What does `verify_key_structure` do?

It checks if the 44-digit sequence is purely numeric, exactly 44 digits long, and passes the Modulo 11 checksum verification.

How can I see the issuer's details?

Use the `extract_key_metadata` tool. It will parse the key and return the CNPJ, State Code, and other relevant metadata.

Does this tool check for tax compliance?

Yes, the `validate_business_compliance` tool audits components like Model and Emission Type against official regulatory catalogs.

NF-e Access Key Validator MCP Connector for Claude

A+

Validate the structural integrity and compliance of Brazilian NF-e access keys.

3 tools Official Updated Jun 28, 2026 Official Vinkius Partner

More Details Connect to Claude

This MCP server provides specialized tools for verifying Brazilian Electronic Invoice (NF-e) access keys. Use verify_key_structure to check the 44-digit sequence for mathematical validity using the Modulo 11 algorithm. The extract_key_metadata tool decomposes a valid key into its constituent parts, such as CNPJ and State Code, while validate_business_compliance audits these components against official tax authority standards.

nfebraziltaxinvoicevalidation

Connect to Claude

Subscribe on Vinkius, then add this connector to Claude.ai or Claude Code.

① Claude.ai (web app)

Go to Settings → Connectors → Add custom connector
Paste the MCP endpoint URL below

https://edge.vinkius.com/vk_preview_IRwsYmnDubhWF6CADb8mHPMbLhjrqO48Mkm0iChQ/mcp

② Claude Code (terminal)

claude mcp add --transport http nf-e-access-key-validator https://edge.vinkius.com/vk_preview_IRwsYmnDubhWF6CADb8mHPMbLhjrqO48Mkm0iChQ/mcp

③ Claude Desktop

Add to claude_desktop_config.json:

{
  "mcpServers": {
    "nf-e-access-key-validator": {
      "url": "https://edge.vinkius.com/vk_preview_IRwsYmnDubhWF6CADb8mHPMbLhjrqO48Mkm0iChQ/mcp"
    }
  }
}

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