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

# AI agents: what they are and when to use one

> An AI agent replies to customers automatically on the channels you assign it. What it can do, what it costs, and how to turn it off.

An AI agent answers customer messages on its own, on the channels you assign it to. It
uses instructions you write, knowledge you give it, and optionally **tools** that let it
look things up or take action.

## When an agent replies — and when it stops

This is the part worth understanding before you turn one on.

<Steps>
  <Step title="A message arrives on an assigned channel">
    Only channels you explicitly assign in the agent's **Assign** step. An agent with no
    channels assigned does nothing at all.
  </Step>

  <Step title="The agent replies">
    Using its instructions, knowledge and enabled tools.
  </Step>

  <Step title="A human takes the conversation">
    If **Pause AI when a chat is assigned** is on (the default), the agent stops replying
    the moment an agent owns the chat. See
    [How assignment works](/help/routing/how-assignment-works).
  </Step>
</Steps>

You can also pause the AI in a single conversation from the inbox, without changing
anything globally.

## Turning AI off

Three levels, from narrowest to widest:

| Scope            | How                                                    |
| ---------------- | ------------------------------------------------------ |
| One conversation | **Pause AI** in the conversation header                |
| One channel      | **AI Agents → the agent → Assign**, untick the channel |
| Everywhere       | Set the agent **Inactive**, or delete it               |

<Warning>
  Deleting an agent removes its training data, knowledge files and channel assignments, and
  it stops replying immediately. This is permanent. If you only want it to stop for now, set
  it inactive instead.
</Warning>

## The default agent

One agent can be marked **Default**. Set it from the agent list — **Set as Default**.

## Cost

AI replies draw from your plan's shared monthly unit pool, and each AI reply uses one unit.
**Billing** shows what you have used. If your plan does not include AI, the option is
unavailable rather than silently free.

<Note>
  The help assistant you are reading this from is *not* an AI agent and does not use your
  units. It is part of the product.
</Note>

## Eval score

Each agent shows an eval score once compiled — a rough measure of how well it answered its
own training questions. Treat it as a smoke test, not a guarantee. Real confidence comes
from watching its first conversations.

## Next

<CardGroup cols={2}>
  <Card title="Build an agent" icon="wand-magic-sparkles" href="/help/ai/agent-wizard">
    The six-step wizard, start to finish.
  </Card>

  <Card title="Guardrails" icon="shield" href="/help/ai/guardrails">
    Limiting what it will and will not say.
  </Card>

  <Card title="Tools" icon="screwdriver-wrench" href="/help/ai/tools">
    Letting the agent look things up and take action.
  </Card>

  <Card title="Automations" icon="bolt" href="/help/automation/overview">
    Deterministic rules, as opposed to a model deciding.
  </Card>
</CardGroup>