hak-axelar-plugin

Axelar Network cross-chain plugin for Hedera Agent Kit (HAK)

Lets AI agents bridge tokens and send general-message-passing (GMP) messages from Hedera to 60+ chains using the Axelar Network protocol. Built as a first-class HAK plugin — drop it in, register it, and your agent gains five new cross-chain tools with no additional setup required.

Strategic positioning: Axelar vs LayerZero

This plugin complements hak-layerzero-plugin and addresses different use cases:

| Concern | hak-axelar-plugin | hak-layerzero-plugin | |---|---|---| | Security model | Proof-of-Stake validator set | Decentralized Verifier Network (DVN) | | Token standard | Interchain Token Service (ITS) | Omnichain Fungible Token (OFT) | | Confirmed Hedera routes | Ethereum, Base, Arbitrum, Avalanche, Optimism, Polygon, BSC, XRPL, Monad, Berachain, Flow EVM, Scroll | Ethereum, Base, Arbitrum, Avalanche, Optimism, Polygon, BSC | | XRPL support | Yes (confirmed live GMP txs) | No | | Bridge architecture | Axelar Amplifier | LayerZero V2 |

Choose Axelar when you need XRPL, Berachain, Flow EVM, or Monad destinations, or when your token is already registered with Axelar ITS.

Installation

npm install hak-axelar-plugin

Peer dependencies

npm install @hashgraph/hedera-agent-kit @hiero-ledger/sdk

Quick start

import { HederaAgentKit } from "@hashgraph/hedera-agent-kit";
import { axelarPlugin } from "hak-axelar-plugin";

// Register the plugin with HAK
const kit = new HederaAgentKit({
  accountId: process.env.HEDERA_ACCOUNT_ID!,
  privateKey: process.env.HEDERA_PRIVATE_KEY!,
  network: "mainnet",
});

kit.registerPlugin(axelarPlugin);

// The agent now has access to all 5 Axelar tools.
// Example: ask the agent to list supported chains
const result = await kit.runTool("axelar_get_supported_chains", {});
console.log(result);

// Example: estimate the fee to send a GMP message to Ethereum
const fee = await kit.runTool("axelar_get_message_fee", {
  destinationChain: "ethereum",
  gasLimit: 200000,
});
console.log(fee);
// { baseFee: "5000000", executionFee: "...", executionFeeWithMultiplier: "...", gasMultiplier: 1.1, isExpressSupported: false }

Tools

| Tool name | Description | Type | |---|---|---| | axelar_get_supported_chains | Lists all chains reachable from Hedera via Axelar. Calls the AxelarScan API — no transaction required. | Query | | axelar_get_message_fee | Estimates the HBAR fee (in tinybars) needed to pay for GMP message execution on a destination chain. | Query | | axelar_send_message | Sends a GMP message from Hedera to a destination chain contract. Submits two Hedera transactions: gas payment + gateway call. | Transaction | | axelar_send_token | Bridges an ITS-registered token from Hedera to any supported destination chain. Single Hedera transaction. | Transaction | | axelar_get_message_status | Checks the delivery status of a cross-chain message by source transaction hash. | Query |

See docs/TOOLS.md for full per-tool parameter reference and examples.

Supported chains (confirmed mainnet routes from Hedera)

| Chain | Status | Notes | |---|---|---| | Ethereum | Confirmed | High liquidity, many ITS tokens | | Base | Confirmed | Low fees | | Arbitrum | Confirmed | | | Avalanche | Confirmed | | | Optimism | Confirmed | | | Polygon | Confirmed | | | BSC | Confirmed | Binance Smart Chain | | XRPL EVM | Confirmed | Unique to Axelar vs LayerZero | | Monad | Confirmed | | | Berachain | Confirmed | | | Flow EVM | Confirmed | | | Scroll | Confirmed | | | Solana | Partial | Technically supported by Axelar; 0 confirmed GMP txs from Hedera as of research | | 50+ others | Via Axelar | Query axelar_get_supported_chains for the live list |

Use axelar_get_supported_chains at runtime for the authoritative list — the Axelar network continues to add new chains.

Network defaults

Contract addresses

| Contract | Mainnet (chainId 295) | Testnet (chainId 296) | |---|---|---| | AxelarGateway | 0xe432150cce91c13a887f7D836923d5597adD8E31 | 0xe432150cce91c13a887f7D836923d5597adD8E31 | | AxelarGasService | 0x2d5d7d31F671F86C782533cc367F14109a082712 | 0xbE406F0189A0B4cf3A05C286473D23791Dd44Cc6 | | ITS (Interchain Token Service) | 0xB5FB4BE02232B1bBA4dC8f81dc24C26980dE9e3C | 0xB5FB4BE02232B1bBA4dC8f81dc24C26980dE9e3C | | WHBAR | 0xb1F616b8134F602c3Bb465fB5b5e6565cCAd37Ed | — |

API endpoints

| Network | GMP API | |---|---| | Mainnet | https://api.gmp.axelarscan.io | | Testnet | https://testnet.api.gmp.axelarscan.io |

No API keys required.

Important notes

Amplifier architecture

Hedera is connected to Axelar via the Axelar Amplifier architecture, not the classic gateway. This means:

• Classic axlUSDC deposit-address bridging does not work on Hedera.
• Only tokens registered with the Interchain Token Service (ITS) can be bridged via axelar_send_token.
• To bridge HBAR, use WHBAR (0xb1F616b8134F602c3Bb465fB5b5e6565cCAd37Ed) — native HBAR cannot be bridged directly.

ITS token requirement

axelar_send_token requires an interchainTokenId (a 32-byte hex identifier assigned by the ITS contract). This is not the same as the ERC-20 token address. Look up the token ID via the Axelar ITS Portal or by calling the ITS contract's interchainTokenId() view function.

AxelarExecutable requirement

Destination contracts that receive GMP messages via axelar_send_message must implement the AxelarExecutable interface from @axelar-network/axelar-gmp-sdk-solidity. Plain EOAs and contracts that do not implement this interface will not receive messages correctly.

HBAR decimal duality

Hedera has two decimal representations for HBAR:

• Tinybars (8 decimals) — native Hedera SDK denomination, used throughout this plugin's API.
• Weibars (18 decimals) — used in EVM / msg.value contexts.

All HBAR amounts in this plugin (gas fees, gasTinybars parameter) are expressed in tinybars. 1 HBAR = 100,000,000 tinybars.

HTS token association

Before a Hedera account can receive bridged tokens, the account must be associated with the HTS token. This is a Hedera-specific requirement not present on EVM chains. Use hak-hts or the Hedera SDK to associate before initiating a bridge that returns tokens to Hedera.

Links

• Axelar Documentation
• AxelarScan Explorer
• Axelar Amplifier Overview
• Interchain Token Service
• Hedera Agent Kit
• hak-layerzero-plugin
• Axelar GMP SDK (Solidity)