diff --git a/scripts/e2e-install-test.sh b/scripts/e2e-install-test.sh
index 3bca778c..b289ad24 100755
--- a/scripts/e2e-install-test.sh
+++ b/scripts/e2e-install-test.sh
@@ -36,7 +36,8 @@ KEEP_DATA=false bash scripts/uninstall.sh 2>/dev/null || true
 # Phase 2: Install from source
 # =============================================================================
 info "Phase 2: Installing from source..."
-BRANCH=$(git rev-parse --abbrev-ref HEAD)
+# Use the ref GitHub provides; on tag pushes rev-parse returns a detached "HEAD"
+BRANCH="${GITHUB_REF_NAME:-$(git rev-parse --abbrev-ref HEAD)}"
 # Build CLI from source too when CLI_BRANCH is set (e.g., for testing unreleased CLI features)
 BRANCH="$BRANCH" CLI_BRANCH="${CLI_BRANCH:-}" bash scripts/install.sh