Koskamo

US Federal Holidays and Business Days MCP

An MCP server that computes exact U.S. federal holidays and business days from 1971 to 2100, handling OPM observed dates and Federal Reserve banking calendars. It provides tools to list holidays, check business days, add/subtract business days, count business days between dates, and calculate invoice due dates based on net terms.

Endpoint and access

No sign-in to connect and list tools. Individual tools may still need a vendor account, credentials, or permissions; check the documented prerequisites.

US Federal Holidays and Business Days MCP logo, by theluckystrikeCommunity listingStreamable HTTPNo sign-inEndpoint checked 2026-11-01Published by theluckystrike
MCP endpoint (Streamable HTTP)
https://us-federal-holidays-business-days-mcp.lipmichal.workers.dev/mcp
Vendor documentation

What you can do with it

  • List all federal holidays for a specific year with legal and observed dates
  • Check if a specific date is a business day on the federal or Federal Reserve calendar
  • Calculate invoice due dates by adding net terms to an issue date
  • Count business days between two dates excluding weekends and holidays

Source and maintenance

Community listingRegistry 1.0.0
mcp-registry: io.github.theluckystrike/us-federal-holidays-business-days-mcp@1.0.0Source repositoryProject website
Maintenance checked

Protocol and capabilities

Server
us-federal-holidays-business-days-mcp 1.0.0
MCP protocol
2025-06-18
Tools
5 advertised
Resources
Not advertised
Resource templates
Not advertised
Prompts
Not advertised
Server-advertised capabilities
{
  "tools": {
    "listChanged": true
  }
}

Server-provided instructions

Untrusted server output shown for inspection. It is not Koskamo guidance and is excluded from knowledge search.

Exact U.S. federal holiday and business-day arithmetic, 1971-2100. Use it instead of computing dates yourself whenever a deadline, settlement date, SLA or invoice due date depends on weekends or holidays. calendar=federal follows OPM observance; calendar=fed_banking follows the Federal Reserve (open on the Friday before a Saturday holiday).

Tools

5 advertised

list_federal_holidays — List U.S. federal holidays for a year
Advertised by the server during the last successful anonymous check.
Advertised read-only

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.

list_federal_holidays input schema
{
  "type": "object",
  "$schema": "http://json-schema.org/draft-07/schema#",
  "required": [
    "year"
  ],
  "properties": {
    "year": {
      "type": "integer",
      "maximum": 2100,
      "minimum": 1971,
      "description": "Calendar year, 1971-2100."
    }
  },
  "additionalProperties": false
}
list_federal_holidays annotations
{
  "title": "List federal holidays",
  "readOnlyHint": true,
  "openWorldHint": false,
  "idempotentHint": true,
  "destructiveHint": false
}
is_business_day — Check if a date is a U.S. business day
Advertised by the server during the last successful anonymous check.
Advertised read-only

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.

is_business_day input schema
{
  "type": "object",
  "$schema": "http://json-schema.org/draft-07/schema#",
  "required": [
    "date"
  ],
  "properties": {
    "date": {
      "type": "string",
      "pattern": "^\\d{4}-\\d{2}-\\d{2}$"
    },
    "calendar": {
      "enum": [
        "federal",
        "fed_banking"
      ],
      "type": "string",
      "default": "federal",
      "description": "federal = OPM observance for federal employees (Saturday holiday -> Friday off). fed_banking = Federal Reserve Banks (Saturday holiday -> open Friday; Sunday -> closed Monday). Use fed_banking for ACH, wire and bank settlement dates."
    },
    "extra_closed_dates": {
      "type": "array",
      "items": {
        "$ref": "#/properties/date"
      },
      "maxItems": 100,
      "description": "Extra closed dates to treat as holidays, e.g. a one-off executive order closure such as 2025-01-09."
    },
    "include_inauguration_day": {
      "type": "boolean",
      "default": false,
      "description": "federal calendar only: also close Inauguration Day (DC-area federal employees only, every 4 years)."
    }
  },
  "additionalProperties": false
}
is_business_day annotations
{
  "title": "Is business day",
  "readOnlyHint": true,
  "openWorldHint": false,
  "idempotentHint": true,
  "destructiveHint": false
}
add_business_days — Add or subtract U.S. business days
Advertised by the server during the last successful anonymous check.
Advertised read-only

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.

add_business_days input schema
{
  "type": "object",
  "$schema": "http://json-schema.org/draft-07/schema#",
  "required": [
    "start_date",
    "business_days"
  ],
  "properties": {
    "calendar": {
      "enum": [
        "federal",
        "fed_banking"
      ],
      "type": "string",
      "default": "federal",
      "description": "federal = OPM observance for federal employees (Saturday holiday -> Friday off). fed_banking = Federal Reserve Banks (Saturday holiday -> open Friday; Sunday -> closed Monday). Use fed_banking for ACH, wire and bank settlement dates."
    },
    "start_date": {
      "type": "string",
      "pattern": "^\\d{4}-\\d{2}-\\d{2}$"
    },
    "business_days": {
      "type": "integer",
      "maximum": 20000,
      "minimum": -20000,
      "description": "Business days to add; negative to go back."
    },
    "extra_closed_dates": {
      "type": "array",
      "items": {
        "$ref": "#/properties/start_date"
      },
      "maxItems": 100,
      "description": "Extra closed dates to treat as holidays, e.g. a one-off executive order closure such as 2025-01-09."
    },
    "include_inauguration_day": {
      "type": "boolean",
      "default": false,
      "description": "federal calendar only: also close Inauguration Day (DC-area federal employees only, every 4 years)."
    }
  },
  "additionalProperties": false
}
add_business_days annotations
{
  "title": "Add business days",
  "readOnlyHint": true,
  "openWorldHint": false,
  "idempotentHint": true,
  "destructiveHint": false
}
count_business_days — Count U.S. business days between two dates
Advertised by the server during the last successful anonymous check.
Advertised read-only

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.

count_business_days input schema
{
  "type": "object",
  "$schema": "http://json-schema.org/draft-07/schema#",
  "required": [
    "start_date",
    "end_date"
  ],
  "properties": {
    "calendar": {
      "enum": [
        "federal",
        "fed_banking"
      ],
      "type": "string",
      "default": "federal",
      "description": "federal = OPM observance for federal employees (Saturday holiday -> Friday off). fed_banking = Federal Reserve Banks (Saturday holiday -> open Friday; Sunday -> closed Monday). Use fed_banking for ACH, wire and bank settlement dates."
    },
    "end_date": {
      "$ref": "#/properties/start_date"
    },
    "start_date": {
      "type": "string",
      "pattern": "^\\d{4}-\\d{2}-\\d{2}$"
    },
    "include_end": {
      "type": "boolean",
      "default": true
    },
    "include_start": {
      "type": "boolean",
      "default": true
    },
    "extra_closed_dates": {
      "type": "array",
      "items": {
        "$ref": "#/properties/start_date"
      },
      "maxItems": 100,
      "description": "Extra closed dates to treat as holidays, e.g. a one-off executive order closure such as 2025-01-09."
    },
    "include_inauguration_day": {
      "type": "boolean",
      "default": false,
      "description": "federal calendar only: also close Inauguration Day (DC-area federal employees only, every 4 years)."
    }
  },
  "additionalProperties": false
}
count_business_days annotations
{
  "title": "Count business days",
  "readOnlyHint": true,
  "openWorldHint": false,
  "idempotentHint": true,
  "destructiveHint": false
}
invoice_due_date — Invoice due date from net terms
Advertised by the server during the last successful anonymous check.
Advertised read-only

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.

invoice_due_date input schema
{
  "type": "object",
  "$schema": "http://json-schema.org/draft-07/schema#",
  "required": [
    "issue_date",
    "net_days"
  ],
  "properties": {
    "roll": {
      "enum": [
        "none",
        "following",
        "preceding",
        "modified_following"
      ],
      "type": "string",
      "default": "following",
      "description": "How to move a due date that is not a business day."
    },
    "calendar": {
      "enum": [
        "federal",
        "fed_banking"
      ],
      "type": "string",
      "default": "fed_banking",
      "description": "fed_banking (default) matches when banks settle payments; federal uses OPM observance."
    },
    "net_days": {
      "type": "integer",
      "maximum": 3650,
      "minimum": 0,
      "description": "Net terms in calendar days, e.g. 30 for Net 30."
    },
    "issue_date": {
      "type": "string",
      "pattern": "^\\d{4}-\\d{2}-\\d{2}$"
    },
    "extra_closed_dates": {
      "type": "array",
      "items": {
        "$ref": "#/properties/issue_date"
      },
      "maxItems": 100,
      "description": "Extra closed dates to treat as holidays, e.g. a one-off executive order closure such as 2025-01-09."
    }
  },
  "additionalProperties": false
}
invoice_due_date annotations
{
  "title": "Invoice due date",
  "readOnlyHint": true,
  "openWorldHint": false,
  "idempotentHint": true,
  "destructiveHint": false
}

Prompts

Not advertised

No prompt definitions available.

Resources

Not advertised

No resource definitions available.

30-day availability

Aggregated from read-only remote checks; this is not a tool-execution or security guarantee.

Successful checks
1 of 1 (100%)
Average latency
439 ms
95th percentile latency
439 ms

Maintenance history

Public check and source-refresh events. Editorial and ownership records remain private.

  • · probe · passed · 439 ms · metadata changed · 5 tool(s)

Connect from your client

Each snippet registers the same endpoint; pick the client you use.

This server is operated by the named third party. Listing and endpoint checks are not an endorsement or a security audit. Review the operator's permissions, terms, and data handling before connecting. How listings are checked and corrected.

Claude Code

Run this once in a terminal. It registers the remote server. Use --scope project to write .mcp.json for the repo.
Claude Code configuration
claude mcp add --transport http us-federal-holidays-and-business-days-mcp https://us-federal-holidays-business-days-mcp.lipmichal.workers.dev/mcp

Codex

Run this once. Codex stores MCP servers in ~/.codex/config.toml (or .codex/config.toml in a trusted project).
Codex configuration
codex mcp add us-federal-holidays-and-business-days-mcp --url https://us-federal-holidays-business-days-mcp.lipmichal.workers.dev/mcp

Cursor

Merge this server into .cursor/mcp.json in your project, then enable us-federal-holidays-and-business-days-mcp in your MCP settings.
Cursor configuration
{
  "mcpServers": {
    "us-federal-holidays-and-business-days-mcp": {
      "url": "https://us-federal-holidays-business-days-mcp.lipmichal.workers.dev/mcp"
    }
  }
}

Cline

Merge this into cline_mcp_settings.json (Cline → MCP Servers → Configure).
Cline configuration
{
  "mcpServers": {
    "us-federal-holidays-and-business-days-mcp": {
      "type": "streamableHttp",
      "url": "https://us-federal-holidays-business-days-mcp.lipmichal.workers.dev/mcp",
      "disabled": false
    }
  }
}

VS Code

Merge this server into .vscode/mcp.json. Use MCP: List Servers to start us-federal-holidays-and-business-days-mcp and inspect its tools.
VS Code configuration
{
  "servers": {
    "us-federal-holidays-and-business-days-mcp": {
      "type": "http",
      "url": "https://us-federal-holidays-business-days-mcp.lipmichal.workers.dev/mcp"
    }
  }
}

Gemini CLI

Run this once. It writes .gemini/settings.json in the current project; pass --scope user for ~/.gemini/settings.json.
Gemini CLI configuration
gemini mcp add --transport http us-federal-holidays-and-business-days-mcp https://us-federal-holidays-business-days-mcp.lipmichal.workers.dev/mcp

Claude Desktop

Merge this into claude_desktop_config.json (macOS: ~/Library/Application Support/Claude/, Windows: %APPDATA%\Claude\), then restart Claude Desktop.
Claude Desktop configuration
{
  "mcpServers": {
    "us-federal-holidays-and-business-days-mcp": {
      "url": "https://us-federal-holidays-business-days-mcp.lipmichal.workers.dev/mcp"
    }
  }
}

Windsurf

Merge this into ~/.codeium/windsurf/mcp_config.json, then refresh MCP in Cascade. Windsurf remote servers use serverUrl, not url.
Windsurf configuration
{
  "mcpServers": {
    "us-federal-holidays-and-business-days-mcp": {
      "serverUrl": "https://us-federal-holidays-business-days-mcp.lipmichal.workers.dev/mcp"
    }
  }
}

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