diff --git a/.ci/unit-tests/File_Toolkit_Tests/Adapter/PushPullTests.cs b/.ci/unit-tests/File_Toolkit_Tests/Adapter/PushPullTests.cs
index 2f21e23a..60d98bca 100644
--- a/.ci/unit-tests/File_Toolkit_Tests/Adapter/PushPullTests.cs
+++ b/.ci/unit-tests/File_Toolkit_Tests/Adapter/PushPullTests.cs
@@ -104,3 +104,6 @@ private static void OverwriteWithFormattedJson(string filepath)
 }
 
 
+
+// validation probe: concurrency/cancel behaviour under a required check (ruleset 20630326)
+// probe B, commit B: supersede the in-flight run
diff --git a/.validation/count-zero-probe.md b/.validation/count-zero-probe.md
new file mode 100644
index 00000000..099b9fdf
--- /dev/null
+++ b/.validation/count-zero-probe.md
@@ -0,0 +1,3 @@
+Validation probe A: docs-only change to exercise the ci-versioning count=0 self-skip
+under an ACTIVE ruleset requiring the ci-versioning context.
+Ruleset 20630326. Safe to delete.