> ## Documentation Index
> Fetch the complete documentation index at: https://explore.airia.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Variables

> Pass data between steps, reference user inputs, and access execution context — all using the {{ }} expression syntax.

Variables let you wire data through your agent. Any field in any step that shows `{{Steps.StepName.Property}}` as a placeholder accepts a variable expression. Type `{{` in that field to open autocomplete and browse everything available at that point in the agent.

***

## Syntax

All variable expressions use double curly braces:

```
{{Namespace.Path}}
```

| Part        | What it means                            |
| ----------- | ---------------------------------------- |
| `{{` `}}`   | Marks the start and end of an expression |
| `Namespace` | The category of data (see table below)   |
| `Path`      | Dot-separated path to the exact value    |

Spaces in step names are replaced with underscores in expressions — a step called `Get File` becomes `{{Steps.Get_File.FileContent}}`.

***

## Namespaces at a glance

| Namespace         | What it contains                                      | Example                               |
| ----------------- | ----------------------------------------------------- | ------------------------------------- |
| `Variables`       | Custom inputs defined on the Input step               | `{{Variables.CustomerName}}`          |
| `Steps`           | Outputs from **any** previous step                    | `{{Steps.Parse_Doc.MarkdownContent}}` |
| `Inputs`          | Outputs from **directly connected** parent steps only | `{{Inputs.My_Step.Value}}`            |
| `Execution`       | Runtime metadata (IDs, timestamps)                    | `{{Execution.executionId}}`           |
| `User`            | Identity of the person running the agent              | `{{User.email}}`                      |
| `Helpers`         | Utility functions available at runtime                | `{{Helpers.currentDateTime}}`         |
| `InputSchema`     | Fields from a Tool Interface input schema             | `{{InputSchema.ticketId}}`            |
| `PromptVariables` | Template slots in prompt segments                     | `{{PromptVariables.tone}}`            |

***

## Input Variables — `{{Variables.Name}}`

Input variables are declared on the **Input step** and filled in by whoever runs the agent — a user in chat, an API caller, or an upstream step.

**Defining them:** Open the Input step → Variables tab → click **Add Variable**. Give it a name, choose a type (String, Number, Integer, URL, Email), and optionally write a description so callers know what to provide.

**Using them downstream:** Reference them anywhere in the agent with `{{Variables.YourVariableName}}`.

```
{{Variables.CustomerEmail}}
{{Variables.OrderId}}
{{Variables.MaxResults}}
```

Input variables are the **entry point for external data**. They are set once before the agent starts and remain constant throughout the run.

<Tip>
  The variable name you define on the Input step is exactly what you type after `Variables.` — casing is preserved.
</Tip>

***

## Set Variables — updating values mid-run

The **Set Variable step** lets you assign a new value to an input variable at any point in the agent. Use it when a step produces data you want to carry forward under a consistent name.

**Workflow:**

1. The variable must already exist on the Input step (create it there first, or click **Create New Variable** directly from the Set Variable step panel).
2. Add a **Set Variable** step where you want the assignment to happen.
3. Select the variable from the dropdown and set its value — you can hardcode it or use an expression like `{{Steps.My_Step.Result}}`.
4. Downstream steps read the updated value via `{{Variables.Name}}` as usual.

|                            | Input Variables                             | Set Variables                                          |
| -------------------------- | ------------------------------------------- | ------------------------------------------------------ |
| **Where defined**          | Input step → Variables tab                  | Set Variable step                                      |
| **When set**               | Before the agent starts                     | At a specific point mid-run                            |
| **Who provides the value** | External caller (user, API, upstream agent) | The agent itself, from step outputs                    |
| **Syntax to read**         | `{{Variables.Name}}`                        | `{{Variables.Name}}` (same namespace)                  |
| **Typical use**            | Receive user input, API parameters          | Store intermediate results, counters, accumulated text |

***

## Step Outputs — `{{Steps.StepName.Property}}`

Every step produces one or more output properties. Reference them in any downstream step using the step's title (spaces → underscores) and the property name.

```
{{Steps.Download_File.FileContentBase64}}
{{Steps.Parse_Document.MarkdownContent}}
{{Steps.AI_Model.Value}}
{{Steps.Get_Order.OrderStatus}}
```

`Steps` gives you access to **all** previous steps in the agent, not just the ones directly connected. If you only want to reference outputs from a step that is directly wired to the current one, use `Inputs` instead — the behaviour is identical but the scope is narrower.

### Array access

When a step returns an array, use bracket notation to access individual elements:

```
{{Steps.My_Step.Results[0].Name}}    — first item
{{Steps.My_Step.Results[-1].Name}}   — last item
```

***

## Execution context — `{{Execution.*}}`

Always available. No setup required.

| Variable                       | Type   | Description                    |
| ------------------------------ | ------ | ------------------------------ |
| `{{Execution.executionId}}`    | string | Unique ID for this agent run   |
| `{{Execution.conversationId}}` | string | ID of the conversation session |

***

## User context — `{{User.*}}`

Available when the agent is run by an authenticated user.

| Variable          | Type      | Description                |
| ----------------- | --------- | -------------------------- |
| `{{User.id}}`     | string    | User's unique identifier   |
| `{{User.name}}`   | string    | User's display name        |
| `{{User.email}}`  | string    | User's email address       |
| `{{User.roles}}`  | string\[] | Roles assigned to the user |
| `{{User.groups}}` | string\[] | Groups the user belongs to |

***

## Helpers — `{{Helpers.*}}`

Runtime utilities that generate values on demand.

| Variable                      | Description                        |
| ----------------------------- | ---------------------------------- |
| `{{Helpers.currentDateTime}}` | Current date and time at execution |

***

## Autocomplete

Any field that supports expressions shows autocomplete when you type `{{`. The autocomplete list updates as you type:

* Type `{{` to see all top-level namespaces
* Type `{{Steps.` to see every available previous step
* Type `{{Steps.My_Step.` to see all properties that step exposes
* Continue typing to filter the list

The autocomplete only shows steps that come **before** the current step in the agent — you cannot reference outputs from steps that haven't run yet.

***

## Mixing expressions and plain text

Expressions can be embedded inside longer strings. Everything outside `{{ }}` is treated as literal text:

```
Hello {{Variables.FirstName}}, your order {{Variables.OrderId}} is {{Steps.Check_Status.Status}}.
```

You can use multiple expressions in a single field and combine them with any text you like.

***

## Common mistakes

**Using `Inputs` when you mean `Steps`**
`Inputs` only includes outputs from steps that are directly connected to the current step via an edge. If the step you want is two or more hops away, use `Steps`.

**Referencing a step that runs after the current one**
The autocomplete only surfaces steps that come before the current step. If a step doesn't appear, it either hasn't run yet or is not on a path that leads to the current step.

**Wrong casing or space handling**
Step names are case-sensitive and spaces become underscores. A step titled `Send Email` must be referenced as `{{Steps.Send_Email.Property}}`.

**Expecting a single value from an array**
If a step returns a list, `{{Steps.My_Step.Items}}` gives you the whole array. Use `[0]` or `[-1]` to get a specific element, or pass the array into a Loop step to process each item individually.

**Using `{{Variables.Name}}` before it has been set**
If a variable is defined on the Input step but not filled in by the caller, it arrives as an empty string. Use a Set Variable step earlier in the agent to assign a default if needed.