mcp-cfdi-mx 🇲🇽

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A Python MCP server providing tools for Mexican electronic invoicing compliant with CFDI 4.0 and Complemento de Pagos 2.0, per SAT's Anexo 20 technical standard. It enables AI agents (Claude, IDEs) to build, XSD-validate, and seal CFDI 4.0 documents (Ingreso, Egreso, and Complemento de Pagos 2.0), verify a PAC-returned Timbre Fiscal Digital stamp, and validate Mexican RFC tax identifiers.

Phase 1 scope. This package covers CFDI 4.0 Ingreso, Egreso, and Complemento de Pagos 2.0 only — Carta Porte, Complemento de Nómina, Retenciones, and Comercio Exterior are not yet supported, and it does not submit to any PAC. See Available tools for exactly what is implemented today.

Introduction

This package is built on mcp-einvoicing-core, the shared base library for e-invoicing MCP servers. It provides the InvoiceDocument model base, the TaxIdentifier.validate_mx_rfc RFC validator, and SelloDigitalSigner — the MX-specific concrete implementation of core's document-signing abstraction (SHA-256 digest of the cadena original, RSA-PKCS#1v1.5-signed with the emisor's CSD, per SAT's Anexo 20).

mcp-einvoicing-core is installed automatically as a dependency, no additional step is required.

CFDI is a clearance-model standard: a CFDI becomes legally valid only once a PAC (Proveedor Autorizado de Certificación) certifies it and returns a Timbre Fiscal Digital (TFD). This package does not submit to a PAC — it is PAC-agnostic, producing either a locally-sealed CFDI (ready to hand to any PAC that accepts pre-sealed documents) or an unsealed, schema-valid CFDI (for a PAC that seals on the emisor's behalf), selected via a sealing_mode parameter.

Installation

Via PyPI (recommended)

pip install mcp-cfdi-mx

Or without prior installation using uvx:

uvx mcp-cfdi-mx

From source

git clone https://github.com/cmendezs/mcp-cfdi-mx.git
cd mcp-cfdi-mx
uv sync --all-extras

Configuration (environment variables)

This package has no required environment variables. CSD certificate/key paths and passwords are passed as tool arguments (file paths or environment references — never plaintext key material embedded in a request), not read from a fixed environment variable name.

Claude Desktop integration

Add the following configuration to your claude_desktop_config.json file:

{
  "mcpServers": {
    "cfdi-mx": {
      "command": "uvx",
      "args": ["mcp-cfdi-mx"]
    }
  }
}

Cursor integration

Cursor supports MCP servers via stdio. Add the configuration to:

• Globally (all projects): ~/.cursor/mcp.json
• Per project (this repository only): .cursor/mcp.json

{
  "mcpServers": {
    "cfdi-mx": {
      "command": "uvx",
      "args": ["mcp-cfdi-mx"]
    }
  }
}

Reload the Cursor window (Ctrl+Shift+P → Reload Window) after saving changes.

Kiro integration

Kiro supports MCP servers through a dedicated configuration file:

• Globally: ~/.kiro/settings/mcp.json
• Workspace: .kiro/settings/mcp.json

{
  "mcpServers": {
    "cfdi-mx": {
      "command": "uvx",
      "args": ["mcp-cfdi-mx"],
      "disabled": false,
      "autoApprove": []
    }
  }
}

Security tip: if a future tool version accepts credentials via environment reference, use the syntax "VAR_NAME": "${VAR_NAME}" so Kiro resolves it from the shell rather than storing it in plaintext.

Available tools

Build

Validate and seal

Scope

See docs/TOOLS.md for the full parameter reference of every tool, generated from the live tool registry.

Not yet implemented

PAC submission transport (this package is PAC-agnostic and does not submit to any specific PAC), and later-phase complementos (Carta Porte, Complemento de Nómina, Retenciones, Comercio Exterior).

Architecture

mcp_cfdi_mx.models.CFDIComprobante extends mcp_einvoicing_core.models.InvoiceDocument (the non-EN 16931 pathway — CFDI predates and has no lineage to CEN TC 434, the same determination as mcp-nfe-br). RFC validation for both Emisor and Receptor routes through TaxIdentifier.validate_mx_rfc (core). Sealing routes through mcp_einvoicing_core.digital_signature.SelloDigitalSigner, the MX-specific concrete implementation of core's BaseDocumentSigner — the same pattern ES (XAdES), BR (XML-DSig), and IT (CAdES) use for their own signature standards.

[ ERP System / Application ] <--> [ MCP Server ] <--> [ PAC (any, PAC-agnostic) / SAT ]
          ^                           |
          |                           v
   [ AI Agent (Claude) ] <--- (CFDI 4.0 / Pagos 2.0)

Vendor neutrality

This server implements the standard itself: it builds, validates, and signs the document locally. It is not a client for a commercial invoicing platform, and your signing keys and credentials never leave your own infrastructure.

A PAC (Proveedor Autorizado de Certificación) must stamp the CFDI; this server seals it locally with your own CSD and hands any PAC an already-sealed document.

Supported standards

See specs/README.md for the full source bundle and retrieval dates.

Tests

uv run pytest tests/ -v

Contributing

Contributions are welcome — see CONTRIBUTING.md for guidelines.

Other e-invoicing MCP servers

License

This project is distributed under the Apache 2.0 license. See the LICENSE file for details. For the full version history, see CHANGELOG.md.