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CCPA AI Agents

System Prompts

What Are System Prompts?

Section titled “What Are System Prompts?”

A system prompt is a set of hidden instructions that you give to the AI before the conversation starts. Unlike user prompts (the messages you type in the chat), system prompts run in the background. The person chatting with the AI usually never sees them, but they shape everything about how the AI responds.

Think of it this way: if the user prompt is like telling a waiter what you want to order, the system prompt is like the training manual the restaurant gave the waiter before they started their shift. The training manual defines how the waiter greets customers, what they recommend, what topics they avoid, and how they handle complaints. The customer never sees the manual, but it shapes every interaction.

How System Prompts Differ from User Prompts

Section titled “How System Prompts Differ from User Prompts”
FeatureUser PromptSystem Prompt
Who sees it?The user types it and sees it in the chatUsually hidden from the end user
When is it used?Every message in the conversationSet once, before the conversation begins
What does it do?Asks a specific question or requests a specific taskDefines the AI’s overall personality, role, and rules
Can it change?Changes with every messageStays the same for the entire session
Example”Write me a poem about the ocean.""You are a creative writing assistant. Always use vivid imagery and a poetic tone.”

Why System Prompts Matter

Section titled “Why System Prompts Matter”

System prompts are the foundation of every AI agent you will build in this course. Without a system prompt, the AI is a general-purpose assistant that tries to help with anything. With a system prompt, the AI becomes a specialized agent that has a clear role, consistent behavior, and defined boundaries.

Here is what a system prompt can control:

  • Role: “You are a customer support agent for a shoe company.”
  • Tone: “Always respond in a friendly, professional tone.”
  • Language: “Respond in Spanish unless the user writes in English.”
  • Constraints: “Never discuss competitor products. Never make up information.”
  • Output format: “Always respond with a numbered list of action items.”
  • Knowledge boundaries: “If you do not know the answer, say so. Do not guess.”

The Role-Tone-Constraints-Format Pattern

Section titled “The Role-Tone-Constraints-Format Pattern”

When writing system prompts, you can follow a simple pattern to make sure you cover all the important elements. We call this the Role-Tone-Constraints-Format pattern:

You are a [ROLE].


Your tone should be [TONE DESCRIPTION].


Rules:
- [CONSTRAINT 1]
- [CONSTRAINT 2]
- [CONSTRAINT 3]


Always format your responses as [FORMAT].

Example: A Spanish Writing Assistant

Section titled “Example: A Spanish Writing Assistant”
You are a helpful writing assistant that responds in Spanish.


Your tone should be friendly, patient, and encouraging, like a supportive teacher.


Rules:
- Always respond in Spanish, even if the user writes in English.
- If you correct a grammar mistake, explain why it is wrong in simple terms.
- Never use slang or informal abbreviations.
- If you are unsure about a regional variation, use the Latin American standard.


Always format your responses as:
1. The corrected text
2. A brief explanation of any changes you made

Where to Set System Prompts on Each Platform

Section titled “Where to Set System Prompts on Each Platform”

Every AI platform has a different place where you enter system prompts. Here is how to find it on each of the platforms we use in this course.

Claude (claude.ai)

Claude offers system prompts through its Projects feature:

  1. Go to claude.ai and log in.
  2. Click Projects in the left sidebar.
  3. Create a new project or open an existing one.
  4. In the project settings, find the Instructions field.
  5. Type your system prompt in this field.
  6. Every conversation you start inside this project will use your system prompt.

Alternatively, if you are using Claude Code (the command-line tool), you write your system prompt in a file called CLAUDE.md in your project folder. We will cover this in the next lesson on Configuration Files.

You are a helpful assistant for students at CCPA.
Always respond in a supportive, encouraging tone.
If a student asks about a topic outside the course, gently redirect them.

Common System Prompt Patterns

Section titled “Common System Prompt Patterns”

Here are some patterns you will see frequently as you build agents throughout this course.

The Expert Agent

Section titled “The Expert Agent”
You are an expert nutritionist with 20 years of experience.
Only give advice based on established nutritional science.
If someone asks about a medical condition, recommend they see a doctor.
Always include serving sizes when recommending foods.

The Formatter Agent

Section titled “The Formatter Agent”
You are a data formatting assistant.
When given raw text, organize it into a clean markdown table.
Always include headers in the first row.
If data is missing, write "N/A" in the cell.
Never add data that was not in the original text.

The Gatekeeper Agent

Section titled “The Gatekeeper Agent”
You are a customer support agent for TechCo.
Only answer questions about TechCo products.
If someone asks about a competitor, say: "I can only help with TechCo products."
If you do not know the answer, say: "Let me connect you with a human agent."
Never make up product features or pricing.

Key Takeaways

Section titled “Key Takeaways”
  • A system prompt is a hidden instruction that defines the AI’s role, tone, rules, and output format before a conversation begins.
  • The Role-Tone-Constraints-Format pattern is a reliable formula for writing effective system prompts.
  • Every platform has a different place to set system prompts, but the concept is the same everywhere.
  • System prompts turn a general-purpose AI into a specialized agent with consistent behavior.