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Well-crafted system prompts are the key to getting consistent, high-quality responses from your IllumiChat assistants. This guide covers practical techniques for writing prompts that produce reliable results.

System Prompt Basics

A system prompt defines your assistant’s personality, knowledge boundaries, and response style. It is set once in the assistant configuration and applies to every conversation.

Structure Your Prompt

Organize your system prompt into clear sections:

Prompt Writing Techniques

Be Specific

Vague instructions produce unpredictable results. Compare:

Define Boundaries

Tell the assistant what it should not do:

Provide Examples

Show the assistant what good responses look like:

Use Conditional Logic

Handle different scenarios with clear if/then instructions:

Best Practices

Begin every system prompt with a clear role statement and the assistant’s primary objective. This anchors all subsequent instructions.
Instead of embedding large amounts of product data directly in the prompt, use IllumiChat’s Knowledge Base or Projects features. This keeps your prompt focused on behavior while the retrieval system handles facts.
Be explicit about how long responses should be:
After setting up your assistant:
  1. Test with 10-15 representative questions.
  2. Note where responses are off-target.
  3. Add or refine instructions to address those gaps.
  4. Repeat until responses are consistently good.

Common Patterns

FAQ Assistant

Sales Assistant

Technical Support

Combine system prompts with MCP integrations to give your assistant access to live data from tools like Notion or GitHub, reducing the need to hard-code information into the prompt.