diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 12bccde0..4f9ee19c 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -18,7 +18,9 @@ on:
 
 env:
   DOTNET_VERSION: ${{ '8.0.201' }}
-  ENABLE_DIAGNOSTICS: true
+  # Debug logging enabled via GitHub UI during reruns or set as repo secret.
+  # See also https://docs.github.com/en/actions/monitoring-and-troubleshooting-workflows/enabling-debug-logging
+  ENABLE_DIAGNOSTICS: ${{ runner.debug }}
   MSBUILD_VERBOSITY: normal
   #COREHOST_TRACE: 1
   COREHOST_TRACEFILE: corehosttrace.log