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

# Source of an external incident

> Read what the source side knows of an incident an alert source opened: the source, the dedup key and the alerts of the notification group.

```http theme={null}
GET /api/v1/alerts/incidents/{id}/source
```

Returns what the source side knows of an incident an [alert source](https://docs.molesignal.com/en-US/alerting/sources.md) opened. It requires `alerts.incidents.read`. Such an incident carries the label `alert.source=external`, and its `rule_id` is the source's ID.

| Field | Description |
| - | - |
| `source` | The source, as in [List alert sources](https://docs.molesignal.com/en-US/api/alerting/list-sources.md); `null` once the source was deleted. |
| `dedup_key` | The dedup key. |
| `last_event_at` | The latest sender time this dedup key used, in microseconds; older messages are ignored. `null` for the API kind. |
| `last_intake_at` | When the alert was last received, in microseconds. |
| `members` | The alerts of an Alertmanager or Grafana notification group, up to 100: `status` (`firing` or `resolved`), `labels`, `summary`, `starts_at`, `ends_at` and the `url` back to the sender. Empty for the other kinds. |

```bash cURL theme={null}
curl http://localhost:5080/api/v1/alerts/incidents/$INCIDENT_ID/source \
  -H "authorization: Bearer $MS_TOKEN"
```

```json 200 theme={null}
{
  "source": { "id": "3KEJ1mZqf0bY0b8XUgD4tkd2Vwq", "name": "Production Prometheus", "kind": "alertmanager", "...": "..." },
  "dedup_key": "http://alertmanager.example.com:9093|{}:{alertname=\"HighCPU\"}",
  "last_event_at": 1790000240000000,
  "last_intake_at": 1790000300000000,
  "members": [
    {
      "status": "firing",
      "labels": { "alertname": "HighCPU", "instance": "web-1:9100", "job": "node" },
      "summary": "CPU above 90% on web-1",
      "starts_at": 1790000000000000,
      "url": "http://prometheus.example.com:9090/graph"
    }
  ]
}
```

**Errors**

| Status | Cause |
| - | - |
| `404` | The incident does not exist, or no alert source opened it. |


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