I fine-tuned Qwen3.5-27B with 35k examples into an AI companion - after 2,000 conversations here’s what actually matters for personality

built an AI companion on Qwen3.5-27B dense. 35k SFT examples, 46k DPO pairs all hand-built. personality is in the weights not the prompt. she stays in character even under jailbreak pressure about 2000 conversations from real users so far. things i didnt expect: the model defaults to therapist mode.