Custom widget: build your own tool

The Custom widget turns a description into a working tool on your desk. Write what you need, for example "a print-size calculator that converts pixel dimensions to mm at a chosen DPI", and Plexii builds it inside the widget and gives it a name.

Use it for the small, specific tools that no other widget covers: a tracker with a progress bar, a calculator for the sums you do every week, a checklist, a log, a reference card or a counter. A built widget can remember what you type into it, read the widgets you connect to it, and, if you allow it, add rows to a table or save notes for you.

More about this widget Coming soon

Before you start

• The Custom widget is part of the Pro and Team plans. See Plans and pricing Coming soon.
• Building and changing a Custom widget uses your own Anthropic API key, even when you are signed in and use PlexiDesk credits for other AI. Add your key under Settings > AI. See Add your own API keys.
• Once a widget is built, using it needs no AI. Only building and changing it do.

Add a Custom widget

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

The Add widget menu groups widgets into columns by what they are for. Custom is in the Build & automate column. You can also type custom in the search box at the top of the menu and press Enter.

You can also press ⌘ K on a Mac or Ctrl K on Windows, type custom and choose Add Custom.

A new Custom widget says Describe the widget you need. Under that is a box to write in, a few example ideas, and three buttons: Build it, Guide me and My widgets.

Build it from a description

1. Click in the box and describe the tool. Say what it should keep, what it should work out for you and how it should look. To start from an example, click one of the ideas under the box, then change the wording to suit you.
2. If the tool should read something else, type @ and pick it from the list, for example a table, a desk, a document or a file. There is more about this under Give it something to read, below.
3. Click Build it, or press ⌘ Enter on a Mac or Ctrl Enter on Windows.

The widget shows Building your widget… while Plexii writes it. This usually takes 15 to 40 seconds. When it is ready, your tool appears in the widget and the title bar shows a short name for it, taken from your description.

A new tool starts empty. It does not come with sample rows or made-up numbers, so everything you see in it is what you put there.

Build it by answering questions

If you would rather not write a description, click Guide me. Seven short questions take you through what the tool is, one at a time.

1. Click Guide me. The panel says Build a widget, with the question number at the top right, starting at 1 / 7.
2. Click the option that fits. A question with one answer moves on as soon as you click. For a question that takes several answers, click each one that fits, then click Next.
3. To answer in your own words, click Something else…, type your answer and click Add. You can type @ here to point at something, too.
4. Click Skip to leave a question unanswered, or Back to change an earlier answer.
5. On the last page, Ready to build, check the summary of your answers. Then click Build it. You need to have answered at least one question.

To close the questions without building, click the × at the top right or press Esc.

Your answers are kept with the widget. When you change the tool later with Change what it does…, the questions open with what you chose last time, so you only change the answers that matter.

Give it something to read

A Custom widget sees only what you point it at. There are two ways:

• Wire a widget into it. On the title bar of the widget it should read, click the link button (its tooltip says Link to another widget), then click the Custom widget. When How should this connect? appears, choose Feed in as context. See Link widgets and set up wires.
• @ mention it in the description, or in an answer to the questions.

A wired or mentioned table arrives with its real rows and columns, so the tool can add them up, filter them or chart them. When something it reads changes, the tool updates. A Custom widget reads up to 12 wired or mentioned items.

Use your tool

Use the built tool like any other part of your desk: type into it, click its buttons, tick its boxes. If you asked it to remember what you put in, your entries are saved with the widget and are there when you come back.

The tool follows PlexiDesk's light or dark theme, so it matches the rest of your desk.

Change it

Every change keeps the version before it, so you can always go back.

While a change is being made, the widget shows Rebuilding your widget….

The title bar menu

Right-click the Custom widget's title bar. A built tool adds these commands near the top of the menu:

On an empty Custom widget, the menu offers My widgets…. The rest of the menu is the one every widget shares. See Right-click menus.

Permissions: internet access and making changes

Both permissions start off, and you can change them at any time from the title bar menu.

Internet access

With Internet access: off, the tool works only with what you type into it and what you wire into it. Turn it on only for a tool you want to fetch live information from the web, such as exchange rates. When you turn it on, PlexiDesk asks you to confirm, because a tool that can use the internet can also send what you type into it.

Can make changes

A tool you build can ask to do things for you:

• add rows to a table, or update cells in one
• add a task on this desk, or change a task you pointed it at
• put an event in your calendar
• save a note to your knowledge base in Brain

It can only change tables and tasks you wired into it or @ mentioned.

With Can make changes: off, the tool asks you each time: a box describes the change, and nothing happens unless you confirm. Turn on Can make changes, then confirm, to let it go ahead without asking. Leave it off if you would like to check each change.

Opening a link and starting an email draft do not need this permission. A draft opens for you to read and send yourself.

Save and reuse your tools

Saving a tool puts it in My widgets, your library, so you can place it on any desk, as many times as you like.

Save a tool

1. Right-click the title bar and choose Save to my widgets….
2. Check the name, or type a new one.
3. Click Save.

If you change the tool later and save it again, the saved copy is updated. The library keeps the tool itself, not what you typed into it, so each copy you place starts empty.

Place a saved tool

1. Add a new Custom widget to the desk.
2. Click My widgets.
3. Click the tool you want. It appears in the widget straight away.

Each saved tool shows how many times you have placed it, and whether it uses the internet. Use an empty Custom widget for this: picking a saved tool replaces whatever that widget held.

Delete a saved tool

1. Open My widgets from any Custom widget.
2. Point at the tool and click the bin icon.
3. Confirm. The tool leaves your library, and copies already on your desks keep working.

Ideas for good tools

• A retainer tracker that shows hours used against hours bought for each client.
• A print-size calculator that converts pixels to millimetres at a chosen DPI.
• A colour contrast checker with two colour pickers and the contrast ratio.
• A counter of revision rounds per deliverable, so you can see who is over their included rounds.
• A tool that reads a wired table of expenses and shows the total by category.

Common questions

It says I need an Anthropic API key

Building and changing a Custom widget uses your own Anthropic key, even when you are signed in. Add one under Settings > AI, then click Build it again. See Add your own API keys.

A note across the top says the widget was not finished

Click Rebuild it from your description to build it again from what you wrote, or Or say what it should do differently to add a line to your description first.

A message has appeared along the bottom of the tool

The tool is telling you something it could not do. Read the message, then click Describe the fix and say what should happen instead. The tool is rebuilt with your fix, and the version before is kept.

It does not see my table

Check that the table is wired into the Custom widget (you will see a line between them) or @ mentioned in its description. Then use Tell it what to change to say how it should use the table.

Can I share a tool with someone?

Your library is your own. To share the code, right-click the title bar, choose View source and click Copy. When you share a desk as a live public view, a Custom widget appears there as a placeholder. See Publish a live view of a desk.

Related tasks

• Build & automate widgets
• Link widgets and set up wires
• Link desks, widgets and people with @
• Desk agent widget
• Custom block widget: design a form