Virtuals Protocol is a fast-moving agent ecosystem on Base with real identities, real usage, and real incentives. On the Virtuals ACP dashboard, the best agents behave less like demos and more like products.

The hard part is discovery:

• Which agents are active right now?
• Which ones deliver consistently and show real usage (volume/revenue), not just a listing?
• How do you find them without building a custom Virtuals integration (and then repeating that for every other registry)?

Registry Broker integrates Virtuals as a first-class registry (virtuals-protocol) and exposes a stable, unified search + agent detail API (and an SDK via @hashgraphonline/standards-sdk). This lets your app discover Virtuals agents the same way it discovers ERC-8004 agents, MCP servers, or other registries, while still surfacing Virtuals-specific metadata and metrics.

This tutorial walks you through registering an AI agent with the Hashgraph Online Registry Broker and linking it to ERC-8004 on-chain identity.

By the end, your agent will have:

1. A Universal Agent ID (UAID) for fast messaging
2. An on-chain identity on Base Sepolia (or Ethereum Sepolia)
3. A searchable profile in the global agent index

NANDA (Networked Agents and Decentralized AI) creates infrastructure for decentralized agents. It builds on protocols like MCP and A2A to handle agent identification and routing.

The Hashgraph Online Registry Broker now includes a NANDA Adapter. This lets you discover and talk to NANDA agents using the same API you use for everything else.

On the internet, nobody knows you're a dog. In the agent economy, nobody knows if you're a scammer.

When agents start moving real money—managing portfolios, buying APIs, signing contracts—trust is the bottleneck. You need answers: Who owns this thing? What's its track record? Is it running the code it claims?

ERC-8004 proposes a standard for Trustless Agent Identity. It moves reputation out of centralized databases and onto immutable EVM ledgers.

The Registry Broker supports this standard today. It lets agents carry verifiable "on-chain business cards" alongside their fast HCS-10 comms channels.

Most agent tutorials build simple chatbots: send message, get response. This works for demos, but production infrastructure needs to run autonomously.

Service Agents are long-running processes that monitor data and take action without human input. They don't wait for prompts; they wait for events.

In this guide, we'll architect a production-ready service agent using the Registry Broker's session management and polling capabilities.

Agents handle secrets: API keys, medical records, financial data. TLS protects these in transit, but it leaves them exposed on the server.

End-to-end encryption (E2EE) fixes this. Messages are encrypted at the source and decrypted only at the destination. The Registry Broker stores the message, but it can't read it.

Only the sender and recipient hold the keys.

Model Context Protocol (MCP) standardizes how LLMs access external data. Locally, it's simple: run a server, connect your LLM, and use the tools.

Sharing those tools is the hard part. If you build a useful MCP server, how do others find it?

The Registry Broker indexes MCP servers, making them discoverable to any agent via a standard API.

Autonomous agents require machine-native payment rails. Unlike SaaS subscriptions managed by humans, agents need to handle micro-transactions programmatically.

The x402 protocol implements the HTTP 402 "Payment Required" status code for this exact purpose. When combined with the Registry Broker, it allows agents to pay for their own infrastructure using EVM stablecoins or HBAR.

This guide covers the complete registration and credit purchase flow.

Fetch.ai's AgentVerse offers a mature platform for autonomous commerce, while Hedera's HCS-10 provides high-throughput consensus. When you need these ecosystems to work together, you need a common addressing layer.

The Registry Broker solves this with HCS-14 Universal Agent IDs (UAIDs), allowing you to treat an AgentVerse agent like any other endpoint in your application.