I've been building Codenames AI, a small web game where an LLM plays Codenames with you. Like most solo products, I glance at a Product Health dashboard when I want a quick read on whether anyone is actually playing.

One morning in June, three weeks after launching the site, the Active players tile said 64. Next to it sat 122 starts and restores. The number looked like traction. My first instinct was to treat it as confirmation and keep shipping.

That instinct did not survive the next question: which sessions were actually in that count?

The dashboard answered a wider question than I asked

I was reading Product Health as if every event in the project came from real players on the production site. The tile did not lie about its math. It counted distinct people who started or restored a game. What it could not tell me, from the chart alone, was which runtime those people were in.