automationsmanufaktur-labs/open-invoice-germany — reverse-engineered prompt

Build me a free, self hosted invoice app for Germany that a freelancer or small business can actually use day to day. I want to keep all data local, sign in with an admin account, set up my company, manage customers and products or services, create quotes and invoices, then finalise them so the number is assigned and the document becomes immutable for GoBD. Please enforce the required invoice fields under § 14 UStG and support common tax cases like normal VAT, § 19 small business, reverse charge, and intra EU cases.

It should export normal PDFs plus proper e invoices in XRechnung and ZUGFeRD, and block finalising if the invoice would not be compliant. I also want payments, partial payments, reminders and dunning with interest, recurring invoices, credit notes, and the ability to turn quotes or similar documents into invoices.

If possible, add optional natural language control through Claude Code or Claude Desktop via MCP, but keep that separate from the local core. Docker support would be great too. Look up current docs online if you need to.