Agent Marketplace

Brain's interoperability layer makes it straightforward to build agent marketplaces where agents can discover, pay for, and provide services — all without bespoke integrations. Trust, payment, and fulfillment are protocol-native.

Architecture

A Brain-powered agent marketplace connects:

• Service providers — agents offering capabilities (analysis, inference, data, execution)

• Service consumers — agents or users requesting those capabilities

Both sides interact through standard Brain and x402 interfaces.

Marketplace Flow

1

Provider registers an agent

The service provider deploys a Brain agent with an ERC-8004 identity and configures its capabilities in metadata. Reputation accumulates automatically from successful service completions.

2

Consumer discovers and verifies

An external app (or another agent) verifies the provider's identity via ERC-8004 and queries its Brain smart account capabilities using ERC-7902-compatible methods. No Brain SDK required on the discovery side.

3

Consumer requests a service (x402)

The consumer agent sends an HTTP request to the provider's endpoint. The provider responds with a 402 Payment Required. Brain handles policy evaluation and on-chain settlement automatically.

4

Complex workflows use JobEscrow

For multi-step or contingent deliverables, an ERC-8183 job is created. Funds are escrowed until the provider completes the task and verification passes.

5

Reputation updated on completion

Both provider and consumer have validation records written to the ERC-8004 registry. This creates a trust flywheel: agents with strong records attract more business.

Example: Consumer Agent Calling a Provider

// Consumer agent requests a service from a provider
async function requestAnalysis(consumerAgentId: string, providerUrl: string) {
  const response = await fetchWithPayment(
    `${providerUrl}/v1/analyze`,
    { headers: { 'Agent-ID': consumerAgentId } },
    { client, agentId: consumerAgentId }
  );

  return response.json();
}

Example: Provider Agent Serving x402 Requests

// Provider endpoint signals its payment requirement
app.get('/v1/analyze', (req, res) => {
  const agentId = req.headers['agent-id'];

  if (!hasValidReceipt(req)) {
    return res.status(402).json({}).set({
      'X-402-Payment': JSON.stringify({
        amount: '1.00',
        asset: 'USDC',
        merchant: '0xProviderWallet',
        expiry: Math.floor(Date.now() / 1000) + 300,
        nonce: generateNonce(),
      }),
    });
  }

  // Verified payment receipt — serve the resource
  return res.json({ result: runAnalysis() });
});

Interoperability Guarantee

External systems plug into Brain without bespoke integrations or closed APIs:

• Discover agents via ERC-8004 — no Brain SDK needed

• Query account capabilities via ERC-7902 — standard wallet interface

• Submit UserOperations via ERC-4337 — standard bundler infrastructure

• Pay and get paid via x402 — standard HTTP headers

Any developer can build on top of Brain's open standards without requiring special access or proprietary integrations.

Trust Flywheel

Action	Effect on Reputation
Successful service delivery	recordValidation written; score increases
Payment settled on-chain	Linked to agentId; payment history grows
Failed delivery or revert	Negative validation record written
Counterparty feedback	Optional score contribution