MCP Server: Automate Invoices, Estimates and Reports with AI
AI assistants like Claude can access GrandTotal directly via the Model Context Protocol (MCP) – analyze revenue, review outstanding invoices, generate complex estimates from customer inquiries or create invoices. Personal customer data can be pseudonymized. See how photographer Simon Iannelli uses this in practice.
What is MCP?
The Model Context Protocol is an open standard that lets AI assistants access local data sources. Instead of manually copying data into a chat, GrandTotal provides the AI with structured tools: revenue queries, document search, client lists.
The MCP server can also be used without AI – for example, for custom scripts that query data from GrandTotal or create documents automatically.
Access Control
Activate the MCP server under Settings › MCP Server. The connection is secured via a token that GrandTotal generates automatically. You can regenerate the token at any time – existing connections will be invalidated. There you also decide for each open document individually:
- No access: The AI cannot see the document
- Read only: Queries and reports, no changes
- Full access: Create clients and invoices as well
Privacy
With the Redact info option, GrandTotal shortens names, addresses, email addresses, phone numbers and bank details before data leaves the Mac: of each word, only the first and the last letter remain. “Erika Musterfrau” becomes “E*a M*u”. This way you can tell who is meant in your AI program’s answers, while the provider never learns the name. Subject, notes and item texts stay readable; names in them are shortened as well. Amounts, dates and document numbers stay readable. “Privacy with AI: Client Names Stay on Your Mac” shows how this works in detail.
The AI cannot filter by names, addresses or other personal data. Names that are not in your client data are recognized by the macOS language analysis, and it sometimes misses one. The question mark next to the option shows how a client reaches the AI. Invoice PDFs remain blocked because they contain all client data in plain text. What you type into the AI program yourself goes straight to its provider; in Ask GrandTotal, GrandTotal also hides the names in your question.
The AI can also only edit records it created itself during the current session. Existing data remains protected from changes.
If you use a local model, you can disable pseudonymization.
▸ Which client data does the AI see in detail?
| Field | Sent to the AI |
|---|---|
| Company, name, salutation, title, department | first and last letter per word |
| Street, ZIP, city, state | first and last letter per word |
| Contacts (all text fields) | first and last letter per word |
| Email address, phone number | shortened as a whole |
| IBAN, BIC | shortened as a whole |
| VAT ID, tax number | shortened as a whole |
| Subject, notes, item texts | readable, names and contact data in them shortened |
| Client number, document number | unchanged |
| Country, country code | unchanged |
| Internal record ID, creation date | unchanged |
| Numeric, date and yes/no values (payment terms, discount, currency) | unchanged |
The name cannot be calculated back from the shortened form. The readable fields are a fixed allowlist: any field not listed there is hidden.
Creating Invoices
If the AI doesn't know the client's name – how does it create an invoice? You refer to the client by name. GrandTotal looks the client up on the Mac and gives the AI only its internal number and the shortened name.
The AI creates the invoice and links it to the right client without ever having seen their name or address.
Typical Use Cases
- Revenue analysis: "How did revenue develop compared to last year?"
- Outstanding invoices: "Which invoices are overdue by more than 30 days?"
- Data migration: Import clients and items from FileMaker, 4D or SQLite
- Product catalogs: Import supplier catalogs and create them as items in GrandTotal
- Reports: Custom evaluations beyond the built-in reports
- Integrations: Build custom tool connections – see AI Plugins and MCP Server or AI-Written Plugin?
Importing from Other Systems
Switching from another application to GrandTotal? The MCP server turns the AI into a migration assistant.
Supported Data Sources
The MCP server can read FileMaker and 4th Dimension databases directly – two formats still common in many established office environments. SQLite databases are natively supported by macOS and are also available as a source.
How It Works
You point the AI to your old database – the MCP server reads the structure of the source data, the AI maps the fields and creates clients, items or catalog entries directly in GrandTotal. No manual retyping or error-prone CSV workarounds.
Privacy
Pseudonymization
Names, addresses and contact data shortened (E*a M*u)
Query Validation
No filtering by personal data
PDF Block
No PDF access with pseudonymization
Token Authentication
Access only with valid token
Per-Document Rights
No access, read only or full access
Data Import
FileMaker, 4th Dimension, SQLite
Session Isolation
AI can only modify its own records
The MCP server runs inside GrandTotal on your Mac: the AI works with pseudonyms, the data stays local.