> ## Documentation Index
> Fetch the complete documentation index at: https://docs.assist.fm/llms.txt
> Use this file to discover all available pages before exploring further.

# Agent overview

> Understand what an agent is and how its components work together.

## What is an agent?

An agent is your AI-powered virtual receptionist. It answers phone calls, speaks naturally with callers, retrieves information from your knowledge base, and can transfer calls or trigger actions via connected tools.

Each agent is fully independent with its own:

* **Instructions** — personality, behavior rules, and conversation guidelines
* **Voice** — the speaking voice callers hear
* **Knowledge base** — documents and website content for answering questions
* **Call flow** — visual routing logic for transfers and conditional behavior
* **Tools** — external APIs the agent can invoke during calls
* **Phone number** — a dedicated inbound number linked to the agent

## Agent architecture

```mermaid theme={null}
graph TD
    A[Inbound call] --> B[Telephony layer]
    B --> C[Agent]
    C --> D[Instructions]
    C --> E[Knowledge base / RAG]
    C --> F[Connected tools]
    C --> G[Call flow]
    G --> H[Transfer to human]
    C --> I[Transcript + analysis]
```

## Configuration areas

> [card] [Instructions](https://docs.assist.fm/agents/instructions)
>
> Define how your agent behaves, what it knows, and how it responds.

> [card] [Voice and speech](https://docs.assist.fm/agents/voice-and-speech)
>
> Choose a voice, adjust speed, and configure audio settings.

> [card] [AI models](https://docs.assist.fm/agents/models)
>
> Select the AI model that powers your agent's conversations.

> [card] [Knowledge base](https://docs.assist.fm/agents/knowledge-base)
>
> Upload files or crawl websites to give your agent domain expertise.

> [card] [Flow builder](https://docs.assist.fm/agents/flow-builder)
>
> Design visual call flows with transfer and routing logic.

## Agent limits

The number of agents you can create depends on your plan:

| Plan | Agent limit |
| - | - |
| Free | 1 |
| Starter | 3 |
| Professional | 10 |
| Enterprise | Unlimited |

> [!NOTE]
>
> See [plans and pricing](https://docs.assist.fm/billing/plans) for full plan details.


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