Model Context Protocol (MCP)

The Model Context Protocol (MCP) is an open standard that lets AI assistants interact with external services. Think of it as a USB-C port for AI — one protocol to connect any AI tool to e-invoice.be. The e-invoice.be MCP server gives AI agents access to your invoices, credit notes, Peppol network data, and usage statistics — all through natural language.

All MCP tools are read-only. No data can be created, modified, or deleted through MCP. To create or send documents, use the REST API.

Prerequisites

Before setting up MCP, you need:

An e-invoice.be account — sign up at app.e-invoice.be
An API key — go to Settings → API Keys in your dashboard (learn more)

Server URL: https://api.e-invoice.be/mcp The endpoint is the same across all clients. Transport is streamable HTTP, authenticated with your API key as a Bearer token.

Setup

Claude Code

Claude Code supports remote MCP servers natively via streamable HTTP.CLI (recommended):

claude mcp add --transport http e-invoice https://api.e-invoice.be/mcp \
  --header "Authorization: Bearer YOUR_API_KEY"

This registers the server at user scope. To add it at project scope, append --scope project.Manual JSON — add to ~/.claude.json (user scope) or .claude/settings.local.json (project scope):

{
  "mcpServers": {
    "e-invoice": {
      "type": "http",
      "url": "https://api.e-invoice.be/mcp",
      "headers": {
        "Authorization": "Bearer YOUR_API_KEY"
      }
    }
  }
}

After adding, restart Claude Code or run /mcp to verify the server appears in the list.

Claude Code MCP docs

Official documentation for MCP in Claude Code

Claude Desktop

Claude Desktop does not yet support remote streamable HTTP MCP servers directly. You need mcp-remote as a bridge (requires Node.js ≥ v18).Step 1 — Open the config file from Claude → Settings → Developer → Edit Config:

OS	Config path
macOS	`~/Library/Application Support/Claude/claude_desktop_config.json`
Windows	`%APPDATA%\Claude\claude_desktop_config.json`
Linux	`~/.config/Claude/claude_desktop_config.json`

Step 2 — Add (or merge into) the mcpServers key:

{
  "mcpServers": {
    "e-invoice": {
      "command": "npx",
      "args": [
        "mcp-remote@latest",
        "https://api.e-invoice.be/mcp",
        "--header",
        "Authorization: Bearer YOUR_API_KEY"
      ]
    }
  }
}

Step 3 — Restart Claude Desktop. The e-invoice tools appear under the hammer (🔨) icon in the composer.

Claude Desktop MCP docs

Official documentation for connecting MCP servers to Claude Desktop

ChatGPT

ChatGPT supports remote MCP servers as custom connectors (available on Plus, Pro, Business, and Enterprise plans).

Custom connectors via developer mode are currently not available for all account types in the EEA, GB, and CH regions. Since most e-invoice.be users are in the EU, verify that your ChatGPT plan supports this feature before proceeding.

Setup flow:

Open chatgpt.com → Settings → Connectors → Advanced → Developer mode (toggle on)
Click Create → Add custom connector
Fill in the connector details:
- Name: e-invoice
- Description: Send, validate, and look up Peppol invoices
- MCP server URL: https://api.e-invoice.be/mcp
- Authentication: Custom header
  - Header name: Authorization
  - Header value: Bearer YOUR_API_KEY
Save and accept the trust prompt
Enable the connector inside any chat via the + → Connectors menu

ChatGPT connectors overview

Learn about connectors in ChatGPT

Developer mode docs

Enable custom MCP connectors

Cursor

Add to ~/.cursor/mcp.json (global) or .cursor/mcp.json (per-project):

{
  "mcpServers": {
    "e-invoice": {
      "url": "https://api.e-invoice.be/mcp",
      "headers": {
        "Authorization": "Bearer YOUR_API_KEY"
      }
    }
  }
}

After saving, restart Cursor or open a new chat session. The tools will appear in the MCP tools list.

Cursor MCP docs

Official documentation for MCP in Cursor

VS Code (GitHub Copilot)

Add to .vscode/mcp.json in your project root:

{
  "servers": {
    "e-invoice": {
      "type": "http",
      "url": "https://api.e-invoice.be/mcp",
      "headers": {
        "Authorization": "Bearer YOUR_API_KEY"
      }
    }
  }
}

Alternatively, add to your user or workspace settings.json under the mcp.servers key.

VS Code MCP docs

Official documentation for MCP in VS Code

Windsurf

Add to ~/.codeium/windsurf/mcp_config.json:

{
  "mcpServers": {
    "e-invoice": {
      "type": "http",
      "url": "https://api.e-invoice.be/mcp",
      "headers": {
        "Authorization": "Bearer YOUR_API_KEY"
      }
    }
  }
}

Restart Windsurf after saving the configuration.

Don’t have an API key yet? See the Authentication guide to create one.

Available Tools

Documents

Tool	Description
`get_document`	Retrieve a single invoice or credit note by ID, including line items, tax details, payment info, and attachments
`get_document_attachments`	List all attachments for a document
`get_document_attachment`	Get a specific attachment with a signed download URL (valid for 1 hour)
`get_document_timeline`	Get the chronological event history for a document (creation, validation, transmission, delivery)

Inbox

Tool	Description
`get_inbox`	List all received documents with filtering by type, sender, date range, and full-text search
`get_inbox_invoices`	List only received invoices
`get_inbox_credit_notes`	List only received credit notes

Outbox

Tool	Description
`get_outbox`	List all sent documents with filtering by receiver, date range, and full-text search

Drafts

Tool	Description
`get_drafts`	List draft documents with filtering by state (DRAFT, TRANSIT, FAILED), type, and date range

Peppol Lookup

These tools are public and do not require authentication.

Tool	Description
`get_lookup_peppol_id`	Verify if a participant is registered on the Peppol network and retrieve their supported document types
`get_lookup_participants`	Search for Peppol participants by name, with optional country filter

Statistics

Tool	Description
`get_stats`	Retrieve sending and receiving statistics, grouped by day, week, or month

Example Prompts

Once connected, you can interact with your e-invoice.be account using natural language:

“Show me all invoices received this month”
“Get the details and timeline of document doc_abc123”
“Is the company with VAT number BE0848934496 registered on Peppol?”
“Search for Peppol participants named ‘OpenPeppol’ in Belgium”
“Show my sending and receiving stats for the last 3 months, aggregated by month”
“List all failed documents in my drafts”
“What attachments are on invoice doc_xyz789?”

Troubleshooting

Tools not appearing after setup

Restart the application — most MCP clients only load server configurations on startup.

Verify your API key — run a quick test with curl to confirm it works:

curl -s https://api.e-invoice.be/api/me/ \
  -H "Authorization: Bearer YOUR_API_KEY"

Check the server URL — make sure you’re using https://api.e-invoice.be/mcp (no trailing slash).

Claude Desktop: tools not showing

Check the log file for errors:
- macOS: tail -n 50 ~/Library/Logs/Claude/mcp.log
- Windows: open %APPDATA%\Claude\logs\mcp.log
Verify Node.js is installed and on your PATH: node --version (v18+ required).

Test mcp-remote manually to surface auth errors:

npx mcp-remote@latest https://api.e-invoice.be/mcp \
  --header "Authorization: Bearer YOUR_API_KEY"

Ensure your JSON is valid — a trailing comma or missing quote will silently prevent loading.

ChatGPT: connector not available

Custom connectors require Developer mode to be enabled under Settings → Connectors → Advanced.
Developer mode is not available on all plans or in all regions (EEA/GB/CH restrictions may apply).
After adding the connector, you must explicitly enable it in each new chat via the + → Connectors menu.

Authentication errors

API keys are prefixed with your tenant — make sure you copied the full key.
Keys created for the Admin API (reseller keys) will not work with MCP.
If you recently rotated your key, update the configuration file and restart the client.

Security

Your API key gives MCP access to all read-only data within your tenant. Treat it with the same care as any API credential.

Read-only access — MCP tools cannot create, modify, or delete any data
Tenant-scoped — your API key determines which tenant’s data is accessible
Lookup tools are public — get_lookup_peppol_id and get_lookup_participants work without authentication
Best practice — consider creating a dedicated API key for MCP access, separate from your application’s key

Next Steps

Authentication

Get your API key and learn about authentication

API Reference

Full REST API for creating and sending documents

Webhooks

Receive real-time notifications for document events

​Prerequisites

​Setup

​Claude Code

Claude Code MCP docs

​Claude Desktop

Claude Desktop MCP docs

​ChatGPT

ChatGPT connectors overview

Developer mode docs

​Cursor

Cursor MCP docs

​VS Code (GitHub Copilot)

VS Code MCP docs

​Windsurf

​Available Tools

​Documents

​Inbox

​Outbox

​Drafts

​Peppol Lookup

​Statistics

​Example Prompts

​Troubleshooting

​Tools not appearing after setup

​Claude Desktop: tools not showing

​ChatGPT: connector not available

​Authentication errors

​Security

​Next Steps

Authentication

API Reference

Webhooks

Prerequisites

Setup

Claude Code

Claude Desktop

ChatGPT

Cursor

VS Code (GitHub Copilot)

Windsurf

Available Tools

Documents

Inbox

Outbox

Drafts

Peppol Lookup

Statistics

Example Prompts

Troubleshooting

Tools not appearing after setup

Claude Desktop: tools not showing

ChatGPT: connector not available

Authentication errors

Security

Next Steps