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ERC-8217 (RFC) / 8004A

ERC-8217 is a permanent luggage tag. It says one ERC-8004 agent ID belongs with one master token. When that master token is sold, control of the agent registration follows the new holder. The tag is not supposed to be peeled off and stuck on a different token.

Read the current text at ERC-8217. 8004A is the nickname for a master NFT registered this way.

How the tag works

1. Two things, one link. The agent still has its ERC-8004 identity. The picture, character, or other asset still lives in its own token. The binding says they go together.
2. What the record stores. bindingOf(agentId) returns the token type, the contract address, and the token number. The type can be ERC-721, ERC-1155, or ERC-6909.
3. Where you find the binder. The agent record can point at the binding contract with the agent-binding note. You then ask that contract what the master token is.
4. It stays put. Once the binding is written, both the stored contract and the answer from bindingOf must stay the same. The agent ID is not rewritten to a new master later.
5. Control follows the master. The owner of the master token is meant to control the bound agent registration. Sell the master, and that control moves. The binding itself does not get a new target.

What the binding does not do

• It does not move a website, a password, a server, or a legal right. Those need their own handover.
• It does not check that the master art and the agent software actually match in the real world.
• It does not let you re-tag the same agent ID onto a different NFT later.

Professional use

• A certificate you already hold can become the master that controls your public agent ID.
• A client can check the master token, then trust that the same holder controls the agent card.
• Selling the certificate is the sale of that control, if the binding was set up this way.

Business use

• A brand can keep its character NFT as the master and let the agent registration follow whoever holds the character.
• A buyer of the character can see the riveted link instead of trusting a private spreadsheet.
• The company must still hand over offchain systems in the purchase agreement. The tag does not do that.

Personal use

• A picture you already own, such as a muse, can stay the item you sell.
• The agent card follows that picture instead of being a second thing you might forget to transfer.
• You cannot later point that same agent ID at a different picture. Choose the master before the tag is written.

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