Let your AI assistant check invoices

the assistant asks. The rules answer.

Model Context Protocol (MCP) connects your AI assistant to Attestwire’s tools. It can explain errors, check invoice data and create invoice XML. Six tools need no API key. Add a key when you need checks that use your monthly allowance.

The checks themselves are fixed rules, so the same invoice and rule set always give the same result; the assistant only calls them. There are fourteen tools in total. Check the live version at GET /v1/versions, without a key.

Connect your assistant

Use https://api.attestwire.com/mcp as the server address. Choose streamable HTTP, the remote connection method, if your client asks for a transport.

claude mcp add --transport http attestwire https://api.attestwire.com/mcp

• Streamable HTTP clients: use https://api.attestwire.com/mcp.
• Local-process clients: @attestwire/mcp bridges stdio to the same endpoint. The config block
• No key needed to start: connect without a credential and use the six public tools. Add a key later for document calls. See the steps

If your client can only spawn a local process

The bridge is @attestwire/mcp on npm. It does nothing but relay, so new tools appear without upgrading it. Paste this into claude_desktop_config.json, .cursor/mcp.json, or whatever your client calls its config:

{
  "mcpServers": {
    "attestwire": {
      "command": "npx",
      "args": ["-y", "@attestwire/mcp"],
      "env": { "ATTESTWIRE_API_KEY": "aw_live_..." }
    }
  }
}

ATTESTWIRE_API_KEY is optional: drop the env block and the six keyless tools still work. ATTESTWIRE_MCP_URL overrides the endpoint.

Fourteen tools, in three access classes

Seven of the tools are metered: each call counts as one document toward the same monthly allowance as the HTTP API, 100 a month on the free plan. Before you ask for lookup_peppol_participant, make sure you have the buyer’s identifier and its scheme. The Peppol identifier guide shows which of the look-alike invoice fields is the delivery address and what each lookup status means.

Free tier, quotas and paid plans

The metered tools and the HTTP endpoints they wrap share one monthly allowance per key. It starts at 100 documents a month with no card, and the paid plans raise it:

Every metered tool result ends with a quota line — documents left, plan, and the date the counter resets (the 1st, 00:00 UTC) — so an agent can size the rest of the month on it. The call that crosses 80% of the allowance carries a one-time notice naming the next plan; nothing repeats it, and nothing is bought.

At the limit the tool returns quota_exceeded and names the two ways to upgrade: get_upgrade_link, which returns a checkout link for a human to open, and the upgrade form. Refused calls never consume a document and there is no overage billing. Full pricing and cancellation terms

Add an API key when you need one

Creating a key does not automatically add it to your assistant. Save it, add it to your client configuration, then reconnect.

1. Connect with no credential. explain_rule, check_vies_status, check_french_readiness, list_approved_platforms, issue_api_key and send_feedback answer immediately.
2. Create a key and save it outside the chat. issue_api_key takes an email address and returns a working key with 100 documents a month and no card. The form at attestwire.com/pricing#keyform creates the same key from the same endpoint. The key is shown once, so save it in a password manager, .env file or secret store. Do not leave it as a message in an agent conversation and do not paste it back into one.
3. Configure it in your MCP client, then reconnect. Over HTTP that is an Authorization: Bearer header; through the stdio bridge it is the ATTESTWIRE_API_KEY environment variable in the config block above. After you reconnect, the metered tools take no key argument. Restart or reconnect the client so it reads the new credential.

   claude mcp remove attestwire
   claude mcp add --transport http attestwire https://api.attestwire.com/mcp \
     --header "Authorization: Bearer aw_live_..."

4. Verify with one metered call. Ask for validate_invoice on an invoice. If you receive missing_api_key, check the configuration and reconnect.

A person must complete an upgrade. get_upgrade_link needs a key, costs no documents, and returns a checkout URL. It does not buy anything. This is the only tool with an optional key argument; prefer the configured header when possible. Compare plans

What these tools do not do

validate_invoice_xml reads a UBL or CII XML file, or a Factur-X / ZUGFeRD PDF (the French and German names for a PDF with the invoice XML attached inside it) sent base64-encoded. The attachment and the XMP metadata are checked too, as findings that never fail the result; PDF/A conformance itself, and whether the drawn page agrees with the XML, are not — the REST endpoint POST /v1/validate shares the same limit, whether the PDF arrives there as application/pdf or here as base64.

The check reads the invoice's contents; the receiving platform also checks the file's structure and can still reject it. check_french_readiness finds the company and explains its mandate; it cannot confirm the company has registered with an approved platform, which lives only in the CAPTCHA-protected DGFiP directory. Read the full limits

claude mcp add --transport http attestwire https://api.attestwire.com/mcp