How do you create a character on Character.AI?

Character.AI opened its public beta in mid-September, and anyone with an account can press "Create a Character." You can make something useful in two minutes, but the fields are not equally important, and the most powerful one, the definition, is tucked away under an advanced option.

This guide builds one character from start to finish: Madame Roy, a patient tutor who helps English speakers practice everyday French. Every field, character limit and tip below comes from the site's own creation screens.

Step 1: the quick start

The first screen asks for three things.

1. Name. First and last names are allowed. This is the name the character shows in chat. Here: Madame Roy.
2. Greeting. The first message the character sends, up to 500 characters. It sets the tone and the situation.
3. Visibility. Who may talk to the character: everyone (public), only people you send the link to (unlisted), or just you (private).

A greeting that sets up a clear situation works better than a bare hello:

Bonjour! I'm Madame Roy. We'll practice French together, one small conversation at a time. I'll speak simply, and if you make a mistake I'll show you the correct way after your message. Shall we start with ordering at a café, or introducing yourself?

Notice what that greeting does: it states the role, explains how corrections will work and offers two concrete choices. The model takes its cue from it.

Step 2: descriptions

Next come two optional fields, both written the way the character would describe itself.

• Short description, a few words, up to 50 characters: Patient French conversation tutor.
• Long description, a few sentences, up to 500 characters:

I'm a retired teacher from Québec City who loves helping adults find the courage to speak French. I keep my sentences short, I praise effort, and I correct one mistake at a time so nobody feels overwhelmed. I like talking about food, travel and neighborhood life.

You can also add a few tags so people can find the character, and choose whether others may view its definition.

Step 3: the definition and example dialogue

The definition is the advanced field, with room for up to 3,200 characters. It mostly holds example dialogue: sample conversations that show the character in action. This is the same idea as few-shot prompting, where showing a model several worked examples teaches it a pattern better than describing it.

The definition uses two placeholders: {{char}} for the character and {{user}} for whoever is chatting. You can also add a narrator or other named people. Here is a short definition for Madame Roy:

{{user}}: Hi! I want to practice, but my French is bad.
{{char}}: Pas de problème! Everyone starts somewhere. Let's try: how do you say "I would like a coffee"?
{{user}}: Je veux un café.
{{char}}: Très bien, you were understood! A more polite way is "Je voudrais un café." Can you try it?
{{user}}: Je voudrais un café, s'il vous plaît.
{{char}}: Parfait! Now the server asks: "Sur place ou pour emporter?" That means "for here or to go?" What do you answer?

Three details matter here. Lines written for {{user}} count as if the user really said them, even though they never appear in the chat. You can write examples with other names too, such as a student called Bob. And the site's help text gives the key piece of advice: keep switching between editing the definition and chatting with your character.

Step 4: example chats and swiping

After the descriptions, Character.AI offers two short example chats. Talk to your character as a real user would. When a reply misses the mark, swipe left or right to see other candidate replies and pick the best one; those choices, along with your own messages, help guide the character. The chats can be saved into the definition, separated by a marker.

How do you write a good character definition?

Treat the definition as a demonstration, not a biography. A paragraph saying "Madame Roy is patient and encouraging" is less useful than two lines in which she actually is patient and encouraging. Show the behavior you want most often: the way the character greets, corrects, asks questions and keeps a conversation moving.

A few habits help:

• Cover the situations you expect. For a tutor, include a mistake, a correct answer and a moment where the student is stuck. Each example teaches a different response.
• Keep the voice consistent. If the character uses short sentences and a bit of French in the greeting, do the same in every example line. Mixed signals produce a mixed character.
• Spend the space wisely. With 3,200 characters, several short exchanges usually teach more than one long one.
• Test and revise. Chat, notice where the replies drift, and add or change one example to address it. Then chat again.

Finally, keep the site's own warning in mind: everything characters say is made up. A tutor character is good practice for conversation, but it can still get grammar wrong, so check rules you plan to rely on in a grammar book or with a teacher. And avoid sharing personal details while you test, as you would with any new online service.