Template Variables

Template variables let you create dynamic prompts that change based on variable values. Instead of writing a separate prompt for every variation, you define placeholders using the {variable_name} syntax and swap values at generation time — ideal for batch generation across different products, names, or descriptions.

What Are Variables?

A template variable is a named placeholder inside a prompt. When you run a generation, XainFlow replaces each placeholder with the value you provide. This turns a single prompt template into a reusable blueprint for many outputs.

Example prompt with variables:

A professional photo of {product_name} on a {background_type} background,
studio lighting, {style} style

When you generate, you provide values like product_name = "running shoes", background_type = "white marble", and style = "minimalist", and the AI receives the fully substituted prompt.

Variable Types

Type	Description	Example Value
Text	Free-form text input	"running shoes", "sunset beach"
Number	Numeric values	3, 1080, 0.5
Image	Reference to an image asset	An uploaded product photo

Image Variables

Image variables let you reference visual assets directly in your prompts. When you use an image variable, the referenced asset is included as a generation input alongside the text prompt.

You can add an optional description field to guide how the AI interprets the image. For example, if the image is a photo of a person wearing a specific outfit, you might set the description to "Focus on the outfit style, ignore the person" to direct the AI's attention.

Creating Variables

1. Open a workflow in Flow Studio.
2. Select a node that accepts prompts (such as the Prompt Generator Node).
3. In the prompt field, type { to start a variable placeholder, then enter the variable name and close with }.
4. The variable appears in the Variables Panel on the side, where you can set its type and default value.

Setting a Default Value

Each variable can have one of its values marked as the default. The default value is used whenever a prompt references the variable but no explicit selection is made — for example, when an MCP tool or skill expands the prompt without choosing a specific value.

Marking a Default

1. Open the Variables Panel for your workflow.
2. Click the variable you want to edit.
3. Hover over the value you want as the default and click the star icon.
4. The starred value is now the default. Only one value can be the default at a time.

The same star pill appears in the inline tag editor when you write prompts, so you can mark a default without leaving the prompt field.

How Defaults Affect Generation

Scenario	Behavior
Prompt uses {variable} with no node-level selection	The default value is used
A node selects a single value via variableSelections	That value overrides the default for that node
A node selects multiple values via variableSelections	All selected values expand combinatorially
No default is set and no selection is made	The first value in the list is used

tip

Set a sensible default for any variable used in skills or MCP-driven generations. This keeps prompts deterministic when the agent expands a template without explicitly picking a value.

Execution Modes

When you provide multiple values for your variables, XainFlow can combine them in two ways:

Combinatorial Mode

Generates all possible combinations of variable values. If you have 2 products and 3 backgrounds, you get 2 × 3 = 6 prompts.

Example:

Variable	Values
product_name	shoes, bag
background_type	white, wood, marble

Result: 6 generations — shoes/white, shoes/wood, shoes/marble, bag/white, bag/wood, bag/marble.

Sequential Mode

Pairs variable values by index. The first value of each variable is combined, then the second, and so on. All variables must have the same number of values.

Example:

Variable	Values
product_name	shoes, bag, watch
background_type	white, wood, marble

Result: 3 generations — shoes/white, bag/wood, watch/marble.

warning

XainFlow limits batch generation to 50 expanded prompts per run. If your variable combinations exceed this limit, reduce the number of values or switch to sequential mode.

Variable Management

You can manage all variables for a workflow from the Variables Panel:

• Edit — change a variable's name, type, or default value.
• Delete — remove a variable you no longer need. Any prompt references to that variable will show as unresolved.
• Reorder — drag variables to change their display order in the panel.

tip

Use descriptive variable names like {product_name} or {scene_description} rather than generic names like {var1}. This makes your templates easier to understand and maintain, especially when sharing workflows with team members.

Related Pages

• Prompt Generator Node — the primary node where variables are used
• Custom Styles — pair variables with style presets for maximum flexibility
• Flow Studio