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

# Activity Chronicle Trigger

> Receive activity chronicle lifecycle events from the Worlds platform

The Activity Chronicle Trigger registers a webhook with the state machine and receives activity chronicle lifecycle events as they occur. Unlike the [Detection Webhook Trigger](/nodes/detection-webhook-trigger), which carries computer-vision track and zone data, this trigger carries **activity chronicles** — externally-produced event summaries created on the Worlds platform (for example, by an external system, an operator, or another automation) rather than derived from raw detections.

Use this trigger when your workflow needs to react to the lifecycle of those chronicles: when one is created, when it changes, and when it closes.

## When to use

Use this node as the first node in any workflow that reacts to activity chronicle lifecycle events. It requires the **n8n-state-machine** service to be deployed and reachable — the same service that powers the [Detection Webhook Trigger](/nodes/detection-webhook-trigger) — since the state machine maintains the subscription to the Worlds API and delivers the webhook.

## Credentials

Select your **GraphQL Subscription API** credentials. These authenticate with the Worlds API and determine which chronicles are available to you. Credentials can be obtained from the Worlds platform and are shared across workflows — if you've already configured credentials in another workflow, the same ones will be available here.

See [Prerequisites](/getting-started/prerequisites) for setup details.

<Note>
  Activity chronicle subscriptions are **streaming only** — there is no batch mode. The state machine registers one unfiltered chronicle subscription per unique credential set and applies filtering and deduplication locally before delivering to your workflow.
</Note>

## Lifecycle signals

This trigger fires on **every** activity chronicle lifecycle change — there is no signal selector. The payload's `signal` field identifies which change occurred: `chronicle_created`, `chronicle_updated`, or `chronicle_closed`. Route on this field downstream with an **IF** or **Switch** node if your workflow only needs to act on some of the lifecycle.

| Signal              | When it fires                                                                                                                                                                                                                |
| ------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `chronicle_created` | The first time the state machine sees this chronicle ID, and the chronicle is still open (`endTime` is null)                                                                                                                 |
| `chronicle_updated` | Any other content change to a chronicle the state machine already knows about, including edits made after the chronicle closed                                                                                               |
| `chronicle_closed`  | The chronicle's `endTime` transitions from null to set — or, if the state machine sees the chronicle for the first time and it is already closed, `chronicle_closed` fires immediately with no preceding `chronicle_created` |

<Note>
  **Dedup guarantee**: the state machine emits exactly one `chronicle_created` per chronicle ID. Deduplication is content-based — the state machine stores a hash of the chronicle's raw JSON and suppresses byte-identical re-deliveries. This lifecycle state survives state machine restarts.
</Note>

## Chronicle Producers

**Chronicle Producers** is the primary filter, shown at the top level of the node. It's a multi-select populated with the chronicle producers (agents) available in your environment — use it to choose which agents to read chronicles from. Leave it empty to receive chronicles from every producer.

## Additional Filters

The remaining filters are secondary and live in the collapsed **Additional Filters** collection. Every filter is a list; within a single filter, values are matched with **OR** (any value matches). Across different filters, matches are combined with **AND**. An empty filter matches all chronicles.

| Parameter              | Type                 | Description                                               |
| ---------------------- | -------------------- | --------------------------------------------------------- |
| **Chronicle IDs**      | Comma-separated text | Specific chronicle IDs to receive updates for             |
| **Data Sources**       | Multi-select         | Only chronicles associated with these data sources        |
| **Sites**              | Multi-select         | Only chronicles associated with these sites               |
| **Tags**               | Multi-select         | Only chronicles tagged with these tag IDs                 |
| **Points of Interest** | Multi-select         | Only chronicles associated with these points of interest  |
| **Labels**             | Comma-separated text | Match against the chronicle's labels. Case-insensitive.   |
| **Locations**          | Comma-separated text | Match against the chronicle's location. Case-insensitive. |
| **Statuses**           | Comma-separated text | Match against the chronicle's status. Case-insensitive.   |
| **Priorities**         | Comma-separated text | Match against the chronicle's priority. Case-insensitive. |

## Output

```json theme={null}
{
  "signal": "chronicle_updated",
  "chronicle": {
    "...": "raw ActivityChronicle object from the Worlds API, passed through unmodified"
  },
  "timestamp": "2026-08-19T10:00:05.000Z",
  "trigger_config": {
    "signal_type": "activity_chronicle",
    "workflow": { "id": "...", "name": "My Workflow" }
  }
}
```

| Field            | Description                                                                                                                  |
| ---------------- | ---------------------------------------------------------------------------------------------------------------------------- |
| `signal`         | One of `chronicle_created`, `chronicle_updated`, `chronicle_closed` — use this to route the execution downstream             |
| `chronicle`      | The raw `ActivityChronicle` object from the Worlds API, passed through unmodified — no fields are added, removed, or renamed |
| `timestamp`      | The time the state machine emitted this signal (ISO 8601, UTC) — not the chronicle's `updatedAt`                             |
| `trigger_config` | Metadata about the trigger that produced this execution: the signal type and the workflow's ID and name                      |

<Note>
  `chronicle` is a passthrough of the Worlds API's `ActivityChronicle` object — its shape follows the Worlds API, not this node. Inspect a live execution to see the exact fields available for your tenant.
</Note>

## Requirements

* The **n8n-state-machine** service must be deployed and reachable from n8n. This trigger registers its subscription with the state machine's REST API (`signal_type: "activity_chronicle"`) the same way the Detection Webhook Trigger does.
* Activity chronicles must exist on the Worlds platform for the credentials and filters you configure — this trigger does not create chronicles, it only reports their lifecycle.