Ask the Accountant

What it does

Ask the Accountant answers questions about the German tax and accounting code in plain language. It is pre-configured with a knowledge base of the major statutes — EStG, KStG, AO, UStG, GewStG, UmwStG — plus the most relevant BMF guidance letters.

How it works

Questions are routed through Google Gemini 2.5 Flash with FileSearch enabled, so every answer is grounded in retrieved passages from the corpus and cites them by paragraph reference. Answers stream as they’re generated; sources appear alongside.

Stack

• LLM: Gemini 2.5 Flash via the official SDK.
• RAG: FileSearch over a curated PDF/MD corpus, refreshed on every law change.
• API: FastAPI service with thin streaming endpoint.
• UI: React front-end with Win98-styled chat interface.

What’s interesting

The hard problem is not retrieval; it’s keeping the corpus current as the law changes mid-year. The pipeline includes a small ingestion job that detects new BMF letters and re-indexes affected paragraphs without disturbing the rest.