A profession profile is a system prompt that tells the model who it is, in detail — “you are an experienced bioinformatician”, then four thousand tokens of workflow, standards, tools and troubleshooting. Scored against four controls on nine science benchmarks, the full profile landed 0.6 percentage points below “You are a helpful assistant”, with no benchmark clearly improved, at 2.2 to 4.5 times the cost per answer. On the one task set with tools and a budget it was 10 points worse.