@hashgraphonline/standards-sdk

Hashgraph Online Standards SDK

	A lightweight SDK providing reference implementations for Hashgraph Consensus Standards (HCS) created by Hashgraph Online. This SDK is built and maintained by Hashgraph Online, a consortium of leading Hedera Organizations within the Hedera ecosystem. 📚 Standards SDK Documentation 📖 HCS Standards Documentation

Quick Start

npm install @hol-org/standards-sdk
# Legacy scope:
# npm install @hashgraphonline/standards-sdk

For the standalone Registry Broker client with a smaller footprint:

npm install @hol-org/rb-client

HOL-scoped distributions are published in parallel:

• @hol-org/rb-client: registry broker client only
• @hol-org/standards-sdk: full SDK under the HOL scope

Optional dependencies for @hol-org/rb-client

The client ships with zero network transports bundled. Install these peers when you need the related features:

• axios + x402-axios + x402 for X402 credit purchases and payments
• viem for EVM-based ledger authentication
• @hashgraph/sdk for Hedera ledger authentication

Core agent search/chat flows only require a fetch implementation.

Documentation

For complete documentation, examples, and API references, visit:

• Standards SDK Documentation

Registry Broker skill verification (DNS TXT domain proof)

The RegistryBrokerClient supports version-scoped skill verification plus DNS TXT domain proof:

import { RegistryBrokerClient } from '@hashgraphonline/standards-sdk';

const client = new RegistryBrokerClient({
  apiKey: process.env.REGISTRY_BROKER_API_KEY,
});

await client.requestSkillVerification({
  name: 'demo-skill',
  version: '1.0.0',
  tier: 'basic', // or 'express'
});

const challenge = await client.createSkillDomainProofChallenge({
  name: 'demo-skill',
  version: '1.0.0',
  domain: 'example.com',
});

const challengeToken = challenge.txtRecordValue.replace(/^hol-skill-verification=/, '');

await client.verifySkillDomainProof({
  name: 'demo-skill',
  version: '1.0.0',
  domain: 'example.com',
  challengeToken,
});

Runnable demo: pnpm -C standards-sdk tsx demo/registry-broker/skill-domain-proof-demo.ts --skill-name=<name> --base-url=<broker-api-url>.

Registry Broker UAID DNS verification (HCS-14 DNS TXT profile)

The RegistryBrokerClient can verify and persist _uaid.<nativeId> TXT proof for an agent UAID:

import { RegistryBrokerClient } from '@hashgraphonline/standards-sdk';

const client = new RegistryBrokerClient({
  baseUrl: 'https://hol.org/registry/api/v1',
});

const verify = await client.verifyUaidDnsTxt({
  uaid: 'uaid:aid:...;uid=...;proto=a2a;nativeId=agent.hol.org',
  persist: true,
});

const status = await client.getVerificationDnsStatus(
  'uaid:aid:...;uid=...;proto=a2a;nativeId=agent.hol.org',
  { refresh: true, persist: false },
);

Runnable demo: pnpm -C standards-sdk run demo:registry-broker-uaid-dns -- --uaid=<uaid> --base-url=<broker-api-url>.

Interactive CLI and Demos

Launch the bundled CLI to explore registry broker demos, inspect required env vars, and run helper scripts:

pnpm run cli

The CLI surfaces:

• Guided registry broker demos (OpenRouter, chat history, ledger auth) plus the HCS-10 agent flows.
• A map of required env vars so you can bootstrap Hedera credentials and adapters quickly.
• Links back to the docs plus the demo scripts you can run manually (demo/registry-broker, demo/hcs-10).

See cli/standards-cli/README.md for advanced and non-interactive commands.

Supported Standards

Standard	Description
HCS-1	File Storage
HCS-2	Registry and Indexing Standard
HCS-3	Recursive File Loading
HCS-7	Smart Hashinals
HCS-10	Trustless Peer-to-Peer Communication for Agents and AI
HCS-11	Decentralized Profile and Identity Standard
HCS-20	Auditable Points
HCS-27	Transparency Logs

Running Demos

The SDK includes demo implementations that showcase registry broker flows (discovery, chat, ledger auth, OpenRouter) and HCS-10 agent communication. Follow these steps to run them:

• Clone the repository

  git clone https://github.com/hashgraph-online/standards-sdk.git
  cd standards-sdk
  

• Install dependencies

  npm install
  

• Set up environment variables

  cp .env.example .env
  

• Edit the .env file with your Hedera credentials:

  HEDERA_ACCOUNT_ID=0.0.12345
  HEDERA_PRIVATE_KEY=your_private_key_here
  HEDERA_NETWORK=testnet
  REGISTRY_URL=https://moonscape.tech
  

  The CLI can also auto-persist agent state in .env if a demo is interrupted. See .env.example for generated state fields.

• Start a demo (or use pnpm run cli for an interactive launcher):

  npm run demo:registry-broker
  

  npm run demo:hcs-10
  

Each demo directory contains README instructions plus you can review demo/registry-broker and demo/hcs-10 for fine-grained scripts covering OpenRouter, history snapshots, ledger authentication, and fee flows.

Demo Descriptions

Inscribe Demo

The inscribe demo (demo/inscribe-demo.ts) showcases different file inscription capabilities:

• Text inscription using buffers
• URL-based inscriptions
• File buffer inscriptions
• Creating Hashinal NFTs from URLs
• Creating Hashinal NFTs from buffers
• Creating Hashinal NFTs from text content

Each inscription demonstrates different options and metadata capabilities.

HCS-10 AI Agent Communication Demo

The HCS-10 demo (demo/hcs-10/index.ts) demonstrates trustless peer-to-peer communication between AI agents:

• Agent creation and registration (Alice and Bob)
• Agent metadata and profile management
• Connection establishment between agents
• Sending and retrieving small messages
• Sending and retrieving large messages with recursive storage
• Message data processing
• Resumable agent creation: If agent creation is interrupted, the SDK automatically resumes from where it left off using state saved in environment variables

The demo automatically handles agent funding, topic creation, and registration with the global registry. Agent creation progress is tracked in real-time and saved to the .env file, allowing recovery from any interruption.

Contributing

Please read our Contributing Guide and Code of Conduct before contributing to this project.

For bugs and feature requests, please use the issue templates.

Security

For security concerns, please refer to our Security Policy.

Maintainers

See MAINTAINERS.md for a list of project maintainers.

Resources

• HCS Standards Documentation
• Hedera Documentation
• Telegram Community

📝 Blog Tutorials

• Building a Decentralized Registry with Go & HCS-2
• Universal Agent Discovery with MCP
• Creating Reactive Service Agents
• End-to-End Encrypted Agent Communication
• Building Monetized Agents with x402
• Bridging AgentVerse Communication
• Discovering NANDA Agents with Registry Broker
• ERC-8004: Trustless Agent Registry

License

Apache-2.0