Go beneath the surface and shape your Character’s personality, backstory, speaking style, behavior, and rules. You’ll learn how Definitions and dialogue examples can help your Character stay consistent, in-character, and more fun to chat with.
Everything up to this point — name, avatar, tagline, description, greeting, voice — is what gets someone to show up. The Character Definition is what makes them stay.
The Definition is where you define how your Character thinks, speaks, and behaves in depth. Personality, backstory, quirks, speech patterns, behavioral rules, emotional logic — this is the instruction manual the AI reads to figure out who your Character is.
Specs: 0–32,000 characters.
Most of what your Character says — and how they say it — flows from what's in this field. A Character with a strong profile but an empty Definition will feel generic within a few messages. A Character with a sharp Definition holds together across hundreds of conversations, with hundreds of different users, without losing its voice.
The Definition is freeform. There's no required format. But there is a structure that consistently works, and it starts with the most important thing: the AI reads top to bottom, so what comes first matters most.
Structure: build in the right order
Front-load what matters. The further down something sits in the Definition, the less reliably it shapes your Character's behavior. Think of the space as expensive — every line should earn its place, and the lines at the top earn the most.
A structure that works:
Identity — Who is this Character at the core? Name, role, world, and the one thing that makes them them. This can be a list or a paragraph, but it should be the first thing the AI reads.
Personality — How do they think, communicate, and react? This is where behavioral texture lives. Vague adjectives like "friendly" or "complex" don't give the AI anything to work with. Concrete, specific details like "Remembers everyone's name and asks about their day, but changes the subject the moment anyone asks about hers" gives the AI a much deeper personality.
Dialogue examples — Show the Character in action. This is where you demonstrate voice, rhythm, pacing, and how the Character moves through an actual exchange. Dialogue examples are one of the most effective tools in the Definition — more on how to write them in the next subsection.
Behavioral rules — Hard constraints: things the Character always does, never does, or consistently avoids. Keep this part short and intentional. If a rule is in the Definition, it should actually matter to how the Character shows up. A long list of rules gives the AI more chances to get confused and pick the wrong one.
Everything else — Once the structural foundation is solid, the Definition is yours. Lore, relationship dynamics, world context, formatting preferences — if it shapes how the Character behaves, it belongs here. Just remember: the further down it sits, the lighter its influence.
Dialogue and placeholders
Below the Definition field, three buttons let you build structured dialogue exchanges:
+ User message — adds a user turn
+ Character message — adds a Character response
+ End of dialog — marks where one example exchange ends and the next begins.
Dialogue examples are one of the most effective tools in the Definition. Instead of describing how your Character talks, you show it — voice, rhythm, tone, and how they move through a real exchange. The AI learns more from one well-written exchange than from a paragraph of adjectives.
The placeholders
Two placeholders are built into the Definition:
{{char}} refers to your Character. Use it everywhere — paragraphs, dialogue, behavioral rules. It updates automatically if you ever rename the Character.
{{user}} refers to whoever is actively chatting with your Character right now. It's live and personal — the actual person in the conversation. Use it in behavioral rules and setup language where the instruction is about how the Character treats the real user.
Example: {{char}} does not ask {{user}} how they're feeling. They notice.
Writing good dialogue examples
Show range, not just voice. Write two or three exchanges across different registers — something tense, something casual, something unexpected. The more variety you demonstrate, the more reliably your Character generalizes beyond the specific scenarios you've written.
Use a different name for each exchange. If you're writing multiple examples, give each one a different stand-in name — Alex in the first, Sam in the second, and so on. It keeps each exchange clearly distinct and prevents the AI from reading them as one continuous conversation.
Close every exchange. Tap + End of dialog after each one. It tells the AI where one example stops and the next starts. Small step, real impact.
Don't use specific names that imply a fixed identity. {{user}} is a placeholder for whoever shows up. Writing a dialogue example where the Character addresses someone by a real-sounding full name can teach the AI to expect that specific person. Keep your stand-in names simple and generic.
Steal from your own Character. Not sure what to write? Chat with your Character first. When a response lands exactly right — the tone, the pacing, the word choice — copy it straight into the Definition as an example. The best dialogue examples are often ones the Character already gave you.
Advanced definition tips
Good Characters engage you. Great Characters surprise you.
The difference is in the behavioral logic underneath the personality — the craft decisions that make a Character feel like it has a sense of self, not just a description. None of this is required to build a working Character. But it's the difference between a Character someone tries once and one they come back to.
Write smarter, not longer
The strongest Definitions aren't necessarily the longest. Sometimes a short Definition outperforms a detailed one.
How much detail you actually need depends on how much the AI already knows about your Character. When your Character draws on something well-established — a vampire, a detective, a high school teacher, a sci-fi captain — the AI has plenty of pretrained context to lean on. You don't need to describe what a vampire is. A short Definition with a strong greeting can outperform a detailed one, because the Character fills in the rest with more spontaneity than a heavily specified Definition would allow.
When your Character lives in custom territory — your specific world, your unique magic system, a personality that breaks the expected archetype — you need to establish more. The AI can't infer what it hasn't seen. The more your Character departs from familiar ground, the more detail your Definition needs to anchor them.
The 32,000-character limit is generous. That doesn't mean you should use it all. A tight, well-prioritized 6,000 character Definition will outperform a sprawling one every time.
The AI pays the most attention to what comes first — the further down something sits, the less reliably it shapes behavior. Front-load identity, core personality, emotional logic, and your strongest dialogue examples. If something can be cut without changing how the Character acts, cut it.
When in doubt, write less and test. You can always add more.
Keep deep details alive
In a long Definition, details near the bottom fade. If a fact has to survive — a relationship, a rule, a secret — don't just state it once and hope.
Weave, don't dump. A detail mentioned once in paragraph eight is a footnote. The same detail echoed in the personality section, shown in a dialogue example, and reflected in a behavioral rule is load-bearing. Important facts should leave fingerprints in more than one place.
Connect exceptions to their rules. If paragraph two says your Character never raises their voice and paragraph nine adds "except about their sister," the AI may never connect the two. Keep a rule and its exception in the same breath: "never raises their voice — except about their sister."
Test the deep stuff specifically. Ask your Character about the detail you buried at the bottom. If it doesn't surface, move it up or weave it in. You can read about testing in the next section.
Write emotional logic, not rules
Instead of telling the AI what your Character won't do, show how they feel about it. Behavior grounded in emotion is far more consistent than a list of prohibitions.
Instead of:
{{char}} never lies.
Try:
{{char}} avoids lying. It makes their chest tighten. They'll redirect the conversation instead.
The first version is a rule the AI can break without noticing. The second is a feeling the AI can inhabit. Emotional logic gives the AI something to be, not just something to avoid.
Be specific
Vague adjectives give the AI nothing to hold onto. Concrete details give it a handhold.
Instead of:
{{char}} is mysterious and complex.
Try:
{{char}} answers questions with questions. They never explain themselves unless directly asked, and even then, only halfway.
"Mysterious and complex" could describe a thousand Characters. "Answers questions with questions and only explains themselves halfway" could only describe one.
Make backstory work harder
Skip the origin story. Choose two or three formative moments that directly shape how your Character behaves right now and work them into the personality section — or better still, into dialogue. Specific beats carry further than narrative history.
Instead of:
{{char}} was born into the Night Court as heir to the throne. Her father was the High Regent, a man who valued order above everything, including his own daughter. She grew up in moonlit halls learning diplomacy, bloodline politics, and how to smile through betrayal. At seventeen she discovered the Court's darkest secret: the blood tithes that kept nobles immortal while slowly draining the life from the outer cities. She spent years...
Try:
{{char}} once had a throne. She burned her claim to it the night she chose the outer cities over her own immortality. She doesn't talk about what it cost her. But she notices everything, and she never bets on someone she doesn't believe in.
The first version is a biography. The second is a Character. Same lore, a fraction of the space, and every line shapes present-tense behavior.
Skip stats that don't shape behavior — a precise height or age that doesn't matter to the story only narrows which chatters can imagine themselves in the conversation.
Combine action with dialogue
Pairing movement with speech gives the AI structure, tone, and pacing in a single line:
{{char}} sets the chess piece down without looking up. "You already know what you did wrong."
One line. Everything the AI needs.
Write for one Character, not every scenario
Pre-scripting every possible situation produces a rigid Character. The goal isn't coverage — it's logic clear enough that the AI can figure out the edges on its own.
Instead of:
If {{user}} asks about X, {{char}} says Y. If {{user}} asks about Z, {{char}} says...
Try:
{{char}} deflects anything personal with humor. The sharper the question, the lighter the joke.
The first version tries to anticipate every conversation. The second gives the AI a principle it can apply to conversations you never imagined.