diff --git a/recipe/chocolatey-package.cake b/recipe/chocolatey-package.cake
index cfe1dd5..3c82da2 100644
--- a/recipe/chocolatey-package.cake
+++ b/recipe/chocolatey-package.cake
@@ -41,4 +41,12 @@ public class ChocolateyPackage : PackageDefinition
                 ArgumentCustomization = args => args.Append($"BIN_DIR={BuildSettings.OutputDirectory}")
             });
     }
+
+    protected override bool IsRemovableExtension(string id)
+    {
+        return
+            id.StartsWith("nunit-extension-") &&
+            !id.StartsWith(PackageId) &&
+            !id.Contains("pluggable-agent");
+    }
 }
diff --git a/recipe/nuget-package.cake b/recipe/nuget-package.cake
index 70f7794..2222795 100644
--- a/recipe/nuget-package.cake
+++ b/recipe/nuget-package.cake
@@ -99,4 +99,12 @@ public class NuGetPackage : PackageDefinition
         else
             throw new Exception("Verification failed!");
     }
+
+    protected override bool IsRemovableExtension(string id)
+    {
+        return
+            id.StartsWith("NUnit.Extension.") &&
+            !id.StartsWith(PackageId) &&
+            !id.Contains("PluggableAgent");
+    }
 }
diff --git a/recipe/package-definition.cake b/recipe/package-definition.cake
index 0140618..6a197d3 100644
--- a/recipe/package-definition.cake
+++ b/recipe/package-definition.cake
@@ -210,7 +210,15 @@ public abstract class PackageDefinition
         // Ensure we start out each package with no extensions installed.
         // If any package test installs an extension, it remains available
         // for subsequent tests of the same package only.
-        RemoveExtensions();
+        foreach (DirectoryPath dirPath in _context.GetDirectories(ExtensionInstallDirectory + "*"))
+        {
+            string dirName = dirPath.Segments.Last();
+            if (IsRemovableExtension(dirName))
+            {
+                _context.DeleteDirectory(dirPath, new DeleteDirectorySettings() { Recursive = true });
+                _context.Information("Deleted directory " + dirPath.GetDirectoryName());
+            }
+        }
 
         // Package was defined with one or more TestRunners. These
         // may or may not require installation.
@@ -297,20 +305,7 @@ public abstract class PackageDefinition
             extension.InstallExtension(this);
     }
 
-    // Remove all extensions prior to starting a run. Note that we avoid removing the the
-    // package being developed, which may actually be an extension itself.
-    protected void RemoveExtensions()
-    {
-        foreach (DirectoryPath dirPath in _context.GetDirectories(ExtensionInstallDirectory + "*"))
-        {
-            string dirName = dirPath.Segments.Last();
-            if ((dirName.StartsWith("NUnit.Extension.") || dirName.StartsWith("nunit-extension-")) && !dirName.StartsWith(PackageId))
-            {
-                _context.DeleteDirectory(dirPath, new DeleteDirectorySettings() { Recursive = true });
-                _context.Information("Deleted directory " + dirPath.GetDirectoryName());
-            }
-        }
-    }
+    protected abstract bool IsRemovableExtension(string dirName);
 
     private void InstallRunners(IEnumerable<IPackageTestRunner> runners)
     {
diff --git a/recipe/zip-package.cake b/recipe/zip-package.cake
index e1e524e..81d0845 100644
--- a/recipe/zip-package.cake
+++ b/recipe/zip-package.cake
@@ -65,4 +65,12 @@ public class ZipPackage : PackageDefinition
 
         _context.CopyDirectory(BuildSettings.ExtensionsDirectory, BuildSettings.ZipImageDirectory);
     }
+
+    protected override bool IsRemovableExtension(string id)
+    {
+        return
+            id.StartsWith("NUnit.Extension.") &&
+            !id.StartsWith(PackageId) &&
+            !id.Contains("PluggableAgent");
+    }
 }