> ## Documentation Index
> Fetch the complete documentation index at: https://langchain-5e9cc07a-preview-usagev-1776718497-b6ed428.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Models

> Configure model providers and parameters for Deep Agents

Deep Agents work with any [LangChain chat model](/oss/javascript/langchain/models) that supports [tool calling](/oss/javascript/langchain/models#tool-calling).

## Supported models

Specify models in `provider:model` format (for example, `google_genai:gemini-3.1-pro-preview`, `openai:gpt-5.4`, or `anthropic:claude-sonnet-4-6`). For valid provider strings, see the `model_provider` parameter of [`init_chat_model`](https://reference.langchain.com/javascript/langchain/chat_models/universal/initChatModel). For provider-specific configuration, see [chat model integrations](/oss/javascript/integrations/chat).

### Suggested models

These models perform well on the [Deep Agents eval suite](https://github.com/langchain-ai/deepagents/tree/main/libs/evals#readme), which tests basic agent operations. Passing these evals is necessary but not sufficient for strong performance on longer, more complex tasks.

| Provider                                                      | Models                                                                                                                                   |
| ------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------- |
| [Google](/oss/javascript/integrations/providers/google)       | `gemini-3.1-pro-preview`, `gemini-3-flash-preview`                                                                                       |
| [OpenAI](/oss/javascript/integrations/providers/openai)       | `gpt-5.4`, `gpt-4o`, `gpt-4.1`, `o4-mini`, `gpt-5.2-codex`, `gpt-4o-mini`, `o3`                                                          |
| [Anthropic](/oss/javascript/integrations/providers/anthropic) | `claude-opus-4-6`, `claude-opus-4-5`, `claude-sonnet-4-6`, `claude-sonnet-4`, `claude-sonnet-4-5`, `claude-haiku-4-5`, `claude-opus-4-1` |
| Open-weight                                                   | `GLM-5`, `Kimi-K2.5`, `MiniMax-M2.5`, `qwen3.5-397B-A17B`, `devstral-2-123B`                                                             |

Open-weight models are available through providers like [OpenRouter](/oss/javascript/integrations/chat/openrouter), [Fireworks](/oss/javascript/integrations/chat/fireworks) or [Ollama](/oss/javascript/integrations/chat/ollama).

## Configure model parameters

Pass a model string to [`createDeepAgent`](https://reference.langchain.com/javascript/deepagents/agent/createDeepAgent) in `provider:model` format, or pass a configured model instance for full control. Under the hood, model strings are resolved via [`init_chat_model`](https://reference.langchain.com/javascript/langchain/chat_models/universal/initChatModel).

To configure model-specific parameters, use [`init_chat_model`](https://reference.langchain.com/javascript/langchain/chat_models/universal/initChatModel) or instantiate a provider model class directly:

<CodeGroup>
  ```typescript initChatModel theme={"theme":{"light":"catppuccin-latte","dark":"catppuccin-mocha"}}
  import { initChatModel } from "langchain/chat_models/universal";
  import { createDeepAgent } from "deepagents";

  const model = await initChatModel("google_genai:gemini-3.1-pro-preview", {
      reasoningEffort: "medium",  // [!code highlight]
  });
  const agent = createDeepAgent({ model });
  ```

  ```typescript Provider package theme={"theme":{"light":"catppuccin-latte","dark":"catppuccin-mocha"}}
  import { ChatGoogle } from "@langchain/google";
  import { createDeepAgent } from "deepagents";

  const model = new ChatGoogle({
      model: "gemini-3.1-pro-preview",
      reasoningEffort: "medium",  // [!code highlight]
  });
  const agent = createDeepAgent({ model });
  ```
</CodeGroup>

<Note>
  Available parameters vary by provider. See the [chat model integrations](/oss/javascript/integrations/chat) page for provider-specific configuration options.
</Note>

## Select a model at runtime

If your application lets users choose a model (for example using a dropdown in the UI), use [middleware](/oss/javascript/langchain/middleware) to swap the model at runtime without rebuilding the agent.

```typescript theme={"theme":{"light":"catppuccin-latte","dark":"catppuccin-mocha"}}
import { initChatModel, createMiddleware } from "langchain";
import { createDeepAgent } from "deepagents";
import * as z from "zod";

const contextSchema = z.object({
  model: z.string(),
});

const configurableModel = createMiddleware({
  name: "ConfigurableModel",
  wrapModelCall: async (request, handler) => {
    const modelName = request.runtime.context.model;
    const model = await initChatModel(modelName);
    return handler({ ...request, model });
  },
});

const agent = await createDeepAgent({
  model: "google_genai:gemini-3.1-pro-preview",
  middleware: [configurableModel],
  contextSchema,
});

// Invoke with the user's model selection
const result = await agent.invoke(
  { messages: [{ role: "user", content: "Hello!" }] },
  { context: { model: "openai:gpt-5.4" } },
);
```

<Tip>
  For more dynamic model patterns (for example routing based on conversation complexity or cost optimization), see [Dynamic model](/oss/javascript/langchain/agents#dynamic-model) in the LangChain agents guide.
</Tip>

## Learn more

* [Models in LangChain](/oss/javascript/langchain/models): chat model features including tool calling, structured output, and multimodality

***

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