Modelis

Access 9 Modelis models through Mastra's model router. Authentication is handled automatically using the MODELIS_API_KEY environment variable.

Learn more in the Modelis documentation.

.env

MODELIS_API_KEY=your-api-key

src/mastra/agents/my-agent.ts

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

const agent = new Agent({
  id: "my-agent",
  name: "My Agent",
  instructions: "You are a helpful assistant",
  model: "modelis/claude-fable-5"
});

// 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);
}

info

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

Models

9 available models

Model	Context	Tools	Reasoning	Image	Audio	Video	Input $/1M	Output $/1M
modelis/claude-fable-5	1.0M						$10	$50
modelis/claude-opus-4-8	1.0M						$5	$25
modelis/claude-sonnet-4-6	1.0M						$3	$15
modelis/deepseek-v4-flash	1.0M						$0.10	$0.20
modelis/deepseek-v4-pro	1.0M						$0.43	$0.87
modelis/gemini-2.5-flash	1.0M						$0.30	$3
modelis/gemini-2.5-pro	1.0M						$1	$10
modelis/qwen/qwen3.7-max	1.0M						$3	$9
modelis/qwen/qwen3.7-plus	1.0M						$0.77	$3

Advanced configuration

Custom headers

src/mastra/agents/my-agent.ts

const agent = new Agent({
  id: "custom-agent",
  name: "custom-agent",
  model: {
    url: "https://modelishub.com/v1",
    id: "modelis/claude-fable-5",
    apiKey: process.env.MODELIS_API_KEY,
    headers: {
      "X-Custom-Header": "value"
    }
  }
});

Dynamic model selection

src/mastra/agents/my-agent.ts

const agent = new Agent({
  id: "dynamic-agent",
  name: "Dynamic Agent",
  model: ({ requestContext }) => {
    const useAdvanced = requestContext.task === "complex";
    return useAdvanced
      ? "modelis/qwen/qwen3.7-plus"
      : "modelis/claude-fable-5";
  }
});