Customizing AI behavior (system prompts)

System prompts define how your AI agent behaves, and partially about what it knows.

They control tone, style, rules, and boundaries for how the AI responds to customers.


What a system prompt is

A system prompt is a set of instructions that tells the AI:

  • How to speak

  • What role it should play

  • What it should and should not do

  • How to handle uncertainty

It does not add new knowledge.
Knowledge comes from your sources.


Using prompt templates

HaloDesk provides pre-built prompt templates, such as:

  • Support Agent

  • Sales Assistant

These templates are based on proven support patterns and can be used as-is or customized.

Selecting a template automatically fills the system prompt for you.


Customizing the prompt

You can edit the system prompt to define:

  • Tone (formal, friendly, concise)

  • Rules (when to escalate, when to refuse)

  • Writing style

  • Brand voice

Changes take effect immediately and can be tested in the Playground.


What system prompts are best for

System prompts are ideal for:

  • Enforcing consistent tone

  • Preventing hallucinated answers

  • Guiding escalation behavior

  • Aligning AI responses with your brand


What to avoid

  • Don’t paste large documents into the system prompt

  • Don’t duplicate knowledge that already exists in sources

  • Don’t give conflicting instructions

If the prompt is too complex, responses may become inconsistent.


Best practices

  • Keep prompts concise and clear

  • Use bullet-style rules when possible

  • Test changes in the Playground

  • Update prompts only when behavior needs adjustment


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