diff --git a/src/applications/diffusion/ssh/DiffusionGitSSHWorkflow.php b/src/applications/diffusion/ssh/DiffusionGitSSHWorkflow.php
index 52a8478fdc..6de16e723d 100644
--- a/src/applications/diffusion/ssh/DiffusionGitSSHWorkflow.php
+++ b/src/applications/diffusion/ssh/DiffusionGitSSHWorkflow.php
@@ -35,4 +35,14 @@ abstract class DiffusionGitSSHWorkflow
     }
   }
 
+  protected function raiseWrongVCSException(
+    PhabricatorRepository $repository) {
+    throw new Exception(
+      pht(
+        'This repository ("%s") is not a Git repository. Use "%s" to '.
+        'interact with this repository.',
+        $repository->getDisplayName(),
+        $repository->getVersionControlSystem()));
+  }
+
 }
diff --git a/src/applications/diffusion/ssh/DiffusionMercurialServeSSHWorkflow.php b/src/applications/diffusion/ssh/DiffusionMercurialServeSSHWorkflow.php
index 15dd9d7c6b..4508ae53da 100644
--- a/src/applications/diffusion/ssh/DiffusionMercurialServeSSHWorkflow.php
+++ b/src/applications/diffusion/ssh/DiffusionMercurialServeSSHWorkflow.php
@@ -119,4 +119,14 @@ final class DiffusionMercurialServeSSHWorkflow
     return $raw_message;
   }
 
+  protected function raiseWrongVCSException(
+    PhabricatorRepository $repository) {
+    throw new Exception(
+      pht(
+        'This repository ("%s") is not a Mercurial repository. Use "%s" to '.
+        'interact with this repository.',
+        $repository->getDisplayName(),
+        $repository->getVersionControlSystem()));
+  }
+
 }
diff --git a/src/applications/diffusion/ssh/DiffusionSSHWorkflow.php b/src/applications/diffusion/ssh/DiffusionSSHWorkflow.php
index 0115858832..0e5ad7bbe1 100644
--- a/src/applications/diffusion/ssh/DiffusionSSHWorkflow.php
+++ b/src/applications/diffusion/ssh/DiffusionSSHWorkflow.php
@@ -43,6 +43,8 @@ abstract class DiffusionSSHWorkflow extends PhabricatorSSHWorkflow {
    */
   abstract protected function identifyRepository();
   abstract protected function executeRepositoryOperations();
+  abstract protected function raiseWrongVCSException(
+    PhabricatorRepository $repository);
 
   protected function getBaseRequestPath() {
     return $this->baseRequestPath;
@@ -199,6 +201,10 @@ abstract class DiffusionSSHWorkflow extends PhabricatorSSHWorkflow {
           $repository->getDisplayName()));
     }
 
+    if ($repository->getVersionControlSystem() != $vcs) {
+      $this->raiseWrongVCSException($repository);
+    }
+
     return $repository;
   }
 
diff --git a/src/applications/diffusion/ssh/DiffusionSubversionServeSSHWorkflow.php b/src/applications/diffusion/ssh/DiffusionSubversionServeSSHWorkflow.php
index 3a8b516443..f2a932f2bb 100644
--- a/src/applications/diffusion/ssh/DiffusionSubversionServeSSHWorkflow.php
+++ b/src/applications/diffusion/ssh/DiffusionSubversionServeSSHWorkflow.php
@@ -449,4 +449,14 @@ final class DiffusionSubversionServeSSHWorkflow
     return $path;
   }
 
+  protected function raiseWrongVCSException(
+    PhabricatorRepository $repository) {
+    throw new Exception(
+      pht(
+        'This repository ("%s") is not a Subversion repository. Use "%s" to '.
+        'interact with this repository.',
+        $repository->getDisplayName(),
+        $repository->getVersionControlSystem()));
+  }
+
 }