Function trace

trace<T>(nameOrOptions: string | TraceOptions, fn: () => Promise<T>): Promise<T>
Execute a function within a trace context. Creates a root "agent" span that contains all LLM calls and tool executions.

Output Auto-Extraction: If the function returns an object with common text fields (text, content, message, output, response, result, answer), the SDK automatically extracts that field for cleaner display. Use outputKey to specify a custom field, or outputKey: false to disable.
Type Parameters
- T
Parameters
- nameOrOptions: string | TraceOptions
- fn: () => Promise<T>
Returns Promise<T>
Example: Simple usage
```
await trace('sales-agent', async () => {
  return { text: 'Hello!', tokens: 100 };
  // Output shown: "Hello!" (auto-extracted from 'text')
});
```
Example: With options and explicit outputKey
```
await trace({ name: 'agent', outputKey: 'reply' }, async () => {
  return { reply: 'Hello!', cost: 0.01 };
  // Output shown: "Hello!"
});
```
Example: Disable auto-extraction
```
await trace({ name: 'agent', outputKey: false }, async () => {
  return { a: 1, b: 2 };
  // Output shown: { a: 1, b: 2 }
});
```
- Defined in core/context.ts:273