ragflow/docs/guides/agent/agent_component_reference/begin.mdx

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slug: /begin_component
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# Begin component

The starting component in a workflow.

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The **Begin** component sets an opening greeting or accepts inputs from the user. It is automatically populated onto the canvas when you create an agent, whether from a template or from scratch (from a blank template). There should be only one **Begin** component in the workflow.

## Scenarios

A **Begin** component is essential in all cases. Every agent includes a **Begin** component, which cannot be deleted.

## Configurations

Click the component to display its **Configuration** window. Here, you can set an opening greeting and the input parameters (global variables) for the agent.

### ID

The ID is the unique identifier for the component within the workflow. Unlike the IDs of other components, the ID of the **Begin** component *cannot* be changed.

### Opening greeting

An opening greeting is the agent's first message to the user. It can be a welcoming remark or an instruction to guide the user forward.

### Global variables

You can set global variables within the **Begin** component, which can be either required or optional. Once established, users will need to provide values for these variables when interacting or chatting with the agent. Click **+ Add variable** to add a global variable, each with the following attributes:

:::caution WARNING
If your agent's **Begin** component takes a variable, you *cannot* embed it into a webpage.
:::

- **Key**: *Required*  
  The unique variable name.
- **Name**: *Required*  
  A descriptive name providing additional details about the variable.  
  For example, if **Key** is set to `lang`, you can set its **Name** to `Target language`.
- **Type**: *Required*  
  The type of the variable:  
  - **line**: Accepts a single line of text without line breaks.
  - **paragraph**: Accepts multiple lines of text, including line breaks.
  - **options**: Requires the user to select a value for this variable from a dropdown menu. And you are required to set *at least* one option for the dropdown menu.
  - **file**: Requires the user to upload one or multiple files.
  - **integer**: Accepts an integer as input.
  - **boolean**: Requires the user to toggle between on and off.
- **Optional**: A toggle indicating whether the variable is optional. 

## Examples

As mentioned earlier, the **Begin** component is indispensable for an agent. Still, you can take a look at our three-step interpreter agent template, where the **Begin** component takes two global variables:

1. Click the **Agent** tab at the top center of the page to access the **Agent** page.
2. Click **+ Create agent** on the top right of the page to open the **agent template** page.
3. On the **agent template** page, hover over the **Interpreter** card and click **Use this template**.
4. Name your new agent and click **OK** to enter the workflow editor.
5. Click on the **Begin** component to display its **Configuration** window.

## Frequently asked questions

### Is the uploaded file in a knowledge base?

No. Files uploaded to an agent as input are not stored in a knowledge base and will not be chunked using RAGFlow's built-in chunk methods. However, RAGFlow's built-in OSR, DLR, and TSR models will still be applied to process the document.

### How to upload a webpage or file from a URL?

If you set the type of a variable as **file**, your users will be able to upload a file either from their local device or from an accessible URL. For example:

![upload_file](https://github.com/user-attachments/assets/7ad2a352-0807-4b74-b8d1-d09e5cd37997)

### File size limit for an uploaded file

The maximum file size for each uploaded file is determined by the variable `MAX_CONTENT_LENGTH` in `/docker/.env`. It defaults to 128 MB. If you change the default file size, ensure you also update the value of `client_max_body_size` in `/docker/nginx/nginx.conf` accordingly.