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

# Class: SubAgent

> TypeScript SDK reference

[weave](../) / SubAgent

A nested agent invocation — used when the current agent hands work to
another named agent (e.g. a planner calling a researcher). Emits an
`invoke_agent` span tagged with the sub-agent's name and (optionally)
its model.

Created by `weave.startSubagent()` (or `turn.startAgent()`, or
`llm.startAgent()`) and terminated with `end()`.

`Example`

```ts twoslash theme={null}
// @noErrors
const sub = weave.startSubagent({name: 'researcher', model: 'gpt-4o'});
try {
  // ... orchestrate the sub-agent's LLM/Tool calls ...
} finally {
  sub.end();
}
```

## Hierarchy

* `SpanBase`

  ↳ `SubAgent`

## Table of contents

### Properties

* [model](./subagent#model)
* [name](./subagent#name)

### Methods

* [addEvent](./subagent#addevent)
* [end](./subagent#end)
* [setAttributes](./subagent#setattributes)
* [create](./subagent#create)

## Properties

### model

• `Readonly` **model**: `string`

#### Defined in

[src/genai/subagent.ts:41](https://github.com/wandb/weave/blob/9591aba8a5e77309ee0858e5ba94d31c1bd7e404/sdks/node/src/genai/subagent.ts#L41)

***

### name

• `Readonly` **name**: `string`

#### Defined in

[src/genai/subagent.ts:40](https://github.com/wandb/weave/blob/9591aba8a5e77309ee0858e5ba94d31c1bd7e404/sdks/node/src/genai/subagent.ts#L40)

## Methods

### addEvent

▸ **addEvent**(`name`, `attributes?`, `startTime?`): `this`

Add a named event to the span. Useful for marking non-span moments such as
context compaction, tool-loop detection, or guardrail trips. Warns and
no-ops after `end()`. Mirrors OTel `Span.addEvent`.

#### Parameters

| Name          | Type         |
| :------------ | :----------- |
| `name`        | `string`     |
| `attributes?` | `Attributes` |
| `startTime?`  | `TimeInput`  |

#### Returns

`this`

`Example`

```ts twoslash theme={null}
// @noErrors
span.addEvent('context_compacted', {removedMessages: 12});
```

#### Inherited from

SpanBase.addEvent

#### Defined in

[src/genai/spanBase.ts:77](https://github.com/wandb/weave/blob/9591aba8a5e77309ee0858e5ba94d31c1bd7e404/sdks/node/src/genai/spanBase.ts#L77)

***

### end

▸ **end**(`opts?`): `void`

Close the SubAgent span. Idempotent. Pass `error` to mark it as failed;
pass `endTime` to backdate the close.

#### Parameters

| Name    | Type             |
| :------ | :--------------- |
| `opts?` | `SpanEndOptions` |

#### Returns

`void`

#### Defined in

[src/genai/subagent.ts:72](https://github.com/wandb/weave/blob/9591aba8a5e77309ee0858e5ba94d31c1bd7e404/sdks/node/src/genai/subagent.ts#L72)

***

### setAttributes

▸ **setAttributes**(`attributes`): `this`

Set multiple attributes on the span at once. Warns and no-ops after
`end()`. Mirrors OTel `Span.setAttributes` (and the Python SDK's
`set_attributes`).

#### Parameters

| Name         | Type         |
| :----------- | :----------- |
| `attributes` | `Attributes` |

#### Returns

`this`

`Example`

```ts twoslash theme={null}
// @noErrors
span.setAttributes({'weave.tag': 'prod', 'gen_ai.response.id': id});
```

#### Inherited from

SpanBase.setAttributes

#### Defined in

[src/genai/spanBase.ts:63](https://github.com/wandb/weave/blob/9591aba8a5e77309ee0858e5ba94d31c1bd7e404/sdks/node/src/genai/spanBase.ts#L63)

***

### create

▸ **create**(`opts`): [`SubAgent`](./subagent)

#### Parameters

| Name   | Type                                                              |
| :----- | :---------------------------------------------------------------- |
| `opts` | [`SubAgentInit`](../interfaces/subagentinit) & `ChildSpanContext` |

#### Returns

[`SubAgent`](./subagent)

#### Defined in

[src/genai/subagent.ts:46](https://github.com/wandb/weave/blob/9591aba8a5e77309ee0858e5ba94d31c1bd7e404/sdks/node/src/genai/subagent.ts#L46)