NIP-85
======

`d` Tag References in Addressable Events
----------------------------------------

`draft` `optional`

Addressable events have a `d` tag whose value is an arbitrary identifier. Usually it's a made-up name such as a blog post slug or a reverse-DNS identifier, but it can also be a reference to another user or event on the network.

When a new addressable kind is defined, it may invoke this NIP by including a third parameter in the `d` tag: a [standardized tag](./README.md#standardized-tags) name such as "e", "p", or "a". In addition, exactly one of those tags MUST be included in the tags list, and its value MUST match the `d` tag value.

For example, an addressable kind that references another event:

```js
[
  ["d", eventId, "e"],
  ["e", eventId, ...rest],
]
```

Another addressable kind that references a user:

```js
[
  ["d", userId, "p"],
  ["p", userId, ...rest],
]
```

This NIP does not define any kinds on its own. It's meant to be adopted on a per-kind basis. It is only applicable when the event kind will ONLY ever reference a single other standardized tag in its `d` tag.

Clients implementing this NIP MUST validate events of applicable kinds by disposing of them if they do not adhere to the above rules.