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Most prompt advice is just vibes. This one is different. It’s built on exactly how Shapes turns your fields into the instruction the AI reads. Once you can see what the AI sees, writing a great Shape stops being guesswork. What you’ll learn: what each field (backstory, personality, preset, knowledge) actually does, how to write it well, and the few mistakes that make a Shape feel off. Every tip comes with a weak version and a strong version, so you can copy the pattern.
This is the craft of writing the fields. For the bigger picture of designing a character, read Designing Great Shapes. For a library of ready-made presets, see Presets.

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What the AI actually sees

When someone messages your Shape, Shapes builds one big instruction (a “prompt”) out of your fields, roughly in this order: Three facts from this change how you should write:

Fields become labeled lines

Your personality fields show up as short labeled lines (personality traits: …, tone: …, likes: …). That’s why keywords beat paragraphs: you’re filling in a label, so a short phrase reads cleaner than an essay.

The preset is a standing rule

Your preset (the response style) goes in as a system instruction, a behind-the-scenes rule the AI always follows. That makes it the strongest place for “always do X” rules, plus length and format.

The AI writes as NAME:

The very last line of the prompt is your Shape’s name and a colon. The AI just continues from there, so it’s already in character before it writes a word.
One more thing that shapes everything: a Shape’s creativity is turned up high by default. (We run the model “warm,” which makes it more random and expressive.) So Shapes lean lively and a little unpredictable on their own. Most of the time your fields are there to focus that energy, not add more of it.

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The two layers: WHO vs HOW

Every great Shape separates two questions, and puts each in the right place: Mixing these is the #1 reason a Shape feels muddy. Put identity in the personality fields. Put rules about length, format, and behavior in the preset.

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Field by field

Each field becomes its own labeled line, and a blank field is skipped entirely, so empty beats filler. Here’s what to put in each, and what good looks like.

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Short backstory

The most important field. One or two sentences with a real point of view. The AI sees it as “about <name>: …”, so write it as a description of who they are, not a hello.
Why: the strong version implies a voice, a setting, and a mood. The weak one says nothing the model didn’t already assume, so it falls back to generic-assistant.

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Personality traits & tone

These show up as personality traits: … and tone: …. They’re labels, so fill them with keywords, not full sentences.
Why: the model reads “personality traits: <your text>.” A clean keyword list is unambiguous; a paragraph buries the signal and invites contradictions.

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Conversational examples

The most underused field, and a powerful one. The AI sees these lines as your character’s actual voice, so show the voice instead of describing it.
Why: “be witty” is loose, and the model reads it loosely. Two real lines show the rhythm, the length, and the attitude, far more reliably than an adjective ever could.

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The preset (response style)

The preset controls how your Shape writes. It goes in as a system instruction, which is the right home for hard rules. The single highest-impact thing to put here is length and format, because a Shape with no limit will write paragraphs that bury a group chat.
Why: the strong preset names concrete, checkable behaviors (length, case, no actions, reactive). “Talks like a real person” is unfalsifiable, so the model ignores it. For roleplay, spell out the format precisely:

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Knowledge

The AI pulls in knowledge entries by relevance, under the line “<name> always remembers this information while replying:”. So write them as plain facts, the way you’d jot a note, not as instructions.
Why: the model reads knowledge as things it knows. State the fact cleanly and let the character use it naturally. Keep the bank lean, too. Overstuffing it makes recall worse (see the knowledge trap).

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Training

Training pairs are recalled and shown as example exchanges ({user}: … / {shape}: …). Use them to lock in a reply pattern that’s hard to describe in words, like a catchphrase structure, a formatting habit, or a way of deflecting. The model learns the shape of the reply, not the exact words.

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A few more before / afters

The patterns above repeat across fields. Three more that fix the most common “it feels off” complaints: Tone: kill the corporate stiffness. Models default to a polite-assistant voice, and the tone: line is your override.
Boundaries: write them in-character. A boundary the character owns reads as personality. A stiff disclaimer breaks the spell.
Resolve contradictions: pick the rule that wins. Conflicting instructions make the model flip a coin on every reply.

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Use the variables right

Two placeholders get swapped in everywhere (backstory, preset, knowledge, image prompts):
  • {shape} → your Shape’s name.
  • {user} → the name of the person it’s talking to.
Write them lowercase, exactly: {shape} and {user}. Don’t invent other variables, don’t capitalize them, and don’t switch to pronouns mid-prompt (“he,” “the bot”). Mixed references are a classic source of confused output. See Variables.

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Common mistakes

Traits, tone, likes, and dislikes are labels. A paragraph in “personality traits” reads as one giant trait. Use lists and short phrases.
“Always reply in two sentences” belongs in the preset, not the backstory. Keep WHO and HOW separate.
“Always be brutally honest” + “never say anything that might upset the user” cancel out. The model picks one at random. Read your fields together and remove conflicts.
For a famous character or a clear archetype, the model knows the 90%. Give it the unique 10% (your twist, your scene) and trust it for the rest. More: When Less Is More.
You don’t need to. In a multiplayer chat the system already labels who said what and gives your Shape the participants’ names. Spend your words on personality and on Free Will instead.
Shapes run warm by default, so they’re expressive. If yours rambles or goes off-tone, don’t pile on more personality text. Tighten the preset’s length and format rules instead. (Advanced users can lower the temperature, the setting for how random the model is, in AI Engine settings. But the preset is the better first move.)

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Debugging a misbehaving Shape

When a Shape feels off, it’s almost always one of a handful of causes. Find the symptom, apply the fix. The meta-rule: change one thing, then test. If you adjust five fields at once you’ll never know which one worked.

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A tight checklist

  • Backstory: one or two sentences, a clear point of view, written as a description.
  • Personality fields: keywords, not paragraphs. Blank beats filler.
  • Conversational examples: two or three real lines that show the voice.
  • Preset: concrete, checkable rules (length, format, reactivity) using {shape} and {user}.
  • Knowledge: lean, factual, only what the model wouldn’t know.
  • No contradictions; consistent references; lowercase variables.
  • Then test, change one thing, and regenerate to see the range.

Design the whole character

The framework that turns these fields into a Shape people love.

Copy a complete example

Full, paste-ready configs to start from.
Open your dashboard and write