Writing Effective Agent Prompts

Best practices for writing natural language instructions that make your Spara agents perform well.

Every Spara agent — Chat, Email, Voice, and Text — is powered by a natural language prompt that defines how it behaves. The prompt is the single most important factor in your agent's performance. This guide covers how to write prompts that convert.

Prompt Structure

The Agent Editor organizes your prompt into collapsible sections using markdown headings. Common sections include:

• Goal — The agent's primary objective and success criteria

• Brand Guidelines — Voice, tone, and trust rules that stay consistent across agents

• Agent Persona — The identity, role, and demeanor the agent should adopt

You can create additional sections with # (primary) and ## (subsection) headings.

The Agent Editor's AI Instructions tab is where you write your prompt. It displays your instructions with line numbers for easy reference, alongside testing tools on the right.

The AI Instructions tab in the Agent Editor showing a Chat agent prompt.

Writing Principles

1

Be specific about the goal

Bad: "Be helpful and answer questions."

Good: "Your goal is to qualify incoming leads by determining fit, urgency, and intent — then route qualified leads to a scheduled call and give non-fits a clear, respectful outcome."

2

Give concrete instructions, not vague guidance

Bad: "Ask good questions."

Good: "Ask about their current solution, timeline for making a change, and who else is involved in the decision. Never ask more than one question at a time."

3

Define what NOT to do

Agents follow positive instructions well, but explicit guardrails prevent common mistakes:

• "Never invent product capabilities or pricing that aren't in the knowledge base."

• "Never propose a meeting without confirmed interest."

• "If you don't know the answer, say so and offer to connect them with a sales rep."

4

Keep it scannable

Use short sentences, bullet lists, and numbered steps. Avoid long paragraphs — agents interpret structured instructions more reliably than prose.

5

Test and iterate

Use the Testing interface in the Agent Editor to simulate conversations. Click the lightbulb icon to understand why the agent responded a certain way, or the thumbs-down icon to get specific improvement suggestions from Ask AI.

Example: Chat Agent Goal Section

Your goal is to qualify incoming leads by determining fit, urgency, and intent — 
then route good fits to a booked call with sales and give non-fits a clear, 
respectful outcome.

- Identify whether the lead matches the ideal customer profile based on 
  company size, role, and use case.
- Assess buying intent by uncovering budget, timeline, and decision-making authority.
- Move qualified leads toward a scheduled call; never propose a meeting 
  without confirmed interest.
- Route nurture leads into a follow-up sequence with a clear reason for 
  future re-engagement.
- Disqualify gracefully: explain why it's not a fit and offer alternative 
  resources when possible.

Where Prompts Are Used

Feature	What you're writing
AI Instructions	The core behavior for Chat, Email, Voice, and Text agents
Prompt Step	Custom AI instructions that classify leads, research accounts, or extract data
Email sequences	AI instructions that personalize automated email content

Tips

• Start simple. Write a short prompt, test it, then add specificity where the agent underperforms.

• Use the knowledge base. Don't put product details in the prompt — upload them to Knowledge and let the agent reference them.

• Separate shared from unique. Brand Guidelines and Agent Persona can be shared across agents. Keep the Goal section unique to each agent's purpose.

• Review real conversations. The best prompt improvements come from reading actual lead conversations and identifying where the agent missed.