***

title: File Slots
position: 0
excerpt: >-
Learn how to use the File slot type to receive file attachments from users in
plugins.
deprecated: false
hidden: false
link:
new\_tab: false
metadata:
robots: index
next:
description: "Learn how to configure File Slots below \U0001F447"
pages:

* slug: http-action-files
  title: HTTP Action Files
  type: basic

***

The `File` slot type enables plugins to receive file attachments from users. It is resolved only when the user interacts with the dedicated "Upload file" button in the assistant interface.

<iframe src="https://www.tella.tv/video/cmhwn2j2x000a04jvf2ibb2s7/embed?b=0&title=0&a=1&loop=0&t=0&muted=0&wt=0" width="100%" height="500" frameBorder="0" allowFullScreen allowTransparency />

# File Object Structure

When a an attachment is added to the File slot, it generates this object structure:

```json
{
  "file_name": string, // Name used when uploading to the external system's API
  "location": string,  // File location
	"content": string, // base-64 encoded
}
```

# Supported file extensions (case-insensitive)

(case-insensitive)

`.png`, `.jpg`, `.jpeg`, `.pdf`, `.txt`, `.csv`, `.xlsx`, `.xlsm`, `.xls`, `.xltx`, `.xltm`

<Callout intent="info">
  **Callout**: Only these extensions are allowed as ticket attachments. Attempts to upload unsupported types will fail validation.
</Callout>

# Upload Interface

![](https://files.readme.io/18aff6906d8fb8ac7cc9e8cd4ec4a8b335c309c22d38d1fa5b93cc0d2db71c7a-CleanShot_2025-11-12_at_17.50.422x.png)

> *Users must use the **"Upload file"** button.*

# Limitations

| Limitation                           | Details                                                                                                                                                                                                             |
| :----------------------------------- | :------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| **File size limit**                  | Maximum file size is **5MB**. Files exceeding this limit will fail to upload.                                                                                                                                       |
| **No file delivery to users**        | Files cannot be sent back to end users in chat responses.                                                                                                                                                           |
| **No content manipulation**          | The system cannot read, parse, or modify file contents beyond base64 encoding.                                                                                                                                      |
| **Upload only via dedicated button** | Uploading files directly in chat (e.g., Slack drag-and-drop) will not populate the `File` slot — it triggers BriefMe instead. Use only the **"Upload file" pop-up** that appears when the `File` slot is requested. |

***

# Workarounds

## Use Case: Avoid Local File Download

**Problem:**

You do not want users to download files to their machine. Instead, you want users to paste a link (e.g., from Google Drive, OneDrive, or internal file server) directly into the assistant.

**Limitation:**

The platform **cannot download** files from external URLs on behalf of the user.

**Solution:**

Use a string slot named `file_link` instead of `File`.

#### Customer API responsibility:

Your API will **need** to handle the file download from the link passed by the user.

* Download file from `file_url`
* Validate content/type
* Process as needed

<Callout intent="info">
  *This bypasses local upload entirely. No file is stored or transmitted through the assistant.*
</Callout>