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US Federal Holidays and Business Days

io.github.theluckystrike/us-federal-holidays-business-days-mcptheluckystrikestreamable-httpv1.0.0Scanned

Exact U.S. federal holidays and business days 1971-2100, OPM and Federal Reserve observance.

5 tools: 3 change things and 2 only read.

Tools: 0 delete, 0 irreversible, 3 write, 2 read.
  • Reads private data · 1
  • Reads text others write · 0
  • Can send data out · 0
  • 1 finding

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3 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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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.

5 tools

Changes things 3Claude Code: ask
  • add_business_daysAdds (or with a negative number subtracts) N business days to a date, skipping weekends and observed U.S.1 finding

    Why it is in this group

    • The name "add_business_days" says "add": a word for a change.
    • The server marks it read-only (readOnlyHint: true), but an annotation never lowers a class.

    Findings

    • Warn

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

      Matched text

      annotations: {"readOnlyHint":true,"destructiveHint":false,"idempotentHint":true,"openWorldHint":false}; The name "add_business_days" says "add": a word for a change.

      What this check looks for
    Description, as the server wrote it
    Adds (or with a negative number subtracts) N business days to a date, skipping weekends and observed U.S. federal or Federal Reserve holidays exactly. The start date is not counted. With 0, returns the start date if it is a business day, otherwise the next one. Lists every holiday skipped.

    Annotations the server declares

    • title: Add business days
    • readOnlyHint: true
    • destructiveHint: false
    • idempotentHint: true
    • openWorldHint: false
  • invoice_due_dateComputes an invoice due date from an issue date and net terms in calendar days (Net 30 = 30), then optionally rolls a weekend or U.S.No 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.
    Description, as the server wrote it
    Computes an invoice due date from an issue date and net terms in calendar days (Net 30 = 30), then optionally rolls a weekend or U.S. holiday due date: following (next business day), preceding, or modified_following (next business day unless it crosses into the next month). Uses exact observed federal or Federal Reserve holidays.

    Annotations the server declares

    • title: Invoice due date
    • readOnlyHint: true
    • destructiveHint: false
    • idempotentHint: true
    • openWorldHint: false
  • is_business_daySays whether a date (1971-2100) is a business day on the U.S.No 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.
    Description, as the server wrote it
    Says whether a date (1971-2100) is a business day on the U.S. federal (OPM) calendar or the Federal Reserve banking calendar, names the holiday if any, and returns the previous and next business day. The two calendars differ when a holiday falls on Saturday: 2026-07-03 is a federal holiday but a Fed banking day.

    Annotations the server declares

    • title: Is business day
    • readOnlyHint: true
    • destructiveHint: false
    • idempotentHint: true
    • openWorldHint: false
Only reads 2Show 2 read-only tools
  • count_business_daysCounts business days between two dates (1971-2100) on the U.S.Reads private dataNo findings

    Why it is in this group

    • The name "count_business_days" says "count": a word for reading.

    What it can reach

    • private-dataThe input names a calendar (input.calendar), and the tool reads: it reads calendars.
    Description, as the server wrote it
    Counts business days between two dates (1971-2100) on the U.S. federal or Federal Reserve calendar, excluding weekends and observed holidays. include_start and include_end default to true, like Excel NETWORKDAYS. If end is before start the count is negative. Lists the weekday holidays that were excluded.

    Annotations the server declares

    • title: Count business days
    • readOnlyHint: true
    • destructiveHint: false
    • idempotentHint: true
    • openWorldHint: false
  • list_federal_holidaysExact U.S.No findings

    Why it is in this group

    • The name "list_federal_holidays" says "list": a word for reading.
    Description, as the server wrote it
    Exact U.S. federal holidays for any year 1971-2100 under 5 U.S.C. 6103: legal date, OPM observed date (Saturday -> Friday, Sunday -> Monday, so New Year's Day 2022 is observed Friday 2021-12-31) and the Federal Reserve closure date (Fed Banks stay OPEN the Friday before a Saturday holiday). Applies the rule history a model tends to get wrong: Juneteenth from 2021, MLK Day from 1986, Veterans Day on the 4th Monday of October 1971-1977, and Inauguration Day (DC area only, flagged optional). No network calls.

    Annotations the server declares

    • title: List federal holidays
    • 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 untrusted-input or outbound.

Reads private data1
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
  • Warnadd_business_days

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

    Matched text

    annotations: {"readOnlyHint":true,"destructiveHint":false,"idempotentHint":true,"openWorldHint":false}; The name "add_business_days" says "add": a word for a change.

    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 1.0.0. Values in angle brackets are yours to fill in.

claude mcp add --transport http us-federal-holidays-business-days https://us-federal-holidays-business-days-mcp.lipmichal.workers.dev/mcp
claude mcp add --transport http us-federal-holidays-business-days https://us-federal-holidays-business-days-mcp.lipmichal.workers.dev/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__us-federal-holidays-business-days__list_federal_holidays",
      "mcp__us-federal-holidays-business-days__count_business_days"
    ],
    "ask": [
      "mcp__us-federal-holidays-business-days__is_business_day",
      "mcp__us-federal-holidays-business-days__add_business_days",
      "mcp__us-federal-holidays-business-days__invoice_due_date"
    ],
    "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 us-federal-holidays-business-days. Review it before you use it.

Capability tags behind 1 rule
  • mcp__us-federal-holidays-business-days__count_business_days private-data

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/io.github.theluckystrike/us-federal-holidays-business-days-mcp/verify?hash=1ff12b80b3dbd6e2f1574f6cccd2f4112763f74e3497983a2d40d804b9e9ac0c" | jq -e '.changed == false'

Pinned hash 1ff12b80b3db, from Oct 30, 2026, 00:18 UTC.

Watch

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

https://anlyon.dev/servers/io.github.theluckystrike/us-federal-holidays-business-days-mcp/changes.xml

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Source: MCP Registry · repository. Synced Oct 30, 2026, 01:17 UTC.