Fix real client chat cache compatibility

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()