> Fetch clean Markdown by appending `.md` to any page URL under https://signalwire.com/docs or requesting it with the HTTP header `Accept: text/markdown`. The root index at https://signalwire.com/docs/llms.txt lists the available documentation indexes. # DiagnosticEvent > A single diagnostic event in the session timeline. A single diagnostic event in the session timeline. ## **Properties** **`category`** `error | call | connection | device | recovery` — required Category of the event. --- **`details`** `Readonly>` Additional details about the event. --- **`event`** `string` — required Event description string. --- **`timestamp`** `number` — required Timestamp when the event occurred (epoch ms). --- > A single diagnostic event in the session timeline.