# arb.eth : full technical context for AI agents

Last updated: 2026-07-13
Status: technical demonstration / pitch. Not affiliated with the Arbitrum Foundation
or Offchain Labs. Name claims on the website are currently simulated. Read this file
before attempting any programmatic interaction.

## What this is

A demonstration of ENS-based usernames for the Arbitrum ecosystem: alice.arb.eth
instead of a hex address, resolvable anywhere ENS works. It shows how Arbitrum could
give its users human-readable names using existing ENS infrastructure, with no new
protocol and no per-wallet integration work.

The demo is served from the DNS domain arb.domains. The namespace shown (arb.eth) is
aspirational: issuing arb.eth subnames requires control of the arb.eth ENS name.
Two production paths exist:
  A) Import a DNS domain (e.g. arb.domains) into ENS via DNSSEC and issue subnames
     under it. Doable today by the domain owner.
  B) Issue subnames under arb.eth directly. Requires the arb.eth ENS name to point
     its resolver at the offchain resolver.

## Subname architecture (integrated, awaiting activation)

Issuance path uses the Namespace platform (namespace.ninja):

- SDK: @thenamespace/offchain-manager (npm)
- Names are issued offchain and served over CCIP-Read (ERC-3668), so issuing a
  subname costs zero gas and scales without limit.
- Registration fee: 0.01 ETH flat per name (design parameter of this demo).
- Subnames resolve in every ENS-aware wallet/app once the parent resolver points at
  the offchain resolver. Precedents using this pattern: world.id (World App),
  uni.eth (Uniswap), base.eth (Basenames), gemini.eth.

## Resolving ENS names (live now, standard)

- ENS registry (Ethereum mainnet): 0x00000000000C2E074eC69A0dFb2997BA6C7d2e1e
- Use any ENS library (viem's getEnsAddress, ethers' resolveName) or one eth_call to
  the ENS Universal Resolver. No API key, no custom SDK.

## Planned agent interface (NOT LIVE - do not call yet)

When activated, agents will be able to register names autonomously:

1. GET https://arb.domains/quote?name=<label>
   -> { name, priceWei, usd }
2. POST https://arb.domains/register  {"name":"<label>","owner":"0x..."}
   -> HTTP 402 with x402 payment options; on settlement the subname is issued to
   the owner address.
3. MCP server (Streamable HTTP) at https://arb.domains/api/mcp with tools:
   resolve_name, reverse_resolve, check_availability, register_name.

Until those endpoints exist, the only live programmatic surface is standard ENS
resolution.

## For humans

Website: https://arb.domains (interactive demo; MetaMask connect works, claims are
simulated). The page at /?demo=1 auto-plays the full claim flow.