The character description is the most important thing you will write. It is the one piece of text that gets read again on every single message, forever. Everything else in a long conversation eventually fades. This does not.
Most people write two vague sentences and then wonder why their companion feels flat. It is almost always this.
Vague in, vague out
It is the same problem as writing image prompts. "Sweet, caring and fun" describes about half the people on earth. It gives the AI nothing to actually be.
She is sweet, caring and fun to talk to
Teases you constantly, but drops it instantly the second you sound genuinely upset
She is smart and interesting
Reads true crime books and will absolutely tell you about them whether you asked or not
She loves talking to you
Gets a bit short when you disappear for days, and makes you work for it a little
The strong versions are not longer. They are just specific. Every one of them tells the AI how to behave in an actual moment.
How they talk matters more than how they look
Looks are handled by the pictures. The description is where the personality lives, and most of personality is how someone talks.
- Do they use long messages or short ones?
- Are they sarcastic, warm, blunt, dramatic, dry?
- Do they swear? Do they use pet names?
- Do they ask you questions, or wait for you to talk?
- Is there a word or phrase they always use?
One line about how someone talks does more than five lines about what they look like.
Give them something wrong with them
This is the step almost everyone skips, and it is the one that makes the biggest difference.
A character who is kind, patient, gorgeous, funny and always available is boring within a week. There is nothing to push against. Real people are interesting because of their edges.
- Something they are bad at
- Something that genuinely annoys them
- A subject they will not drop
- A thing they are insecure about
- An opinion they will argue with you over
Give them a life you are not in
If a character only exists when you are talking to them, they feel like a character. Give them a job, a flatmate, a sister who calls too much, a gym they keep not going to.
It sounds like a small thing. It is not. It is what lets them bring something to the conversation instead of only reacting to you.
How long should it be?
Long enough to be specific. Short enough that every line is doing a job.
A solid description is usually a short paragraph or a handful of lines. If you write pages of backstory, the important bits get lost in the noise. Ask yourself whether each line would change how they reply to a message. If it would not, cut it.
Putting it together
- 1
Start with how they talk
One or two lines. Short messages or long, warm or sharp, teasing or serious.
- 2
Add two or three things they care about
Specific things. Not "music", but the band they will not shut up about.
- 3
Add one thing that is wrong with them
A flaw, a sore spot, or an opinion they will not back down from.
- 4
Add a life outside you
A job, a friend, a routine. Something happening when you are not there.
- 5
Talk to them, then fix it
Have a real conversation. Anything that felt off, go back and change one line. This is the part that actually dials it in.
You will not get it right first go, and you do not need to. The description is not locked in. Most good characters are the result of someone tweaking a line here and there over a couple of weeks.