# Build & automate widgets

> Custom, Field, Custom block, Desk agent, Send to a URL and Receive from a URL: what each one does, which to choose, and how they work together.

Source: https://plexiidesk.com/help/widgets-build-and-automate
Section: Widgets > Build and automate
Plans: All plans
Updated: 2026-10-10

The **Build & automate** widgets let a desk do more than hold your notes. Three of them hold information in a shape you choose, one is an AI worker that acts on what you give it, and two connect your desk to other services on the web.

This page explains what each one is for, what you need before you start, and how they work together. Each widget has its own guide, linked below.

## The six widgets

They appear in this order in the **Add widget** menu.

| Widget | What it does | Choose it when |
| --- | --- | --- |
| **Custom** | You describe a tool in your own words, or answer a few questions, and Plexii builds it on the desk. | You need a small tracker, calculator, checklist or log that no other widget offers. See [Custom widget: build your own tool](https://plexiidesk.com/help/widget-custom). |
| **Field** | Holds one typed value: text, a number, a date, a choice from a list, files, a button and more. | You want one value, such as a status or a due date, to sit on the desk where you can see it. See [Field widget](https://plexiidesk.com/help/widget-field). |
| **Custom block** | A form you lay out yourself from typed fields, then fill in. | You record the same set of details again and again, such as a client intake or a call log. See [Custom block widget: design a form](https://plexiidesk.com/help/widget-custom-block). |
| **Desk agent** | A standing AI worker. Wire widgets into it, give it an instruction and choose when it runs. | You want something summarised, watched, drafted or filled in without asking each time. See [Desk agent widget](https://plexiidesk.com/help/widget-desk-agent). |
| **Send to a URL** | Sends a widget's content to a web address you give it, each time that content changes. | Another service should hear about changes on your desk. See [Send to a URL widget](https://plexiidesk.com/help). |
| **Receive from a URL** | Gives you a web address of its own. What another service sends to that address lands in the widget. | Another service should send information onto your desk. See [Receive from a URL widget](https://plexiidesk.com/help). |

## How they work together

It helps to think of three parts:

- **Widgets hold information.** A Field, a Custom block, a note or a table keeps what you type.
- **Wires move it.** A link drawn from one widget to another passes the first one's content along. When you draw a link you choose how it works: **Feed in as context**, **Transform it** or **Keep in sync**. See [Link widgets and set up wires](https://plexiidesk.com/help/canvas-link-widgets).
- **Agents act on it.** A Desk agent reads every widget wired into it, follows its standing instruction, and offers its result for you to review.

**Send to a URL** and **Receive from a URL** are the doors to the rest of the web: one sends information out, the other brings it in.

For example, you might wire two meeting notes into a Desk agent and ask it to keep a short weekly summary in a Markdown note beside them. Each time you run it, the summary is written for you to review.



## Which one should I use?

- **One value you want to see at a glance**, such as a status, a budget figure or a deadline: use a **Field**.
- **Several details you fill in together**, the same way each time: use a **Custom block**.
- **A tool that works something out for you**, such as a total, a conversion or progress towards a target: use **Custom**.
- **Work you want done again and again**, such as a summary that stays current: use a **Desk agent**.
- **Information that should leave or arrive from another service**: use **Send to a URL** or **Receive from a URL**.

## What you need

| Widget | Plans | Also needs |
| --- | --- | --- |
| **Custom** | Pro and Team | Your own Anthropic API key to build and change it. See [Add your own API keys](https://plexiidesk.com/help/api-keys). |
| **Field** | All plans | AI set up, only if you make a **Button** field that runs an AI prompt. |
| **Custom block** | All plans | Nothing else. |
| **Desk agent** | All plans | AI set up: PlexiDesk credits while you are signed in, or your own Anthropic key. See [AI credits and where your AI runs](https://plexiidesk.com/help). |
| **Send to a URL** | All plans | The web address of the service that should receive your updates. |
| **Receive from a URL** | All plans | To be signed in, so the widget can create its own address. |

For every widget's needs in one place, see [Widget sizes, limits and what some widgets need](https://plexiidesk.com/help/widget-requirements). For plans, see [Plans and pricing](https://plexiidesk.com/help).

## Add one to a desk

1. Open the desk you want it on.
2. Click **Add widget** in the centre of the header.
3. Click the widget you want.

The **Add widget** menu groups widgets into columns by what they are for. All six of these are in the **Build & automate** column. You can also type a name, such as agent, in the search box at the top of the menu and press `Enter` to add the first match.

Other ways to add one:

- **Press `F`** on an open desk, when you are not typing, to add a Field. Field is the only one of these six with a quick-add key. See [Add widgets with a single key](https://plexiidesk.com/help/quick-add-keys).
- **Use the command palette.** Press `⌘` `K` on a Mac or `Ctrl` `K` on Windows, type the widget's name and choose, for example, **Add Desk agent**.
- **Start from another widget.** Right-click a widget and choose **Create & link**, then **Automate with an agent**, **Send to a URL** or **Field**. The new widget appears beside it, already linked to it.

## See what runs on its own

Desk agents and live wires can run without you pressing anything. To see them all:

- On a desk, click the lightning-bolt button in the corner of the canvas (its tooltip says **Automations on this desk**). It lists everything on that desk that runs by itself, with an on/off switch for each. See [See what runs on its own on a desk](https://plexiidesk.com/help/canvas-automations).
- **Brain > Agents** lists every Desk agent in your workspace and the desk it sits on. See [See and manage all your agents](https://plexiidesk.com/help).

## Guides in this section

- [Custom widget: build your own tool](https://plexiidesk.com/help/widget-custom)
- [Field widget](https://plexiidesk.com/help/widget-field)
- [Custom block widget: design a form](https://plexiidesk.com/help/widget-custom-block)
- [Desk agent widget](https://plexiidesk.com/help/widget-desk-agent)
- [Send to a URL widget](https://plexiidesk.com/help)
- [Receive from a URL widget](https://plexiidesk.com/help)
- [Keep a running summary with a desk agent](https://plexiidesk.com/help)
- [Send desk updates to other services and receive events back](https://plexiidesk.com/help)
- [Link widgets and set up wires](https://plexiidesk.com/help/canvas-link-widgets)
- [See what runs on its own on a desk](https://plexiidesk.com/help/canvas-automations)

## Related tasks

- [Add a widget to a desk](https://plexiidesk.com/help/add-a-widget)
- [The controls on every widget](https://plexiidesk.com/help/widget-title-bar)
- [Choose or create an agent role](https://plexiidesk.com/help)