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721T, the ERC-8048 profile

721T is not a new kind of NFT. It is a shared list of labels for notes stored on an NFT. ERC-8048 is the shelf. 721T is the agreement about what to write on the folders so every app looks in the same place.

The spec is still a Draft, so the labels can change. 721T does not add a new contract function. Apps use the ERC-8048 call metadata(tokenId, key).

How the labels work

Think of a locker with labeled drawers. The locker number is the token. Each drawer has a name. Anyone can open a drawer and read what is inside. Who is allowed to change a drawer depends on that locker’s own rules, not on the label list.

1. The instructions. The context drawer holds text about the agent. Markdown is the suggested form. A project may also tuck a small machine-readable block inside that text. This is the “what this agent is” note.
2. How to reach it. An endpoint drawer holds one web address for one way of talking. The name says which way. Common names are endpoint[mcp] for tools, endpoint[a2a] for agent-to-agent talk, endpoint[web] for a normal site, and endpoint[x402] for a pay-as-you-call service. The spelling must be lowercase. Capital letters do not count as the same drawer.
3. Where to pay. An address drawer names the agent’s account on one chain. The drawer name includes that chain’s id, so an Ethereum account is not mixed up with an account on another chain. Apps should send funds to this address.
4. Extra accounts. account drawers are optional. They can list more accounts on the same chain, such as a wallet that belongs to the NFT. Do not assume those extra accounts accept payment. The pay address is the address drawer.
5. Who may edit. ERC-8048 does not decide that. One contract may let the NFT owner edit. Another may lock the notes, or give edit rights to a different manager. Read that contract before you trust a change.
6. What a sale moves. Selling the NFT sells control of these onchain notes, if the contract ties editing to the owner. It does not move the website, the password, the money in a wallet, or the chat history that a note only mentions.

What 721T does not do

• It does not run the agent. A link is not a working tool.
• It does not check that the website in a drawer belongs to the owner.
• It does not set permissions. The contract does that, and only if the author wrote those rules.
• It does not replace ERC-721. The token, the owner, and the transfer are still ERC-721.
• It does not replace ERC-8004. That registry is a separate ID card. 721T is notes on a token.

Apps are told to treat the instructions and the links as untrusted input. Read them. Do not obey them blindly.

Professional use

A person can put their work agent’s public card on the NFT itself.

• A designer can store a short brief in context and a portfolio link in endpoint[web].
• A developer can list the tool link in endpoint[mcp] so a client’s app knows where to call.
• A consultant can publish the account that should receive a payment, without hiding it in a private email.

A new client can read the same drawers every time. If you sell the NFT, the next owner gets the notes. They do not get your laptop files unless you hand those over separately.

Business use

A company can use the labels so its own apps, and other companies’ apps, do not guess.

• A support agent can publish the customer link and the account that receives fees.
• A shop can read endpoint[a2a] when its purchasing agent needs to talk to that agent.
• A treasury can keep the pay address on the token, and extra operating accounts in the optional drawers, with a clear rule that only one of them is for incoming funds.

The company still has to decide who may rewrite the drawers. If any owner can edit after a sale, the notes can change the moment the token changes hands.

Personal use

A person can use the same drawers for an agent that is just theirs.

• A muse or a game character can keep its voice instructions in context.
• A personal assistant can list the one link your other apps should open.
• You can show friends which account belongs to that agent, instead of pasting a new address in chat every time.

Reading the notes is a chain call. Changing them costs a network fee. The picture, the model, and the chat log stay where they already live. The drawers only point at them.

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