OpenRouter Agent SDK - Darwin

Use OpenRouter’s MCP adapter to discover Darwin’s tools and pass them directly to the Agent SDK. Install the two SDKs and Zod:

npm install @openrouter/agent @openrouter/mcp

import { OpenRouter } from '@openrouter/agent';
import { callModel } from '@openrouter/agent/call-model';
import { createMCPTools } from '@openrouter/mcp';

const client = new OpenRouter({ apiKey: process.env.OPENROUTER_API_KEY });
const mcp = await createMCPTools({ url: 'https://mcp.darwin.so/mcp' });

try {
  const result = callModel(client, {
    model: 'openai/gpt-5',
    input: 'Search for a PDF text extraction capability. Do not start it.',
    tools: mcp.tools,
  });
  console.log(await result.getText());
} finally {
  await mcp.close();
}

Add Action tools deliberately

Tool class	Application responsibility
Search	Preserve canonical order and the selected capability revision.
Start / Update / Approve / Stop	Validate input server-side and use one stable `requestId` per change.
Get / List	Recover authoritative Action state after retries or process restarts.

Provide an OpenRouter OAuthClientProvider when the application needs Action scopes. Persist actionId outside model messages and return Darwin’s structured pauses to the application without rewriting them as success prose.

Keep Darwin and OpenRouter credentials on the server. Provider tokens, payment data, and approval payloads do not belong in prompts or client-visible tool arguments.

View the complete Darwin recipe or OpenRouter’s MCP tools documentation.

Last modified on September 22, 2026