diff --git a/nanobot/providers/anthropic_oauth.py b/nanobot/providers/anthropic_oauth.py
index 586e7aa..431746e 100644
--- a/nanobot/providers/anthropic_oauth.py
+++ b/nanobot/providers/anthropic_oauth.py
@@ -455,7 +455,7 @@ class AnthropicOAuthProvider(LLMProvider):
             import datetime
             import os
             header_dump = {
-                "timestamp": datetime.datetime.utcnow().isoformat(),
+                "timestamp": datetime.datetime.now(datetime.UTC).isoformat(),
                 "status_code": response.status_code,
                 "model": payload.get("model"),
                 "headers": dict(response.headers),
diff --git a/tests/test_agent_loop_tool_result.py b/tests/test_agent_loop_tool_result.py
index 44cc0d7..57b0a2a 100644
--- a/tests/test_agent_loop_tool_result.py
+++ b/tests/test_agent_loop_tool_result.py
@@ -28,7 +28,7 @@ def mock_session_manager():
         "messages": [],
         "metadata": {},
     })
-    session_mgr.save = AsyncMock()
+    session_mgr.save = MagicMock()  # Synchronous in production, not async
     return session_mgr