iÚčetní inside your Claude or ChatGPT

The Model Context Protocol (MCP) connects your invoices, customers and expenses with the AI you already use. The connection is free in every iÚčetní plan.

Connect in Claude

1. In Claude (web, desktop or mobile) open Settings → Connectors and choose Add custom connector.
2. Enter iÚčetní as the name and https://mcp.iucetni.com/mcp/ as the URL.
3. Click Connect. The iÚčetní sign-in page opens. Sign in with your account email and password.
4. Approve access. That's it: in a new chat, try “Who hasn't paid me yet?”

Connect in ChatGPT

In ChatGPT settings, add a custom MCP connector (app) with the URL https://mcp.iucetni.com/mcp/. Sign-in and approval work the same way as in Claude. Availability of custom connectors depends on your ChatGPT plan.

Other clients and AI agents

The server supports the Streamable HTTP transport. OAuth-capable clients (Claude Code, Cursor and others) sign in on their own:

For your own agents and automations without a sign-in window, issue an AI key in the app (Settings → AI keys → Issue key). You can limit it to selected companies and set an expiry. The key is shown only once and is sent as a header:

An agent can, for example, read orders in its own mailbox on namailu.cz, prepare a matching invoice in iÚčetní and send it to the customer.

Authorization for developers

The MCP server implements OAuth 2.1 as defined by the MCP authorization specification:

• Authorization Code with PKCE (S256), refresh tokens and token revocation.
• Dynamic Client Registration (RFC 7591) at https://mcp.iucetni.com/oauth/register.
• Authorization server metadata (RFC 8414): /.well-known/oauth-authorization-server.
• Protected resource metadata (RFC 9728): /.well-known/oauth-protected-resource, referenced from the WWW-Authenticate header of 401 responses.
• Scope: mcp.
• Issuer and authorization server: https://mcp.iucetni.com. The sign-in and consent pages are available in Czech and English, chosen by ui_locales or the browser language.

The previous address https://api.iucetni.com/mcp keeps working, so existing connectors don't need to change.

When a user authorizes a client, they sign in with their iÚčetní account and approve access on a consent screen. Each authorization appears in the app under Settings → AI keys with an OAuth label and can be revoked there at any time.

What the AI can do over MCP

Main tools exposed by the server:

• list_invoices, get_invoice – documents and their status
• get_invoice_pdf – PDF of an issued document (optionally with ISDOC) for emailing
• create_draft, update_invoice – draft invoices
• issue_invoice – issue a draft with the next number
• mark_invoice_paid – record a payment
• list_customers, create_customer – customers
• lookup_ares – company details from the Czech ARES registry
• list_catalog, create_catalog_item – price list
• list_expenses, create_expense, update_expense – expenses
• read_receipt – read a receipt or invoice
• list_companies, list_bank_accounts – companies and accounts

Security and control

• Drafts instead of finished documents. Anything the AI creates is labelled “Draft · AI” and expenses carry an AI badge, so you can spot them at once.
• Open documents are protected. The AI never writes to a document you have open in the app.
• Revoke with one tap. Settings → AI keys lists every access (Claude and ChatGPT connections are labelled OAuth) and when it was last used.
• Data stays in the EU. We store it on servers in the European Union. Only what the AI requests in a conversation is passed to your AI provider. See our Privacy Policy.

Policies and contact

Operator: NEMOSERVIS Praha s.r.o., Czech Republic. Privacy Policy · Terms of Use · Support · support@iucetni.com