Instructional/System Prompts

Instructional or system prompts provide explicit instructions or system-level messages to guide the language model's behavior, tone, or output format. These prompts are essential for setting boundaries, defining tasks, and ensuring the model responds in a controlled and predictable manner.

Key Concepts

• Explicit Instructions: Directly tell the model what to do, how to behave, or what format to use.
• System Messages: Set the overall context, rules, or persona for the model.
• Behavioral Control: Influence the model’s tone, verbosity, and style.
• Task Framing: Clearly define the scope and requirements of the task.

Best Practices

1. Be Direct and Unambiguous

   • Use clear, concise language.
   • Avoid vague or open-ended instructions.
   • Specify exactly what you want the model to do.

2. Set Boundaries and Constraints

   • Define what the model should and should not do.
   • Include formatting, length, or style requirements.
   • State any limitations or exclusions.

3. Use System-level Framing

   • Start with a system message or instruction that sets the context.
   • Reinforce the desired behavior throughout the prompt.

4. Combine with Examples (if needed)

   • Pair instructions with examples for clarity.
   • Use input-output pairs to demonstrate expectations.

Examples

Basic Instructional Prompt

Summarize the following article in three sentences or less.
Article: [Insert article text here]

System Message Example

You are a helpful and concise assistant. Always answer in bullet points.
Question: What are the main causes of climate change?

Formatting Constraint Example

List three benefits of regular exercise. Respond in a numbered list.

Behavioral Control Example

Respond to all questions in a formal and professional tone.
Question: How should I prepare for a job interview?

Common Pitfalls

1. Vague Instructions

   • Not specifying the desired output format or style.
   • Leaving room for interpretation that leads to inconsistent results.

2. Overly Complex or Contradictory Instructions

   • Giving too many or conflicting requirements.
   • Making the prompt hard for the model to follow.

3. Lack of Context

   • Failing to provide necessary background or task framing.
   • Assuming the model knows implicit expectations.

4. Ignoring Model Limitations

   • Expecting the model to follow instructions beyond its capabilities.
   • Not testing for edge cases or ambiguous scenarios.

Use Cases

1. Task Definition

   • Summarization
   • Paraphrasing
   • Data extraction

2. Behavioral Control

   • Tone and style adjustment
   • Formality or informality
   • Length constraints

3. Output Formatting

   • Lists, tables, or structured data
   • Code generation with specific style
   • Consistent response templates

4. System-level Guidance

   • Setting the model’s persona or role
   • Defining boundaries for safe or ethical responses

When to Use Instructional/System Prompts

Instructional/system prompts are ideal when:

• You need precise control over the model’s output or behavior.
• The task requires a specific format, tone, or style.
• You want to set boundaries or rules for the model.
• Consistency and predictability are important.

When to Consider Alternatives

Consider other techniques when:

• The task benefits from demonstration (use one-shot or few-shot).
• The model consistently misinterprets instructions (add examples or context).
• The output requires creativity or open-ended responses (relax constraints).

Tips for Optimization

1. Iterative Testing

   • Refine instructions based on model outputs.
   • Test with different phrasings for clarity.

2. Combine with Examples

   • Use examples to reinforce instructions.
   • Show both correct and incorrect outputs if needed.

3. Monitor for Drift

   • In multi-turn conversations, restate instructions as needed.
   • Remind the model of constraints if it deviates.

4. Validate Outputs

   • Check for compliance with instructions.
   • Revise prompts if results are inconsistent or off-target.