Kind 1985: Label

Overview

Kind 1985 events provide a mechanism for attaching labels to various entities in the Nostr ecosystem. Labels allow for distributed moderation, content classification, license assignment, collection management, and other forms of metadata annotation. This kind enables users to create semantic connections and categorizations across the network without requiring centralized authority or coordination.

Specification

Property	Value
Kind Number	1985
Event Range	Regular
Defined in	NIP-32

Content Format

The content field can contain additional information explaining the label, such as reasoning behind the label assignment or further context. For simple label assignments, this field may be empty.

Schema

"content": "This pubkey is associated with the 'permies' topic because they frequently post about permaculture."

Tags

Tag Name	Description	Format	Required
L	Label namespace	["L", "<namespace>"]	Recommended
l	Label value	["l", "<label>", "<namespace>"]	Yes
e	Event to label	["e", "<event-id>", "<relay-url>"]	Conditional*
p	Pubkey to label	["p", "<pubkey>", "<relay-url>"]	Conditional*
a	Address to label	["a", "<address>", "<relay-url>"]	Conditional*
r	URL to label	["r", "<url>"]	Conditional*
t	Topic to label	["t", "<topic>"]	Conditional*

*At least one target tag (e, p, a, r, or t) must be included.

Client Behavior

Clients should:

1. Allow users to create and apply labels to various entities
2. Support filtering and sorting content based on labels
3. Display relevant labels when showing content to help users understand context
4. Enable searching by label namespace and specific label values
5. Support both self-labeling and third-party labeling
6. Consider how to handle potentially conflicting labels from different sources

Relay Behavior

Relays should:

1. Store and serve label events like other regular events
2. Support filtering by label tags to enable efficient queries
3. Optionally use labels for internal content categorization or moderation

Use Cases

• Content moderation and classification
• Assigning licenses to creative works
• Categorizing posts by topic, language, or location
• Building collaborative content curation systems
• Implementing distributed reputation systems
• Organizing content into collections
• Flagging content with specific properties (NSFW, educational, etc.)

Example

Labeling multiple pubkeys with a topic:

{
  "id": "4376c65d2f232afbe9b882a35baa4f6fe8667c4e684749af565f981833ed6a65",
  "pubkey": "79dff8f82963424e0bb02708a22e44b4980893e3a4be0fa3cb60a43b946764e3",
  "created_at": 1671217411,
  "kind": 1985,
  "tags": [
    ["L", "#t"],
    ["l", "permaculture", "#t"],
    ["p", "f7234bd4c1394dda46d09f35bd384dd30cc552ad5541990f98844fb06676e9ca", "wss://relay.example.com"],
    ["p", "3c9849383bdea883b0bd16fece1ed36d37e37cdde3ce43b17ea4e9192ec11289", "wss://relay.example.com"]
  ],
  "content": "These accounts frequently post valuable content about permaculture practices.",
  "sig": "908a15e46fb4d8675bab026fc230a0e3542bfade63da02d542fb78b2a8513fcd0092619a2c8c1221e581946e0191f2af505dfdf8657a414dbca329186f009262"
}

Applying a license to an event:

{
  "id": "fe8b1c9a37218cf5ce604a8dce596c9c3ae0c650df2336f3c60c78e61a7b2031",
  "pubkey": "79dff8f82963424e0bb02708a22e44b4980893e3a4be0fa3cb60a43b946764e3",
  "created_at": 1671217500,
  "kind": 1985,
  "tags": [
    ["L", "license"],
    ["l", "CC-BY-4.0", "license"],
    ["e", "a1a2a3a4b1b2b3b4c1c2c3c4d1d2d3d4e1e2e3e4f1f2f3f4aaabbbcccddd", "wss://relay.example.com"]
  ],
  "content": "Applying Creative Commons Attribution 4.0 International license to this content.",
  "sig": "a76f39224cebd44cf04eeebe01d5ab2e8f7a3e5e56c83cadd252e7bc5e2e34fd7ad7148cf7a2c7620d9490ccf2e1bac521995725f2e1f543159b8eb98bfdd405"
}

Moderation suggestion for a chat event:

{
  "id": "a6c49604e8b105829f27804c56ba1eef8c487ceabc1a2eaffab3d9c9a312dfca",
  "pubkey": "79dff8f82963424e0bb02708a22e44b4980893e3a4be0fa3cb60a43b946764e3",
  "created_at": 1671218000,
  "kind": 1985,
  "tags": [
    ["L", "nip28.moderation"],
    ["l", "approve", "nip28.moderation"],
    ["e", "5c83da77af1dec6d7289834998ad7aafbd9e2191396d75ec3cc27f5a77226f36", "wss://relay.example.com"]
  ],
  "content": "This channel message adheres to community guidelines.",
  "sig": "5f8ac6d9c2dab830ebbdb231ad6123ef0121c4710218f339d9d3b5b22fd74c0a7b1be0de52ffce6022e87dfa5b7ae3f2749a126b09c82c3ea31eb4c69d25091c"
}

References

• NIP-32: Labeling
• NIP-09: Event Deletion (for deleting and replacing labels)

Related Kinds

• Kind 1984: Reporting - Often uses labels for categorizing reports
• Kind 1: Short Text Note - Can include self-labels in tags
• Kind 0: User Metadata - Profiles that can be labeled

Notes

• Labels can also be self-applied by including L and l tags directly in events of other kinds
• For self-labeling, the labels refer to the event itself
• Namespace collisions can be avoided by using reverse domain name notation (e.g., "com.example.ontology")
• Namespaces starting with # indicate that the label target should be associated with the label's value
• The special namespace ugc ("user-generated content") can be used when labels are provided by end users
• When using labels for moderation or categorization, consider established ontologies rather than creating new ones
• For bulk labeling, events can be updated using NIP-09 deletion and replacement
• Limit labeling events to a single namespace to avoid ambiguity when querying