Use variables

Article
04/15/2022
5 minutes to read

Select the version of Power Virtual Agents you're using here:

Save customers' responses in a bot conversation to variables and reuse them later in the conversation.

For example, save a customer's name in a variable called UserName and the bot can address the customer by name as the conversation continues. Or, use variables to create logical expressions that dynamically route the customer down different conversation paths. You can also feed variables to Power Automate and Bot Framework skills as input parameters, and save the output results from those actions.

Prerequisites

Learn more about what you can do with Power Virtual Agents.

Entity and variable type

Power Virtual Agents uses entities to identify a specific type of information from a user's responses. A variable type is associated with the identified information when it's saved. The variable type is analogous with the entity.

Each entity or variable type maps to a base type, as listed in the following table. The base type determines the operators that you can use when you construct a logical expression with the corresponding variable. It also determines whether you can feed a variable to a flow or Bot Framework skill as an input parameter.

For example, a boolean base type maps to an operator "is equal to" with possible values being True or False. A number base type gives you numeric operators such as "is equal to," "is greater than," or "is greater than or equal to," and so on.

Entity	Variable Base Type
Multiple choice options	String
User's entire response	String
Age	Number
Boolean	Boolean
City	String
Color	String
Continent	String
Country or region	String
Date and time	String
Duration	String
Email	String
Event	String
Language	String
Money	String
Number	String
Ordinal	String
Organization	String
Percentage	Number
Person name	String
Phone number	String
Point of interest	String
Speed	Number
State	String
Street address	String
Temperature	Number
URL	String
Weight	Number
Zip code	String
Custom entity	String

Create a variable

In the bot authoring canvas, add a question node. A variable is created automatically in the node.

Go to your bot's Topics page and open the topic you want to add a variable to.
Select the plus (+) icon, and then select Ask a question.

A variable that contains the user's response is automatically created.

Pick an entity to use

By default, a question node is created with multiple-choice options. To use a different prebuilt or custom entity, choose what to identify from the node.

Screenshot of selecting an entity.

Rename a variable

Automatically created variables come with a default name. To rename a variable, select the variable name, enter a new name, and select Done.

Screenshot of renaming a variable.

Use variables in action nodes

When you use a variable in an action node, if its base type matches a parameter type that's specified for a flow or Bot Framework skill, you can feed it to that parameter. The output from action nodes generates new variables.

Screenshot of using an entity in an action node.

Use literal values in action nodes

You can type a literal value into the variable input field in an action node instead of selecting a variable from the menu.

Screenshot showing the use of literal values for action inputs.

Passing variables between topics

When you redirect to other topics, you can pass values into variables in the destination topic or get variables back from it. Passing variables between topics is especially useful when you already have information that the topic needs. Your users will appreciate not having to answer the question again. It's also helpful when you refactor and separate your topics into reusable components and you want to pass variables across the topics.

Note

Variables of type Custom Entity, Date Time, and Duration can't be passed between topics.

Receive values from other topics

When a topic defines a variable (for example, by a question node), the bot asks the user the question to fill in the variable’s value. If the bot has already acquired the value, there's no reason to ask the question again. In these cases, you can define the variable as Receive values from other topics. When another topic redirects to this one, it can pass a variable (or literal values) into this variable and skip the question. The experience for the user talking to the bot is seamless.

To receive values from other topics, set the variable's property:

In the Question node, select the variable that you want to receive values from other topics.
In the Variables properties pane, under Topic (limited scope) select Receive values from other topics.
Save the topic.
Go to a topic that you want to redirect to. Follow the steps in Redirect to another topic to redirect to the correct topic.
Select + Add input for destination topic.

Select a variable in the redirected topic that you want to pass the variable to.
Under Enter or select a value, select the variable in the current topic that you want to pass to the redirected topic.

The variable is shown in the redirected node.

Return values to original topics

When a topic asks a question, or obtains a variable from an action in some other way, the variable can be returned to the original topic that redirected to it.

In this case, the variable also becomes part of the original topic and can be used like any other variable. This helps you construct the topic so that information the bot obtains is available across topics, reducing the need for global variables.

To return a variable to the original topic, set the variable's property:

In the Question node, select the variable that you want to receive values from other topics.
In the Variables properties pane, under Topic (limited scope) select Return values to original topics.
Save the topic.
Go to a topic that you want to redirect to. Follow the steps in Redirect to another topic to redirect to the correct topic.

The variable that's being returned to the topic is shown in the redirected topic. Use the returned variable in your topic.

Using the Variables pane

Use the Variables pane to select the receive or return status of multiple variables at once.

On the topic's menu bar, select Variables.
For each of the variables in the topic, select whether you want the values to be passed, received, or both between topics.

Using literal values on variable inputs

You can pass literal values as well as variables to a topic. To pass a literal value, type the value you want to use as the input instead of selecting a variable.

Screenshot of the authoring canvas showing literal input on an input variable in a redirect node.