Weights & Biases

Access 10 Weights & Biases models through Mastra's model router. Authentication is handled automatically using the WANDB_API_KEY environment variable.

Learn more in the Weights & Biases documentation.

WANDB_API_KEY=your-api-key

import { Agent } from "@mastra/core";

const agent = new Agent({
  name: "my-agent",
  instructions: "You are a helpful assistant",
  model: "wandb/Qwen/Qwen3-235B-A22B-Instruct-2507",
});

// Generate a response
const response = await agent.generate("Hello!");

// Stream a response
const stream = await agent.stream("Tell me a story");
for await (const chunk of stream) {
  console.log(chunk);
}

OpenAI Compatibility

Mastra uses the OpenAI-compatible /chat/completions endpoint. Some provider-specific features may not be available. Check the Weights & Biases documentation for details.

Models

Model	Image	Audio	Video	Tools	Streaming	Context Window
wandb/moonshotai/Kimi-K2-Instruct	✗	✗	✗	✓	✗	128,000
wandb/microsoft/Phi-4-mini-instruct	✗	✗	✗	✓	✗	128,000
wandb/meta-llama/Llama-3.1-8B-Instruct	✗	✗	✗	✓	✗	128,000
wandb/meta-llama/Llama-3.3-70B-Instruct	✗	✗	✗	✓	✗	128,000
wandb/meta-llama/Llama-4-Scout-17B-16E-Instruct	✓	✗	✗	✓	✗	64,000
wandb/Qwen/Qwen3-235B-A22B-Instruct-2507	✗	✗	✗	✓	✗	262,144
wandb/Qwen/Qwen3-Coder-480B-A35B-Instruct	✗	✗	✗	✓	✗	262,144
wandb/Qwen/Qwen3-235B-A22B-Thinking-2507	✗	✗	✗	✓	✗	262,144
wandb/deepseek-ai/DeepSeek-R1-0528	✗	✗	✗	✓	✗	161,000
wandb/deepseek-ai/DeepSeek-V3-0324	✗	✗	✗	✓	✗	161,000

Advanced Configuration

Custom Headers

const agent = new Agent({
  name: "custom-agent",
  model: {
    url: "https://api.inference.wandb.ai/v1",
    modelId: "Qwen/Qwen3-235B-A22B-Instruct-2507",
    apiKey: process.env.WANDB_API_KEY,
    headers: {
      "X-Custom-Header": "value",
    },
  },
});

Dynamic Model Selection

const agent = new Agent({
  name: "dynamic-agent",
  model: ({ runtimeContext }) => {
    const useAdvanced = runtimeContext.task === "complex";
    return useAdvanced
      ? "wandb/moonshotai/Kimi-K2-Instruct"
      : "wandb/Qwen/Qwen3-235B-A22B-Instruct-2507";
  },
});