Field Authority Interface

In order to implement holder-editable metadata, we've built a new interface that works in concert with the Token Metadata Interface: the Field Authority Interface

The Token Metadata Interface only has a single update authority. If you want grant write access to a user for a specific field, you must grant write access to all fields. This limitation exists in Metaplex's program as well, and it's unworkable for NFT utility. For example, in our AI Aliens collection, we want users to be able to assign nicknames and special characteristics to their alien, but not change the NFT's name or image. Doing so would confuse other users and lose the asset's value.

The Field Authority Interface enables metadata programs to grant write access to public keys for specific fields only. These field authorities can be basic user keypairs or PDAs of programs (A.K.A. plugins) that implement their own unique logic. Here are the new instructions:

pub fn add_field_authority(
    program_id: &Pubkey,
    payer: &Pubkey,
    metadata: &Pubkey,
    update_authority: &Pubkey,
    field: Field,
    field_authority: &Pubkey,
) -> Instruction { ... }

pub fn update_field_with_field_authority(
    program_id: &Pubkey,
    metadata: &Pubkey,
    field_authority: &Pubkey,
    field: Field,
    value: String,
) -> Instruction { ... }

pub fn remove_field_authority(
    program_id: &Pubkey,
    metadata: &Pubkey,
    update_authority: &Pubkey,
    field: Field,
) -> Instruction { ... }

source code

This interface is meant to work in concert with the Token Metadata Interface. The update_authority is the same as the Token Metadata Interface's update authority, and it holds the ability to assign an extra field_authority to each field.

Next, we'll show you how the Holder Metadata Program functions as a field authority allowing token holders to edit specific fields.