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

# Overview

# Scenario Event Schema

The Simulations visualizer is powered by a single endpoint that receives events from your test runs. All events are sent via a `POST` request to the following endpoint:

```
/api/scenario-events
```

The request body should be a JSON object representing one of the event types described below. These events allow LangWatch to reconstruct the entire history of your simulation sets, batches, and individual scenario runs.

For a detailed look at the request and response models, see the [Create Event endpoint reference](/api-reference/scenarios/create-event).

## Common Properties

All scenario events share a common set of properties to identify and organize them:

* `type`: The specific type of the event.
* `timestamp`: A Unix timestamp (in milliseconds) of when the event occurred.
* `batchRunId`: An ID that groups all scenarios run within the same test execution or process.
* `scenarioId`: A stable identifier for a specific scenario (e.g., "test\_vegetarian\_recipe").
* `scenarioRunId`: A unique ID for a single execution of a scenario.
* `scenarioSetId`: The top-level grouping for a collection of scenarios, which defaults to `"default"`.

***

## Event Types

There are three main types of events that you can send.

### 1. `SCENARIO_RUN_STARTED`

This event marks the beginning of a new scenario run.

* **`metadata`**:
  * `name`: The display name of the scenario.
  * `description`: A longer description of what the scenario tests.

### 2. `SCENARIO_MESSAGE_SNAPSHOT`

This event captures the state of the conversation at a specific point in time. It includes an array of messages exchanged between the user, agent, and tools.

* **`messages`**: An array of message objects. The schema for these messages (user, assistant, tool, etc.) is detailed in the OpenAPI specification.

### 3. `SCENARIO_RUN_FINISHED`

This event marks the end of a scenario run and includes the final results.

* **`status`**: The final status of the run (`SUCCESS`, `FAILED`, `ERROR`, etc.).
* **`results`**: An object containing the final verdict from a Judge Agent, including:
  * `verdict`: The final outcome (`success`, `failure`).
  * `reasoning`: The explanation for the verdict.
  * `metCriteria`: A list of criteria that were satisfied.
  * `unmetCriteria`: A list of criteria that were not met.