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You can create a Nuwa-Compatible MCP server by using the Nuwa Payment Kit and Identityt Kit.
  • Nuwa Identity Kit helps to manage your DID key and signs transactions on your MCP server.
  • Nuwa Payment Kit provides a drop-in replacement version of the FastMCP server wrapper (createFastMcpServerFromEnv) that lets you config paid MCP tools easily.
With these SDKs, you can expose a single /mcp endpoint and declare free and paid tools in the same way you build your MCP.

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Quick start

Before you start: you need a Service Key for your service DID. Follow the Service Key guide to create one on cadop-web and copy it as SERVICE_KEY.
You can find a starter template in the Nuwa Kit Examples.
1

Install

pnpm add @nuwa-ai/payment-kit @nuwa-ai/identity-kit
2

Create a minimal server (from env)

mcp/index.ts
import { IdentityKit, KeyManager } from '@nuwa-ai/identity-kit';
import { createFastMcpServerFromEnv } from '@nuwa-ai/payment-kit/mcp';
import { z } from 'zod';

async function main() {
  const serviceKey = process.env.SERVICE_KEY || '';
  if (!serviceKey) throw new Error('SERVICE_KEY is required');

  const keyManager = await KeyManager.fromSerializedKey(serviceKey);
  const serviceDid = await keyManager.getDid();

  const env = await IdentityKit.bootstrap({
    method: 'rooch',
    keyStore: keyManager.getStore(),
    vdrOptions: { network: 'test' },
  });

  const server = await createFastMcpServerFromEnv(env, {
    serviceId: 'nuwa-mcp-demo',
    adminDid: serviceDid,
    debug: true,
    port: Number(process.env.PORT || 8080),
    endpoint: '/mcp',
  });

  // Paid tool
  server.paidTool({
    name: 'analyze',
    description: 'Analyze input',
    pricePicoUSD: 1_000_000_000n, // 0.001 USD
    parameters: { text: z.string().describe('Text to analyze') },
    async execute({ text }) { return { summary: `Analysis of: ${text}` }; },
  });

  // Free tool
  server.freeTool({
    name: 'ping',
    description: 'Health check',
    parameters: z.object({}),
    async execute() { return { ok: true }; },
  });

  await server.start();
}

main().catch(err => { console.error(err); process.exit(1); });
3

Set environment variables and run

export SERVICE_KEY=...    # ServiceDID private key (serialized)
export PORT=8080          # optional
node server.js            # or tsx src/index.ts in your project
The SERVICE_KEY value is generated in the Service Key guide when you add an authentication method to your Agent DID.
4

Try Your MCP with Cap Studio

Go to Nuwa Cap Studio and use the MCP tools to try your MCP server.MCP Tool in the Cap Studio

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createFastMcpServerFromEnv

createFastMcpServerFromEnv is a drop-in replacement for the FastMCP server wrapper (createFastMcpServer). It injects extra fields in the input and output to make the it Nuwa-Compatible and payment possible:
  • The wrapper injects __nuwa_auth and __nuwa_payment into the input.
  • For output, it adds a payment resource to the returned object.
For more details, refer to the Nuwa Payment Kit.

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Tool Caller DID

You can obtain the DID of the MCP tool caller via the context input: 
server.freeTool({
  name: 'get_did',
  description: 'Get the DID of the caller.',
  parameters: {},
  async execute(_args: unknown, context: any) {
    const did = context?.didInfo?.did || "unknown";
    return { did };
  },
});

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Relevant Docs

Revenue

View balances, withdraw, and audit revenue history

Service Key

How to obtain and configure SERVICE_KEY