diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index fc905d66..d1fdec6d 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -465,9 +465,7 @@ jobs:
         run: |
           set -euo pipefail
           SOURCE_PACKAGES_DIR="$PWD/.ci-source-packages"
-          HARNESS_DIR="${RUNNER_TEMP}/cmux-display-churn-${GITHUB_RUN_ID}-${GITHUB_RUN_ATTEMPT}"
-          mkdir -p "$HARNESS_DIR"
-          PREFIX="${HARNESS_DIR}/cmux-display-churn"
+          PREFIX="/tmp/cmux-display-churn-${GITHUB_RUN_ID}-${GITHUB_RUN_ATTEMPT}"
           READY_PATH="${PREFIX}.ready"
           DISPLAY_ID_PATH="${PREFIX}.id"
           START_PATH="${PREFIX}.start"
diff --git a/.github/workflows/test-e2e.yml b/.github/workflows/test-e2e.yml
index 7e5105ae..e538b6c5 100644
--- a/.github/workflows/test-e2e.yml
+++ b/.github/workflows/test-e2e.yml
@@ -208,9 +208,7 @@ jobs:
           DISPLAY_ENV_PREFIX=()
 
           if [ "$TEST_FILTER" = "DisplayResolutionRegressionUITests" ]; then
-            HARNESS_DIR="${RUNNER_TEMP}/cmux-display-churn-${{ github.run_id }}-${{ github.run_attempt }}"
-            mkdir -p "$HARNESS_DIR"
-            PREFIX="${HARNESS_DIR}/cmux-display-churn"
+            PREFIX="/tmp/cmux-display-churn-${{ github.run_id }}-${{ github.run_attempt }}"
             READY_PATH="${PREFIX}.ready"
             DISPLAY_ID_PATH="${PREFIX}.id"
             START_PATH="${PREFIX}.start"