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Access 27 OpenAI models through Mastra's model router. Authentication is handled automatically using the OPENAI_API_KEY environment variable.

Learn more in the OpenAI documentation.

OPENAI_API_KEY=your-api-key
import { Agent } from "@mastra/core";

const agent = new Agent({
name: "my-agent",
instructions: "You are a helpful assistant",
model: "openai/codex-mini-latest",
});

// 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);
}

Models

ModelImageAudioVideoToolsStreamingContext Window
openai/gpt-4.1-nano1,047,576
openai/gpt-48,192
openai/o1-pro200,000
openai/gpt-4o-2024-05-13128,000
openai/gpt-4o-2024-08-06128,000
openai/gpt-4.1-mini1,047,576
openai/o3-deep-research200,000
openai/gpt-3.5-turbo16,385
openai/gpt-4-turbo128,000
openai/o1-preview128,000
openai/o3-mini200,000
openai/codex-mini-latest200,000
openai/gpt-5-nano400,000
openai/gpt-5-codex400,000
openai/gpt-4o128,000
openai/gpt-4.11,047,576
openai/o4-mini200,000
openai/o1200,000
openai/gpt-5-mini400,000
openai/o1-mini128,000
openai/o3-pro200,000
openai/gpt-4o-2024-11-20128,000
openai/o3200,000
openai/o4-mini-deep-research200,000
openai/gpt-5-chat-latest400,000
openai/gpt-4o-mini128,000
openai/gpt-5400,000

Advanced Configuration

Custom Headers

const agent = new Agent({
name: "custom-agent",
model: {
modelId: "codex-mini-latest",
apiKey: process.env.OPENAI_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
? "openai/o4-mini-deep-research"
: "openai/codex-mini-latest";
},
});

Direct Provider Installation

This provider can also be installed directly as a standalone package, which can be used instead of the Mastra model router string. View the package documentation for more details.

npm install @ai-sdk/openai