Variables

Learn how to properly leverage variables in your AI Workflows

Variables in MindStudio are dynamic placeholders that store data during workflow execution. They allow you to pass information between blocks and workflows seamlessly.

Example:

Variable Name: userName
Usage: "Hello {{username}}! Welcome to our app."

Types of Variables

Runtime Variables

Most blocks, such as Generate Text Blocks or User Input Blocks, assign values for the variable while the workflow is running. For Example, after performing a Google Search, the block can store the results in a variable called google_result.

Launch Variables

These are defined in the Start Block of your workflow. Values for these variables are passed in as arguments when a workflow is run via API or via the Run Workflow block.

Global Variables

These variables values are stored in between Agent Runs. They are assigned in the onboarding flow or can be defined in blocks using global.myVariable syntax.

Creating Variables

Variables are created automatically in MindStudio whenever:

A User Input collects data.
A block generates an output (e.g., Generate Text Block, Analyze Image Block).
You manually define them in the Start Block.

Using Variables

To use a variable in any block or prompt, reference it by enclosing the variable name in double curly braces: {{variable_name}}.

Example Using Variables in a Generate Text Block:

Summarize the article titled "{{articleTitle}}". 

In the summary, make sure to write about the following topic: 
{{topic}}

Tips for Working with Large Variables

Variables are replaced with their values before the text is sent to the AI model. You must make sure your message will be coherent and legible after the variables have been substituted with their values. For longer variables, this means using things like XML tags to offset variable content from instructions.

Incorrect:

Summarize this article {{articleContent}} and find all mentions of {{personName}}.

This pattern does not work because {{articleContent}} will be replaced with the raw text or HTML of an article. If you execute this prompt and view its logs in the Debugger, you will see that what is sent to the model is a giant sentence like "Summarize this article The history of lorem ipsum has long been thought to contain dolor sit amet [...1000 more words from the article directly pasted in] and find all mentions of Taylor Swift".

While AI models are great at parsing text, using simple formatting can make prompts dramatically more effective, as well as easier for you to maintain.

Correct:

<article_content>
{{articleContent}}
</article_content>

Using the provided article content, create a summary of the article as well as a list of all mentions of {{personName}}.

Offsetting with XML-style tags (it doesn't matter what the actual tags are, you can make up anything you like as long as it makes sense) helps the model understand which aspects of your prompt are instructions and which are context. Anthropic found that placing long variables at the top of the prompt using XML tags improved response quality by up to 30%.

To achieve best results, you should strive to make your prompt as easy to read for a human as possible. A handy test is to imagine that you were to print out your prompt on paper (after all variables have been substituted) and give it to someone. Would they be able to understand what you want them to do? Or would it look like gibberish?

MindStudio leverages the Handlebars templating language to make working with variables intuitive and powerful. Handlebars allows you to include, manipulate, and conditionally render data directly in your prompts, outputs, and logic.

Using Handlebars Templating

Conditional Logic

Handlebars supports if-else logic for dynamic outputs, as well as other control expressions. For a full list of expressions, visit the Handlebars Documentation site.

{{#if userName}}
Hello, {{userName}}! How can we assist you today?
{{else}}
Hello! Please log in to get started.
{{/if}}

`{{#if condition}}`

Converts a conditional block that renders content only when the condition is true.

Example:

If isLoggedIn is true

Usage:

{{#if isLoggedIn}}
  Welcome back!
{{/if}}

Output:

Welcome back!

`{{#unless condition}}`

Converts a conditional block that renders content only when the condition is false.

Example:

If isLoggedIn is false

Usage:

{{#unless isLoggedIn}}
  Please sign in.
{{/unless}}

Output:

Please sign in.

`{{#each array}}`

Iterates over an array or object and renders the block for every item.

Example:

If items contains:

["Apple", "Banana", "Cherry"]

Usage:

{{#each items}}
  {{this}}
{{/each}}

Output:

opyApple
Banana
Cherry

`{{#with object}}`

Changes the evaluation context to the provided object for the enclosed block.

Example:

If user contains:

{ "name": "Alice", "age": 25 }

Usage:

{{#with user}}
  {{name}} is {{age}} years old.
{{/with}}

Output:

Alice is 25 years old.

Special Handlebars Methods in MindStudio

In addition to standard Handlebars features, MindStudio introduces special methods for advanced functionality:

`{{json varName}}`

Converts a JSON object into a string format.

Example:

If userProfile contains:

{
    "name": "John",
    "age": 30
}

Usage:

{{json userProfile}}

Output:

{"name":"John","age":30}

`{{sample varName number token}}`

Extracts a portion of the variable's content based on specified parameters.

Parameters:
- varName: The variable to sample.
- number: The number of items (e.g., lines, words, or letters). If negative, starts from the end.
- token: The type of unit to extract (line, word, or letter).
Examples:
- Extract the first 5 words:
  {{sample textVar 5 "word"}}
- Extract the last 3 lines:
  {{sample textVar -3 "line"}}
- Extract the first 10 letters:
  {{sample textVar 10 "letter"}}

`{{lookup object key}}`

Dynamically looks up a property from an object using a key.

Example:

If user contains:

{ "name": "Alice", "role": "admin" }

Usage:

{{lookup user "role"}}

Output:

admin

`{{get varName "property"}}`

Retrieves a nested property using a JSONPath expression from a JSON object.

Example:

If userDatacontains:

{
  "name": "Alice",
  "contact": { "email": "[email protected]" }
}

Usage:

{{get userData "$.contact.email"}}

Output:

[email protected]

`{{add num increment}}`

Adds a numeric increment to a given number.

Example:

If num is:

Usage:

{{add 5 3}}

Output:

`{{subtract num decrement}}`

Subtracts a numeric value from a given number.

Example:

If num is:

Usage:

{{subtract 10 4}}

Output:

`{{multiply value multiplier}}`

Multiplies two numbers.

Example:

If value is:

Usage:

{{multiply 2 5}}

Output:

`{{divide dividend divisor}}`

Divides one number by another.

Example:

If dividend is:

Usage:

{{divide 10 2}}

Output:

`{{eq var1 var2}}`

Checks if two values are equal using the double-equals operator.

Example:

If var1 contains:

and var2 contains:

"5"

Usage:

{{eq 5 "5"}}

Output:

true

`{{gt value1 value2}}`

Checks if the first value is greater than the second value.

Example:

If value1 is:

and value2 is:

Usage:

{{gt 10 5}}

Output:

true

`{{gte value1 value2}}`

Checks if the first value is greater than or equal to the second value.

Example:

If value1 is:

and value2 is:

Usage:

{{gte 10 10}}

Output:

true

`{{lt value1 value2}}`

Checks if the first value is less than the second value.

Example:

If value1 is:

and value2 is:

Usage:

{{lt 5 10}}

Output:

true

`{{lte value1 value2}}`

Checks if the first value is less than or equal to the second value.

Example:

If value1 is:

and value2 is:

Usage:

{{lte 5 5}}

Output:

true

`{{isEmpty varName}}`

Evaluates whether a variable is empty (null, undefined, an empty string, an empty array, or an empty object).

Example:

If data contains:

""

Usage:

{{isEmpty data}}

Output:

true

`{{length varName}}`

Returns the length of an array or a string. Returns "NaN" if the variable is not an array or string.

Example:

If list contains:

["a", "b", "c"]

Usage:

{{length list}}

Output:

`{{itemAt varName index}}`

Return an item from an array.

Example:

If list contains:

["a", "b", "c"]

Usage:

{{itemAt list 1}}

Output:

Note that the first item in an array is always index 0.

`{{firstItem varName}}`

Return the first item from an array.

Example:

If list contains:

["a", "b", "c"]

Usage:

{{firstItem list}}

Output:

`{{lastItem varName}}`

Return the last item from an array.

Example:

If list contains:

["a", "b", "c"]

Usage:

{{lastItem list}}

Output:

`{{markdown varName}}`

Converts a Markdown-formatted string into HTML.

Example:

If markdownText contains:

# Hello World
This is **bold** text.

Usage:

{{markdown markdownText}}

Output:

<h1>Hello World</h1>
<p>This is <strong>bold</strong> text.</p>

`{{formattedNumber number fractionDigits}}`

Formats a number using locale‑specific formatting with a fixed number of fractional digits.

Example:

If amount is:

1234.567

Usage:

{{formattedNumber 1234.567 2}}

Output:

1,234.57

`{{abbreviatedNumber number fractionDigits}}`

Formats a number into a compact, abbreviated notation (e.g., 1K, 1M) with a specified number of fractional digits.

Example:

If amount is:

Usage:

{{abbreviatedNumber 1500 1}}

Output:

1.5k

`{{date varName format}}`

Formats a date string according to the specified format. Supports both custom formats (e.g., "YYYY-MM-DD") and relative keywords like "fromNow" or "toNow". Any Moment.js-compatible date format can be used.

Example:

If dateString contains:

2020-01-01T00:00:00Z

Usage:

{{date dateString "YYYY-MM-DD"}}

Output:

2020-01-01

You can also format the current date by using currentDate as the variable:

Usage:

{{date currentDate "dddd, MMMM Do YYYY, h:mm:ss a"}}

Output:

Monday, June 9th 2025, 3:25:50 pm

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