diff --git a/tests/routes/test_messages.py b/tests/routes/test_messages.py
index 07040e20..a121cfe0 100644
--- a/tests/routes/test_messages.py
+++ b/tests/routes/test_messages.py
@@ -1001,8 +1001,10 @@ async def test_create_message_without_timestamp_uses_default(
     db_session.add(test_session)
     await db_session.commit()
 
-    # Record time before request
-    before_request = datetime.datetime.now(datetime.timezone.utc)
+    # Pad the window to absorb client/Postgres clock skew under Docker.
+    before_request = datetime.datetime.now(datetime.timezone.utc) - datetime.timedelta(
+        seconds=1
+    )
 
     response = client.post(
         f"/v3/workspaces/{test_workspace.name}/sessions/{test_session.name}/messages",
@@ -1017,8 +1019,9 @@ async def test_create_message_without_timestamp_uses_default(
         },
     )
 
-    # Record time after request
-    after_request = datetime.datetime.now(datetime.timezone.utc)
+    after_request = datetime.datetime.now(datetime.timezone.utc) + datetime.timedelta(
+        seconds=1
+    )
 
     assert response.status_code == 201
     data = response.json()
@@ -1053,8 +1056,9 @@ async def test_create_batch_messages_with_mixed_timestamps(
     timestamp1 = datetime.datetime(2023, 1, 1, 12, 0, 0, tzinfo=datetime.timezone.utc)
     timestamp2 = datetime.datetime(2023, 1, 2, 12, 0, 0, tzinfo=datetime.timezone.utc)
 
-    # Record time before request for default timestamp
-    before_request = datetime.datetime.now(datetime.timezone.utc)
+    before_request = datetime.datetime.now(datetime.timezone.utc) - datetime.timedelta(
+        seconds=1
+    )
 
     response = client.post(
         f"/v3/workspaces/{test_workspace.name}/sessions/{test_session.name}/messages",
@@ -1081,7 +1085,9 @@ async def test_create_batch_messages_with_mixed_timestamps(
         },
     )
 
-    after_request = datetime.datetime.now(datetime.timezone.utc)
+    after_request = datetime.datetime.now(datetime.timezone.utc) + datetime.timedelta(
+        seconds=1
+    )
 
     assert response.status_code == 201
     data = response.json()
@@ -1124,8 +1130,9 @@ async def test_create_message_with_null_timestamp(
     db_session.add(test_session)
     await db_session.commit()
 
-    # Record time before request
-    before_request = datetime.datetime.now(datetime.timezone.utc)
+    before_request = datetime.datetime.now(datetime.timezone.utc) - datetime.timedelta(
+        seconds=1
+    )
 
     response = client.post(
         f"/v3/workspaces/{test_workspace.name}/sessions/{test_session.name}/messages",
@@ -1141,7 +1148,9 @@ async def test_create_message_with_null_timestamp(
         },
     )
 
-    after_request = datetime.datetime.now(datetime.timezone.utc)
+    after_request = datetime.datetime.now(datetime.timezone.utc) + datetime.timedelta(
+        seconds=1
+    )
 
     assert response.status_code == 201
     data = response.json()