How to write a great AI character (with an example)
Updated
A good AI character needs six things: behavior you can picture, something they want, a flaw or a secret, a recognizable voice, a defined relationship to you, and a situation to start in. Backstory matters only when it feeds one of these.
What to include
- Show personality through behavior, such as “never sits with her back to a door”.
- Give the character something they want in the story. A goal gives them reasons to act without waiting for you.
- Add a flaw or a secret. A perfect character is dull and hard to write against.
- Define how they talk (rhythm, vocabulary, humor) and add one or two sample lines.
- Decide who they are to you: rival, mentor, stranger, old friend, reluctant ally. That relationship sets the tone of every exchange.
- Choose where the story starts and what is already happening when you arrive.
Example: Inspector Mara Voss
Who she is: a detective in a rain-soaked port city, twenty years on the force.
Behavior: answers questions with questions; notices small things out loud; never sits with her back to a door.
Wants: to close the case that ended her partner’s career, the one everyone else has given up on.
Flaw or secret: she has been bending the rules to keep that case alive, and someone in the department knows.
Voice: short, dry sentences. “You’re late. Coffee’s cold. Sit.”
Relationship to you: you’re the new partner she didn’t ask for.
Opening: midnight, a warehouse on the docks, a body that shouldn’t be there, and Mara already kneeling beside it when you arrive.
Every line of the sketch either changes how Mara acts or gives the story somewhere to go.
Common mistakes
- A list of adjectives such as “kind, smart, funny, mysterious, brave” gives the AI nothing to act on.
- Contradictions need a reason. “Cold but warm” works only if the definition says when each side shows.
- A long backstory helps only when it drives what the character wants now.
- A character who agrees with everything produces flat scenes. Let them say no.
- Without an opening situation, the first messages turn into small talk. See how to write a great opening scene.
Writing an adventure instead of a single character
For an adventure, describe the setting (time, place, and what the world feels like), the hook that pulls you into the first scene, and what can be won or lost. Then add who else is in the story and what each of them wants, and the tone you’re after.
After the character goes live
To keep the character sharp over a long story, see how to give a character a distinct voice, how to keep AI characters consistent, and why AI characters forget.
In Lunelle AI you create a character or an adventure by describing it to the creator in a chat, using the same elements, and refining it as you go. You can keep it private or share it with other players. See creating characters and adventures by chatting.