# Environment variables

A task's Liquid code always has access to a set of **environment variables**, defined by Mechanic.

{% hint style="info" %}
Environment variables may be reassigned as needed. (When preparing a task preview, this may be a necessary technique.) To learn more, see [Stub data](/core/tasks/previews/stub-data.md).
{% endhint %}

| Variable  | Contents                                                                                                                                                   |
| --------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `shop`    | An object containing [Shopify's REST representation of the current Shopify store](https://shopify.dev/docs/admin-api/rest/reference/store-properties/shop) |
| `event`   | An object containing information about the current event                                                                                                   |
| `cache`   | The current store's [Mechanic cache](/platform/liquid/objects/cache.md) object, supporting lookups for cached values                                       |
| `task`    | An object containing information about the current task                                                                                                    |
| `options` | An object containing task [**options**](/core/tasks/options.md), configured by the user                                                                    |

{% hint style="info" %}
The \[Shopify variables]\(environment-variables.md#shopify-variables) available to tasks always contain data drawn from the event itself. If a task has a offset event subscription, this data may be outdated by the time the task runs.

To reload the data in a Shopify variable, use something like this:

```liquid
{% unless event.preview %}
  {% assign customer = customer.reload %}
{% endunless %}
```

Remember, Mechanic does not permit access to the Shopify API during [event preview](/core/tasks/previews.md). Using this `unless` statement ensures that reloading only happens during a live event.
{% endhint %}

## Event subject variables

When a task is actually invoked for an event, it may have access to an additional variable, determined by the specific event it is responding to. When this is the case, the additional variable will be named after the event subject, and its contents will be established by the event's data. The name of this variable is communicated by the Mechanic task editor, based on the task's current [**subscriptions**](/core/tasks/subscriptions.md).

For example, a subscription to shopify/customers/create will make available a variable called `customer`. A subscription to shopify/products/update will expose a variable called `product`, etc.

## Shopify variables

All Shopify events support an additional variable named after the event topic. For example, when a task responds to a shopify/customers/create event, it will have access to an additional variable named `customer`, containing the customer data contained in the event.

Shopify events always contain data from Shopify's REST representation of each resource; therefore, automatic Shopify variables always contain data from the REST representation as well. The best resource for the data available for each variable type is [Shopify's REST Admin API reference](https://shopify.dev/docs/admin-api/rest/reference).

{% hint style="warning" %}
**Shopify variables in Mechanic do not necessarily contain the same attributes as Liquid variables used in Shopify (in places like themes or email templates) – even if they share the same name.**

In Mechanic, Shopify variables always contain data from Shopify events, which are delivered to Mechanic via webhook. This means that Shopify variables always have the same data structure as Shopify webhooks, corresponding to Shopify's REST representation for this data.

For example, while Shopify themes support `customer.name`, Mechanic does not (because [Shopify's REST representation of the customer resource](https://shopify.dev/docs/admin-api/rest/reference/customers/customer) does not contain a "name" property). On the other hand, Mechanic supports `customer.created_at`, while Shopify themes do not.
{% endhint %}


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://learn.mechanic.dev/core/tasks/code/environment-variables.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.