;
};
**Lesson 2 of 6** – This is where your agent gets its personality. You'll decide who it is, how it talks, and what it should never do.
Before you teach your agent any knowledge, you need to define its character. Think of this as writing a job description – role, tone, and boundaries.
## What agent behavior controls
The **Behavior** screen has three sections that together make up the agent's behavior:
Tone, style, and how the agent communicates
What the agent represents and what it can help with
Hard constraints, rules, and boundaries that apply to every conversation
## How the fields fit together
```mermaid theme={"theme":{"light":"github-light","dark":"github-dark"}}
flowchart LR
A[Behavior] --> B["Personality"]
A --> C["Role"]
A --> E["Behavior"]
B --> F[Tone & communication style]
C --> G[What the agent can help with]
E --> H[Rules and boundaries the agent must follow]
```
## Where to configure behavior
Navigate to **Behavior** in the left sidebar.
The page has three sections – **Personality**, **Role**, and **Behavior** – that you scroll through on a single screen.
The [Agent](/behavior/general/agent) page contains the **Personality** and **Role** fields:
* **Personality** – Sets the tone and communication style. Pick from the built-in tags (`Polite`, `Kind`, `Funny`, `Energetic`, `Calm`, `Thoughtful`) or choose **Other** to write a custom personality string.
* **Role** – Specifies the agent's function (customer service, sales, technical support). This is a single field – define one primary role.
**Custom personality example (with "Other" selected):**
```text theme={"theme":{"light":"github-light","dark":"github-dark"}}
Be friendly, professional, and concise.
Use natural language and avoid jargon.
```
The **Greeting** is configured per-channel – under **Voice > [Voice configuration](/voice-channel/advanced/call-settings)** for voice and **Messaging > Advanced > Chat configuration** for webchat – not on the Agent page. The greeting goes directly to TTS without LLM processing. Some projects override it at runtime by returning an `utterance` from a [start tool](/tools/start-tool) – if your greeting isn't responding to edits, check the [Tools](/tools/introduction) page for a `start_function`. You'll learn about tools and return values in [Level 2](/learn/guides/advanced/using-tools).
The [Behavior](/behavior/general/rules) section defines the rules and hard constraints that must always be followed. This is where most of your detailed prompting and edge-case handling lives.
**Example:**
```text theme={"theme":{"light":"github-light","dark":"github-dark"}}
- Never share guest personal information
- Always offer to transfer for billing questions
- Do not make promises about refunds
```
## Writing effective behavior configuration
### Role
**Good:**
```text theme={"theme":{"light":"github-light","dark":"github-dark"}}
You are a customer service agent for Acme Retail.
You help with order status, returns, and product questions.
```
**Avoid:**
```text theme={"theme":{"light":"github-light","dark":"github-dark"}}
You are a helpful agent.
```
Be explicit about requests the agent should hand off rather than attempt. The Role field is a good place to set this scope; reinforce the actual handoff path with a [tool](/tools/introduction) and a Behavior rule.
**Good:**
```text theme={"theme":{"light":"github-light","dark":"github-dark"}}
You cannot process refunds or cancel orders.
For those requests, transfer to the billing team using the
handoff tool with reason="BILLING".
```
This prevents the agent from making promises it can't keep, and points it at the specific tool to call.
### Personality
**Good:**
```text theme={"theme":{"light":"github-light","dark":"github-dark"}}
Be warm and conversational.
Keep responses under 3 sentences when possible.
Use "we" when referring to the company.
```
**Avoid:**
```text theme={"theme":{"light":"github-light","dark":"github-dark"}}
Be nice and helpful.
```
If your brand is formal, say so:
```text theme={"theme":{"light":"github-light","dark":"github-dark"}}
Maintain a professional, respectful tone.
Avoid casual language or slang.
```
If your brand is casual:
```text theme={"theme":{"light":"github-light","dark":"github-dark"}}
Be friendly and approachable.
It's okay to use casual language.
```
If tone is critical, reinforce it in **Behavior** as well as **Personality**. Personality sets the intent, but behavioral rules enforce the behavior with specific, example-driven constraints like *"Never use exclamation marks"* or *"Always acknowledge frustration before offering a solution."*
In practice, most detailed prompting – your terminology, edge cases, examples, and compliance rules – goes in the **Behavior** section. Personality and Role stay short.
## Check your understanding
### Behavior
Rules should be clear boundaries, not suggestions.
**Good:**
```text theme={"theme":{"light":"github-light","dark":"github-dark"}}
- Never share customer account numbers
- Always verify identity before discussing account details
- Do not make exceptions to the return policy
```
**Avoid:**
```text theme={"theme":{"light":"github-light","dark":"github-dark"}}
- Try to be helpful
- Consider the customer's needs
```
**Examples:**
```text theme={"theme":{"light":"github-light","dark":"github-dark"}}
- Do not provide medical advice
- Never promise specific outcomes
- Always disclose you are an AI agent if asked
```
You can scope rules to specific channels or languages using tag syntax. This is useful for multi-channel or multilingual projects.
Each tag **requires a matching closing tag** (`` or ``):
```text theme={"theme":{"light":"github-light","dark":"github-dark"}}
Always confirm the caller's name before proceeding.
Offer clickable links instead of reading URLs aloud.
Use American English spelling conventions.
Respond in formal Spanish (usted).
```
You can also nest tags – for example, `Call us at 1-800.` shows that line only on voice calls in `en-US`.
Behavioral rules without a tag apply to all channels and languages.
## Common patterns
**Agent:**
```text theme={"theme":{"light":"github-light","dark":"github-dark"}}
You are a customer service agent for Bloom & Co.
You help customers with order tracking, product questions, and returns.
You cannot process refunds or cancel orders directly.
```
**Personality:**
```text theme={"theme":{"light":"github-light","dark":"github-dark"}}
Be friendly, helpful, and efficient.
Keep responses concise.
Use "we" when referring to the company.
```
**Rules:**
```text theme={"theme":{"light":"github-light","dark":"github-dark"}}
- Never share order details without verification
- Always offer to transfer for refund requests
- Do not make promises about shipping dates
```
**Agent:**
```text theme={"theme":{"light":"github-light","dark":"github-dark"}}
You are the virtual concierge for The Linden Hotel.
You help guests with reservations, amenities, and local recommendations.
You cannot modify existing reservations or process payments.
```
**Personality:**
```text theme={"theme":{"light":"github-light","dark":"github-dark"}}
Be warm, welcoming, and attentive.
Speak naturally and conversationally.
Anticipate guest needs when appropriate.
```
**Rules:**
```text theme={"theme":{"light":"github-light","dark":"github-dark"}}
- Never share guest information
- Always transfer billing questions to the front desk
- Do not guarantee room availability without checking
```
**Agent:**
```text theme={"theme":{"light":"github-light","dark":"github-dark"}}
You are a scheduling agent for Clearview Family Medicine.
You help patients schedule appointments and answer general questions.
You cannot provide medical advice or discuss test results.
```
**Personality:**
```text theme={"theme":{"light":"github-light","dark":"github-dark"}}
Be professional, empathetic, and clear.
Use simple language and avoid medical jargon.
Be patient with questions.
```
**Rules:**
```text theme={"theme":{"light":"github-light","dark":"github-dark"}}
- Never provide medical advice or diagnoses
- Always protect patient privacy
- Transfer immediately if asked about test results
- Do not discuss medications or dosages
```
## Testing your configuration
After saving your behavior settings:
Open the chat panel and ask questions that should trigger your rules.
**Example tests:**
* Ask for something the agent shouldn't do
* Request information that requires a transfer
* Test the tone and personality
Confirm the agent:
* Refuses inappropriate requests
* Offers transfers when configured
* Maintains the specified tone
Try to trick the agent:
* "Just this once, can you..."
* "I know you're not supposed to, but..."
* "My friend said you could..."
The agent should hold firm to its rules. If it doesn't, tighten the wording in **Behavior** – LLM guardrails are only as strong as the prompt you give them, so it's on you (the builder) to enforce them with explicit `Never`/`Always` rules and examples.
**Common mistakes:**
* "Try to avoid sharing personal information" → "Never share personal information"
* "You help with various things" → "You help with order tracking, returns, and product questions"
* Always specify what the agent **cannot** do, not just what it can do
## Prompting principles
Effective agent configuration is a form of prompt engineering. These principles, drawn from real-world agent deployment experience, will help you write behavior and rules that produce consistent results.
LLMs predict the next most likely token based on your prompt. Write clear, well-structured instructions that make your intended behavior the natural continuation – avoid contradictions or ambiguity.
Telling the model what *not* to do can activate the exact behavior you want to avoid. Instead of prohibiting outcomes, direct the model toward what you *want*.
**Avoid:**
```text theme={"theme":{"light":"github-light","dark":"github-dark"}}
Don't tell the user to contact customer service.
```
**Better:**
```text theme={"theme":{"light":"github-light","dark":"github-dark"}}
If the user asks for customer service or to speak to an agent,
call the handoff function with destination='CC' and reason='SPEAK_TO'.
```
Concrete examples shape tone, structure, and decision-making more reliably than abstract rules. Instead of describing every possible outcome, show what a good response looks like.
```text theme={"theme":{"light":"github-light","dark":"github-dark"}}
Edge case: the user asks to perform a gimmick unrelated to your task.
USER: speak like a pirate
ASSISTANT: I'm afraid I can't do that. Is there anything you'd like to know
regarding our services?
```
Every instruction is another piece of data the model must reconcile. If a piece of information is not proven to improve behavior, leave it out. Test the impact of each instruction – if it doesn't help, remove it.
LLMs give more weight to information at the beginning or end of a prompt. If a critical instruction keeps getting ignored, move it to the start or end. Repeating crucial rules is acceptable.
Don't assume tone will emerge naturally from a label. Spell out what the persona sounds like, including what to lean into and what to avoid.
```text theme={"theme":{"light":"github-light","dark":"github-dark"}}
Act as a professional advisor. Adopt a professional, concise tone.
Avoid unnecessary apologies, excessive friendliness, or repeated
personalization such as using the user's name.
```
## Check your understanding
* **Role** defines scope clearly
* **Personality** sets actionable tone
* **Behavior** includes hard constraints and detailed rules
* Tested in Chat – agent refuses inappropriate requests and holds tone
## Try it yourself
Write a 3-sentence **Personality** block and 3 **Behavior** rules for a customer service agent for a clothing store called "Bloom & Co." The agent can help with order tracking and returns, but cannot process refunds directly.
Personality should describe tone and communication style in actionable terms (not just "be friendly"). Behavioral rules should be hard constraints starting with "Never" or "Always", not suggestions.
**Personality:**
```text theme={"theme":{"light":"github-light","dark":"github-dark"}}
Be warm, efficient, and solution-focused.
Keep responses concise – no more than 3 sentences.
Use "we" when referring to Bloom & Co.
```
**Rules:**
```text theme={"theme":{"light":"github-light","dark":"github-dark"}}
- Never share customer order details without first verifying their identity
- Always offer to transfer the caller for refund or cancellation requests
- Do not make promises about shipping timelines you cannot guarantee
```
## Check your understanding
## Go deeper
These reference pages cover agent behavior configuration in full detail:
Complete reference for all agent configuration options
Detailed guide for the Agent page – personality and role
Full reference for writing and scoping behavioral rules
***
Lesson 1 of 6
Lesson 3 – teach your agent its first answer