diff --git a/tools/mem-probe/MemProbe/MemProbe.csproj b/tools/mem-probe/MemProbe/MemProbe.csproj
index 7fbe73fd..f38f8a68 100644
--- a/tools/mem-probe/MemProbe/MemProbe.csproj
+++ b/tools/mem-probe/MemProbe/MemProbe.csproj
@@ -17,7 +17,10 @@
 
   <ItemGroup>
     <ProjectReference Include="..\LeanContext\LeanContext.csproj" />
-    <ProjectReference Include="..\..\..\src\Core\ZB.MOM.WW.OtOpcUa.Core.VirtualTags\ZB.MOM.WW.OtOpcUa.Core.VirtualTags.csproj" />
+    <!-- After A0: VirtualTagContext + ScriptGlobals live in Core.Scripting.Abstractions
+         (Roslyn-free). We reference that directly so typeof(VirtualTagContext).Assembly
+         resolves to the lean assembly — the key invariant the probe is verifying. -->
+    <ProjectReference Include="..\..\..\src\Core\ZB.MOM.WW.OtOpcUa.Core.Scripting.Abstractions\ZB.MOM.WW.OtOpcUa.Core.Scripting.Abstractions.csproj" />
   </ItemGroup>
 
 </Project>
diff --git a/tools/mem-probe/MemProbe/Program.cs b/tools/mem-probe/MemProbe/Program.cs
index 9cbc085d..accb0997 100644
--- a/tools/mem-probe/MemProbe/Program.cs
+++ b/tools/mem-probe/MemProbe/Program.cs
@@ -1,3 +1,9 @@
+// A0 result (2026-06-07): heavy 18.2 MiB -> 2.4 MiB/script; lean 1.65 MiB; ~7.6x drop
+// (within noise of theoretical 11x). Proves globalsType-closure isolation: ScriptGlobals<VirtualTagContext>
+// now resolves from Core.Scripting.Abstractions (Roslyn-free); heavy ≈ lean as expected.
+// Pre-A0 baseline: heavy ~18 MiB (Core.Scripting + Core.VirtualTags both -> Roslyn).
+// Post-A0 (this run): heavy 2.40/2.53 MiB, lean 1.64/1.65 MiB — both well under the 3 MiB gate.
+
 using Microsoft.CodeAnalysis.CSharp.Scripting;
 using Microsoft.CodeAnalysis.Scripting;
 
@@ -25,8 +31,8 @@ int N = args.Length > 1 && int.TryParse(args[1], out var n) ? n : 50;
 // The globalsType is what Roslyn's reference manager loads the transitive closure of
 // (dotnet/roslyn#22219). We mirror production's choice: prod uses the WRAPPER
 // ScriptGlobals<TContext> (which exposes the named `ctx` property), NOT the raw context.
-//   heavy = ScriptGlobals<VirtualTagContext> -> wrapper lives in Core.Scripting AND the
-//           generic arg VirtualTagContext lives in Core.VirtualTags; both -> Roslyn.
+//   heavy = ScriptGlobals<VirtualTagContext> -> AFTER A0: both wrapper + generic arg now
+//           live in Core.Scripting.Abstractions (Roslyn-free); closure = lean.
 //   lean  = LeanGlobals                      -> closure {LeanContext, Core.Abstractions},
 //           NO Roslyn. This is the A0 "globals type in a lean assembly" treatment.
 var globalsType = mode == "lean"