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

Defined in: [src/models/streaming.ts:374](https://github.com/strands-agents/harness-sdk/blob/ca4c20fea3f7d62c29b021c85f336eba5937012f/strands-ts/src/models/streaming.ts#L374)

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