feat: reply with kind 1111 to new Amethyst kind-1 thread roots

When replying to a note that is a kind 1 TextNoteEvent, is the root of a
new thread (no e-tags), and was itself posted from Amethyst (NIP-89
client tag), build a NIP-22 kind 1111 CommentEvent instead of a kind 1
reply. Forks keep using kind 1.

Applies across all kind-1 reply paths: the Android composer
(ShortNotePostViewModel), the notification quick-reply
(NotificationReplyReceiver), and the desktop composer (ComposeNoteDialog).

Adds Event.isClient / TagArray.isClient helpers (NIP-89, case-insensitive)
with unit coverage.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01V7RyevA6jL1NuY7uev2agS

amethyst/src/main/java/com/vitorpamplona/amethyst/service/notifications/NotificationReplyReceiver.kt

@@ -29,11 +29,13 @@ import androidx.core.content.ContextCompat
 import com.vitorpamplona.amethyst.Amethyst
 import com.vitorpamplona.amethyst.LocalPreferences
 import com.vitorpamplona.amethyst.model.LocalCache
+import com.vitorpamplona.amethyst.model.accountsCache.AccountCacheState
 import com.vitorpamplona.quartz.nip01Core.hints.EventHintBundle
 import com.vitorpamplona.quartz.nip01Core.tags.people.PTag
 import com.vitorpamplona.quartz.nip10Notes.TextNoteEvent
 import com.vitorpamplona.quartz.nip17Dm.messages.ChatMessageEvent
 import com.vitorpamplona.quartz.nip22Comments.CommentEvent
+import com.vitorpamplona.quartz.nip89AppHandlers.clientTag.isClient
 import com.vitorpamplona.quartz.utils.Log
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Dispatchers
@@ -198,8 +200,19 @@ class NotificationReplyReceiver : BroadcastReceiver() {
         val targetEvent = LocalCache.getNoteIfExists(targetEventId)?.event ?: return
 
         val template =
-            when (targetEvent) {
-                is TextNoteEvent -> {
+            when {
+                // A brand-new Amethyst kind-1 thread root is replied to with a NIP-22
+                // kind 1111 Comment instead of a kind 1 reply.
+                targetEvent is TextNoteEvent &&
+                    targetEvent.isNewThread() &&
+                    targetEvent.isClient(AccountCacheState.CLIENT_TAG_NAME) -> {
+                    CommentEvent.replyBuilder(
+                        msg = replyText,
+                        replyingTo = EventHintBundle(targetEvent),
+                    )
+                }
+
+                targetEvent is TextNoteEvent -> {
                     TextNoteEvent.build(
                         note = replyText,
                         replyingTo = EventHintBundle(targetEvent),

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/home/ShortNotePostViewModel.kt

@@ -45,6 +45,7 @@ import com.vitorpamplona.amethyst.model.BooleanType
 import com.vitorpamplona.amethyst.model.LocalCache
 import com.vitorpamplona.amethyst.model.Note
 import com.vitorpamplona.amethyst.model.User
+import com.vitorpamplona.amethyst.model.accountsCache.AccountCacheState
 import com.vitorpamplona.amethyst.service.ai.MockWritingAssistant
 import com.vitorpamplona.amethyst.service.ai.WritingAssistant
 import com.vitorpamplona.amethyst.service.ai.WritingAssistantFactory
@@ -113,6 +114,7 @@ import com.vitorpamplona.quartz.nip10Notes.tags.prepareETagsAsReplyTo
 import com.vitorpamplona.quartz.nip18Reposts.quotes.quotes
 import com.vitorpamplona.quartz.nip18Reposts.quotes.taggedQuoteIds
 import com.vitorpamplona.quartz.nip22Comments.CommentEvent
+import com.vitorpamplona.quartz.nip22Comments.notify
 import com.vitorpamplona.quartz.nip30CustomEmoji.CustomEmoji
 import com.vitorpamplona.quartz.nip30CustomEmoji.EmojiUrlTag
 import com.vitorpamplona.quartz.nip30CustomEmoji.emojis
@@ -132,6 +134,7 @@ import com.vitorpamplona.quartz.nip72ModCommunities.definition.CommunityDefiniti
 import com.vitorpamplona.quartz.nip88Polls.poll.PollEvent
 import com.vitorpamplona.quartz.nip88Polls.poll.tags.OptionTag
 import com.vitorpamplona.quartz.nip88Polls.poll.tags.PollType
+import com.vitorpamplona.quartz.nip89AppHandlers.clientTag.isClient
 import com.vitorpamplona.quartz.nip92IMeta.IMetaTagBuilder
 import com.vitorpamplona.quartz.nip92IMeta.imetas
 import com.vitorpamplona.quartz.nip94FileMetadata.alt
@@ -1087,6 +1090,38 @@ open class ShortNotePostViewModel :
                 contentWarningReason?.let { contentWarning(it) }
                 localExpirationDate?.let { expiration(it) }
 
+                emojis(emojis)
+                imetas(usedAttachments)
+            }
+        } else if (shouldReplyAsComment()) {
+            // NIP-22: replies to a brand-new Amethyst kind-1 thread root are sent as
+            // kind 1111 Comments instead of kind 1 replies.
+            val eventHint = originalNote?.toEventHint<Event>() ?: return null
+
+            CommentEvent.replyBuilder(tagger.message, eventHint) {
+                tagger.pTags?.let { userList ->
+                    val tags =
+                        userList.map {
+                            val tag = it.toPTag()
+                            if (tag.relayHint == null) {
+                                tag.copy(relayHint = LocalCache.relayHints.hintsForKey(it.pubkeyHex).firstOrNull())
+                            } else {
+                                tag
+                            }
+                        }
+                    notify(tags)
+                }
+
+                hashtags(findHashtags(tagger.message))
+                references(findURLs(tagger.message))
+                quotes(findNostrUris(tagger.message))
+
+                geoHash?.let { geohash(it) }
+                localZapRaiserAmount?.let { zapraiser(it) }
+                zapReceiver?.let { zapSplits(it) }
+                contentWarningReason?.let { contentWarning(it) }
+                localExpirationDate?.let { expiration(it) }
+
                 emojis(emojis)
                 imetas(usedAttachments)
             }
@@ -1149,6 +1184,19 @@ open class ShortNotePostViewModel :
         }
     }
 
+    /**
+     * NIP-22: a reply should be a kind 1111 Comment (instead of a kind 1 reply) when
+     * the note being replied to is a kind 1 [TextNoteEvent], is the root of a new
+     * thread, and was itself posted from Amethyst. Forks keep using kind 1.
+     */
+    private fun shouldReplyAsComment(): Boolean {
+        if (forkedFromNote != null) return false
+        val replyingToEvent = originalNote?.event ?: return false
+        return replyingToEvent is TextNoteEvent &&
+            replyingToEvent.isNewThread() &&
+            replyingToEvent.isClient(AccountCacheState.CLIENT_TAG_NAME)
+    }
+
     fun findEmoji(
         message: String,
         myEmojiSet: List<EmojiMedia>?,

desktopApp/src/jvmMain/kotlin/com/vitorpamplona/amethyst/desktop/ui/ComposeNoteDialog.kt

@@ -71,6 +71,7 @@ import com.vitorpamplona.amethyst.commons.ui.components.UserAvatar
 import com.vitorpamplona.amethyst.desktop.DesktopPreferences
 import com.vitorpamplona.amethyst.desktop.ImageCompressionStore
 import com.vitorpamplona.amethyst.desktop.account.AccountState
+import com.vitorpamplona.amethyst.desktop.model.DesktopIAccount
 import com.vitorpamplona.amethyst.desktop.network.DesktopRelayConnectionManager
 import com.vitorpamplona.amethyst.desktop.service.upload.DesktopUploadTracker
 import com.vitorpamplona.amethyst.desktop.ui.compose.ComposeRelayPicker
@@ -84,6 +85,7 @@ import com.vitorpamplona.amethyst.desktop.ui.media.QualitySelectorChip
 import com.vitorpamplona.amethyst.desktop.ui.media.buildPreview
 import com.vitorpamplona.amethyst.desktop.ui.media.cleanupPreviewTemps
 import com.vitorpamplona.quartz.nip01Core.core.Event
+import com.vitorpamplona.quartz.nip01Core.hints.EventHintBundle
 import com.vitorpamplona.quartz.nip01Core.relay.normalizer.NormalizedRelayUrl
 import com.vitorpamplona.quartz.nip01Core.tags.events.ETag
 import com.vitorpamplona.quartz.nip01Core.tags.events.eTag
@@ -97,6 +99,8 @@ import com.vitorpamplona.quartz.nip10Notes.content.findURLs
 import com.vitorpamplona.quartz.nip18Reposts.quotes.QEventTag
 import com.vitorpamplona.quartz.nip18Reposts.quotes.quote
 import com.vitorpamplona.quartz.nip19Bech32.entities.NEvent
+import com.vitorpamplona.quartz.nip22Comments.CommentEvent
+import com.vitorpamplona.quartz.nip89AppHandlers.clientTag.isClient
 import com.vitorpamplona.quartz.nip92IMeta.IMetaTag
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.launch
@@ -805,22 +809,38 @@ private suspend fun publishNote(
         }
 
         val template =
-            TextNoteEvent.build(content) {
-                if (replyTo != null) {
-                    val etag = ETag(replyTo.id)
-                    etag.relay = null
-                    etag.author = replyTo.pubKey
-                    eTag(etag)
-                    pTag(PTag(replyTo.pubKey, relayHint = null))
+            if (replyTo is TextNoteEvent && replyTo.isNewThread() && replyTo.isClient(DesktopIAccount.CLIENT_TAG_NAME)) {
+                // NIP-22: replying to a brand-new Amethyst kind-1 thread root produces
+                // a kind 1111 Comment instead of a kind 1 reply.
+                CommentEvent.replyBuilder(content, EventHintBundle(replyTo)) {
+                    if (quoteOf != null) {
+                        quote(QEventTag(quoteOf.id, relayHint = null, authorPubKeyHex = quoteOf.pubKey))
+                        pTag(PTag(quoteOf.pubKey, relayHint = null))
+                    }
+                    hashtags(findHashtags(content))
+                    references(findURLs(content))
+                    for (imeta in imetaTags) {
+                        add(imeta.toTagArray())
+                    }
                 }
-                if (quoteOf != null) {
-                    quote(QEventTag(quoteOf.id, relayHint = null, authorPubKeyHex = quoteOf.pubKey))
-                    pTag(PTag(quoteOf.pubKey, relayHint = null))
-                }
-                hashtags(findHashtags(content))
-                references(findURLs(content))
-                for (imeta in imetaTags) {
-                    add(imeta.toTagArray())
+            } else {
+                TextNoteEvent.build(content) {
+                    if (replyTo != null) {
+                        val etag = ETag(replyTo.id)
+                        etag.relay = null
+                        etag.author = replyTo.pubKey
+                        eTag(etag)
+                        pTag(PTag(replyTo.pubKey, relayHint = null))
+                    }
+                    if (quoteOf != null) {
+                        quote(QEventTag(quoteOf.id, relayHint = null, authorPubKeyHex = quoteOf.pubKey))
+                        pTag(PTag(quoteOf.pubKey, relayHint = null))
+                    }
+                    hashtags(findHashtags(content))
+                    references(findURLs(content))
+                    for (imeta in imetaTags) {
+                        add(imeta.toTagArray())
+                    }
                 }
             }
 

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip89AppHandlers/clientTag/EventExt.kt

@@ -23,3 +23,6 @@ package com.vitorpamplona.quartz.nip89AppHandlers.clientTag
 import com.vitorpamplona.quartz.nip01Core.core.Event
 
 fun Event.client() = tags.client()
+
+/** True when this event was published by the client named [name] (NIP-89, case-insensitive). */
+fun Event.isClient(name: String) = tags.isClient(name)

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip89AppHandlers/clientTag/TagArrayExt.kt

@@ -23,3 +23,6 @@ package com.vitorpamplona.quartz.nip89AppHandlers.clientTag
 import com.vitorpamplona.quartz.nip01Core.core.TagArray
 
 fun TagArray.client() = this.mapNotNull(ClientTag::parse)
+
+/** True when any client tag (NIP-89) names [name] (case-insensitive). */
+fun TagArray.isClient(name: String) = this.any { ClientTag.isTag(it) && it[1].equals(name, ignoreCase = true) }

quartz/src/commonTest/kotlin/com/vitorpamplona/quartz/nip89AppHandlers/clientTag/IsClientTest.kt

@@ -0,0 +1,63 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.quartz.nip89AppHandlers.clientTag
+
+import kotlin.test.Test
+import kotlin.test.assertFalse
+import kotlin.test.assertTrue
+
+class IsClientTest {
+    @Test
+    fun matchesClientTagByName() {
+        val tags = arrayOf(arrayOf("client", "Amethyst"))
+        assertTrue(tags.isClient("Amethyst"))
+    }
+
+    @Test
+    fun matchesIgnoringCase() {
+        val tags = arrayOf(arrayOf("client", "amethyst"))
+        assertTrue(tags.isClient("Amethyst"))
+    }
+
+    @Test
+    fun matchesWithAddressAndRelayHint() {
+        val tags = arrayOf(arrayOf("client", "Amethyst", "31990:abc123:amethyst", "wss://relay.example.com"))
+        assertTrue(tags.isClient("Amethyst"))
+    }
+
+    @Test
+    fun doesNotMatchDifferentClient() {
+        val tags = arrayOf(arrayOf("client", "OtherClient"))
+        assertFalse(tags.isClient("Amethyst"))
+    }
+
+    @Test
+    fun doesNotMatchWhenNoClientTag() {
+        val tags = arrayOf(arrayOf("e", "abc"), arrayOf("p", "def"))
+        assertFalse(tags.isClient("Amethyst"))
+    }
+
+    @Test
+    fun doesNotMatchEmptyClientName() {
+        val tags = arrayOf(arrayOf("client", ""))
+        assertFalse(tags.isClient("Amethyst"))
+    }
+}