diff --git a/.gitignore b/.gitignore
index c704992..3cc874d 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,6 +1,10 @@
 /link/
 /link
 
+# Generated build output is never source or package input.
+**/bin/
+**/obj/
+
 # DocumentAutomation generated files and local source data
 DocumentAutomation/**/bin/
 DocumentAutomation/**/obj/
diff --git a/Plant3D2026/P_Rec_Update/src/PRecUpdate.Plant3D2026/EntryPoint.cs b/Plant3D2026/P_Rec_Update/src/PRecUpdate.Plant3D2026/EntryPoint.cs
index 7c487cc..2b6aef8 100644
--- a/Plant3D2026/P_Rec_Update/src/PRecUpdate.Plant3D2026/EntryPoint.cs
+++ b/Plant3D2026/P_Rec_Update/src/PRecUpdate.Plant3D2026/EntryPoint.cs
@@ -9,8 +9,18 @@ public sealed class EntryPoint : IExtensionApplication
 {
     public void Initialize()
     {
-        RuntimeMarker.Write("AssemblyInitializeStarted");
-        RuntimeMarker.Write("AssemblyInitializeCompleted");
+        // Keep the load boundary free of Plant/DataLinks access. Any exception
+        // here must remain observable independently of a project fixture.
+        RuntimeMarker.Write("InitializeEntered");
+        try
+        {
+            RuntimeMarker.Write("AssemblyInitializeCompleted");
+        }
+        catch (System.Exception exception)
+        {
+            RuntimeMarker.Write("AssemblyInitializeFailed", exception.GetType().Name + ":" + exception.Message);
+            throw;
+        }
     }
 
     public void Terminate() => RuntimeMarker.Write("AssemblyTerminateCompleted");
@@ -37,8 +47,27 @@ public sealed class EntryPoint : IExtensionApplication
             },
             UpdateExecutionMode.DryRun,
             ControlledFixturePermit: false));
+        var status = new
+        {
+            schemaVersion = 1,
+            operationId = Environment.GetEnvironmentVariable("P_REC_UPDATE_OPERATION_ID") ?? "unknown",
+            processId = Environment.ProcessId,
+            command,
+            assemblyVersion = typeof(EntryPoint).Assembly.GetName().Version?.ToString(),
+            assemblySha256 = RuntimeMarker.AssemblySha256(),
+            product = "Plant3D",
+            productYear = 2026,
+            activeDocumentPresent = document is not null,
+            activePlantProjectPresent = HasPlantProject(),
+            dryRunInfrastructure = "Available",
+            domainApply = "BlockedByExactFixture",
+            diagnostics = plan.Diagnostics
+        };
         document?.Editor.WriteMessage($"\nP_Rec_Update {command}: {(plan.Accepted ? "DryRun planned; no project data changed." : string.Join(", ", plan.Diagnostics))}");
-        RuntimeMarker.Write(plan.Accepted ? "CommandRegistrationVerified" : "CommandPreflightRejected");
+        // STATUS proves registration and reports preflight state; it must not
+        // be classified as a failed command merely because no controlled Plant
+        // project fixture is open.
+        RuntimeMarker.Write(command == "P-R-UPD-STATUS" || plan.Accepted ? "CommandRegistrationVerified" : "CommandPreflightRejected", System.Text.Json.JsonSerializer.Serialize(status));
     }
 
     private static bool HasPlantProject()
diff --git a/Plant3D2026/P_Rec_Update/src/PRecUpdate.Plant3D2026/RuntimeMarker.cs b/Plant3D2026/P_Rec_Update/src/PRecUpdate.Plant3D2026/RuntimeMarker.cs
index b6f3b4a..60c8b03 100644
--- a/Plant3D2026/P_Rec_Update/src/PRecUpdate.Plant3D2026/RuntimeMarker.cs
+++ b/Plant3D2026/P_Rec_Update/src/PRecUpdate.Plant3D2026/RuntimeMarker.cs
@@ -1,19 +1,30 @@
 using System.Security.Cryptography;
 using System.Text;
+using System.Text.Json;
 
 namespace PRecUpdate.Plant3D2026;
 
 internal static class RuntimeMarker
 {
-    internal static void Write(string state)
+    internal static void Write(string state, string? detail = null)
     {
         var root = Environment.GetEnvironmentVariable("P_REC_UPDATE_MARKER_ROOT");
         if (string.IsNullOrWhiteSpace(root)) return;
         try
         {
             Directory.CreateDirectory(root);
-            var payload = $"{DateTimeOffset.UtcNow:O}|{state}|{typeof(EntryPoint).Assembly.GetName().Name}";
-            File.WriteAllText(Path.Combine(root, state + ".marker"), payload, new UTF8Encoding(false));
+            var payload = JsonSerializer.Serialize(new
+            {
+                schemaVersion = 1,
+                operationId = Environment.GetEnvironmentVariable("P_REC_UPDATE_OPERATION_ID") ?? "unknown",
+                processId = Environment.ProcessId,
+                timestampUtc = DateTimeOffset.UtcNow,
+                state,
+                detail,
+                assembly = typeof(EntryPoint).Assembly.GetName().Name,
+                assemblySha256 = AssemblySha256()
+            });
+            File.WriteAllText(Path.Combine(root, state + ".marker.json"), payload, new UTF8Encoding(false));
         }
         catch { /* Evidence cannot make Plant initialization fail. */ }
     }
diff --git a/Plant3D2026/P_Rec_Update/tests/PRecUpdate.Core.Tests/UpdatePlanBuilderTests.cs b/Plant3D2026/P_Rec_Update/tests/PRecUpdate.Core.Tests/UpdatePlanBuilderTests.cs
index 1c1d3dc..9fcace0 100644
--- a/Plant3D2026/P_Rec_Update/tests/PRecUpdate.Core.Tests/UpdatePlanBuilderTests.cs
+++ b/Plant3D2026/P_Rec_Update/tests/PRecUpdate.Core.Tests/UpdatePlanBuilderTests.cs
@@ -46,4 +46,17 @@ public sealed class UpdatePlanBuilderTests
         Assert.True(plan.MayWriteDrawing);
         Assert.True(plan.MayWriteProjectData);
     }
+
+    [Fact]
+    public void Status_probe_preflight_is_deterministic_and_never_write_capable()
+    {
+        var request = new UpdateRequest(true, false, false, new HashSet<UpdateOperation>(), UpdateExecutionMode.DryRun, false);
+        var first = builder.Build(request);
+        var second = builder.Build(request);
+        Assert.False(first.Accepted);
+        Assert.Equal(first.Diagnostics, second.Diagnostics);
+        Assert.False(first.MayWriteDrawing);
+        Assert.False(first.MayWriteProjectData);
+        Assert.Contains("PLANT_PROJECT_REQUIRED", first.Diagnostics);
+    }
 }