mcp-us-business-validator

Validate US business entities, EINs, and addresses in real-time — no external API calls required.

Install in Claude Desktop

Add to ~/Library/Application Support/Claude/claude_desktop_config.json:

{
  "mcpServers": {
    "us-business-validator": {
      "command": "npx",
      "args": ["-y", "mcp-us-business-validator"]
    }
  }
}

Restart Claude Desktop. The validate_business tool is now available.

Tools

| Tool | Description | |------|-------------| | validate_business | Validates EIN format + IRS prefix, business name rules, and USPS-compliant address structure |

What it checks

EIN

• Format must be XX-XXXXXXX (accepts 123456789 and normalizes it)
• Prefix must be IRS-assigned (rejects: 00, 07, 08, 09, 17, 18, 19, 28, 29, 49, 69, 70, 78, 79, 89)

Business name

• 2–200 characters
• Must contain at least one alphabetic character

Address

• Street and city must be non-empty
• State must be a valid 2-letter US state or territory abbreviation (all 50 states + DC, PR, GU, VI, AS, MP)
• ZIP accepts 5-digit (12345) or ZIP+4 (12345-6789) format

Example

{
  "method": "tools/call",
  "params": {
    "name": "validate_business",
    "arguments": {
      "business_name": "Acme Corp",
      "ein": "12-3456789",
      "address": {
        "street": "123 Main St",
        "city": "Springfield",
        "state": "IL",
        "zip": "62701"
      }
    }
  }
}

Response:

{
  "is_valid": true,
  "errors": [],
  "formatted_data": {
    "business_name": "Acme Corp",
    "ein": "12-3456789",
    "address": {
      "street": "123 Main St",
      "city": "Springfield",
      "state": "IL",
      "zip": "62701"
    }
  },
  "summary": "✅ \"Acme Corp\" (EIN 12-3456789) passed all validation checks — Springfield, IL 62701"
}

Dev

npm install
npm run build
# Smoke test:
echo '{"jsonrpc":"2.0","id":1,"method":"tools/list","params":{}}' | node dist/index.js

Part of Cosmic API

This MCP server is part of the Cosmic API collection. Browse all tools: npm search mcp cosmic-api