nub

Tiers come from the bot’s own prompt list, which is ordered easiest to hardest, so the line number is the difficulty: Common lines 1–1,000, Familiar lines 1,001–2,500, Uncommon lines 2,501–4,500, Rare lines 4,501–7,000, Brutal lines 7,001+. Not rated covers prompts outside that list — custom games use four-letter fragments, which the index does not cover. They are kept rather than dropped, because they are also the hardest prompts in the data and removing them would flatter the rates above. Median time is a median, not a mean: response times are right-skewed against a hard timeout, so an average sits well above a typical turn.