Once we move from topics to questions, whether in organic search or LLMs, we naturally move deeper into what SEOs would typically call the long-tail. Our fan-out prompt-generation logic aims at a maximum of 12 words, and the dataset averages 8.2 words per prompt (with a range of 3-13, so it behaved reasonably well).
What does an average (roughly 8 words) prompt look like? Here are a few:
- “How to conduct an effective tenant exit interview”
- “Where to find affordable beginner golf club sets”
- “Why do customers leave brands they once liked?”
How long should a fan-out prompt be? We’re collecting search-grounding data from Gemini as we speak, but our goal is to keep the prompts long enough to be specific but broad enough that targeting them could cover many variations. Humans might write paragraphs in Gemini or ChatGPT, but marketers can’t track them all.
It’s interesting to note that Gemini itself, given a maximum of 12 words, settled on an 8.2-word average. So, that tells us something about the prompt length we need to generate interesting fan-outs from topics and subtopics.
![How topical authority spreads (and where it doesn’t) in ChatGPT [Study]](https://mgrowtech.com/wp-content/uploads/2026/08/how-topical-authority-spreads-and-where-it-doesnt-in-chatgpt-study-350x250.png)
