diff --git a/sdk/real.py b/sdk/real.py
index 16b62a4..8e2dba6 100644
--- a/sdk/real.py
+++ b/sdk/real.py
@@ -1,5 +1,6 @@
 from __future__ import annotations
 
+import asyncio
 from typing import AsyncIterator
 
 from sdk.agent_api_wrapper import AgentApiWrapper
@@ -18,18 +19,26 @@ class RealPlatformClient(PlatformClient):
         self._prototype_state = prototype_state
         self._platform = platform
         self._chat_apis: dict[str, AgentApiWrapper] = {}
+        self._chat_api_lock = asyncio.Lock()
 
     @property
     def agent_api(self) -> AgentApiWrapper:
         return self._agent_api
 
-    async def _get_chat_api(self, chat_id: str) -> AgentApiWrapper:
+    async def _get_chat_api(self, chat_id: str):
         chat_key = str(chat_id)
         chat_api = self._chat_apis.get(chat_key)
         if chat_api is None:
-            chat_api = self._agent_api.for_chat(chat_key)
-            await chat_api.connect()
-            self._chat_apis[chat_key] = chat_api
+            chat_api_factory = getattr(self._agent_api, "for_chat", None)
+            if not callable(chat_api_factory):
+                return self._agent_api
+
+            async with self._chat_api_lock:
+                chat_api = self._chat_apis.get(chat_key)
+                if chat_api is None:
+                    chat_api = chat_api_factory(chat_key)
+                    await chat_api.connect()
+                    self._chat_apis[chat_key] = chat_api
         return chat_api
 
     async def get_or_create_user(
@@ -77,7 +86,8 @@ class RealPlatformClient(PlatformClient):
         attachments: list[Attachment] | None = None,
     ) -> AsyncIterator[MessageChunk]:
         chat_api = await self._get_chat_api(chat_id)
-        chat_api.last_tokens_used = 0
+        if hasattr(chat_api, "last_tokens_used"):
+            chat_api.last_tokens_used = 0
         async for event in chat_api.send_message(text):
             yield MessageChunk(
                 message_id=user_id,
@@ -88,7 +98,7 @@ class RealPlatformClient(PlatformClient):
             message_id=user_id,
             delta="",
             finished=True,
-            tokens_used=chat_api.last_tokens_used,
+            tokens_used=getattr(chat_api, "last_tokens_used", 0),
         )
 
     async def get_settings(self, user_id: str) -> UserSettings:
@@ -99,5 +109,11 @@ class RealPlatformClient(PlatformClient):
 
     async def close(self) -> None:
         for chat_api in list(self._chat_apis.values()):
-            await chat_api.close()
+            close = getattr(chat_api, "close", None)
+            if callable(close):
+                await close()
         self._chat_apis.clear()
+        if not callable(getattr(self._agent_api, "for_chat", None)):
+            close = getattr(self._agent_api, "close", None)
+            if callable(close):
+                await close()
diff --git a/tests/platform/test_real.py b/tests/platform/test_real.py
index 1097937..94b9520 100644
--- a/tests/platform/test_real.py
+++ b/tests/platform/test_real.py
@@ -1,3 +1,5 @@
+import asyncio
+
 import pytest
 
 from core.protocol import SettingsAction
@@ -45,6 +47,18 @@ class FakeAgentApiFactory:
         return chat_api
 
 
+class LegacyAgentApi:
+    def __init__(self) -> None:
+        self.calls: list[str] = []
+        self.last_tokens_used = 0
+
+    async def send_message(self, text: str):
+        self.calls.append(text)
+        yield FakeChunk(text[:2])
+        yield FakeChunk(text[2:])
+        self.last_tokens_used = 7
+
+
 @pytest.mark.asyncio
 async def test_real_platform_client_get_or_create_user_uses_local_state():
     client = RealPlatformClient(
@@ -85,6 +99,26 @@ async def test_real_platform_client_send_message_uses_chat_bound_client():
     assert agent_api.instances["chat-7"].connect_calls == 1
 
 
+@pytest.mark.asyncio
+async def test_real_platform_client_works_with_legacy_agent_api_without_for_chat():
+    legacy_api = LegacyAgentApi()
+    client = RealPlatformClient(
+        agent_api=legacy_api,
+        prototype_state=PrototypeStateStore(),
+        platform="matrix",
+    )
+
+    result = await client.send_message("@alice:example.org", "chat-legacy", "hello")
+
+    assert result == MessageResponse(
+        message_id="@alice:example.org",
+        response="hello",
+        tokens_used=7,
+        finished=True,
+    )
+    assert legacy_api.calls == ["hello"]
+
+
 @pytest.mark.asyncio
 async def test_real_platform_client_reuses_cached_chat_client():
     agent_api = FakeAgentApiFactory()
@@ -102,6 +136,26 @@ async def test_real_platform_client_reuses_cached_chat_client():
     assert agent_api.instances["chat-1"].connect_calls == 1
 
 
+@pytest.mark.asyncio
+async def test_real_platform_client_creates_chat_client_atomically_for_concurrent_requests():
+    agent_api = FakeAgentApiFactory()
+    client = RealPlatformClient(
+        agent_api=agent_api,
+        prototype_state=PrototypeStateStore(),
+        platform="matrix",
+    )
+
+    results = await asyncio.gather(
+        client.send_message("@alice:example.org", "chat-1", "hello"),
+        client.send_message("@alice:example.org", "chat-1", "again"),
+    )
+
+    assert [result.response for result in results] == ["hello", "again"]
+    assert agent_api.created_chat_ids == ["chat-1"]
+    assert agent_api.instances["chat-1"].connect_calls == 1
+    assert agent_api.instances["chat-1"].calls == ["hello", "again"]
+
+
 @pytest.mark.asyncio
 async def test_real_platform_client_creates_distinct_clients_per_chat():
     agent_api = FakeAgentApiFactory()