Structure AI Prompts Like A Pro: When To Use System, User & Assistant

Hi,

Welcome to this week's edition of Leverage AI.

Today, I'll explain the types of prompts you can use with AI models and show you exactly how to use them.

You'll learn:

• The difference between system, user, and assistant prompts

• When to use each type of prompt

• A simple framework for structuring your prompts

• Whether prompt types affect AI performance

Let's dive in.

System vs User vs Assistant?

If you've worked with AI models like ChatGPT or Claude, you've probably seen terms like "system prompt," "user prompt," and "assistant prompt."

But what exactly are they, and when should you use each one?

I found these confusing for a while. Without understanding these different prompt types, you might be structuring your AI prompts inefficiently.

Let's break down each type with clear examples:

System Prompt

These tell the AI how to behave throughout the entire conversation.

For example: "You are a professional content writer. No fluff, no jargon, no unnecessary words. Write as if explaining complex ideas to a smart friend."

User Prompt

These are your actual questions or requests - what do you want the AI to do?

For example: "Write an introduction for a blog post about remote work tools. Focus on the challenges of remote collaboration and why having the right tools matters."

Assistant Prompt

These are the AI's responses, following the guidelines set by the system prompt while directly addressing your user prompt.

When to Use Each:

You’re usually OK with just a system and user prompt.

• Use system prompts to establish overall behaviour, tone, and expertise

• Use user prompts for specific questions or tasks

• Assistant prompts happen automatically as the AI responds

Does It Make a Difference?

Not really, no. While the technical performance might be similar regardless of where you put instructions, organising your prompts this way makes your interactions more structured and maintainable, especially when building applications or having complex conversations.

BONUS: Ask AI Prompt

If you’re unsure, ask AI to help organise your prompts.

Split this prompt into its system and user components. 

Explain your reasoning and show an example output.

<prompt>
[Your prompt here]
</prompt>

💡 Wrap Up

Key Takeaways:

1. System prompts set the foundation for behaviour

2. User prompts drive the actual conversation

3. Assistant prompts are the AI's responses

The organisation matters more than the performance impact. Choose the structure that best fits your specific use case

Thanks,

Owain

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Owain