diff --git a/.kokoro/continuous/continuous.cfg b/.kokoro/continuous/continuous.cfg
index 8f43917d..54593f36 100644
--- a/.kokoro/continuous/continuous.cfg
+++ b/.kokoro/continuous/continuous.cfg
@@ -1 +1,12 @@
-# Format: //devtools/kokoro/config/proto/build.proto
\ No newline at end of file
+# Format: //devtools/kokoro/config/proto/build.proto
+
+# Disable system tests.
+env_vars: {
+    key: "RUN_SYSTEM_TESTS"
+    value: "false"
+}
+
+env_vars: {
+    key: "NOX_SESSION"
+    value: "blacken doctests format"
+}