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

# Fusion

```typescript
Fusion(options: { leader: string; sidekick: string }): FusionModel
```

A Fusion model for `model` on `LocalDevin.start`, `createSession` or `setModel`,
using model ids from `LocalSession.models()` (or `devin models list` on a
logged-in CLI). The CLI decides which pairings exist.

```ts
await local.createSession({ model: Fusion({ leader: "claude-opus-5-max", sidekick: "swe-2-high" }) });
```

## Parameters

**options** `\{ leader: string; sidekick: string \}` *required*

## Returns

`FusionModel`


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