```ts
type ContentBlockStart = ToolUseStart;
```

Defined in: [src/models/streaming.ts:374](https://github.com/strands-agents/harness-sdk/blob/14f0b3355dd082f937ecaea538a370cab71ad4f8/strands-ts/src/models/streaming.ts#L374)

Information about a content block that is starting. Currently only represents tool use starts.