How Should I Structure the System Message in GPT-3.5 Prompts?

Below is a concise explanation of how you can approach designing your prompt for GPT-3.5:

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Using the "System" Message

• Purpose: The system message is intended for setting the context, behavior, and constraints for the model. It acts as a baseline directive that remains in effect throughout the conversation.

• What to Include:

  • Persona & Role: Define the model's identity, perspective, or style if needed (for example, "You are an expert in coding").
  • Global Instructions: You can incorporate essential guidelines or protocols that should be followed in all interactions. This might include formatting rules, tone, or how to handle certain topics.
  • Constraints: Any limitations or specifics (e.g., "Refer only to the provided documentation" or "Avoid discussing sensitive topics").

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Using the "User" Message

• Option 1 (Persona in System Only):
  • Place the model's persona in the system message.
  • The user message then contains both the task instructions and input text.
• Option 2 (Persona & Instructions in System):
  • Include both the model's persona and specific instructions in the system message.
  • The user message then only needs to contain the input text specific to that particular task.

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Best Practice Considerations

• Consistency & Clarity:

  • If your task instructions are constant and should apply to every instance of the task, it is safer to include them in the system message. This ensures the model always adheres to those rules, regardless of how user messages change.

• Flexibility:

  • If the tasks vary widely and the instructions change from one instance to the next, you might prefer to keep those instructions within the user message for flexibility. Using the system message solely for a stable persona or general guidelines prevents accidental overrides.

• Example Setup:

  MARKDOWNCopied
  [System Message]
  You are a coding expert specialized in Python. Follow these guidelines in every response:
  - Provide clear, concise, and example-rich explanations.
  - Ensure all code examples are fully functional.
  - Use markdown formatting with syntax highlighting where applicable.
  
  [User Message]
  Please explain how to write a function that calculates the Fibonacci sequence.

  In this example, the system message covers both persona and global instructions, and the user message focuses exclusively on the task.

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Summary

• Include Persona AND Global Instructions in the system message if your instructions are consistent across tasks.
• If only the persona is needed globally and different tasks have varied instructions, place the task-specific instructions in the user message.

Ultimately, the best choice depends on your use case and whether your task instructions remain consistent or are meant to be dynamic.