diff --git a/lib/core/network/clients/poptart_clients.dart b/lib/core/network/clients/poptart_clients.dart
--- a/lib/core/network/clients/poptart_clients.dart
+++ b/lib/core/network/clients/poptart_clients.dart
@@ -1,5 +1,7 @@
 part of '../poptart_client_adapter.dart';
 
+const _bskyChatProxyHeaders = <String, String>{'atproto-proxy': 'did:web:api.bsky.chat#bsky_chat'};
+
 class Bluesky {
   Bluesky._(this._client);
 
@@ -153,7 +155,7 @@
     return BlueskyChat._(
       PoptartClient.fromSession(
         session,
-        headers: headers,
+        headers: {...?headers, ..._bskyChatProxyHeaders},
         protocol: protocol,
         service: service,
         relayService: relayService,
@@ -179,7 +181,7 @@
     return BlueskyChat._(
       PoptartClient.fromOAuthSession(
         session,
-        headers: headers,
+        headers: {...?headers, ..._bskyChatProxyHeaders},
         protocol: protocol,
         service: service,
         relayService: relayService,
diff --git a/test/features/messages/data/convo_repository_test.dart b/test/features/messages/data/convo_repository_test.dart
--- a/test/features/messages/data/convo_repository_test.dart
+++ b/test/features/messages/data/convo_repository_test.dart
@@ -41,6 +41,28 @@
   });
 
   group('ConvoRepository auth recovery', () {
+    test('listConvos sends requests through the Bluesky chat proxy service', () async {
+      final transport = _ScriptedTransport(
+        getReplies: [
+          _okReply({'convos': const []}),
+        ],
+      );
+      final repository = ConvoRepository(chat: transport.createChat());
+
+      await repository.listConvos();
+
+      expect(transport.lastGetHeaders?['atproto-proxy'], 'did:web:api.bsky.chat#bsky_chat');
+    });
+
+    test('sendMessage sends requests through the Bluesky chat proxy service', () async {
+      final transport = _ScriptedTransport(postReplies: [_okReply(_messageJson('msg-1'))]);
+      final repository = ConvoRepository(chat: transport.createChat());
+
+      await repository.sendMessage('c1', 'Hello');
+
+      expect(transport.lastPostHeaders?['atproto-proxy'], 'did:web:api.bsky.chat#bsky_chat');
+    });
+
     test('listConvos retries once after unauthorized and succeeds with refreshed client', () async {
       final primary = _ScriptedTransport(getReplies: [_unauthorizedReply()]);
       final fallback = _ScriptedTransport(
@@ -130,6 +152,8 @@
 
   int getCalls = 0;
   int postCalls = 0;
+  Map<String, String>? lastGetHeaders;
+  Map<String, String>? lastPostHeaders;
 
   BlueskyChat createChat() {
     return BlueskyChat.fromSession(
@@ -141,6 +165,7 @@
       ),
       getClient: (uri, {headers}) async {
         getCalls += 1;
+        lastGetHeaders = headers;
         if (_getReplies.isEmpty) {
           throw StateError('No scripted GET response queued for $uri');
         }
@@ -148,6 +173,7 @@
       },
       postClient: (uri, {headers, body, encoding}) async {
         postCalls += 1;
+        lastPostHeaders = headers;
         if (_postReplies.isEmpty) {
           throw StateError('No scripted POST response queued for $uri');
         }
@@ -159,6 +185,16 @@
 
 Map<String, Object?> _convoJson(String id) {
   return {'id': id, 'rev': 'rev-$id', 'members': const [], 'muted': false, 'unreadCount': 0};
+}
+
+Map<String, Object?> _messageJson(String id) {
+  return {
+    'id': id,
+    'rev': 'rev-$id',
+    'text': 'Hello',
+    'sender': {'did': 'did:plc:test'},
+    'sentAt': DateTime.utc(2026, 1, 1).toIso8601String(),
+  };
 }
 
 class _ScriptedReply {