Now that we have a handle on steps, let’s understand data flows throughout a Spell. Let’s take another look at the example from the last section:

Simple lead qualification spell in the editor

When a new contact is added to HubSpot, what data is available? How do we use that data to perform the action in later steps? This section will discuss variables and how to use them in step options.

Step Options

Every step has “options” which change its behavior. Let’s examine the Generate Text block:

Generate Text step

Generate Text has 2 required options: Model and Prompt. These options have different types: model is a dropdown, and prompt is text. You can manually enter the values for these options, but you can also use data from previous steps. Variables are how you pass data between steps

For example, you may want to generate a personalized email for the new HubSpot contact above. In Generate Text’s prompt option, you’ll want to reference details from the contact to give the AI context on the email recipient. You would insert a variable into the prompt option like this:

Generate Text step with prompt filled out

Now, when your Spell runs, it will pass the contact’s name into the Generate Text prompt. You can enter any variable into any option, as long as the type matches. We discuss what you can do when the types don’t match below.

Step Outputs

Each step will make variables available to the steps after it. When we speak about variables from steps, we call them “outputs” For example, Generate Text has one output: response.

There are two places where you can view a step’s outputs:

  • A preview list of the most popular output variables on the step block in the editor canvas
  • The outputs tab of the step sidebar

Variable Types & Converters

Every variable has 2 icons next to the name:

  • The icon on the left indicates the type
  • The icon on the right indicates which step the variable comes from

The type of a variable determines how it will be used when passed into the option of another step. If the types match, it will be used directly. For example, passing a text variable into a text option will simply insert the text into the option.

When types don’t match, we need to convert the variable’s type to something else before it can be used. This is where converters come in.

For a full list of types and converters, see our Variable Types and Converters Reference


You can use converters to transform a variable’s value before it gets passed to the step. When you insert a variable into an option, you can hover over the variable to see the available converters:

(image: converter dropdown)

Here, we have inserted an image variable into a text option. That doesn’t make sense on its own, though; we don’t know how you want us to insert an image into the text. We need to convert it to a text type so that they match, and we have a few options:

  • Extract out any text we find in the image (eg. a caption)
  • Describe the image using AI

If we select the Describe Image converter, before that step is run we’ll use AI to describe the image and pass the result as the option.

Converters aren’t only for changing a variable’s type. Sometimes you may just want to transform a variable’s value, but it keeps the same type. For example, maybe you want to summarize text using AI. You can use the Summarize converter on a text variable to do this, instead of adding an entire new Summarize Text step.

Many converters, like Summarize, have the same functionality as a step. Steps provide more options to control the output, but oftentimes it may be quicker and easier to add a converter. Plus, fewer steps makes spells a bit more wieldy!

Using Variables

Ensuring variables are available

In order to use variables from one steps in another one, you need to make sure the two steps are connected. Here’s an example:

(image: a → (b → c), (d → e))

In this example, the Spell has two branches. Branching can be helpful for making your spell faster (as the blocks run simultaneously), and also to help it look cleaner. But how do we pass variables between the steps?

The simple rule is:

If there is a line from step A to step B, you can use step A’s output variables in step B’s options. If there’s a line between, we can pass data.

In this case, A has a line to all other steps. So we can use A’s variables in B, C, D, and E. B has a line to C, so C can also use B’s variables. However, there’s no line between B and D, so there’s no way to pass data between those steps. If you want to allow B to pass variables to D, then you need to move D after B and combine it into one chain of four steps in a row.

Tip: because all steps at some point came from the Start step, all variable outputs from the Start step are available everywhere in the Spell!

Inserting variables in options

Once you know the variables you need are available in a step, you’re ready to fill out that step’s options. Near the option’s input, you’ll find a + button:

(image: insert variable button)

When you click the button, you’ll be shown a dropdown with all of the past steps. If you click a step, it will open the dropdown to show the output variables from that step. Clicking on a variable will insert it into the input.

Different option types may have slightly different experiences. For example, inserting a variable into a file options will show two tabs: a variable picker (same as above), or an option to upload your own file.

(image: file upload insert variable)