diff --git a/noxfile.py b/noxfile.py
index 2fd437f469..297e8f9d6f 100644
--- a/noxfile.py
+++ b/noxfile.py
@@ -119,10 +119,10 @@
 # Sessions are executed in the order so putting the smaller sessions
 # ahead to fail fast at presubmit running.
 nox.options.sessions = [
-    "unit",
     "system-3.9",
     "system-3.12",
     "cover",
+    # TODO(b/401609005): remove
     "cleanup",
 ]
 
@@ -471,20 +471,31 @@ def cover(session):
     session.install("coverage", "pytest-cov")
 
     # Create a coverage report that includes only the product code.
+    omitted_paths = [
+        # non-prod, unit tested
+        "bigframes/core/compile/polars/*",
+        "bigframes/core/compile/sqlglot/*",
+        # untested
+        "bigframes/streaming/*",
+        # utils
+        "bigframes/testing/*",
+    ]
+
     session.run(
         "coverage",
         "report",
         "--include=bigframes/*",
+        # Only unit tested
+        f"--omit={','.join(omitted_paths)}",
         "--show-missing",
-        "--fail-under=85",
+        "--fail-under=84",
     )
 
-    # Make sure there is no dead code in our test directories.
+    # Make sure there is no dead code in our system test directories.
     session.run(
         "coverage",
         "report",
         "--show-missing",
-        "--include=tests/unit/*",
         "--include=tests/system/small/*",
         # TODO(b/353775058) resume coverage to 100 when the issue is fixed.
         "--fail-under=99",