Learn how to assign a persona to an AI in your prompts. This powerful technique helps control the AI’s tone, style, and expertise for more tailored responses. Lecture 06
Giving the AI a Job
Welcome back! Today we’re going to learn one of the most fun and powerful techniques in prompt engineering: giving the AI a persona.
A persona is a character or a role that you ask the AI to play. By telling the AI who to be, you can strongly influence its tone, style, vocabulary, and even its way of thinking. It’s a form of providing very strong context.
Why Use a Persona?
Assigning a persona is like choosing the right expert for a job. You wouldn’t ask a poet to fix your car, and you wouldn’t ask a mechanic to write a sonnet. By setting a persona, you tell the AI which “hat” to wear.
This helps to:
- Control Tone: Make the response formal, funny, serious, or friendly.
- Define Expertise: Get answers from the viewpoint of a specific profession (e.g., a doctor, a lawyer, a scientist).
- Set the Style: Get a response in a particular writing style (e.g., a journalist, a novelist, a technical writer).
- Improve Creativity: Brainstorm ideas from different perspectives.
Example: The Same Question, Different Personas
Let’s ask the same question but give the AI a different persona each time.
Base Question:Explain the importance of the sun.
Prompt 1 (Scientist Persona):You are an astrophysicist. Explain the importance of the sun to our solar system.
The AI will likely give a technical answer about gravity, nuclear fusion, and the habitable zone.
Prompt 2 (Poet Persona):You are a romantic poet. In a short poem, explain the importance of the sun to a lover.
The AI will respond with creative, metaphorical language about light, warmth, and life.
Prompt 3 (Fitness Coach Persona):You are a fitness coach. Explain the importance of the sun for human health.
The AI will focus on Vitamin D, circadian rhythms, and the benefits of getting sunlight for well-being.

How to Create a Persona Prompt
It’s very simple. You just start your prompt with a clear instruction telling the AI what role to adopt. The most common phrases are:
"You are a..."
"Act as a..."
"I want you to be my..."
"Assume the role of a..."
The more details you give the persona, the better. For example, instead of just “Act as a doctor,” you could say, “Act as a friendly pediatrician explaining something to a nervous parent.”
Pro Tip: The Expert Persona
One of the most effective personas is the “expert.” When you tell an AI to act as a world-leading expert in a certain field, it often provides more detailed, accurate, and confident answers. For example:
Act as a world-renowned expert in prompt engineering. Review my following prompt and suggest three ways to improve it for clarity and effectiveness.
Key Takeaways from Lecture 06
- A persona is a role or character you ask the AI to play.
- It’s a powerful way to control the AI’s tone, style, and expertise.
- Start your prompt with phrases like
"Act as a...
"
or"You are a..."
.- Be specific in your persona description for the best results.
- Using an “expert” persona can often lead to higher-quality answers.
End of Lecture 06. You can now direct the AI like a movie director! In our next lecture, we’ll learn about using delimiters to keep our prompts clean and organized.