Do Large Language Models Name German Law Firms? Mention Rates, Stability, and Accuracy — Preregistration

Preregistration of an observational measurement study: whether and which German law firms are named by four commercial LLM APIs (OpenAI, Anthropic, Google, Perplexity) in response to realistic legal-service queries across 12 market cells (4 practice areas × 3 cities), with 10 repetitions per prompt, in German and English. The full design, coding scheme, and analysis plan are in the registration text.