Oh god, so much code for such a minor flow. Ambiguous sender manually fetched prefix DMs are now visible.

frontend/src/components/ChatHeader.tsx

@@ -4,6 +4,7 @@ import { toast } from './ui/sonner';
 import { isFavorite } from '../utils/favorites';
 import { handleKeyboardActivate } from '../utils/a11y';
 import { stripRegionScopePrefix } from '../utils/regionScope';
+import { isPrefixOnlyContact } from '../utils/pubkey';
 import { ContactAvatar } from './ContactAvatar';
 import { ContactStatusInfo } from './ContactStatusInfo';
 import type { Channel, Contact, Conversation, Favorite, RadioConfig } from '../types';
@@ -62,6 +63,13 @@ export function ChatHeader({
     : null;
   const activeFloodScopeDisplay = activeFloodScopeOverride ? activeFloodScopeOverride : null;
   const isPrivateChannel = conversation.type === 'channel' && !activeChannel?.is_hashtag;
+  const activeContact =
+    conversation.type === 'contact'
+      ? contacts.find((contact) => contact.public_key === conversation.id)
+      : null;
+  const activeContactIsPrefixOnly = activeContact
+    ? isPrefixOnlyContact(activeContact.public_key)
+    : false;
 
   const titleClickable =
     (conversation.type === 'contact' && onOpenContactInfo) ||
@@ -214,10 +222,15 @@ export function ChatHeader({
       <div className="flex items-center justify-end gap-0.5 flex-shrink-0">
         {conversation.type === 'contact' && (
           <button
-            className="p-1 rounded hover:bg-accent text-lg leading-none transition-colors focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring"
+            className="p-1 rounded hover:bg-accent text-lg leading-none transition-colors disabled:cursor-not-allowed disabled:opacity-50 focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring"
             onClick={onTrace}
-            title="Direct Trace"
+            title={
+              activeContactIsPrefixOnly
+                ? 'Direct Trace unavailable until the full contact key is known'
+                : 'Direct Trace'
+            }
             aria-label="Direct Trace"
+            disabled={activeContactIsPrefixOnly}
           >
             <Route className="h-4 w-4" aria-hidden="true" />
           </button>

frontend/src/components/ContactInfoPane.tsx

@@ -2,6 +2,11 @@ import { type ReactNode, useEffect, useState } from 'react';
 import { Ban, Search, Star } from 'lucide-react';
 import { api } from '../api';
 import { formatTime } from '../utils/messageParser';
+import {
+  getContactDisplayName,
+  isPrefixOnlyContact,
+  isUnknownFullKeyContact,
+} from '../utils/pubkey';
 import {
   isValidLocation,
   calculateDistance,
@@ -133,6 +138,11 @@ export function ContactInfoPane({
       ? formatPathHashMode(effectiveRoute.pathHashMode)
       : null;
   const learnedRouteLabel = contact ? formatRouteLabel(contact.last_path_len, true) : null;
+  const isPrefixOnlyResolvedContact = contact ? isPrefixOnlyContact(contact.public_key) : false;
+  const isUnknownFullKeyResolvedContact =
+    contact !== null &&
+    !isPrefixOnlyResolvedContact &&
+    isUnknownFullKeyContact(contact.public_key, contact.last_advert);
 
   return (
     <Sheet open={contactKey !== null} onOpenChange={(open) => !open && onClose()}>
@@ -249,7 +259,7 @@ export function ContactInfoPane({
                 />
                 <div className="flex-1 min-w-0">
                   <h2 className="text-lg font-semibold truncate">
-                    {contact.name || contact.public_key.slice(0, 12)}
+                    {getContactDisplayName(contact.name, contact.public_key, contact.last_advert)}
                   </h2>
                   <span
                     className="text-xs font-mono text-muted-foreground cursor-pointer hover:text-primary transition-colors block truncate"
@@ -278,6 +288,22 @@ export function ContactInfoPane({
               </div>
             </div>
 
+            {isPrefixOnlyResolvedContact && (
+              <div className="mx-5 mt-4 rounded-md border border-destructive/30 bg-destructive/10 px-3 py-2 text-sm text-destructive">
+                We only know a key prefix for this sender, which can happen when a fallback DM
+                arrives before we hear an advertisement. This contact stays read-only until the full
+                key resolves from a later advertisement.
+              </div>
+            )}
+
+            {isUnknownFullKeyResolvedContact && (
+              <div className="mx-5 mt-4 rounded-md border border-warning/30 bg-warning/10 px-3 py-2 text-sm text-warning">
+                We know this sender&apos;s full key, but we have not yet heard an advertisement that
+                fills in their identity details. Those details will appear automatically when an
+                advertisement arrives.
+              </div>
+            )}
+
             {/* Info grid */}
             <div className="px-5 py-3 border-b border-border">
               <div className="grid grid-cols-2 gap-x-4 gap-y-2 text-sm">

frontend/src/components/ConversationPane.tsx

@@ -15,6 +15,7 @@ import type {
   RadioConfig,
 } from '../types';
 import { CONTACT_TYPE_REPEATER } from '../types';
+import { isPrefixOnlyContact, isUnknownFullKeyContact } from '../utils/pubkey';
 
 const RepeaterDashboard = lazy(() =>
   import('./RepeaterDashboard').then((m) => ({ default: m.RepeaterDashboard }))
@@ -66,6 +67,25 @@ function LoadingPane({ label }: { label: string }) {
   );
 }
 
+function ContactResolutionBanner({ variant }: { variant: 'unknown-full-key' | 'prefix-only' }) {
+  if (variant === 'prefix-only') {
+    return (
+      <div className="mx-4 mt-3 rounded-md border border-destructive/30 bg-destructive/10 px-3 py-2 text-sm text-destructive">
+        We only know a key prefix for this sender, which can happen when a fallback DM arrives
+        before we learn their full identity. This conversation is read-only until we hear an
+        advertisement that resolves the full key.
+      </div>
+    );
+  }
+
+  return (
+    <div className="mx-4 mt-3 rounded-md border border-warning/30 bg-warning/10 px-3 py-2 text-sm text-warning">
+      A full identity profile is not yet available because we have not heard an advertisement from
+      this sender. The contact will fill in automatically when an advertisement arrives.
+    </div>
+  );
+}
+
 export function ConversationPane({
   activeConversation,
   contacts,
@@ -106,6 +126,17 @@ export function ConversationPane({
     const contact = contacts.find((candidate) => candidate.public_key === activeConversation.id);
     return contact?.type === CONTACT_TYPE_REPEATER;
   }, [activeConversation, contacts]);
+  const activeContact = useMemo(() => {
+    if (!activeConversation || activeConversation.type !== 'contact') return null;
+    return contacts.find((candidate) => candidate.public_key === activeConversation.id) ?? null;
+  }, [activeConversation, contacts]);
+  const isPrefixOnlyActiveContact = activeContact
+    ? isPrefixOnlyContact(activeContact.public_key)
+    : false;
+  const isUnknownFullKeyActiveContact =
+    activeContact !== null &&
+    !isPrefixOnlyActiveContact &&
+    isUnknownFullKeyContact(activeContact.public_key, activeContact.last_advert);
 
   if (!activeConversation) {
     return (
@@ -198,6 +229,12 @@ export function ConversationPane({
         onOpenContactInfo={onOpenContactInfo}
         onOpenChannelInfo={onOpenChannelInfo}
       />
+      {activeConversation.type === 'contact' && isPrefixOnlyActiveContact && (
+        <ContactResolutionBanner variant="prefix-only" />
+      )}
+      {activeConversation.type === 'contact' && isUnknownFullKeyActiveContact && (
+        <ContactResolutionBanner variant="unknown-full-key" />
+      )}
       <MessageList
         key={activeConversation.id}
         messages={messages}
@@ -220,16 +257,20 @@ export function ConversationPane({
         onLoadNewer={onLoadNewer}
         onJumpToBottom={onJumpToBottom}
       />
-      <MessageInput
-        ref={messageInputRef}
-        onSend={onSendMessage}
-        disabled={!health?.radio_connected}
-        conversationType={activeConversation.type}
-        senderName={config?.name}
-        placeholder={
-          !health?.radio_connected ? 'Radio not connected' : `Message ${activeConversation.name}...`
-        }
-      />
+      {activeConversation.type === 'contact' && isPrefixOnlyActiveContact ? null : (
+        <MessageInput
+          ref={messageInputRef}
+          onSend={onSendMessage}
+          disabled={!health?.radio_connected}
+          conversationType={activeConversation.type}
+          senderName={config?.name}
+          placeholder={
+            !health?.radio_connected
+              ? 'Radio not connected'
+              : `Message ${activeConversation.name}...`
+          }
+        />
+      )}
     </>
   );
 }

frontend/src/components/NewMessageModal.tsx

@@ -169,34 +169,40 @@ export function NewMessageModal({
 
           <TabsContent value="existing" className="mt-4">
             <div className="max-h-[300px] overflow-y-auto rounded-md border">
-              {contacts.length === 0 ? (
+              {contacts.filter((contact) => contact.public_key.length === 64).length === 0 ? (
                 <div className="p-4 text-center text-muted-foreground">No contacts available</div>
               ) : (
-                contacts.map((contact) => (
-                  <div
-                    key={contact.public_key}
-                    className="cursor-pointer px-4 py-2 hover:bg-accent focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring focus-visible:ring-inset"
-                    role="button"
-                    tabIndex={0}
-                    onKeyDown={(e) => {
-                      if (e.key === 'Enter' || e.key === ' ') {
-                        e.preventDefault();
-                        (e.currentTarget as HTMLElement).click();
-                      }
-                    }}
-                    onClick={() => {
-                      onSelectConversation({
-                        type: 'contact',
-                        id: contact.public_key,
-                        name: getContactDisplayName(contact.name, contact.public_key),
-                      });
-                      resetForm();
-                      onClose();
-                    }}
-                  >
-                    {getContactDisplayName(contact.name, contact.public_key)}
-                  </div>
-                ))
+                contacts
+                  .filter((contact) => contact.public_key.length === 64)
+                  .map((contact) => (
+                    <div
+                      key={contact.public_key}
+                      className="cursor-pointer px-4 py-2 hover:bg-accent focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring focus-visible:ring-inset"
+                      role="button"
+                      tabIndex={0}
+                      onKeyDown={(e) => {
+                        if (e.key === 'Enter' || e.key === ' ') {
+                          e.preventDefault();
+                          (e.currentTarget as HTMLElement).click();
+                        }
+                      }}
+                      onClick={() => {
+                        onSelectConversation({
+                          type: 'contact',
+                          id: contact.public_key,
+                          name: getContactDisplayName(
+                            contact.name,
+                            contact.public_key,
+                            contact.last_advert
+                          ),
+                        });
+                        resetForm();
+                        onClose();
+                      }}
+                    >
+                      {getContactDisplayName(contact.name, contact.public_key, contact.last_advert)}
+                    </div>
+                  ))
               )}
             </div>
           </TabsContent>

frontend/src/components/Sidebar.tsx

@@ -416,7 +416,7 @@ export function Sidebar({
     key: `${keyPrefix}-${contact.public_key}`,
     type: 'contact',
     id: contact.public_key,
-    name: getContactDisplayName(contact.name, contact.public_key),
+    name: getContactDisplayName(contact.name, contact.public_key, contact.last_advert),
     unreadCount: getUnreadCount('contact', contact.public_key),
     isMention: hasMention('contact', contact.public_key),
     notificationsEnabled: