OpenCode Zen

Access 102 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.

.env

OPENCODE_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: "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);
}

note

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

Models

69 available models

Model	Context	Tools	Reasoning	Image	Audio	Video	Input $/1M	Output $/1M
opencode/big-pickle	200K						—	—
opencode/claude-fable-5	1.0M						$10	$50
opencode/claude-fable-5-1	1.0M						$10	$50
opencode/claude-haiku-4-5	200K						$1	$5
opencode/claude-opus-4-5	200K						$5	$25
opencode/claude-opus-4-6	1.0M						$5	$25
opencode/claude-opus-4-7	1.0M						$5	$25
opencode/claude-opus-4-8	1.0M						$5	$25
opencode/claude-opus-5	1.0M						$5	$25
opencode/claude-sonnet-4	1.0M						$3	$15
opencode/claude-sonnet-4-5	1.0M						$3	$15
opencode/claude-sonnet-4-6	1.0M						$3	$15
opencode/claude-sonnet-5	1.0M						$2	$10
opencode/deepseek-v4-flash	1.0M						$0.14	$0.28
opencode/deepseek-v4-flash-vision-exp	1.0M						$0.14	$0.28
opencode/deepseek-v4-pro	1.0M						$2	$4
opencode/gemini-3-flash	1.0M						$0.50	$3
opencode/gemini-3.1-pro	1.0M						$2	$12
opencode/gemini-3.5-flash	1.0M						$2	$9
opencode/gemini-3.5-flash-lite	1.0M						$0.30	$3
opencode/gemini-3.6-flash	1.0M						$2	$8
opencode/gemini-3.7-flash	1.0M						$2	$8
opencode/gemini-3.8-flash	1.0M						$2	$8
opencode/glm-5	205K						$1	$3
opencode/glm-5.1	205K						$1	$4
opencode/glm-5.2	1.0M						$1	$4
opencode/glm-5.3	1.0M						$1	$4
opencode/glm-5.3-flash	1.0M						$0.15	$0.50
opencode/gpt-5	400K						$1	$9
opencode/gpt-5-codex	400K						$1	$9
opencode/gpt-5-nano	400K						$0.05	$0.40
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/gpt-5.3-codex	400K						$2	$14
opencode/gpt-5.3-codex-spark	128K						$2	$14
opencode/gpt-5.4	1.1M						$3	$15
opencode/gpt-5.4-mini	400K						$0.75	$5
opencode/gpt-5.4-nano	400K						$0.20	$1
opencode/gpt-5.4-pro	1.1M						$30	$180
opencode/gpt-5.5	1.1M						$5	$30
opencode/gpt-5.5-pro	1.1M						$30	$180
opencode/gpt-5.6-luna	1.1M						$0.20	$1
opencode/gpt-5.6-sol	1.1M						$2	$10
opencode/gpt-5.6-terra	1.1M						$3	$15
opencode/gpt-6-astra	1.1M						$10	$50
opencode/grok-4.5	500K						$2	$6
opencode/grok-4.6	500K						$2	$6
opencode/grok-build-0.1	256K						$1	$2
opencode/kimi-k2.5	262K						$0.60	$3
opencode/kimi-k2.6	262K						$0.95	$4
opencode/kimi-k2.7-code	262K						$0.95	$4
opencode/kimi-k3	1.0M						$3	$15
opencode/ling-3.0-flash-fin-free	262K						—	—
opencode/mimo-v2.5-free	200K						—	—
opencode/minimax-m2.5	205K						$0.30	$1
opencode/minimax-m2.7	205K						$0.30	$1
opencode/minimax-m3	512K						$0.30	$1
opencode/muse-spark-1.2	1.0M						$1	$4
opencode/muse-spark-1.2-contributor-free	1.0M						—	—
opencode/muse-spark-1.3	1.0M						$1	$4
opencode/muse-spark-1.3-contributor-free	1.0M						—	—
opencode/nemotron-3-ultra-free	1.0M						—	—
opencode/nemotron-3.5-lightning-free	262K						—	—
opencode/qwen3.5-plus	262K						$0.20	$1
opencode/qwen3.6-plus	262K						$0.50	$3

Model availability, capabilities, context windows, and pricing are sourced from models.dev and may change.

Advanced configuration

Custom headers

src/mastra/agents/my-agent.ts

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

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
      ? "opencode/x-preview-f-free"
      : "opencode/big-pickle";
  }
});