feat: use MIP-00 KeyPackage Relay List for publish/fetch + seed default

- publishMarmotKeyPackage / publishMarmotKeyPackages now target the
  relays advertised in the user's kind:10051 KeyPackage Relay List
  (MIP-00), falling back to outbox relays when the list is empty.
- fetchKeyPackageAndAddMember looks up the invitee's kind:10051
  before falling back to their NIP-65 outbox.
- Add kind:10051 to user metadata + account info subscription filters
  so invitees' KeyPackage relay lists are cached in time for invites.
- Seed a default kind:10051 on signup from the default NIP-65 relay set
  and publish it alongside other account bootstrap events.
- Warn the user when creating a Marmot group without a kind:10051 list
  and offer to create one from their current outbox relays.
- Sync overload for KeyPackageRelayListEvent.create to support the
  signup-time temp signer.

https://claude.ai/code/session_01B7kTUFAPvWarWd6fvQKNBy

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

@@ -1788,23 +1788,32 @@ class Account(
         // Build filter for the member's KeyPackages
         val filter = manager.subscriptionManager.keyPackageFilter(memberPubKey)
 
-        // KeyPackages are published by the invitee to *their own* outbox
+        // Per MIP-00, invitees advertise the relays that host their
-        // (see publishMarmotKeyPackage), so look there first. Union with
+        // KeyPackages in a kind:10051 KeyPackageRelayListEvent. Look
-        // our own outbox so we still find packages that ended up on a
+        // there first, then fall back to the invitee's NIP-65 outbox
-        // shared relay, and as a fallback when we don't know the
+        // (where KeyPackages typically also land), and finally union
-        // invitee's outbox yet.
+        // with our own outbox so we still find packages that ended up
+        // on a shared relay.
         val myOutbox = outboxRelays.flow.value
+        val memberKeyPackageRelays =
+            (
+                cache
+                    .getAddressableNoteIfExists(
+                        com.vitorpamplona.quartz.marmot.mip00KeyPackages.KeyPackageRelayListEvent
+                            .createAddress(memberPubKey),
+                    )?.event as? com.vitorpamplona.quartz.marmot.mip00KeyPackages.KeyPackageRelayListEvent
+            )?.relays()?.toSet().orEmpty()
         val memberOutbox =
             cache
                 .getOrCreateUser(memberPubKey)
                 .outboxRelays()
                 ?.toSet()
                 .orEmpty()
-        val fetchRelays = memberOutbox + myOutbox
+        val fetchRelays = memberKeyPackageRelays + memberOutbox + myOutbox
 
         Log.d("MarmotDbg") {
             "fetchKeyPackageAndAddMember: querying ${fetchRelays.size} relay(s) for ${memberPubKey.take(8)}… KeyPackage " +
-                "(memberOutbox=${memberOutbox.size}, myOutbox=${myOutbox.size}): ${fetchRelays.map { it.url }}"
+                "(memberKeyPackageRelays=${memberKeyPackageRelays.size}, memberOutbox=${memberOutbox.size}, myOutbox=${myOutbox.size}): ${fetchRelays.map { it.url }}"
         }
 
         // Query across the combined relay set
@@ -1939,6 +1948,20 @@ class Account(
         }
     }
 
+    /**
+     * Relays where this account publishes kind:30443 KeyPackage events.
+     *
+     * Per MIP-00, these should match the relays advertised in the user's
+     * kind:10051 KeyPackage Relay List so that other clients can discover
+     * and fetch them. Falls back to the standard outbox set when no list
+     * has been configured yet, since that's also where the user's other
+     * write-oriented events land.
+     */
+    fun keyPackagePublishRelays(): Set<NormalizedRelayUrl> {
+        val list = keyPackageRelayList.flow.value
+        return if (list.isNotEmpty()) list else outboxRelays.flow.value
+    }
+
     /**
      * Publish or rotate KeyPackage events.
      */
@@ -1946,13 +1969,13 @@ class Account(
         val manager = marmotManager ?: return
         if (!isWriteable()) return
 
-        val relays = outboxRelays.flow.value.toList()
+        val relays = keyPackagePublishRelays()
 
         if (manager.needsKeyPackageRotation()) {
-            val rotatedEvents = manager.rotateConsumedKeyPackages(relays)
+            val rotatedEvents = manager.rotateConsumedKeyPackages(relays.toList())
             rotatedEvents.forEach { event ->
                 cache.justConsumeMyOwnEvent(event)
-                client.publish(event, outboxRelays.flow.value)
+                client.publish(event, relays)
             }
         }
     }
@@ -1964,16 +1987,16 @@ class Account(
         val manager = marmotManager ?: return
         if (!isWriteable()) return
 
-        val relays = outboxRelays.flow.value.toList()
+        val relays = keyPackagePublishRelays()
         Log.d("MarmotDbg") {
             "publishMarmotKeyPackage: generating + publishing KeyPackage event → ${relays.size} relay(s): ${relays.map { it.url }}"
         }
-        val event = manager.generateKeyPackageEvent(relays)
+        val event = manager.generateKeyPackageEvent(relays.toList())
         Log.d("MarmotDbg") {
             "publishMarmotKeyPackage: signed kind:${event.kind} id=${event.id.take(8)}… authored=${event.pubKey.take(8)}…"
         }
         cache.justConsumeMyOwnEvent(event)
-        client.publish(event, outboxRelays.flow.value)
+        client.publish(event, relays)
     }
 
     /**

amethyst/src/main/java/com/vitorpamplona/amethyst/service/relayClient/reqCommand/account/metadata/FilterAccountInfoAndListsFromKey.kt

@@ -22,6 +22,7 @@ package com.vitorpamplona.amethyst.service.relayClient.reqCommand.account.metada
 
 import com.vitorpamplona.amethyst.model.nip78AppSpecific.AppSpecificState.Companion.APP_SPECIFIC_DATA_D_TAG
 import com.vitorpamplona.quartz.experimental.nipA3.PaymentTargetsEvent
+import com.vitorpamplona.quartz.marmot.mip00KeyPackages.KeyPackageRelayListEvent
 import com.vitorpamplona.quartz.nip01Core.core.HexKey
 import com.vitorpamplona.quartz.nip01Core.metadata.MetadataEvent
 import com.vitorpamplona.quartz.nip01Core.relay.client.pool.RelayBasedFilter
@@ -53,6 +54,7 @@ val AccountInfoAndListsFromKeyKinds =
         StatusEvent.KIND,
         AdvertisedRelayListEvent.KIND,
         ChatMessageRelayListEvent.KIND,
+        KeyPackageRelayListEvent.KIND,
         SearchRelayListEvent.KIND,
         FileServersEvent.KIND,
         BlossomServersEvent.KIND,

amethyst/src/main/java/com/vitorpamplona/amethyst/service/relayClient/reqCommand/account/metadata/FilterBasicAccountInfoFromKeys.kt

@@ -20,6 +20,7 @@
  */
 package com.vitorpamplona.amethyst.service.relayClient.reqCommand.account.metadata
 
+import com.vitorpamplona.quartz.marmot.mip00KeyPackages.KeyPackageRelayListEvent
 import com.vitorpamplona.quartz.nip01Core.core.HexKey
 import com.vitorpamplona.quartz.nip01Core.metadata.MetadataEvent
 import com.vitorpamplona.quartz.nip01Core.relay.client.pool.RelayBasedFilter
@@ -47,6 +48,7 @@ val BasicAccountInfoKinds =
         ContactListEvent.KIND,
         AdvertisedRelayListEvent.KIND,
         ChatMessageRelayListEvent.KIND,
+        KeyPackageRelayListEvent.KIND,
         SearchRelayListEvent.KIND,
         FileServersEvent.KIND,
         BlossomServersEvent.KIND,

amethyst/src/main/java/com/vitorpamplona/amethyst/service/relayClient/reqCommand/user/watchers/FilterUserMetadataForKey.kt

@@ -23,6 +23,7 @@ package com.vitorpamplona.amethyst.service.relayClient.reqCommand.user.watchers
 import com.vitorpamplona.amethyst.model.LocalCache
 import com.vitorpamplona.amethyst.model.User
 import com.vitorpamplona.amethyst.service.relays.EOSEAccountFast
+import com.vitorpamplona.quartz.marmot.mip00KeyPackages.KeyPackageRelayListEvent
 import com.vitorpamplona.quartz.nip01Core.core.HexKey
 import com.vitorpamplona.quartz.nip01Core.metadata.MetadataEvent
 import com.vitorpamplona.quartz.nip01Core.relay.client.pool.RelayBasedFilter
@@ -41,6 +42,7 @@ val UserMetadataForKeyKinds =
         StatusEvent.KIND,
         AdvertisedRelayListEvent.KIND,
         ChatMessageRelayListEvent.KIND,
+        KeyPackageRelayListEvent.KIND,
     )
 
 fun filterUserMetadataForKey(

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/AccountSessionManager.kt

@@ -34,6 +34,7 @@ import com.vitorpamplona.amethyst.model.DefaultNIP65RelaySet
 import com.vitorpamplona.amethyst.model.DefaultSearchRelayList
 import com.vitorpamplona.amethyst.model.accountsCache.AccountCacheState
 import com.vitorpamplona.amethyst.ui.navigation.routes.Route
+import com.vitorpamplona.quartz.marmot.mip00KeyPackages.KeyPackageRelayListEvent
 import com.vitorpamplona.quartz.nip01Core.core.hexToByteArray
 import com.vitorpamplona.quartz.nip01Core.core.toHexKey
 import com.vitorpamplona.quartz.nip01Core.crypto.KeyPair
@@ -293,6 +294,7 @@ class AccountSessionManager(
                 accountSettings.backupContactList?.let { client.publish(it, toPost) }
                 accountSettings.backupNIP65RelayList?.let { client.publish(it, toPost) }
                 accountSettings.backupDMRelayList?.let { client.publish(it, toPost) }
+                accountSettings.backupKeyPackageRelayList?.let { client.publish(it, toPost) }
                 accountSettings.backupSearchRelayList?.let { client.publish(it, toPost) }
                 accountSettings.backupIndexRelayList?.let { client.publish(it, toPost) }
                 accountSettings.backupRelayFeedsList?.let { client.publish(it, toPost) }
@@ -317,6 +319,10 @@ class AccountSessionManager(
                 ),
             backupNIP65RelayList = AdvertisedRelayListEvent.create(DefaultNIP65List, tempSigner),
             backupDMRelayList = ChatMessageRelayListEvent.create(DefaultDMRelayList, tempSigner),
+            // MIP-00: advertise the default outbox relays as KeyPackage hosts
+            // so other users can discover and fetch this account's KeyPackage
+            // events without having to guess where they were published.
+            backupKeyPackageRelayList = KeyPackageRelayListEvent.create(DefaultNIP65RelaySet.toList(), tempSigner),
             backupSearchRelayList = SearchRelayListEvent.create(DefaultSearchRelayList.toList(), tempSigner),
             backupIndexRelayList = IndexerRelayListEvent.create(DefaultIndexerRelayList.toList(), tempSigner),
             backupChannelList = ChannelListEvent.create(emptyList(), DefaultChannels, tempSigner),

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

@@ -1471,6 +1471,27 @@ class AccountViewModel(
 
     suspend fun hasPublishedKeyPackage(): Boolean = account.hasPublishedKeyPackage()
 
+    /**
+     * Whether this account has a kind:10051 KeyPackage Relay List (MIP-00)
+     * advertising where it publishes KeyPackages.
+     */
+    fun hasKeyPackageRelayList(): Boolean =
+        account.keyPackageRelayList.flow.value
+            .isNotEmpty()
+
+    /**
+     * Publishes a kind:10051 KeyPackage Relay List seeded from the account's
+     * current outbox relays. Used when the user opts in from the
+     * "Create Group" warning dialog.
+     */
+    suspend fun saveKeyPackageRelayListFromOutbox() {
+        val outbox =
+            account.outboxRelays.flow.value
+                .toList()
+        if (outbox.isEmpty()) return
+        account.saveKeyPackageRelayList(outbox)
+    }
+
     suspend fun leaveMarmotGroup(nostrGroupId: String) {
         val relays = marmotGroupRelays(nostrGroupId)
         account.leaveMarmotGroup(nostrGroupId, relays)

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/chats/marmotGroup/CreateGroupScreen.kt

@@ -26,10 +26,12 @@ import androidx.compose.foundation.layout.consumeWindowInsets
 import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.imePadding
 import androidx.compose.foundation.layout.padding
+import androidx.compose.material3.AlertDialog
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.OutlinedTextField
 import androidx.compose.material3.Scaffold
 import androidx.compose.material3.Text
+import androidx.compose.material3.TextButton
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
@@ -55,44 +57,53 @@ fun CreateGroupScreen(
 ) {
     var groupName by remember { mutableStateOf("") }
     var isCreating by remember { mutableStateOf(false) }
+    var showKeyPackageRelayDialog by remember { mutableStateOf(false) }
     val scope = rememberCoroutineScope()
     val context = LocalContext.current
 
+    fun proceedWithCreate() {
+        isCreating = true
+        scope.launch(Dispatchers.IO) {
+            try {
+                val nostrGroupId = RandomInstance.bytes(32).toHexKey()
+                accountViewModel.createMarmotGroup(nostrGroupId)
+                // Always commit an initial metadata extension so that
+                // (a) the name (if any) is persisted in MLS extensions
+                //     and survives app restarts,
+                // (b) the inviter's outbox relays land in the group
+                //     metadata so every member ends up with the same
+                //     canonical relay set for kind:445 — without this,
+                //     invitees would never receive the group's messages.
+                // Both are handled inside `updateMarmotGroupMetadata`.
+                accountViewModel.updateMarmotGroupMetadata(
+                    nostrGroupId = nostrGroupId,
+                    name = groupName.trim(),
+                    description = "",
+                )
+                nav.nav(Route.MarmotGroupChat(nostrGroupId))
+            } catch (e: Exception) {
+                isCreating = false
+                launch(Dispatchers.Main) {
+                    Toast
+                        .makeText(
+                            context,
+                            "Failed to create group: ${e.message}",
+                            Toast.LENGTH_LONG,
+                        ).show()
+                }
+            }
+        }
+    }
+
     Scaffold(
         topBar = {
             CreatingTopBar(
                 onCancel = { nav.popBack() },
                 onPost = {
-                    isCreating = true
+                    if (!accountViewModel.hasKeyPackageRelayList()) {
-                    scope.launch(Dispatchers.IO) {
+                        showKeyPackageRelayDialog = true
-                        try {
+                    } else {
-                            val nostrGroupId = RandomInstance.bytes(32).toHexKey()
+                        proceedWithCreate()
-                            accountViewModel.createMarmotGroup(nostrGroupId)
-                            // Always commit an initial metadata extension so that
-                            // (a) the name (if any) is persisted in MLS extensions
-                            //     and survives app restarts,
-                            // (b) the inviter's outbox relays land in the group
-                            //     metadata so every member ends up with the same
-                            //     canonical relay set for kind:445 — without this,
-                            //     invitees would never receive the group's messages.
-                            // Both are handled inside `updateMarmotGroupMetadata`.
-                            accountViewModel.updateMarmotGroupMetadata(
-                                nostrGroupId = nostrGroupId,
-                                name = groupName.trim(),
-                                description = "",
-                            )
-                            nav.nav(Route.MarmotGroupChat(nostrGroupId))
-                        } catch (e: Exception) {
-                            isCreating = false
-                            launch(Dispatchers.Main) {
-                                Toast
-                                    .makeText(
-                                        context,
-                                        "Failed to create group: ${e.message}",
-                                        Toast.LENGTH_LONG,
-                                    ).show()
-                            }
-                        }
                     }
                 },
                 isActive = { !isCreating },
@@ -129,4 +140,53 @@ fun CreateGroupScreen(
             )
         }
     }
+
+    if (showKeyPackageRelayDialog) {
+        MissingKeyPackageRelayListDialog(
+            onConfirm = {
+                showKeyPackageRelayDialog = false
+                scope.launch(Dispatchers.IO) {
+                    accountViewModel.saveKeyPackageRelayListFromOutbox()
+                }
+                proceedWithCreate()
+            },
+            onDismiss = {
+                showKeyPackageRelayDialog = false
+                proceedWithCreate()
+            },
+            onCancel = {
+                showKeyPackageRelayDialog = false
+            },
+        )
+    }
+}
+
+@Composable
+private fun MissingKeyPackageRelayListDialog(
+    onConfirm: () -> Unit,
+    onDismiss: () -> Unit,
+    onCancel: () -> Unit,
+) {
+    AlertDialog(
+        onDismissRequest = onCancel,
+        title = { Text("KeyPackage Relays not set") },
+        text = {
+            Text(
+                "You don't have a KeyPackage Relay List yet (MIP-00). " +
+                    "This list tells other people where your KeyPackage is " +
+                    "published so they can invite you to group chats.\n\n" +
+                    "Use your current outbox relays for this?",
+            )
+        },
+        confirmButton = {
+            TextButton(onClick = onConfirm) {
+                Text("Use outbox relays")
+            }
+        },
+        dismissButton = {
+            TextButton(onClick = onDismiss) {
+                Text("Skip for now")
+            }
+        },
+    )
 }

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/marmot/mip00KeyPackages/KeyPackageRelayListEvent.kt

@@ -27,6 +27,7 @@ import com.vitorpamplona.quartz.nip01Core.core.HexKey
 import com.vitorpamplona.quartz.nip01Core.relay.normalizer.NormalizedRelayUrl
 import com.vitorpamplona.quartz.nip01Core.relay.normalizer.isLocalHost
 import com.vitorpamplona.quartz.nip01Core.signers.NostrSigner
+import com.vitorpamplona.quartz.nip01Core.signers.NostrSignerSync
 import com.vitorpamplona.quartz.nip31Alts.AltTag
 import com.vitorpamplona.quartz.utils.TimeUtils
 
@@ -70,6 +71,12 @@ class KeyPackageRelayListEvent(
             createdAt: Long = TimeUtils.now(),
         ): KeyPackageRelayListEvent = signer.sign(createdAt, KIND, createTagArray(relays), "")
 
+        fun create(
+            relays: List<NormalizedRelayUrl>,
+            signer: NostrSignerSync,
+            createdAt: Long = TimeUtils.now(),
+        ): KeyPackageRelayListEvent = signer.sign(createdAt, KIND, createTagArray(relays), "")
+
         suspend fun updateRelayList(
             earlierVersion: KeyPackageRelayListEvent,
             relays: List<NormalizedRelayUrl>,