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

# Integrations & Tools – Overview

> How the agent takes action: built-in tools, MCP servers, and domain-system connectors.

For an agent to not just inform but **carry out real transactions**, it calls **tools** in the [flow](/en/flows-bauen) – small, clearly scoped actions like "classify the request", "book an appointment", or "check a balance". Where a tool comes from and whether it talks to an external system depends on its **category**.

## Three categories of tools

<CardGroup cols={3}>
  <Card title="Built-In Tools" icon="wand-magic-sparkles" href="/en/system-tools">
    Platform-native tools that are available in **every agent without any configuration**. No external system, no credentials. Example: `classify`.
  </Card>

  <Card title="MCP Servers" icon="server" href="/en/mcp-server">
    Connect **any MCP server**. The agent reads its tools; you enable per agent what it is allowed to use.
  </Card>

  <Card title="Domain-System Connectors" icon="plug">
    Connect to your **practice or domain software**. Provides domain-specific tools (e.g. appointment booking) and talks to your system for real.
  </Card>
</CardGroup>

<Info>
  This chapter describes how you **select and configure** integrations in the portal. The technical **implementation** of your own interface is not part of this documentation.
</Info>

## Domain-System Connectors

A **connector** links an agent to an external domain system and provides it with the matching tools. Each tool is assigned to exactly **one** connector.

### Available connectors

In the **Connectors** tab of an agent you see the available connector types (with description, number of supported tools, and the supported authentication methods) as well as your already active connectors.

| Connector                         | Purpose                                                                                                                                                                            | Auth         | Status |
| --------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------ | ------ |
| **planorg PVS (Principa)**        | Appointment booking via the FHIR-R4 interface of the practice management system Principa by planorg – search patients, list doctors/calendars, find free slots, book appointments. | Bearer token | Live   |
| **Receivables Management (Demo)** | Demo connector: telephone balance inquiry and installment agreement using fictitious sample data.                                                                                  | API key      | Demo   |
| **Contract Verification (Demo)**  | Demo connector: telephone confirmation call about a concluded contract using fictitious sample data.                                                                               | API key      | Demo   |

<Note>
  The **demo connectors** respond with hardcoded sample data and are ideal for trying out a flow without a real domain system. For production use, choose a domain-system connector like **planorg PVS** or an **[MCP server](/en/mcp-server)**.
</Note>

### Configuring a connector

<Steps>
  <Step title="Choose a connector type">
    Pick the connector type that matches your system.
  </Step>

  <Step title="Enter the base URL">
    Enter the address (base URL) at which your system provides the interface.
  </Step>

  <Step title="Enter credentials">
    Enter the authentication (see below). Which fields appear depends on the chosen method. Secret values are stored encrypted.
  </Step>

  <Step title="Enable tools">
    Enable the tools the agent is allowed to use through this connector.
  </Step>
</Steps>

## Authentication

Domain-system and MCP connectors support two authentication methods. Which one is available is defined by the respective connector type.

| Method           | Field          | How it is sent                                                                                                |
| ---------------- | -------------- | ------------------------------------------------------------------------------------------------------------- |
| **API key**      | `API Key`      | As a fixed key on every request (for MCP in the header `X-API-Key`).                                          |
| **Bearer token** | `Bearer Token` | In the header `Authorization: Bearer <Token>`. The token is passed through unchanged (e.g. a pre-issued JWT). |

<Note>
  Your credentials are stored **encrypted**. Secret fields are no longer shown in plain text in the portal after saving – when editing, leave the field empty to keep the stored value.
</Note>

## Example: appointment booking

The most mature use case is telephone **appointment booking** for healthcare via the **planorg PVS connector**. Among other things, it provides tools to identify patients, list doctors and calendars, determine availability, and book appointments for known and new patients. In your flow you chain these tools together into the complete booking conversation.

<Tip>
  After setting up an integration, you should thoroughly check the agent with a [test call](/en/agenten-testen) before you go live.
</Tip>