by fourzerotwo.si · remote · no sign-in to list tools · v1.0.1 · published by si.fourzerotwo

Time zones and world business days, VAT rates and maths, currency conversion, UK business days…

Final · 3Changes · 13

Compare Registry entry

18 tools: 3 do something that can't be undone, 13 change things and 2 only read.

Scanned Oct 21, 2026

Deletes or cancels0Claude Code: deny
Can't be undone3Claude Code: ask: see these tools
Changes things13Claude Code: ask: see these tools
Only reads2Claude Code: allow: see these tools

3 checks matched something in the tool definitions. No finding is not a safety guarantee. How the checks work.

claude mcp add --transport http tools https://fourzerotwo.si/mcp/v/tools

Findings

Matches of fixed checks, with the text they matched.

3 warn

Warncalculators__postcode-distance
The server marks "calculators__postcode-distance" 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":true}; The input addresses people (input.to): what it sends cannot be taken back.
What this check looks for
Warncalculators__currency-convert
The server marks "calculators__currency-convert" 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":true}; The name "calculators__currency-convert" says "convert": a word for a change.
What this check looks for
Warntime__convert
The server marks "time__convert" 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":true}; The name "time__convert" says "convert": a word for a change.
What this check looks for

Tools

Open a tool for its reasons and full description. Descriptions are the publisher's own words, shown as they are.

18 tools

Can't be undone 3Sends, pays, publishes or merges: once done, it cannot be taken back.Claude Code: ask

calculators__currency-convertConvert between ~30 currencies at the ECB reference rate for today or any date in the last 90 days.Reads text others writeCan send data out1 finding
Why it is in this group
- The name "calculators__currency-convert" says "convert": a word for a change.
- The input addresses people (input.to): what it sends cannot be taken back.
- The server marks it read-only (readOnlyHint: true), but an annotation never lowers a class.
What it can reach
- untrusted-inputThe server marks it openWorldHint: true: it reaches things outside the server's own data.
- outboundThe input takes a destination (input.to): what the tool writes goes there.
Findings
- Warn
  The server marks "calculators__currency-convert" 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":true}; The name "calculators__currency-convert" says "convert": a word for a change.
  What this check looks for
Description, as the server wrote it
Convert between ~30 currencies at the ECB reference rate for today or any date in the last 90 days. Free within the daily allowance, then $0.001 USDC per call via x402.
Annotations the server declares
- title: Calculators: Currency conversion
- readOnlyHint: true
- destructiveHint: false
- idempotentHint: true
- openWorldHint: true
calculators__postcode-distanceStraight-line distance (km and miles) and compass bearing between two UK postcodes.Reads text others writeCan send data out1 finding
Why it is in this group
- The input addresses people (input.to): what it sends cannot be taken back.
- The server marks it read-only (readOnlyHint: true), but an annotation never lowers a class.
What it can reach
- untrusted-inputThe server marks it openWorldHint: true: it reaches things outside the server's own data.
- outboundThe input takes a destination (input.to): what the tool writes goes there.
Findings
- Warn
  The server marks "calculators__postcode-distance" 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":true}; The input addresses people (input.to): what it sends cannot be taken back.
  What this check looks for
Description, as the server wrote it
Straight-line distance (km and miles) and compass bearing between two UK postcodes. Free within the daily allowance, then $0.002 USDC per call via x402.
Annotations the server declares
- title: Calculators: Distance between postcodes
- readOnlyHint: true
- destructiveHint: false
- idempotentHint: true
- openWorldHint: true
time__convertConvert a wall-clock time from one IANA zone to another; says when it is ambiguous (clocks go back) or never happens (clocks go forward).Reads text others writeCan send data out1 finding
Why it is in this group
- The name "time__convert" says "convert": a word for a change.
- The input addresses people (input.to): what it sends cannot be taken back.
- The server marks it read-only (readOnlyHint: true), but an annotation never lowers a class.
What it can reach
- untrusted-inputThe server marks it openWorldHint: true: it reaches things outside the server's own data.
- outboundThe input takes a destination (input.to): what the tool writes goes there.
Findings
- Warn
  The server marks "time__convert" 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":true}; The name "time__convert" says "convert": a word for a change.
  What this check looks for
Description, as the server wrote it
Convert a wall-clock time from one IANA zone to another; says when it is ambiguous (clocks go back) or never happens (clocks go forward). Free within the daily allowance, then $0.001 USDC per call via x402.
Annotations the server declares
- title: Time Zones & Business Days: Convert a local time between zones
- readOnlyHint: true
- destructiveHint: false
- idempotentHint: true
- openWorldHint: true

Changes things 13Creates or changes something that can be changed back.Claude Code: ask

calculators__uk-business-daysIs a date a UK business day; add or subtract N business days; count business days between dates.Reads text others writeNo findings
Why it is in this group
- Nothing in its name or description says what it does, so it is counted as a write.
- The server marks it read-only (readOnlyHint: true), but an annotation never lowers a class.
What it can reach
- untrusted-inputThe server marks it openWorldHint: true: it reaches things outside the server's own data.
Description, as the server wrote it
Is a date a UK business day; add or subtract N business days; count business days between dates. Uses official bank holidays per nation. Free within the daily allowance, then $0.001 USDC per call via x402.
Annotations the server declares
- title: Calculators: UK business days
- readOnlyHint: true
- destructiveHint: false
- idempotentHint: true
- openWorldHint: true
holidays__checkIs a date a public holiday or business day in a country; add N business days; next business day.Reads text others writeNo findings
Why it is in this group
- Nothing in its name or description says what it does, so it is counted as a write.
- The server marks it read-only (readOnlyHint: true), but an annotation never lowers a class.
What it can reach
- untrusted-inputThe server marks it openWorldHint: true: it reaches things outside the server's own data.
Description, as the server wrote it
Is a date a public holiday or business day in a country; add N business days; next business day. Free within the daily allowance, then $0.001 USDC per call via x402.
Annotations the server declares
- title: World Public Holidays: Holiday & business-day check
- readOnlyHint: true
- destructiveHint: false
- idempotentHint: true
- openWorldHint: true
holidays__countriesEvery country and regional provider supported.Reads text others writeNo findings
Why it is in this group
- Nothing in its name or description says what it does, so it is counted as a write.
- The server marks it read-only (readOnlyHint: true), but an annotation never lowers a class.
What it can reach
- untrusted-inputThe server marks it openWorldHint: true: it reaches things outside the server's own data.
Description, as the server wrote it
Every country and regional provider supported. Free within the daily allowance, then $0.0005 USDC per call via x402.
Annotations the server declares
- title: World Public Holidays: Supported countries
- readOnlyHint: true
- destructiveHint: false
- idempotentHint: true
- openWorldHint: true
holidays__yearOfficial public holidays for a country (or region provider, e.g.Reads text others writeNo findings
Why it is in this group
- Nothing in its name or description says what it does, so it is counted as a write.
- The server marks it read-only (readOnlyHint: true), but an annotation never lowers a class.
What it can reach
- untrusted-inputThe server marks it openWorldHint: true: it reaches things outside the server's own data.
Description, as the server wrote it
Official public holidays for a country (or region provider, e.g. Germany/Bavaria) in a year. Free within the daily allowance, then $0.001 USDC per call via x402.
Annotations the server declares
- title: World Public Holidays: Holidays in a year
- readOnlyHint: true
- destructiveHint: false
- idempotentHint: true
- openWorldHint: true
time__nowLocal time, UTC, offset, abbreviation, DST flag, weekday and ISO week for a zone.Reads text others writeNo findings
Why it is in this group
- Nothing in its name or description says what it does, so it is counted as a write.
- The server marks it read-only (readOnlyHint: true), but an annotation never lowers a class.
What it can reach
- untrusted-inputThe server marks it openWorldHint: true: it reaches things outside the server's own data.
Description, as the server wrote it
Local time, UTC, offset, abbreviation, DST flag, weekday and ISO week for a zone. Free within the daily allowance, then $0.001 USDC per call via x402.
Annotations the server declares
- title: Time Zones & Business Days: Current time in a zone
- readOnlyHint: true
- destructiveHint: false
- idempotentHint: true
- openWorldHint: true
time__signedServer UTC time and a request id.Reads text others writeNo findings
Why it is in this group
- Nothing in its name or description says what it does, so it is counted as a write.
- The server marks it read-only (readOnlyHint: true), but an annotation never lowers a class.
What it can reach
- untrusted-inputThe server marks it openWorldHint: true: it reaches things outside the server's own data.
Description, as the server wrote it
Server UTC time and a request id. The cheapest paid endpoint: use it to test an x402 payment end to end. Costs $0.001 USDC per call via x402.
Annotations the server declares
- title: Time Zones & Business Days: Paid test call
- readOnlyHint: true
- destructiveHint: false
- idempotentHint: true
- openWorldHint: true
time__zone-infoOffset, abbreviation and DST at a moment, plus the next clock change, for an IANA zone.Reads text others writeNo findings
Why it is in this group
- Nothing in its name or description says what it does, so it is counted as a write.
- The server marks it read-only (readOnlyHint: true), but an annotation never lowers a class.
What it can reach
- untrusted-inputThe server marks it openWorldHint: true: it reaches things outside the server's own data.
Description, as the server wrote it
Offset, abbreviation and DST at a moment, plus the next clock change, for an IANA zone. Free within the daily allowance, then $0.001 USDC per call via x402.
Annotations the server declares
- title: Time Zones & Business Days: Time zone facts
- readOnlyHint: true
- destructiveHint: false
- idempotentHint: true
- openWorldHint: true
uk-bank-holidays__allEvery published UK bank holiday by division.Reads text others writeNo findings
Why it is in this group
- Nothing in its name or description says what it does, so it is counted as a write.
- The server marks it read-only (readOnlyHint: true), but an annotation never lowers a class.
What it can reach
- untrusted-inputThe server marks it openWorldHint: true: it reaches things outside the server's own data.
Description, as the server wrote it
Every published UK bank holiday by division. Free within the daily allowance, then $0.001 USDC per call via x402.
Annotations the server declares
- title: UK Bank Holidays: All bank holidays
- readOnlyHint: true
- destructiveHint: false
- idempotentHint: true
- openWorldHint: true
uk-bank-holidays__england-and-walesBank holidays in England and Wales.Reads text others writeNo findings
Why it is in this group
- Nothing in its name or description says what it does, so it is counted as a write.
- The server marks it read-only (readOnlyHint: true), but an annotation never lowers a class.
What it can reach
- untrusted-inputThe server marks it openWorldHint: true: it reaches things outside the server's own data.
Description, as the server wrote it
Bank holidays in England and Wales. Free within the daily allowance, then $0.001 USDC per call via x402.
Annotations the server declares
- title: UK Bank Holidays: England & Wales
- readOnlyHint: true
- destructiveHint: false
- idempotentHint: true
- openWorldHint: true
uk-bank-holidays__northern-irelandBank holidays in Northern Ireland.Reads text others writeNo findings
Why it is in this group
- Nothing in its name or description says what it does, so it is counted as a write.
- The server marks it read-only (readOnlyHint: true), but an annotation never lowers a class.
What it can reach
- untrusted-inputThe server marks it openWorldHint: true: it reaches things outside the server's own data.
Description, as the server wrote it
Bank holidays in Northern Ireland. Free within the daily allowance, then $0.001 USDC per call via x402.
Annotations the server declares
- title: UK Bank Holidays: Northern Ireland
- readOnlyHint: true
- destructiveHint: false
- idempotentHint: true
- openWorldHint: true
uk-bank-holidays__scotlandBank holidays in Scotland.Reads text others writeNo findings
Why it is in this group
- Nothing in its name or description says what it does, so it is counted as a write.
- The server marks it read-only (readOnlyHint: true), but an annotation never lowers a class.
What it can reach
- untrusted-inputThe server marks it openWorldHint: true: it reaches things outside the server's own data.
Description, as the server wrote it
Bank holidays in Scotland. Free within the daily allowance, then $0.001 USDC per call via x402.
Annotations the server declares
- title: UK Bank Holidays: Scotland
- readOnlyHint: true
- destructiveHint: false
- idempotentHint: true
- openWorldHint: true
vat__calculateNet to gross or gross to net at a given rate, or at a country's standard rate.Reads text others writeNo findings
Why it is in this group
- Nothing in its name or description says what it does, so it is counted as a write.
- The server marks it read-only (readOnlyHint: true), but an annotation never lowers a class.
What it can reach
- untrusted-inputThe server marks it openWorldHint: true: it reaches things outside the server's own data.
Description, as the server wrote it
Net to gross or gross to net at a given rate, or at a country's standard rate. Free within the daily allowance, then $0.001 USDC per call via x402.
Annotations the server declares
- title: VAT Rates & Checks: Add or remove VAT
- readOnlyHint: true
- destructiveHint: false
- idempotentHint: true
- openWorldHint: true
vat__ratesStandard, reduced and super-reduced VAT rates for one country or all of EU27 + UK, with the date they were checked.Reads text others writeNo findings
Why it is in this group
- Nothing in its name or description says what it does, so it is counted as a write.
- The server marks it read-only (readOnlyHint: true), but an annotation never lowers a class.
What it can reach
- untrusted-inputThe server marks it openWorldHint: true: it reaches things outside the server's own data.
Description, as the server wrote it
Standard, reduced and super-reduced VAT rates for one country or all of EU27 + UK, with the date they were checked. Free within the daily allowance, then $0.001 USDC per call via x402.
Annotations the server declares
- title: VAT Rates & Checks: VAT rates
- readOnlyHint: true
- destructiveHint: false
- idempotentHint: true
- openWorldHint: true

Only reads 2Looks things up and changes nothing.Claude Code: allow

time__business-daysCount business days between two dates, or add business days to a date, skipping weekends and the country's public holidays.Reads text others writeNo findings
Why it is in this group
- The description's first verb is "count": a word for reading.
What it can reach
- untrusted-inputThe server marks it openWorldHint: true: it reaches things outside the server's own data.
Description, as the server wrote it
Count business days between two dates, or add business days to a date, skipping weekends and the country's public holidays. Free within the daily allowance, then $0.001 USDC per call via x402.
Annotations the server declares
- title: Time Zones & Business Days: Business days (any country)
- readOnlyHint: true
- destructiveHint: false
- idempotentHint: true
- openWorldHint: true
vat__validate-formatCountry format and check digit for UK (GB/XI) and EU VAT numbers.Reads text others writeNo findings
Why it is in this group
- The name "vat__validate-format" says "validate": a word for reading.
What it can reach
- untrusted-inputThe server marks it openWorldHint: true: it reaches things outside the server's own data.
Description, as the server wrote it
Country format and check digit for UK (GB/XI) and EU VAT numbers. Does not confirm registration. Free within the daily allowance, then $0.001 USDC per call via x402.
Annotations the server declares
- title: VAT Rates & Checks: Validate a VAT number format
- readOnlyHint: true
- destructiveHint: false
- idempotentHint: true
- openWorldHint: true

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.

Reads private data0: Reads files, mail, messages, databases, secrets, calendars or repositories.
Reads text others write18: Brings in text someone else can write: web pages, inbound email, messages, issues and comments.; calculators__currency-convert
calculators__postcode-distance
calculators__uk-business-days
holidays__check
holidays__countries
holidays__year
time__business-days
time__convert
time__now
time__signed
time__zone-info
uk-bank-holidays__all
and 6 more
Can send data out3: Can carry data to people or systems: it sends, posts or publishes, or takes a recipient, channel or URL.; calculators__currency-convert
calculators__postcode-distance
time__convert

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

Install

Pinned to version 1.0.1. Values in angle brackets are yours to fill in.

claude mcp add --transport http tools https://fourzerotwo.si/mcp/v/tools

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__tools__time__business-days",
      "mcp__tools__vat__validate-format"
    ],
    "ask": [
      "mcp__tools__calculators__uk-business-days",
      "mcp__tools__calculators__postcode-distance",
      "mcp__tools__calculators__currency-convert",
      "mcp__tools__time__convert",
      "mcp__tools__time__now",
      "mcp__tools__time__zone-info",
      "mcp__tools__time__signed",
      "mcp__tools__uk-bank-holidays__all",
      "mcp__tools__uk-bank-holidays__england-and-wales",
      "mcp__tools__uk-bank-holidays__scotland",
      "mcp__tools__uk-bank-holidays__northern-ireland",
      "mcp__tools__vat__rates",
      "mcp__tools__vat__calculate",
      "mcp__tools__holidays__year",
      "mcp__tools__holidays__check",
      "mcp__tools__holidays__countries"
    ],
    "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 tools. Review it before you use it.

Capability tags behind 18 rules

mcp__tools__calculators__uk-business-days untrusted-input
mcp__tools__calculators__postcode-distance untrusted-input, outbound
mcp__tools__calculators__currency-convert untrusted-input, outbound
mcp__tools__time__convert untrusted-input, outbound
mcp__tools__time__now untrusted-input
mcp__tools__time__zone-info untrusted-input
mcp__tools__time__business-days untrusted-input
mcp__tools__time__signed untrusted-input
mcp__tools__uk-bank-holidays__all untrusted-input
mcp__tools__uk-bank-holidays__england-and-wales untrusted-input
mcp__tools__uk-bank-holidays__scotland untrusted-input
mcp__tools__uk-bank-holidays__northern-ireland untrusted-input
mcp__tools__vat__rates untrusted-input
mcp__tools__vat__calculate untrusted-input
mcp__tools__vat__validate-format untrusted-input
mcp__tools__holidays__year untrusted-input
mcp__tools__holidays__check untrusted-input
mcp__tools__holidays__countries untrusted-input

Keep track

Get told when this server's tools change: a new tool, a new description, a new class.

https://anlyon.dev/servers/si.fourzerotwo/tools/changes.xml

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Anlyon alternative

16 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.

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Compare with other servers for the same product.

Source: MCP Registry. Synced Oct 21, 2026, 18:54 UTC.

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