AI connectors (MCP)

Haiku.lt can be connected to an AI assistant through the Model Context Protocol (MCP). Once connected, the assistant can look through your invoices, answer questions about them, and create new ones — working directly in your account instead of asking you to copy data back and forth.

Typical things it can do for you:

• “How much did I invoice last quarter, and how much of it is still unpaid?”
• “Who owes me money right now?”
• “Create an invoice for Company X: 12 hours of consulting at 60 EUR/h, due in 14 days.”
• “Mark invoice INV 42 as paid.”
• “Log a 484 EUR office rent expense from Landlord UAB, dated 5 March.”

The connector address

https://www.haiku.lt/mcp

You can also copy it from Settings → AI connectors (MCP) in the app.

Connecting Claude

1. Open Claude and go to Settings → Connectors.
2. Choose Add custom connector.
3. Paste https://www.haiku.lt/mcp as the server URL and confirm.
4. Claude opens a Haiku.lt page. Sign in with the account you want to connect, if you are not signed in already.
5. Review what the connector is allowed to do and press Allow access.

Claude stores the connection and from then on can use the Haiku.lt tools in any chat where you enable the connector.

Connecting Codex

Codex (and other MCP clients such as the MCP Inspector) connect to the same address as a streamable HTTP server with OAuth:

[mcp_servers.haiku]
url = "https://www.haiku.lt/mcp"

The first request opens the same sign-in and approval page in your browser.

What the assistant can and cannot do

Access is granted in two parts, both shown on the approval screen:

• Read — invoices, expenses, buyers, series and reports.
• Create and edit — new invoices and expenses, changes to existing ones, and marking invoices paid or unpaid.

Deliberately out of reach: an assistant can never delete an invoice or an expense, send email on your behalf, change your settings, or touch invoices that are locked for accounting. Locked invoices stay immutable; if something has to be corrected, issue a credit invoice.

Everything an assistant creates or changes is written to the same audit trail as your own actions, naming the connector that did it — see invoice audit log.

Attaching receipts to expenses

An expense can keep its original PDF or scan, the same file the app stores when you tick “upload to Haiku”. There are two ways it gets there:

• The assistant sends the file. When it genuinely has the file in front of it — an email attachment, for instance — it can pass it straight through. This suits small receipts; a large scan is impractical to send this way.
• The assistant gives you a link. For anything bigger, it hands you a one-time upload link. Open it, choose the file, done. The link works once and expires after 30 minutes.

Either way the file must be a PDF, JPEG, PNG or XML, and at most 2 MB — the same limit as the app. A file attached this way replaces whatever was attached before, and the change is recorded in the audit trail.

Prices and dates

The assistant works with the same conventions as the app: amounts include VAT and are counted in cents (1050 = 10.50 EUR), and dates are written as YYYY-MM-DD. You do not need to think about this — it is here so you know what the assistant is looking at.

Disconnecting

Go to Settings → AI connectors (MCP) and press the bin icon next to the connection. It stops working immediately: any token the assistant still holds becomes useless on its next request. Disconnecting in Claude’s own settings has the same effect.

Security notes

• The assistant never sees your password or your Google account; it only ever holds a token for this one account.
• Sessions where you are managing someone else’s account cannot be used to connect an assistant. The owner has to connect their own account.
• Access is granted per account and lasts until you revoke it.
• Only connect assistants you trust: anything you allow, the assistant can do without asking you again.