US Business Calendar MCP

Provides US federal holidays, business-day calculations, invoice due dates, and IRS deadlines for bookkeeping, payroll, and AI agents. Includes tools for domain trust checks, IBAN validation, and email deliverability.

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.

Community listingStreamable HTTPNo sign-inEndpoint checked 2026-11-01Published by Donnie Morrison

MCP endpoint (Streamable HTTP)

https://us-business-calendar-mcp.donniertf.workers.dev/mcp

Vendor documentation

What you can do with it

Get next 3 US federal holidays and check if today is a business day
Count US business days between two dates excluding weekends and holidays
Calculate due dates after N business days for Net 30/60 terms
Retrieve upcoming IRS filing and payment deadlines

Source and maintenance

Community listingRegistry 1.0.0

mcp-registry: io.github.donniertf-hub/us-business-calendar-mcp@1.0.0 Source repository Project website

Maintenance checked: Nov 1, 2026, 8:44 AM UTC

Protocol and capabilities

Server: us-business-calendar-mcp 1.0.0
MCP protocol: 2025-06-18
Tools: 9 advertised
Resources: Not advertised
Resource templates: Not advertised
Prompts: Not advertised

Server-advertised capabilities

{
  "tools": {
    "listChanged": false
  }
}

Server-provided instructions

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

US Business Calendar. next_holidays is free. Subscribe ($9/month, cancel anytime) at https://us-business-calendar-mcp.donniertf.workers.dev/buy for the paid tools, then pass access_token.

Tools

9 advertised

next_holidays

Advertised by the server during the last successful anonymous check.

FREE. Next 3 US federal holidays (with observed dates) and whether today is a business day.

next_holidays input schema

{
  "type": "object",
  "properties": {}
}

business_days

Advertised by the server during the last successful anonymous check.

PRO. Count US business days between two dates (excludes weekends and federal holidays).

business_days input schema

{
  "type": "object",
  "required": [
    "from",
    "to"
  ],
  "properties": {
    "to": {
      "type": "string"
    },
    "from": {
      "type": "string"
    },
    "access_token": {
      "type": "string",
      "description": "Subscriber token from /success (or Authorization: Bearer)"
    }
  }
}

due_date

Advertised by the server during the last successful anonymous check.

PRO. Due date after N business days or N calendar days (rolled to next business day) — Net 30/60, ACH settlement, contract notice periods.

due_date input schema

{
  "type": "object",
  "required": [
    "days"
  ],
  "properties": {
    "days": {
      "type": "number"
    },
    "from": {
      "type": "string"
    },
    "business": {
      "type": "boolean"
    },
    "access_token": {
      "type": "string",
      "description": "Subscriber token from /success (or Authorization: Bearer)"
    }
  }
}

irs_deadlines

Advertised by the server during the last successful anonymous check.

PRO. Upcoming IRS filing and payment deadlines for the next N months (individual, payroll, corporate), adjusted for weekends/holidays; optional fiscal_year_end.

irs_deadlines input schema

{
  "type": "object",
  "properties": {
    "months": {
      "type": "number"
    },
    "access_token": {
      "type": "string",
      "description": "Subscriber token from /success (or Authorization: Bearer)"
    },
    "fiscal_year_end": {
      "type": "string"
    }
  }
}

domain_age

Advertised by the server during the last successful anonymous check.

FREE. Domain trust quick check: registration date, age in days, registrar, expiry and risk flags from RDAP. Accepts a domain or URL.

domain_age input schema

{
  "type": "object",
  "required": [
    "domain"
  ],
  "properties": {
    "domain": {
      "type": "string"
    }
  }
}

domain_trust_report

Advertised by the server during the last successful anonymous check.

Full domain/URL trust report: RDAP registration, registrar, status, nameservers, plus active TLS certificates and issuers from crt.sh, with risk flags.

domain_trust_report input schema

{
  "type": "object",
  "required": [
    "domain"
  ],
  "properties": {
    "domain": {
      "type": "string"
    },
    "access_token": {
      "type": "string",
      "description": "Subscriber token from /success (or Authorization: Bearer)"
    }
  }
}

cert_history

Advertised by the server during the last successful anonymous check.

Active TLS certificates for a domain from Certificate Transparency logs (crt.sh): issuers, names, validity dates.

cert_history input schema

{
  "type": "object",
  "required": [
    "domain"
  ],
  "properties": {
    "domain": {
      "type": "string"
    },
    "access_token": {
      "type": "string",
      "description": "Subscriber token from /success (or Authorization: Bearer)"
    }
  }
}

email_domain_check

Advertised by the server during the last successful anonymous check.

Email/domain deliverability check: MX records, SPF and DMARC policy for a domain or email address (DNS over HTTPS).

email_domain_check input schema

{
  "type": "object",
  "required": [
    "domain"
  ],
  "properties": {
    "domain": {
      "type": "string",
      "description": "Domain or email address"
    },
    "access_token": {
      "type": "string",
      "description": "Subscriber token from /success (or Authorization: Bearer)"
    }
  }
}

iban_validate

Advertised by the server during the last successful anonymous check.

FREE. Validate an IBAN offline: country, length and ISO 13616 mod-97 checksum, plus bank code and formatted IBAN. No outside source.

iban_validate input schema

{
  "type": "object",
  "required": [
    "iban"
  ],
  "properties": {
    "iban": {
      "type": "string"
    }
  }
}

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: 399 ms
95th percentile latency: 399 ms

Maintenance history

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

Nov 1, 2026, 9:03 AM UTC · probe · passed · 399 ms · metadata changed · 9 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-business-calendar-mcp https://us-business-calendar-mcp.donniertf.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-business-calendar-mcp --url https://us-business-calendar-mcp.donniertf.workers.dev/mcp

Cursor

Merge this server into .cursor/mcp.json in your project, then enable us-business-calendar-mcp in your MCP settings.

Cursor configuration

{
  "mcpServers": {
    "us-business-calendar-mcp": {
      "url": "https://us-business-calendar-mcp.donniertf.workers.dev/mcp"
    }
  }
}

Cline

Merge this into cline_mcp_settings.json (Cline → MCP Servers → Configure).

Cline configuration

{
  "mcpServers": {
    "us-business-calendar-mcp": {
      "type": "streamableHttp",
      "url": "https://us-business-calendar-mcp.donniertf.workers.dev/mcp",
      "disabled": false
    }
  }
}

VS Code

Merge this server into .vscode/mcp.json. Use MCP: List Servers to start us-business-calendar-mcp and inspect its tools.

VS Code configuration

{
  "servers": {
    "us-business-calendar-mcp": {
      "type": "http",
      "url": "https://us-business-calendar-mcp.donniertf.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-business-calendar-mcp https://us-business-calendar-mcp.donniertf.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-business-calendar-mcp": {
      "url": "https://us-business-calendar-mcp.donniertf.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-business-calendar-mcp": {
      "serverUrl": "https://us-business-calendar-mcp.donniertf.workers.dev/mcp"
    }
  }
}

Let your agent find its tools

Find servers like US Business Calendar MCP from your agent. Add Koskamo once to search the index for endpoints, access requirements, and client setup. Public discovery needs no key.

Connect Koskamo Explore workflows