How to Write AI Agent Instructions Your Customers Will Love

Your AI agent can only be as good as the instructions you give it. Two businesses can connect the same website and pick the same model, yet end up with very different agents. One sounds like a helpful member of the team. The other rambles, guesses and forgets to point people to the next step.

The difference is almost always the instructions. The good news is that you don't need to be technical to write great ones. This guide shows you what to include, what to leave out, and how to test the result in a few minutes.

What belongs in your instructions

In Takkie AI, the instructions (also called the root prompt) live in the Playground. They describe how your agent behaves in every conversation. Think of them as the briefing you'd give a new team member on their first day.

Good instructions cover five things:

• Role: who the agent is and who it works for.
• Tone: how it should sound, such as friendly and brief, or calm and formal.
• Goals: what a successful conversation looks like for your business.
• Limits: topics it should avoid and promises it must never make.
• Next step: where it should send people, like a booking page, a product or a human.

Just as important is what to leave out. Product details, prices and policies belong in your Sources in Knowledge, where they stay up to date when you sync. Step-by-step playbooks for specific situations belong in Skills. More on that below.

Start from a template, then make it yours

You don't have to start with a blank page. Takkie AI includes prompt templates for Customer Support, E-commerce, Sales, Real Estate and Restaurant Assistant. Each one already covers role, tone, goals, knowledge use, limits and calls to action.

Pick the closest one and rewrite it in your own voice. Replace the generic company details with yours, and cut anything that doesn't apply to your business.

Six rules for instructions that work

1. Be specific about tone

"Be friendly" means something different to everyone. Describe the voice you want instead: "Write like a helpful shop assistant. Use short sentences, plain words and no jargon. Use the customer's first name if they share it."

2. Say what success looks like

Tell the agent what it should be working toward. For a restaurant, that might be a table reservation. For an online store, it might be helping the shopper find the right product. An agent with a clear goal asks better follow-up questions.

3. Set clear limits

Write down what the agent must never do. For example: never promise refunds or discounts, never give medical or legal advice, and never guess when it doesn't know. Tell it what to do instead, such as offering to connect the customer with your team.

4. Always give a next step

Every answer should leave the customer knowing what to do next. Tell your agent which links, pages or actions to suggest. If you've added a Custom Button or Escalate To Human Action, mention when to use it.

5. Don't paste your website into the prompt

Copying product details into the instructions makes them long and quickly out of date. Add your site and documents as Sources instead and sync them. Your agent looks the information up when it needs it.

6. Keep it short

Instructions can be up to 20,000 characters, but shorter is almost always better. If a rule only matters in some conversations, it doesn't belong here.

Example: before and after

Here's a typical first attempt for a bike shop:

You are a helpful assistant for Wheelhouse Bikes. Answer customer questions. Be nice.

It works, but it leaves the agent guessing about almost everything. Here's a stronger version:

You are Wheelhouse Bikes' online assistant. You help visitors choose a bike, book a repair, and find answers about orders and returns. Write in a warm, upbeat tone with short sentences. When someone is choosing a bike, ask about their riding style and budget before recommending anything. Never promise discounts, repair prices or delivery dates you can't confirm. If you're unsure, offer to connect them with our team. End each answer with a clear next step, like a product link or the repair booking page.

Same business, but now the agent knows its job, its voice, its limits and where to send people.

Move situational playbooks into Skills

As your agent grows, you'll want detailed instructions for specific situations, like handling a complaint, giving size advice or troubleshooting a product. Putting all of that in the root prompt makes every conversation heavier than it needs to be.

Skills solve this. A Skill is an instruction pack your agent loads only when the conversation calls for it. You give it a name, a description of when to use it, the full instructions, and optionally the Actions it needs.

The description matters most, because it's how your agent decides when to load the Skill. "Use when a customer is unhappy with an order or asks for a refund" works much better than "Complaints".

Test it before customers see it

The Playground shows a live preview next to your instructions, so you can test changes right away. Try this:

1. Ask the five questions customers ask most often.
2. Ask something your agent shouldn't answer, and check that it handles it politely.
3. Try an angry or confusing message and see how it responds.
4. Compare up to three models side by side if you're unsure which one fits best.

Once your agent is live, keep an eye on Activity. When an answer misses the mark, use Revise answer to turn it into a Q&A Source, then sync. Small fixes add up quickly.

Write it once, improve it often

Great instructions don't need to be long or clever. They need to be clear about who your agent is, how it sounds, what it's working toward and where it stops. Get those right, keep the details in Sources and Skills, and your agent will feel like part of the team.

Ready to write yours? Create your free agent at app.takkie.ai and start from a template in the Playground. For more tips, visit the Takkie AI docs.