> ## Documentation Index
> Fetch the complete documentation index at: https://www.pagent.ai/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Variables

> Read session and experiment context with window._pgnt.variables()

`window._pgnt.variables()` returns a synchronous snapshot of the current visitor's pagent context: session identifiers, the goal you ask about, and the active experiment the visitor is enrolled in. Use it to read identifiers on the page, link backend conversions to a session, or build readable experiment names for your own analytics or naming tools.

Unlike the [`pagent:event` bus](/docs/guides/integration/events), which pushes events to you as they happen, `variables()` is a pull-based call you make whenever you need the current values.

> **Note:** Call this after the pagent SDK has initialized. Experiment fields are populated once a session is active for an enrolled visitor.

## Call Signature

```javascript theme={"dark"}
window._pgnt.variables()
window._pgnt.variables("goal_label")
```

The argument is optional. Call it with no argument to read session and experiment context. Pass a conversion goal label (for example `"purchase"`) to additionally resolve a `conversion_id` for that goal.

## Fields

| Field                   | Type              | Description                                                                                                                                                                                                                                  |
| ----------------------- | ----------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `session_id`            | `string \| null`  | The current browser session identifier.                                                                                                                                                                                                      |
| `user_id`               | `string \| null`  | The visitor's persistent user identifier, stable across sessions for the same browser.                                                                                                                                                       |
| `visit_id`              | `string \| null`  | The current page view identifier.                                                                                                                                                                                                            |
| `conversion_id`         | `string \| null`  | UUID of the goal matching the label passed as an argument, or `null` if no label is passed or no goal matches.                                                                                                                               |
| `experiment_id`         | `string \| null`  | The experiment UUID.                                                                                                                                                                                                                         |
| `experiment_numeric_id` | `number \| null`  | The sequential test number shown in the pagent dashboard as "Test #N" (for example, `27`). Useful for building human-readable names.                                                                                                         |
| `variation_id`          | `string \| null`  | The UUID of the variation assigned to this visitor.                                                                                                                                                                                          |
| `is_control`            | `boolean \| null` | `true` if the visitor is in the control group, `false` if in a variant.                                                                                                                                                                      |
| `endpoint_path`         | `string \| null`  | The path the test is configured to target, for example `"/pricing"`. For tests targeting a URL pattern (glob), this may be the pattern rather than the exact visited URL. Use `window.location.pathname` if you need the exact current path. |

## Null Semantics

All experiment fields (`experiment_id`, `experiment_numeric_id`, `variation_id`, `is_control`, `endpoint_path`) return `null` when there is no active pagent test on the current page. This includes analytics-only sessions and visitors who are not enrolled in any running test.

`conversion_id` is `null` unless you pass a goal label that matches a configured goal.

> **Important:** Always null-check these fields before composing a name or sending them onward. Recording them unconditionally will produce strings like `"pagent Test null /null"` in your reports.

## Building Readable Experiment Names

The experiment fields let you construct a single machine-readable name that maps back to what you see in the pagent dashboard. Many analytics and naming tools expect one compact token with **no spaces**, so the example below leads with the human-readable parts (the test number) and appends the raw UUIDs at the end.

Wire it to any element on your page — for example a conversion button — and call `convert()` when the visitor acts:

```html theme={"dark"}
<button onclick="convert()">Buy now</button>

<script>
  function convert() {
    var ctx = window._pgnt.variables();

    // Guard: do nothing if no active test is running for this visitor.
    if (
      ctx.experiment_numeric_id == null ||
      ctx.is_control == null
    ) {
      return;
    }

    var experimentName =
      "experiment-" + ctx.experiment_numeric_id +
      "-control-" + ctx.is_control +
      "-eid-" + ctx.experiment_id +
      "-vid-" + ctx.variation_id;

    // Pass experimentName to your analytics or naming tool here.
    // e.g. "experiment-27-control-true-eid-3f2a...-vid-9b1c..."
    console.log(experimentName);
  }
</script>
```

**Notes on the example:**

* Human-readable parts come first (`experiment_numeric_id`, `is_control`) so the name is recognizable at a glance; the UUIDs (`experiment_id`, `variation_id`) are appended for exact reference.
* The output contains no spaces, so it can be used directly as an event name or identifier.

## Conversion Tracking

When you pass a goal label, `variables("goal_label")` also returns the `conversion_id` you need to record conversions from your backend. See [Server-Side Conversions](/docs/guides/integration/server-side-conversions) for the full flow.