The mechanism
What the GPT-5.2 humanizer runs
One request, one completion, returned as the rewritten text alone. The fixed instruction directs the model to accomplish the transformation implied by the tool name while preserving the original meaning and factual claims, and to return only the rewrite with no preamble, commentary, quotation marks or markdown fence.
Two parameters govern the experience. The rewriting branch runs at a markedly higher temperature than the analysis branch on this site, which is why the same passage returns differently worded rewrites across runs. And the completion carries a token ceiling set independently of the input limit.
Nothing else shapes a run except your passage and up to 300 characters of instruction. There is no style model, no learned voice, no stored profile, no mode.