diff --git a/24.md b/24.md
index ef4196bd..1afa7c7a 100644
--- a/24.md
+++ b/24.md
@@ -39,6 +39,7 @@ tags
 
 These tags may be present in multiple event kinds. Whenever a different meaning is not specified by some more specific NIP, they have the following meanings:
 
-  - `r`: a web URL the event is referring to in some way
-  - `i`: an external id the event is referring to in some way - see [NIP-73](73.md)
-  - `title`: name of [NIP-51](51.md) sets, [NIP-52](52.md) calendar event, [NIP-53](53.md) live event or [NIP-99](99.md) listing
+  - `r`: a web URL the event is referring to in some way.
+  - `i`: an external id the event is referring to in some way - see [NIP-73](73.md).
+  - `title`: name of [NIP-51](51.md) sets, [NIP-52](52.md) calendar event, [NIP-53](53.md) live event or [NIP-99](99.md) listing.
+  - `t`: a hashtag. The value MUST be a lowercase string.
diff --git a/README.md b/README.md
index 8bf036b5..80b8dcf2 100644
--- a/README.md
+++ b/README.md
@@ -250,7 +250,7 @@ They exist to document what may be implemented by [Nostr](https://github.com/nos
 | `q`               | event id (hex)                       | relay URL                       | [18](18.md)                           |
 | `r`               | a reference (URL, etc)               | --                              | [24](24.md), [25](25.md)              |
 | `r`               | relay url                            | marker                          | [65](65.md)                           |
-| `t`               | hashtag                              | --                              |                                       |
+| `t`               | hashtag                              | --                              | [24](24.md)                           |
 | `alt`             | summary                              | --                              | [31](31.md)                           |
 | `amount`          | millisatoshis, stringified           | --                              | [57](57.md)                           |
 | `bolt11`          | `bolt11` invoice                     | --                              | [57](57.md)                           |