create-invoice

Help the user create and send an invoice step by step:

1. Identify the client: If a client name is provided in $ARGUMENTS, call list_clients and find the matching client. If ambiguous, ask the user to clarify. If no client exists, offer to create one with create_client.

2. Gather invoice details: Collect the following information (ask for anything not provided):

   • Line items: description, quantity, unit price, VAT rate (default 19% for Germany)
   • Invoice date (default: today)
   • Due date / payment terms (default: 14 days)
   • Any notes or special terms

3. Create the invoice: Call create_invoice with all gathered details. Use the correct client_id from step 1.

4. Review: Show the user a summary of the created invoice including the total amount.

5. Send: Ask the user if they want to send the invoice now. If yes, call send_invoice to email it to the client.

Important:

• Use the company's default currency unless the user names another.
• Default VAT rate in Germany is 19% (7% for reduced rate items like food, books)
• Invoice numbers are auto-generated by Norman
• For recurring work, suggest create_recurring_invoice instead

Invoice appearance and edits:

• Read get_invoice_settings for the company logo and saved defaults. Pass the saved language/currency when the user does not choose others.
• If the user wants a different design, call list_invoice_templates. Show the available choices and plan access. Do not invent template IDs or bypass paid access.
• Both invoice creation tools accept document_design: template, version, logo size (25–100), text size, spacing and table borders. Use font and color_schema for the font and colour. Omit these three options to preserve company branding. A partial design takes the chosen template's defaults.
• Use update_invoice for invoice/quote edits and update_recurring_invoice for schedule edits. Send only changed fields in changes. Keep existing line IDs when editing items. A partial document design keeps the document's other saved controls; changing its template starts from that template's defaults. Explicit false, zero, blank strings and valid nulls are different from omitted fields.
• Use update_invoice_settings only when the user wants to change future document defaults. Existing documents keep their saved design. Show-customer-number, show-contact-person, QR codes and online payment defaults are included.
• Item rates use minor currency units (cents for EUR), including when copying a catalog product. The API calculates totals. Items also support description, unit, product/category IDs and line discounts.
• For services, provide the requested service start/end dates. For goods, provide the delivery date. Recurring schedules use starts_from_date, payment_due_days and billing_in_advance; their legacy issue/service/due-date arguments do not control generated dates.
• Creation and edits accept payment links, QR codes, bank details, discounts, VAT notes, recipient/sender snapshots, and email/reminder settings. Use an empty VAT note only when the user requests no note; omission lets the API choose it.
• Set is_to_send / isToSend only when sending is requested or already authorized. Otherwise save the document without sending it.

Corrections and delivery notes (documents made from an existing document):

• To reverse an issued invoice in full, call cancel_invoice with the invoice id. Norman writes the Stornorechnung with the same lines, the next invoice number and a reference to the invoice, and marks the invoice cancelled. Confirm with the user first: a cancellation is a numbered document the client receives, not an edit. A draft is edited with update_invoice, never cancelled.
• To correct part of an invoice (a wrong quantity, a price reduction, returned goods), call create_credit_note with the invoice id and the lines to credit. Without lines the whole invoice is credited. Norman prints "Rechnungskorrektur", never "Gutschrift", because since 2013 that word means self-billing under § 14 UStG. Use status: "draft" when the user wants to review it first.
• To make a Lieferschein, call create_delivery_note with the invoice id, or the id of a quote the client approved. It prints quantities and units only, no prices, and lands in the company's Files space under "Delivery notes". Pass lines for a partial delivery.
• convert_offer_to_invoice makes a draft invoice from a quote. The quote stays, with the status "invoiced", and the invoice links to it. Issue the invoice with update_invoice (status "saved") before sending it.
• To bill the same thing again, call duplicate_invoice with the invoice or quote id: it makes a draft dated today with the same lines and payment term. Move the service or delivery dates with update_invoice, then set status "saved" to issue it. A draft is never emailed or matched to a payment.
• Both the PDF and the e-invoice XML name the source document, so never repeat the reference in message.