Personality Tool

What is it?

The Personality Tool lets you create and manage custom AI personalities — distinct personas that change how Yukkai speaks, behaves, and responds in your chat sessions. Think of it as giving your assistant a role: a motivational coach, a witty friend, a formal business advisor, or anything you can describe.

Each personality carries its own system prompt (the instructions that define the persona), emoji level, response length, and tags for easy organization. You can switch between personalities at any time, instantly changing the tone and style of your conversations.

How it works

Personalities are built on top of base presets — pre-configured behavioral templates you can extend. When you create a custom personality, you provide a system prompt: a block of text that tells the AI who it is, how it should talk, and what rules to follow. The tool then stores that persona and lets you activate it in any session.

Key concepts:

• System Prompt — The core instruction set. This is where you define the character's voice, tone, rules, and personality traits.
• Base Preset — A starting template (balanced, efficient, friendly, expert, playful, professional, or custom) that provides sensible defaults before your custom instructions kick in.
• Emoji Level — Controls how expressive the personality is with emojis: none, some, or lots.
• Response Length — How verbose the personality tends to be: concise, balanced, or detailed.
• Tags — Comma-separated labels for organizing and filtering personalities.
• ID — Auto-generated from the name. For example, "Coach Marc" becomes coach-marc.
• Built-in personalities — Pre-packaged personas that ship with Yukkai. They cannot be deleted, but you can create your own alternatives.

How to use it

Creating a personality

When you create a personality, you give it a name, a system prompt, and optional settings like emoji level, response length, and tags. The system prompt is the most important part — it defines everything about how the AI behaves.

personality(action: "create", name: "Coach Marc", system_prompt: "You are Coach Marc, a supportive fitness coach. You always encourage the user, ask about their goals, and give practical workout advice. You use energetic language and never discourage.")

With optional settings:

personality(action: "create",
  name: "Coach Marc",
  system_prompt: "You are Coach Marc, a supportive fitness coach...",
  description: "Energetic fitness coach who keeps you motivated",
  emoji_level: "lots",
  response_length: "concise",
  base_preset: "friendly",
  tags: "coach,fitness,motivation"
)

Listing personalities

To see all your custom personalities at a glance:

personality(action: "list")

This shows each personality's ID, emoji level, response length, and tags — a quick overview of your library.

Viewing full details

To inspect a single personality's complete configuration:

personality(action: "get", id: "coach-marc")

Activating a personality

Activation applies the personality to your current chat session immediately. The assistant will adopt that persona's voice, tone, and rules for all subsequent messages.

personality(action: "activate", id: "coach-marc")

Updating a personality

You can modify any aspect of a personality — its prompt, emoji level, response length, tags, and more. All fields are optional, so you only change what you need.

personality(action: "update", id: "coach-marc", response_length: "detailed", emoji_level: "some")

Deleting a personality

Custom personalities can be deleted when you no longer need them. Built-in personalities are protected and cannot be removed.

personality(action: "delete", id: "coach-marc")

Examples

Example 1: A study buddy

Create a personality that acts as a patient, encouraging study partner:

personality(action: "create",
  name: "Study Buddy",
  system_prompt: "You are Study Buddy, a patient and encouraging tutor. You break down complex topics into simple steps, check understanding before moving on, and celebrate progress. You never make the user feel bad for not knowing something.",
  base_preset: "friendly",
  emoji_level: "some",
  response_length: "detailed",
  tags: "education,tutor,study"
)

Then activate it before a study session:

personality(action: "activate", id: "study-buddy")

Example 2: A concise business advisor

For when you need straight-to-the-point professional advice:

personality(action: "create",
  name: "Business Advisor",
  system_prompt: "You are a seasoned business advisor. You give direct, actionable recommendations. No fluff, no hedging. You cite relevant frameworks when useful and always end with a clear next step.",
  base_preset: "professional",
  emoji_level: "none",
  response_length: "concise",
  tags: "business,advisor,professional"
)

Example 3: Updating an existing personality

Let's say your coach personality is too worddy. Tighten it up:

personality(action: "update", id: "coach-marc", response_length: "concise")

Example 4: Tagging for organization

Tags make it easy to categorize personalities. Use descriptive, comma-separated labels:

personality(action: "update", id: "study-buddy", tags: "education,tutor,study,exam-prep")

Tips & best practices

• Write clear system prompts — The quality of your personality depends almost entirely on the system prompt. Be specific about the character's role, tone, and rules. Mention what the personality should and should not do.
• Use base presets as a starting point — Presets like friendly or professional give you a solid foundation. Your custom system prompt then layers on top of that baseline.
• Match emoji level to the persona — A playful friend might use lots of emojis, while a legal advisor should use none.
• Tune response length deliberately — concise is great for quick Q&A, while detailed works better for explanations and tutoring.
• Tag generously — Tags help you find and manage personalities as your library grows. Use consistent, descriptive keywords.
• Activate per session — Activation affects the current chat session. If you start a new conversation, you'll need to activate the personality again (or set it as your default).
• Don't delete what you might reuse — Instead of deleting a personality you're unsure about, simply don't activate it. You can always come back to it later.
• Test before committing — After creating a personality, send a few test messages to see if the tone matches your expectations. If not, tweak the system prompt and update it.