Decide who she is before you decide how she talks

Why the character sheet decides everything

Everyone arrives at a companion app expecting the conversation to be the product. It is not, quite. The conversation is downstream of a few lines you wrote before it started, and those lines are where the interesting work lives.

A persona is not a description of someone. It is a set of reasons she answers one way and not another.

Nobody sits down to design a companion because they want a chatbot. They want the particular pleasure of a character who could only be this character — someone with a way of answering that belongs to her and nobody else. That instinct is worth taking seriously, because it is also the thing most persona builders get wrong on the first try.

The first draft is usually a portrait: hair, height, a job, a hometown. None of that has anywhere to go in a conversation. What a model can act on is behaviour — how she opens, what she asks about, where she pushes back, what she refuses to be drawn into. Written that way, a persona stops being description and becomes instruction.

Specificity does more work than volume. A character who is warm reads as generic; a character who is warm but slow to say what she wants gives every exchange somewhere to travel. Contradiction is the cheapest depth available: one trait that cuts against another produces the small hesitations and reversals we recognise as personality rather than as output.

Week one flatters almost any persona, which is why the honest test comes later. If she has begun answering everything the same agreeable way, tightening a trait rarely helps; the draft has no tension left to find. Starting again with two sharper constraints costs ten minutes and usually buys another month. Persona work is editing, not authorship.

• Temperament first, appearance last
• Two interests she can steer a conversation with
• One thing she reliably refuses
• One contradiction you did not resolve