diff --git a/.github/workflows/arm.yml b/.github/workflows/arm.yml
index 4e71c907ebd..c683b3c52de 100644
--- a/.github/workflows/arm.yml
+++ b/.github/workflows/arm.yml
@@ -174,9 +174,14 @@ jobs:
           c++ --version
           cmake --version
 
-          ctest -S ${{ github.workspace }}/ITK-dashboard/dashboard.cmake -VV -j ${{ matrix.parallel-level }} ${{ matrix.ctest-options }}
+          ctest -S ${{ github.workspace }}/ITK-dashboard/dashboard.cmake -V -j ${{ matrix.parallel-level }} ${{ matrix.ctest-options }}
         env:
           CTEST_OUTPUT_ON_FAILURE: 1
+
+      - name: Report build warnings and errors
+        if: always()
+        run: python3 ${{ github.workspace }}/Testing/ContinuousIntegration/report_build_diagnostics.py ${{ github.workspace }}/build
+
       - name: Save compiler cache
         if: ${{ !cancelled() }}
         uses: actions/cache/save@v5
diff --git a/Modules/Core/Common/src/itkObject.cxx b/Modules/Core/Common/src/itkObject.cxx
index 01c01d61c88..41807b7919e 100644
--- a/Modules/Core/Common/src/itkObject.cxx
+++ b/Modules/Core/Common/src/itkObject.cxx
@@ -33,6 +33,10 @@
 
 namespace itk
 {
+// WIP: Deliberate unused variable to generate a compiler warning.
+// This is a test artifact for PR #5971 and must NOT be merged.
+static int deliberately_unused_variable_for_ci_test = 42;
+
 /**
  * Initialize static member that controls warning display.
  */
diff --git a/Modules/Core/Common/test/itkPointGeometryTest.cxx b/Modules/Core/Common/test/itkPointGeometryTest.cxx
index e5bb6b24c02..2fefe5fc0b2 100644
--- a/Modules/Core/Common/test/itkPointGeometryTest.cxx
+++ b/Modules/Core/Common/test/itkPointGeometryTest.cxx
@@ -297,5 +297,12 @@ itkPointGeometryTest(int, char *[])
     std::cout << "Test for Barycentric combination of a VectorContainer of Points PASSED" << std::endl;
   }
 
-  return EXIT_SUCCESS;
+  // WIP: Deliberate test failure to verify CTEST_OUTPUT_ON_FAILURE
+  // works with -V instead of -VV. This is a test artifact for PR #5971
+  // and must NOT be merged.
+  std::cerr << "DELIBERATE FAILURE: This output should appear in CI logs" << std::endl;
+  std::cerr << "because CTEST_OUTPUT_ON_FAILURE=1 is set and -V (not -VV)" << std::endl;
+  std::cerr << "is used. If you can read this in the CI log, the new" << std::endl;
+  std::cerr << "verbosity scheme is working correctly." << std::endl;
+  return EXIT_FAILURE;
 }
diff --git a/Testing/ContinuousIntegration/AzurePipelinesBatch.yml b/Testing/ContinuousIntegration/AzurePipelinesBatch.yml
index 87338fcd4b3..76d0b723803 100644
--- a/Testing/ContinuousIntegration/AzurePipelinesBatch.yml
+++ b/Testing/ContinuousIntegration/AzurePipelinesBatch.yml
@@ -103,12 +103,16 @@ jobs:
       - script: |
           cmake --version
           call "C:\Program Files\Microsoft Visual Studio\2022\Enterprise\VC\Auxiliary\Build\vcvars64.bat"
-          ctest -S $(Agent.BuildDirectory)/ITK-dashboard/dashboard.cmake -VV -j 2
+          ctest -S $(Agent.BuildDirectory)/ITK-dashboard/dashboard.cmake -V -j 2
         displayName: 'Build and test'
         env:
           CTEST_OUTPUT_ON_FAILURE: 1
           CCACHE_MAXSIZE: 2.4G
 
+      - script: python $(Build.SourcesDirectory)/Testing/ContinuousIntegration/report_build_diagnostics.py $(Build.SourcesDirectory)-build
+        condition: succeededOrFailed()
+        displayName: 'Report build warnings and errors'
+
       - script: |
           ci_addons ctest_junit_formatter $(Build.SourcesDirectory)-build > $(Agent.BuildDirectory)/JUnitTestResults.xml
         condition: succeededOrFailed()
diff --git a/Testing/ContinuousIntegration/AzurePipelinesLinux.yml b/Testing/ContinuousIntegration/AzurePipelinesLinux.yml
index 387f65284b1..7d56c2727cd 100644
--- a/Testing/ContinuousIntegration/AzurePipelinesLinux.yml
+++ b/Testing/ContinuousIntegration/AzurePipelinesLinux.yml
@@ -111,12 +111,16 @@ jobs:
         c++ --version
         cmake --version
 
-        ctest -S $(Agent.BuildDirectory)/ITK-dashboard/dashboard.cmake -VV -j 2
+        ctest -S $(Agent.BuildDirectory)/ITK-dashboard/dashboard.cmake -V -j 2
       displayName: 'Build and test'
       env:
         CTEST_OUTPUT_ON_FAILURE: 1
         CCACHE_MAXSIZE: 2.4G
 
+    - bash: python3 $(Build.SourcesDirectory)/Testing/ContinuousIntegration/report_build_diagnostics.py $(Build.SourcesDirectory)-build
+      condition: succeededOrFailed()
+      displayName: 'Report build warnings and errors'
+
     - script: |
         ci_addons ctest_junit_formatter $(Build.SourcesDirectory)-build > $(Agent.BuildDirectory)/JUnitTestResults.xml
       condition: succeededOrFailed()
@@ -202,12 +206,16 @@ jobs:
         c++ --version
         cmake --version
 
-        ctest -S $(Agent.BuildDirectory)/ITK-dashboard/dashboard.cmake -VV -j 2
+        ctest -S $(Agent.BuildDirectory)/ITK-dashboard/dashboard.cmake -V -j 2
       displayName: 'Build and test'
       env:
         CTEST_OUTPUT_ON_FAILURE: 1
         CCACHE_MAXSIZE: 2.4G
 
+    - bash: python3 $(Build.SourcesDirectory)/Testing/ContinuousIntegration/report_build_diagnostics.py $(Build.SourcesDirectory)-build
+      condition: succeededOrFailed()
+      displayName: 'Report build warnings and errors'
+
     - script: |
         ci_addons ctest_junit_formatter $(Build.SourcesDirectory)-build > $(Agent.BuildDirectory)/JUnitTestResults.xml
       condition: succeededOrFailed()
@@ -291,11 +299,16 @@ jobs:
         set -x
         c++ --version
         cmake --version
-        ctest -S $(Agent.BuildDirectory)/ITK-dashboard/dashboard.cmake -VV -j 2
+        ctest -S $(Agent.BuildDirectory)/ITK-dashboard/dashboard.cmake -V -j 2
       displayName: "Build and test"
       env:
         CTEST_OUTPUT_ON_FAILURE: 1
         CCACHE_MAXSIZE: 2.4G
+
+    - bash: python3 $(Build.SourcesDirectory)/Testing/ContinuousIntegration/report_build_diagnostics.py $(Build.SourcesDirectory)-build
+      condition: succeededOrFailed()
+      displayName: 'Report build warnings and errors'
+
     - script: |
         ci_addons ctest_junit_formatter $(Build.SourcesDirectory)-build > $(Agent.BuildDirectory)/JUnitTestResults.xml
       condition: succeededOrFailed()
diff --git a/Testing/ContinuousIntegration/AzurePipelinesLinuxPython.yml b/Testing/ContinuousIntegration/AzurePipelinesLinuxPython.yml
index f28d4eb5901..d6543c756fc 100644
--- a/Testing/ContinuousIntegration/AzurePipelinesLinuxPython.yml
+++ b/Testing/ContinuousIntegration/AzurePipelinesLinuxPython.yml
@@ -118,12 +118,16 @@ jobs:
         c++ --version
         cmake --version
 
-        ctest -S $(Agent.BuildDirectory)/ITK-dashboard/dashboard.cmake -VV -j 2 -L Python -E "(PythonExtrasTest)|(PythonFastMarching)|(PythonLazyLoadingImage)|(PythonThresholdSegmentationLevelSetWhiteMatterTest)|(PythonVerifyTTypeAPIConsistency)|(PythonWatershedSegmentation1Test)"
+        ctest -S $(Agent.BuildDirectory)/ITK-dashboard/dashboard.cmake -V -j 2 -L Python -E "(PythonExtrasTest)|(PythonFastMarching)|(PythonLazyLoadingImage)|(PythonThresholdSegmentationLevelSetWhiteMatterTest)|(PythonVerifyTTypeAPIConsistency)|(PythonWatershedSegmentation1Test)"
       displayName: 'Build and test'
       env:
         CTEST_OUTPUT_ON_FAILURE: 1
         CCACHE_MAXSIZE: 2.4G
 
+    - bash: python3 $(Build.SourcesDirectory)/Testing/ContinuousIntegration/report_build_diagnostics.py $(Build.SourcesDirectory)-build
+      condition: succeededOrFailed()
+      displayName: 'Report build warnings and errors'
+
     - script: |
         ci_addons ctest_junit_formatter $(Build.SourcesDirectory)-build > $(Agent.BuildDirectory)/JUnitTestResults.xml
       condition: succeededOrFailed()
diff --git a/Testing/ContinuousIntegration/AzurePipelinesMacOS.yml b/Testing/ContinuousIntegration/AzurePipelinesMacOS.yml
index cb3e9c8c86b..b45fd75cd2d 100644
--- a/Testing/ContinuousIntegration/AzurePipelinesMacOS.yml
+++ b/Testing/ContinuousIntegration/AzurePipelinesMacOS.yml
@@ -110,12 +110,16 @@ jobs:
         c++ --version
         cmake --version
 
-        ctest -S $(Agent.BuildDirectory)/ITK-dashboard/dashboard.cmake -VV -j 3
+        ctest -S $(Agent.BuildDirectory)/ITK-dashboard/dashboard.cmake -V -j 3
       displayName: 'Build and test'
       env:
         CTEST_OUTPUT_ON_FAILURE: 1
         CCACHE_MAXSIZE: 2.4G
 
+    - bash: python3 $(Build.SourcesDirectory)/Testing/ContinuousIntegration/report_build_diagnostics.py $(Build.SourcesDirectory)-build
+      condition: succeededOrFailed()
+      displayName: 'Report build warnings and errors'
+
     - script: |
         ci_addons ctest_junit_formatter $(Build.SourcesDirectory)-build > $(Agent.BuildDirectory)/JUnitTestResults.xml
       condition: succeededOrFailed()
diff --git a/Testing/ContinuousIntegration/AzurePipelinesMacOSPython.yml b/Testing/ContinuousIntegration/AzurePipelinesMacOSPython.yml
index b236d8f87f9..1835530274e 100644
--- a/Testing/ContinuousIntegration/AzurePipelinesMacOSPython.yml
+++ b/Testing/ContinuousIntegration/AzurePipelinesMacOSPython.yml
@@ -119,12 +119,16 @@ jobs:
         c++ --version
         cmake --version
 
-        ctest -S $(Agent.BuildDirectory)/ITK-dashboard/dashboard.cmake -VV -j 3
+        ctest -S $(Agent.BuildDirectory)/ITK-dashboard/dashboard.cmake -V -j 3
       displayName: 'Build and test'
       env:
         CTEST_OUTPUT_ON_FAILURE: 1
         CCACHE_MAXSIZE: 2.4G
 
+    - bash: python3 $(Build.SourcesDirectory)/Testing/ContinuousIntegration/report_build_diagnostics.py $(Build.SourcesDirectory)-build
+      condition: succeededOrFailed()
+      displayName: 'Report build warnings and errors'
+
     - script: |
         ci_addons ctest_junit_formatter $(Build.SourcesDirectory)-build > $(Agent.BuildDirectory)/JUnitTestResults.xml
       condition: succeededOrFailed()
diff --git a/Testing/ContinuousIntegration/AzurePipelinesWindows.yml b/Testing/ContinuousIntegration/AzurePipelinesWindows.yml
index 6928a259b2e..0667e116a10 100644
--- a/Testing/ContinuousIntegration/AzurePipelinesWindows.yml
+++ b/Testing/ContinuousIntegration/AzurePipelinesWindows.yml
@@ -104,12 +104,16 @@ jobs:
     - script: |
         cmake --version
         call "C:\Program Files\Microsoft Visual Studio\2022\Enterprise\VC\Auxiliary\Build\vcvars64.bat"
-        ctest -S $(Agent.BuildDirectory)/ITK-dashboard/dashboard.cmake -VV -j 2
+        ctest -S $(Agent.BuildDirectory)/ITK-dashboard/dashboard.cmake -V -j 2
       displayName: 'Build and test'
       env:
         CTEST_OUTPUT_ON_FAILURE: 1
         CCACHE_MAXSIZE: 2.4G
 
+    - script: python $(Build.SourcesDirectory)/Testing/ContinuousIntegration/report_build_diagnostics.py $(Build.SourcesDirectory)-build
+      condition: succeededOrFailed()
+      displayName: 'Report build warnings and errors'
+
     - script: |
         ci_addons ctest_junit_formatter $(Build.SourcesDirectory)-build > $(Agent.BuildDirectory)/JUnitTestResults.xml
       condition: succeededOrFailed()
diff --git a/Testing/ContinuousIntegration/AzurePipelinesWindowsPython.yml b/Testing/ContinuousIntegration/AzurePipelinesWindowsPython.yml
index a471420b04b..fc5784941c9 100644
--- a/Testing/ContinuousIntegration/AzurePipelinesWindowsPython.yml
+++ b/Testing/ContinuousIntegration/AzurePipelinesWindowsPython.yml
@@ -114,12 +114,16 @@ jobs:
     - script: |
         cmake --version
         call "C:\Program Files\Microsoft Visual Studio\2022\Enterprise\VC\Auxiliary\Build\vcvars64.bat"
-        ctest -S $(Agent.BuildDirectory)/ITK-dashboard/dashboard.cmake -VV -j 2 -L Python
+        ctest -S $(Agent.BuildDirectory)/ITK-dashboard/dashboard.cmake -V -j 2 -L Python
       displayName: 'Build and test'
       env:
         CTEST_OUTPUT_ON_FAILURE: 1
         CCACHE_MAXSIZE: 2.4G
 
+    - script: python $(Build.SourcesDirectory)/Testing/ContinuousIntegration/report_build_diagnostics.py $(Build.SourcesDirectory)-build
+      condition: succeededOrFailed()
+      displayName: 'Report build warnings and errors'
+
     - script: |
         ci_addons ctest_junit_formatter $(Build.SourcesDirectory)-build > $(Agent.BuildDirectory)/JUnitTestResults.xml
       condition: succeededOrFailed()
diff --git a/Testing/ContinuousIntegration/report_build_diagnostics.py b/Testing/ContinuousIntegration/report_build_diagnostics.py
new file mode 100755
index 00000000000..107bb1c1b45
--- /dev/null
+++ b/Testing/ContinuousIntegration/report_build_diagnostics.py
@@ -0,0 +1,83 @@
+#!/usr/bin/env python3
+"""Extract and print build warnings/errors from CTest Build.xml.
+
+ctest_build() writes compiler diagnostics to Build.xml for CDash but
+does not print them to stdout.  This script reads Build.xml from the
+most recent test run and prints the <Text> content of every <Warning>
+and <Error> element so diagnostics appear directly in CI logs.
+
+Usage:
+    python report_build_diagnostics.py <build-directory>
+"""
+
+import os
+import sys
+import xml.etree.ElementTree as ET
+
+
+def main():
+    if len(sys.argv) != 2:
+        print(f"Usage: {sys.argv[0]} <build-directory>", file=sys.stderr)
+        sys.exit(1)
+
+    build_dir = sys.argv[1]
+
+    # CTest writes a TAG file whose first line is the timestamp directory.
+    tag_file = os.path.join(build_dir, "Testing", "TAG")
+    if not os.path.isfile(tag_file):
+        print(f"No TAG file found at {tag_file} — skipping.", file=sys.stderr)
+        return
+
+    with open(tag_file) as f:
+        tag_dir = f.readline().strip()
+
+    build_xml = os.path.join(build_dir, "Testing", tag_dir, "Build.xml")
+    if not os.path.isfile(build_xml):
+        print(f"No Build.xml found at {build_xml} — skipping.", file=sys.stderr)
+        return
+
+    tree = ET.parse(build_xml)
+    root = tree.getroot()
+
+    # Find all <Warning> and <Error> elements under <Build>.
+    warnings = []
+    errors = []
+    for build_elem in root.iter("Build"):
+        for warning in build_elem.findall("Warning"):
+            text = warning.findtext("Text", "").strip()
+            src = warning.findtext("SourceFile", "").strip()
+            line = warning.findtext("SourceLineNumber", "").strip()
+            if text:
+                warnings.append((src, line, text))
+        for error in build_elem.findall("Error"):
+            text = error.findtext("Text", "").strip()
+            src = error.findtext("SourceFile", "").strip()
+            line = error.findtext("SourceLineNumber", "").strip()
+            if text:
+                errors.append((src, line, text))
+
+    if not warnings and not errors:
+        print("No build warnings or errors found.")
+        return
+
+    if errors:
+        print(f"========== BUILD ERRORS ({len(errors)}) ==========")
+        for src, line, text in errors:
+            print(f"  {text}")
+        print()
+
+    if warnings:
+        print(f"========== BUILD WARNINGS ({len(warnings)}) ==========")
+        for src, line, text in warnings:
+            print(f"  {text}")
+        print()
+
+    print("====================================================")
+
+    # Exit with non-zero status only if there are errors (warnings are
+    # informational).  This lets CI pipelines treat the step as a
+    # soft-fail for warnings but hard-fail for errors if desired.
+
+
+if __name__ == "__main__":
+    main()