OpenCode Zen

Access 27 OpenCode Zen models through Mastra's model router. Authentication is handled automatically using the OPENCODE_API_KEY environment variable.

Learn more in the OpenCode Zen documentation.

OPENCODE_API_KEY=your-api-key

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

const agent = new Agent({
  name: "my-agent",
  instructions: "You are a helpful assistant",
  model: "opencode/alpha-gd4"
});

// 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 OpenCode Zen documentation for details.

Models

27 available models

Model	Context	Tools	Reasoning	Image	Audio	Video	Input $/1M	Output $/1M
opencode/alpha-gd4	262K						$0.50	$2
opencode/alpha-glm-4.7	205K						$0.60	$2
opencode/big-pickle	200K						—	—
opencode/claude-3-5-haiku	200K						$0.80	$4
opencode/claude-haiku-4-5	200K						$1	$5
opencode/claude-opus-4-1	200K						$15	$75
opencode/claude-opus-4-5	200K						$5	$25
opencode/claude-sonnet-4	1.0M						$3	$15
opencode/claude-sonnet-4-5	1.0M						$3	$15
opencode/gemini-3-flash	1.0M						$0.50	$3
opencode/gemini-3-pro	1.0M						$2	$12
opencode/glm-4.6	205K						$0.60	$2
opencode/glm-4.7-free	205K						—	—
opencode/gpt-5	400K						$1	$9
opencode/gpt-5-codex	400K						$1	$9
opencode/gpt-5-nano	400K						—	—
opencode/gpt-5.1	400K						$1	$9
opencode/gpt-5.1-codex	400K						$1	$9
opencode/gpt-5.1-codex-max	400K						$1	$10
opencode/gpt-5.1-codex-mini	400K						$0.25	$2
opencode/gpt-5.2	400K						$2	$14
opencode/gpt-5.2-codex	400K						$2	$14
opencode/grok-code	256K						—	—
opencode/kimi-k2	262K						$0.40	$3
opencode/kimi-k2-thinking	262K						$0.40	$3
opencode/minimax-m2.1-free	205K						—	—
opencode/qwen3-coder	262K						$0.45	$2

Advanced Configuration

Custom Headers

const agent = new Agent({
  name: "custom-agent",
  model: {
    url: "https://opencode.ai/zen/v1",
    id: "opencode/alpha-gd4",
    apiKey: process.env.OPENCODE_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
      ? "opencode/qwen3-coder"
      : "opencode/alpha-gd4";
  }
});