OpenCode Zen

Access 33 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/agent";

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

// 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

<ProviderModelsTable models={[ { "model": "opencode/big-pickle", "imageInput": false, "audioInput": false, "videoInput": false, "toolUsage": true, "reasoning": true, "contextWindow": 200000, "maxOutput": 128000, "inputCost": null, "outputCost": null }, { "model": "opencode/claude-3-5-haiku", "imageInput": true, "audioInput": false, "videoInput": false, "toolUsage": true, "reasoning": false, "contextWindow": 200000, "maxOutput": 8192, "inputCost": 0.8, "outputCost": 4 }, { "model": "opencode/claude-haiku-4-5", "imageInput": true, "audioInput": false, "videoInput": false, "toolUsage": true, "reasoning": true, "contextWindow": 200000, "maxOutput": 64000, "inputCost": 1, "outputCost": 5 }, { "model": "opencode/claude-opus-4-1", "imageInput": true, "audioInput": false, "videoInput": false, "toolUsage": true, "reasoning": true, "contextWindow": 200000, "maxOutput": 32000, "inputCost": 15, "outputCost": 75 }, { "model": "opencode/claude-opus-4-5", "imageInput": true, "audioInput": false, "videoInput": false, "toolUsage": true, "reasoning": true, "contextWindow": 200000, "maxOutput": 64000, "inputCost": 5, "outputCost": 25 }, { "model": "opencode/claude-opus-4-6", "imageInput": true, "audioInput": false, "videoInput": false, "toolUsage": true, "reasoning": true, "contextWindow": 1000000, "maxOutput": 128000, "inputCost": 5, "outputCost": 25 }, { "model": "opencode/claude-sonnet-4", "imageInput": true, "audioInput": false, "videoInput": false, "toolUsage": true, "reasoning": true, "contextWindow": 1000000, "maxOutput": 64000, "inputCost": 3, "outputCost": 15 }, { "model": "opencode/claude-sonnet-4-5", "imageInput": true, "audioInput": false, "videoInput": false, "toolUsage": true, "reasoning": true, "contextWindow": 1000000, "maxOutput": 64000, "inputCost": 3, "outputCost": 15 }, { "model": "opencode/claude-sonnet-4-6", "imageInput": true, "audioInput": false, "videoInput": false, "toolUsage": true, "reasoning": true, "contextWindow": 1000000, "maxOutput": 64000, "inputCost": 3, "outputCost": 15 }, { "model": "opencode/gemini-3-flash", "imageInput": true, "audioInput": true, "videoInput": true, "toolUsage": true, "reasoning": true, "contextWindow": 1048576, "maxOutput": 65536, "inputCost": 0.5, "outputCost": 3 }, { "model": "opencode/gemini-3.1-pro", "imageInput": true, "audioInput": true, "videoInput": true, "toolUsage": true, "reasoning": true, "contextWindow": 1048576, "maxOutput": 65536, "inputCost": 2, "outputCost": 12 }, { "model": "opencode/glm-5", "imageInput": false, "audioInput": false, "videoInput": false, "toolUsage": true, "reasoning": true, "contextWindow": 204800, "maxOutput": 131072, "inputCost": 1, "outputCost": 3.2 }, { "model": "opencode/gpt-5", "imageInput": true, "audioInput": false, "videoInput": false, "toolUsage": true, "reasoning": true, "contextWindow": 400000, "maxOutput": 128000, "inputCost": 1.07, "outputCost": 8.5 }, { "model": "opencode/gpt-5-codex", "imageInput": true, "audioInput": false, "videoInput": false, "toolUsage": true, "reasoning": true, "contextWindow": 400000, "maxOutput": 128000, "inputCost": 1.07, "outputCost": 8.5 }, { "model": "opencode/gpt-5-nano", "imageInput": true, "audioInput": false, "videoInput": false, "toolUsage": true, "reasoning": true, "contextWindow": 400000, "maxOutput": 128000, "inputCost": null, "outputCost": null }, { "model": "opencode/gpt-5.1", "imageInput": true, "audioInput": false, "videoInput": false, "toolUsage": true, "reasoning": true, "contextWindow": 400000, "maxOutput": 128000, "inputCost": 1.07, "outputCost": 8.5 }, { "model": "opencode/gpt-5.1-codex", "imageInput": true, "audioInput": false, "videoInput": false, "toolUsage": true, "reasoning": true, "contextWindow": 400000, "maxOutput": 128000, "inputCost": 1.07, "outputCost": 8.5 }, { "model": "opencode/gpt-5.1-codex-max", "imageInput": true, "audioInput": false, "videoInput": false, "toolUsage": true, "reasoning": true, "contextWindow": 400000, "maxOutput": 128000, "inputCost": 1.25, "outputCost": 10 }, { "model": "opencode/gpt-5.1-codex-mini", "imageInput": true, "audioInput": false, "videoInput": false, "toolUsage": true, "reasoning": true, "contextWindow": 400000, "maxOutput": 128000, "inputCost": 0.25, "outputCost": 2 }, { "model": "opencode/gpt-5.2", "imageInput": true, "audioInput": false, "videoInput": false, "toolUsage": true, "reasoning": true, "contextWindow": 400000, "maxOutput": 128000, "inputCost": 1.75, "outputCost": 14 }, { "model": "opencode/gpt-5.2-codex", "imageInput": true, "audioInput": false, "videoInput": false, "toolUsage": true, "reasoning": true, "contextWindow": 400000, "maxOutput": 128000, "inputCost": 1.75, "outputCost": 14 }, { "model": "opencode/gpt-5.3-codex", "imageInput": true, "audioInput": false, "videoInput": false, "toolUsage": true, "reasoning": true, "contextWindow": 400000, "maxOutput": 128000, "inputCost": 1.75, "outputCost": 14 }, { "model": "opencode/gpt-5.3-codex-spark", "imageInput": false, "audioInput": false, "videoInput": false, "toolUsage": true, "reasoning": true, "contextWindow": 128000, "maxOutput": 128000, "inputCost": 1.75, "outputCost": 14 }, { "model": "opencode/gpt-5.4", "imageInput": true, "audioInput": false, "videoInput": false, "toolUsage": true, "reasoning": true, "contextWindow": 1050000, "maxOutput": 128000, "inputCost": 2.5, "outputCost": 15 }, { "model": "opencode/gpt-5.4-mini", "imageInput": true, "audioInput": false, "videoInput": false, "toolUsage": true, "reasoning": true, "contextWindow": 400000, "maxOutput": 128000, "inputCost": 0.75, "outputCost": 4.5 }, { "model": "opencode/gpt-5.4-nano", "imageInput": true, "audioInput": false, "videoInput": false, "toolUsage": true, "reasoning": true, "contextWindow": 400000, "maxOutput": 128000, "inputCost": 0.2, "outputCost": 1.25 }, { "model": "opencode/gpt-5.4-pro", "imageInput": true, "audioInput": false, "videoInput": false, "toolUsage": true, "reasoning": true, "contextWindow": 1050000, "maxOutput": 128000, "inputCost": 30, "outputCost": 180 }, { "model": "opencode/kimi-k2.5", "imageInput": true, "audioInput": false, "videoInput": true, "toolUsage": true, "reasoning": true, "contextWindow": 262144, "maxOutput": 65536, "inputCost": 0.6, "outputCost": 3 }, { "model": "opencode/mimo-v2-omni-free", "imageInput": true, "audioInput": true, "videoInput": false, "toolUsage": true, "reasoning": true, "contextWindow": 262144, "maxOutput": 64000, "inputCost": null, "outputCost": null }, { "model": "opencode/mimo-v2-pro-free", "imageInput": false, "audioInput": false, "videoInput": false, "toolUsage": true, "reasoning": true, "contextWindow": 1048576, "maxOutput": 64000, "inputCost": null, "outputCost": null }, { "model": "opencode/minimax-m2.5", "imageInput": false, "audioInput": false, "videoInput": false, "toolUsage": true, "reasoning": true, "contextWindow": 204800, "maxOutput": 131072, "inputCost": 0.3, "outputCost": 1.2 }, { "model": "opencode/minimax-m2.5-free", "imageInput": false, "audioInput": false, "videoInput": false, "toolUsage": true, "reasoning": true, "contextWindow": 204800, "maxOutput": 131072, "inputCost": null, "outputCost": null }, { "model": "opencode/nemotron-3-super-free", "imageInput": false, "audioInput": false, "videoInput": false, "toolUsage": true, "reasoning": true, "contextWindow": 1000000, "maxOutput": 128000, "inputCost": null, "outputCost": null } ]} />

Advanced configuration

Custom headers

const agent = new Agent({
  id: "custom-agent",
  name: "custom-agent",
  model: {
    url: "https://opencode.ai/zen/v1",
    id: "opencode/big-pickle",
    apiKey: process.env.OPENCODE_API_KEY,
    headers: {
      "X-Custom-Header": "value"
    }
  }
});

Dynamic model selection

const agent = new Agent({
  id: "dynamic-agent",
  name: "Dynamic Agent",
  model: ({ requestContext }) => {
    const useAdvanced = requestContext.task === "complex";
    return useAdvanced
      ? "opencode/nemotron-3-super-free"
      : "opencode/big-pickle";
  }
});