feat(privacy): add per-account toggle to disable NIP-89 client tag

Adds a "Don't add client tag to my events" switch under Security Filters.
NostrSignerWithClientTag now consults a runtime predicate at sign-time, so
the toggle takes effect immediately on the live session without rewrapping
the signer or rebuilding Account.

https://claude.ai/code/session_01KhNVTm8LLdVphqyxVkZtDS

amethyst/src/main/java/com/vitorpamplona/amethyst/LocalPreferences.kt

@@ -95,6 +95,7 @@ private object PrefKeys {
     const val LOCAL_RELAY_SERVERS = "localRelayServers"
     const val DEFAULT_FILE_SERVER = "defaultFileServer"
     const val STRIP_LOCATION_ON_UPLOAD = "stripLocationOnUpload"
+    const val DISABLE_CLIENT_TAG = "disableClientTag"
     const val DEFAULT_HOME_FOLLOW_LIST = "defaultHomeFollowList"
     const val DEFAULT_STORIES_FOLLOW_LIST = "defaultStoriesFollowList"
     const val DEFAULT_NOTIFICATION_FOLLOW_LIST = "defaultNotificationFollowList"
@@ -346,6 +347,7 @@ object LocalPreferences {
                     )
 
                     putBoolean(PrefKeys.STRIP_LOCATION_ON_UPLOAD, settings.stripLocationOnUpload)
+                    putBoolean(PrefKeys.DISABLE_CLIENT_TAG, settings.disableClientTag)
 
                     putString(PrefKeys.DEFAULT_HOME_FOLLOW_LIST, JsonMapper.toJson(settings.defaultHomeFollowList.value))
                     putString(PrefKeys.DEFAULT_STORIES_FOLLOW_LIST, JsonMapper.toJson(settings.defaultStoriesFollowList.value))
@@ -513,6 +515,7 @@ object LocalPreferences {
                     Log.d("LocalPreferences") { "Load account from file $npub - keys ready" }
 
                     val stripLocationOnUpload = getBoolean(PrefKeys.STRIP_LOCATION_ON_UPLOAD, true)
+                    val disableClientTag = getBoolean(PrefKeys.DISABLE_CLIENT_TAG, false)
                     val hideDeleteRequestDialog = getBoolean(PrefKeys.HIDE_DELETE_REQUEST_DIALOG, false)
                     val hideBlockAlertDialog = getBoolean(PrefKeys.HIDE_BLOCK_ALERT_DIALOG, false)
                     val hideNIP17WarningDialog = getBoolean(PrefKeys.HIDE_NIP_17_WARNING_DIALOG, false)
@@ -620,6 +623,7 @@ object LocalPreferences {
                         localRelayServers = MutableStateFlow(localRelayServers),
                         defaultFileServer = defaultFileServer.await(),
                         stripLocationOnUpload = stripLocationOnUpload,
+                        disableClientTag = disableClientTag,
                         defaultHomeFollowList = MutableStateFlow(followListPrefs.home),
                         defaultStoriesFollowList = MutableStateFlow(followListPrefs.stories),
                         defaultNotificationFollowList = MutableStateFlow(followListPrefs.notification),

amethyst/src/main/java/com/vitorpamplona/amethyst/model/AccountSettings.kt

@@ -149,6 +149,7 @@ class AccountSettings(
     var localRelayServers: MutableStateFlow<Set<String>> = MutableStateFlow(setOf()),
     var defaultFileServer: ServerName = DEFAULT_MEDIA_SERVERS[0],
     var stripLocationOnUpload: Boolean = true,
+    var disableClientTag: Boolean = false,
     val defaultHomeFollowList: MutableStateFlow<TopFilter> = MutableStateFlow(TopFilter.AllFollows),
     val defaultStoriesFollowList: MutableStateFlow<TopFilter> = MutableStateFlow(TopFilter.Global),
     val defaultNotificationFollowList: MutableStateFlow<TopFilter> = MutableStateFlow(TopFilter.Global),
@@ -403,6 +404,13 @@ class AccountSettings(
         }
     }
 
+    fun changeDisableClientTag(disable: Boolean) {
+        if (disableClientTag != disable) {
+            disableClientTag = disable
+            saveAccountSettings()
+        }
+    }
+
     // ---
     // list names
     // ---

amethyst/src/main/java/com/vitorpamplona/amethyst/model/accountsCache/AccountCacheState.kt

@@ -135,7 +135,12 @@ class AccountCacheState(
         val cached = accounts.value[signer.pubKey]
         if (cached != null) return cached
 
-        val signerWithClientTag = NostrSignerWithClientTag(signer, CLIENT_TAG_NAME)
+        val signerWithClientTag =
+            NostrSignerWithClientTag(
+                inner = signer,
+                clientName = CLIENT_TAG_NAME,
+                disabled = { accountSettings.disableClientTag },
+            )
 
         val accountDir = File(rootFilesDir(), "accounts/${signer.pubKey}").apply { mkdirs() }
 

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/settings/SecurityFiltersScreen.kt

@@ -371,6 +371,21 @@ private fun HeaderOptions(accountViewModel: AccountViewModel) {
             )
         }
 
+        SettingsRow(
+            R.string.disable_client_tag_title,
+            R.string.disable_client_tag_explainer,
+        ) {
+            var disableClientTag by remember { mutableStateOf(accountViewModel.account.settings.disableClientTag) }
+
+            Switch(
+                checked = disableClientTag,
+                onCheckedChange = {
+                    disableClientTag = it
+                    accountViewModel.account.settings.changeDisableClientTag(it)
+                },
+            )
+        }
+
         SettingsRow(
             R.string.show_sensitive_content_title,
             R.string.show_sensitive_content_explainer,

amethyst/src/main/res/values/strings.xml

@@ -1172,6 +1172,8 @@
 
     <string name="filter_spam_from_strangers_title">Filter spam</string>
     <string name="filter_spam_from_strangers_explainer">Hides posts from strangers that were exactly the same for 5 or more times</string>
+    <string name="disable_client_tag_title">Don\'t add client tag to my events</string>
+    <string name="disable_client_tag_explainer">When enabled, Amethyst will not append a NIP-89 client tag to events you publish.</string>
     <string name="warn_when_posts_have_reports_from_your_follows_title">Warn on reports</string>
     <string name="warn_when_posts_have_reports_from_your_follows_explainer">Shows a warning message when posts have 5 or more reports from your follows</string>
     <string name="show_sensitive_content_title">Show sensitive content</string>

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

@@ -40,12 +40,19 @@ import com.vitorpamplona.quartz.nip57Zaps.LnZapRequestEvent
 class NostrSignerWithClientTag(
     val inner: NostrSigner,
     val clientTag: Array<String>,
+    val disabled: () -> Boolean = { false },
 ) : NostrSigner(inner.pubKey) {
     constructor(
         inner: NostrSigner,
         clientName: String,
     ) : this(inner, ClientTag.assemble(clientName))
 
+    constructor(
+        inner: NostrSigner,
+        clientName: String,
+        disabled: () -> Boolean,
+    ) : this(inner, ClientTag.assemble(clientName), disabled)
+
     constructor(
         inner: NostrSigner,
         clientName: String,
@@ -60,7 +67,12 @@ class NostrSignerWithClientTag(
         kind: Int,
         tags: Array<Array<String>>,
         content: String,
-    ): T = inner.sign(createdAt, kind, appendClientTag(tags), content)
+    ): T =
+        if (disabled()) {
+            inner.sign(createdAt, kind, tags, content)
+        } else {
+            inner.sign(createdAt, kind, appendClientTag(tags), content)
+        }
 
     override suspend fun nip04Encrypt(
         plaintext: String,