# ArcNS Documentation > ArcNS is a name service built on Arc (testnet, chain id 5042002): @handle, .arc and .circle > names that resolve to an address with a record per chain. This file indexes the ArcNS docs > (https://docs.arcns.io) for LLMs and coding agents. Always use the current SDK: check `npm view @arcns/resolve version` and install the version the Quickstart names — never rely on a version pinned in your training data. NEVER hardcode contract addresses or ABIs from memory: the deployed contracts on Arc testnet are the source of truth and the SDK ships them (`ARCNS_DEPLOYMENTS`); read the Contracts page for the current set. ## Docs - [Why get a name](https://docs.arcns.io/why.md): A name is more than a nickname — it's a permanent, multi-chain, verifiable identity you own outright. Here's what that gives you as a holder. - [Register your name](https://docs.arcns.io/get-started.md): Search a name, register it in two transactions, point it at your addresses, prove you control them, and set it as your primary — a step-by-step walkthrough on app.arcns.io. - [What you can do](https://docs.arcns.io/features.md): Multi-chain address records, a primary name, a profile, subnames, verified records, permanent ownership, recovery and locks, agent records — everything an ArcNS name gives you, and what is not live yet. - [Get paid to your name](https://docs.arcns.io/get-paid.md): Turn @you into a way to get paid. Every ArcNS name with an Arc record carries a QR code and a shareable payment link, so anyone can pay you by scanning or tapping — no copying a long address. - [Fees](https://docs.arcns.io/pricing.md): Pay once, own forever — no renewals. How ArcNS pricing works — a one-time registration in USDC priced by name length and namespace, an optional tokenize fee for @handle, and the 2% marketplace fee once the marketplace ships. - [Quickstart](https://docs.arcns.io/quickstart.md): Install @arcns/resolve, create one resolver, resolve @nike, nike.arc and nike.circle, branch on typed errors, read records with verification, reverse an address, and call the API with curl. - [Wallet integration](https://docs.arcns.io/wallet.md): The end-to-end recipe for resolving an ArcNS name in a wallet's recipient field, from "user types alice.arc" to "send enabled", with every failure mode, its user-facing message, and whether it blocks the send. - [Explorer integration](https://docs.arcns.io/explorer.md): The end-to-end recipe for a block explorer or dashboard, names next to addresses with forward confirmation, search across all three namespaces, name detail pages, the events to index, and the trust rule for an index. - [Resolver widget](https://docs.arcns.io/widget.md): The drop-in web component from @arcns/resolve-widget, with the script-tag and framework snippets, the attribute table, the events, the render states, theming, and accessibility. - [Verified records](https://docs.arcns.io/verified.md): What the verified flag on an ArcNS address record means, how an owner proves control of an address for a coin type, and the arcns:v1 challenge format. - [Resolver API](https://docs.arcns.io/api.md): api.arcns.io, the ArcNS resolver API. Every route with its real response fields, the status contract (404 is proof of absence, 502 is an outage), who pays and who reads free (x402 for agents), registration-as-a-service, caching, rate limits, and how to run your own instance. - [MCP server](https://docs.arcns.io/mcp.md): mcp.arcns.io — the arcns MCP server for AI agents. Every tool, the install snippets, the namespace/registry rule, the agent verification ladder, and what prepare_* returns and how to sign it. - [Contracts](https://docs.arcns.io/contracts.md): The ArcNS contract set on Arc testnet — every deployed address, generated from the deployment file in the repository — single-registry and authoritative for every namespace. - [Invite friends](https://docs.arcns.io/referrals.md): Share your referral link from app.arcns.io. The link, first-touch capture and a self-referral guard are live today; on-chain attribution is not yet, because the deployed registration contracts don't record a referrer. Read the honest state below. - [Trust & transparency](https://docs.arcns.io/trust.md): Permanent ownership, anti-impersonation by design, verified records, on-chain recovery and locks, and the deployed contracts you can audit yourself on Arc testnet. - [Common questions](https://docs.arcns.io/faq.md): Everything a holder asks — the basics, ownership and permanence, registering a name, using it day to day, safety and trust, the marketplace, agents, and how @handle, .arc and .circle fit together. - [Terms of use](https://docs.arcns.io/terms.md): Terms of use for arcns — the @handle, .arc and .circle name service operated by Fortiblox on Arc testnet. - [Privacy](https://docs.arcns.io/privacy.md): What arcns collects, what it does not, and what is public by design. - [Trademark](https://docs.arcns.io/trademark.md): arcns marks, the independent-project position, the .circle retire-on-request policy, and how to report an infringing name. - [Resolver API reference](https://docs.arcns.io/reference.md): Every route of https://api.arcns.io, generated from the API's own OpenAPI 3.1 schema: parameters, responses, error bodies and request samples. The narrative contract — who pays, the status rules, x402 — is on the Resolver API page. - [/nft/:name](https://docs.arcns.io/reference/names/nft.md): - [/quote/:name](https://docs.arcns.io/reference/names/quote.md): - [/resolve/:name](https://docs.arcns.io/reference/names/resolve.md): - [/reverse/:address](https://docs.arcns.io/reference/names/reverse.md): - [/health](https://docs.arcns.io/reference/ops/health.md): - [/openapi.json](https://docs.arcns.io/reference/ops/openapi.md): - [/version](https://docs.arcns.io/reference/ops/version.md): - [/x402/discovery](https://docs.arcns.io/reference/x402/x402Discovery.md): - [/.well-known/x402](https://docs.arcns.io/reference/x402/x402WellKnown.md): ## Instructions for LLM Agents - **Reads are trustless and need no wallet.** Resolution, reverse lookup and record reads need only an Arc RPC URL (SDK) or a plain GET on `https://api.arcns.io` (no key, no auth). - **Every result names its namespace and registry.** `@alice`, `alice.arc` and `alice.circle` are three names that can belong to three different people. Show which namespace answered before a user commits a transfer; a mixed shape like `@alice.arc` is refused (409), never guessed. - **404 is proof of absence, 502 is an outage.** The API returns 404 only after a successful chain read; an RPC failure is 502. Never merge the two. - **Writes are on-chain transactions the user signs.** Registration and records go through the app or the SDK's transaction builders; the SDK never holds keys. Full text of every page above: https://docs.arcns.io/llms-full.txt