diff --git a/src/applications/diffusion/controller/DiffusionChangeController.php b/src/applications/diffusion/controller/DiffusionChangeController.php
--- a/src/applications/diffusion/controller/DiffusionChangeController.php
+++ b/src/applications/diffusion/controller/DiffusionChangeController.php
@@ -33,7 +33,6 @@
     }
 
     $repository = $drequest->getRepository();
-    $callsign = $repository->getCallsign();
     $changesets = array(
       0 => $changeset,
     );
@@ -59,7 +58,8 @@
     $left_uri = $drequest->generateURI($raw_params);
     $changeset_view->setRawFileURIs($left_uri, $right_uri);
 
-    $changeset_view->setRenderURI('/diffusion/'.$callsign.'/diff/');
+    $changeset_view->setRenderURI($repository->getPathURI('diff/'));
+
     $changeset_view->setWhitespace(
       DifferentialChangesetParser::WHITESPACE_SHOW_ALL);
     $changeset_view->setUser($viewer);
diff --git a/src/applications/diffusion/controller/DiffusionCommitController.php b/src/applications/diffusion/controller/DiffusionCommitController.php
--- a/src/applications/diffusion/controller/DiffusionCommitController.php
+++ b/src/applications/diffusion/controller/DiffusionCommitController.php
@@ -36,7 +36,6 @@
     }
 
     $repository = $drequest->getRepository();
-    $callsign = $repository->getCallsign();
 
     $content = array();
     $commit = id(new DiffusionCommitQuery())
@@ -321,19 +320,21 @@
       $change_list->setChangesets($changesets);
       $change_list->setVisibleChangesets($visible_changesets);
       $change_list->setRenderingReferences($references);
-      $change_list->setRenderURI('/diffusion/'.$callsign.'/diff/');
+      $change_list->setRenderURI(
+        $repository->getPathURI('diff/'));
       $change_list->setRepository($repository);
       $change_list->setUser($user);
 
       // TODO: Try to setBranch() to something reasonable here?
 
       $change_list->setStandaloneURI(
-        '/diffusion/'.$callsign.'/diff/');
+        $repository->getPathURI('diff/'));
+
       $change_list->setRawFileURIs(
         // TODO: Implement this, somewhat tricky if there's an octopus merge
         // or whatever?
         null,
-        '/diffusion/'.$callsign.'/diff/?view=r');
+        $repository->getPathURI('diff/?view=r'));
 
       $change_list->setInlineCommentControllerURI(
         '/diffusion/inline/edit/'.phutil_escape_uri($commit->getPHID()).'/');
@@ -567,8 +568,8 @@
         ),
         pht('Unknown'));
 
-      $callsign = $repository->getCallsign();
-      $root = '/diffusion/'.$callsign.'/commit/'.$commit->getCommitIdentifier();
+      $identifier = $commit->getCommitIdentifier();
+      $root = $repository->getPathURI("commit/{$identifier}");
       Javelin::initBehavior(
         'diffusion-commit-branches',
         array(
@@ -904,8 +905,8 @@
       $commit,
       PhabricatorPolicyCapability::CAN_EDIT);
 
-    $uri = '/diffusion/'.$repository->getCallsign().'/commit/'.
-           $commit->getCommitIdentifier().'/edit/';
+    $identifier = $commit->getCommitIdentifier();
+    $uri = $repository->getPathURI("commit/{$identifier}/edit/");
 
     $action = id(new PhabricatorActionView())
       ->setName(pht('Edit Commit'))
diff --git a/src/applications/diffusion/controller/DiffusionController.php b/src/applications/diffusion/controller/DiffusionController.php
--- a/src/applications/diffusion/controller/DiffusionController.php
+++ b/src/applications/diffusion/controller/DiffusionController.php
@@ -86,7 +86,6 @@
       return $crumb_list;
     }
 
-    $callsign = $repository->getCallsign();
     $repository_name = $repository->getName();
 
     if (!$spec['commit'] && !$spec['tags'] && !$spec['branches']) {
@@ -112,17 +111,14 @@
     $crumb_list[] = $crumb;
 
     $stable_commit = $drequest->getStableCommit();
+    $commit_name = $repository->formatCommitName($stable_commit);
+    $commit_uri = $repository->getCommitURI($stable_commit);
 
     if ($spec['tags']) {
       $crumb = new PHUICrumbView();
       if ($spec['commit']) {
-        $crumb->setName(
-          pht('Tags for %s', 'r'.$callsign.$stable_commit));
-        $crumb->setHref($drequest->generateURI(
-          array(
-            'action' => 'commit',
-            'commit' => $drequest->getStableCommit(),
-          )));
+        $crumb->setName(pht('Tags for %s', $commit_name));
+        $crumb->setHref($commit_uri);
       } else {
         $crumb->setName(pht('Tags'));
       }
@@ -139,8 +135,8 @@
 
     if ($spec['commit']) {
       $crumb = id(new PHUICrumbView())
-        ->setName("r{$callsign}{$stable_commit}")
-        ->setHref("r{$callsign}{$stable_commit}");
+        ->setName($commit_name)
+        ->setHref($commit_uri);
       $crumb_list[] = $crumb;
       return $crumb_list;
     }
@@ -187,7 +183,7 @@
   protected function getRepositoryControllerURI(
     PhabricatorRepository $repository,
     $path) {
-    return $this->getApplicationURI($repository->getCallsign().'/'.$path);
+    return $repository->getPathURI($path);
   }
 
   protected function renderPathLinks(DiffusionRequest $drequest, $action) {
diff --git a/src/applications/diffusion/controller/DiffusionExternalController.php b/src/applications/diffusion/controller/DiffusionExternalController.php
--- a/src/applications/diffusion/controller/DiffusionExternalController.php
+++ b/src/applications/diffusion/controller/DiffusionExternalController.php
@@ -48,7 +48,7 @@
         $redirect = DiffusionRequest::generateDiffusionURI(
           array(
             'action'    => 'browse',
-            'callsign'  => $repository->getCallsign(),
+            'repository'  => $repository,
             'branch'    => $repository->getDefaultBranch(),
             'commit'    => $id,
           ));
@@ -86,7 +86,7 @@
       $redirect = DiffusionRequest::generateDiffusionURI(
         array(
           'action'    => 'browse',
-          'callsign'  => $repo->getCallsign(),
+          'repository'  => $repo,
           'branch'    => $repo->getDefaultBranch(),
           'commit'    => $commit->getCommitIdentifier(),
         ));
@@ -99,7 +99,7 @@
         $href = DiffusionRequest::generateDiffusionURI(
           array(
             'action'    => 'browse',
-            'callsign'  => $repo->getCallsign(),
+            'repository' => $repo,
             'branch'    => $repo->getDefaultBranch(),
             'commit'    => $commit->getCommitIdentifier(),
           ));
diff --git a/src/applications/diffusion/controller/DiffusionRepositoryController.php b/src/applications/diffusion/controller/DiffusionRepositoryController.php
--- a/src/applications/diffusion/controller/DiffusionRepositoryController.php
+++ b/src/applications/diffusion/controller/DiffusionRepositoryController.php
@@ -480,7 +480,7 @@
   private function buildActionList(PhabricatorRepository $repository) {
     $viewer = $this->getRequest()->getUser();
 
-    $edit_uri = $this->getApplicationURI($repository->getCallsign().'/edit/');
+    $edit_uri = $repository->getPathURI('edit/');
 
     $view = id(new PhabricatorActionListView())
       ->setUser($viewer)
diff --git a/src/applications/diffusion/herald/DiffusionCommitBranchesHeraldField.php b/src/applications/diffusion/herald/DiffusionCommitBranchesHeraldField.php
--- a/src/applications/diffusion/herald/DiffusionCommitBranchesHeraldField.php
+++ b/src/applications/diffusion/herald/DiffusionCommitBranchesHeraldField.php
@@ -14,7 +14,7 @@
     $repository = $object->getRepository();
 
     $params = array(
-      'callsign' => $repository->getCallsign(),
+      'repository' => $repository->getPHID(),
       'contains' => $commit->getCommitIdentifier(),
     );
 
diff --git a/src/applications/diffusion/query/DiffusionQuery.php b/src/applications/diffusion/query/DiffusionQuery.php
--- a/src/applications/diffusion/query/DiffusionQuery.php
+++ b/src/applications/diffusion/query/DiffusionQuery.php
@@ -53,7 +53,7 @@
     $repository = $drequest->getRepository();
 
     $core_params = array(
-      'callsign' => $repository->getCallsign(),
+      'repository' => $repository->getPHID(),
     );
 
     if ($drequest->getBranch() !== null) {
diff --git a/src/applications/diffusion/request/DiffusionRequest.php b/src/applications/diffusion/request/DiffusionRequest.php
--- a/src/applications/diffusion/request/DiffusionRequest.php
+++ b/src/applications/diffusion/request/DiffusionRequest.php
@@ -465,7 +465,7 @@
     }
 
     $defaults = array(
-      'callsign'  => $this->getCallsign(),
+      'repository' => $this->getRepository(),
       'path'      => $this->getPath(),
       'branch'    => $this->getBranch(),
       'commit'    => $default_commit,
@@ -487,6 +487,7 @@
    *   - `action` One of `history`, `browse`, `change`, `lastmodified`,
    *     `branch`, `tags`, `branches`,  or `revision-ref`. The action specified
    *      by the URI.
+   *   - `repository` Repository.
    *   - `callsign` Repository callsign.
    *   - `branch` Optional if action is not `branch`, branch name.
    *   - `path` Optional, path to file.
@@ -504,7 +505,14 @@
   public static function generateDiffusionURI(array $params) {
     $action = idx($params, 'action');
 
-    $callsign = idx($params, 'callsign');
+    $repository = idx($params, 'repository');
+
+    if ($repository) {
+      $callsign = $repository->getCallsign();
+    } else {
+      $callsign = idx($params, 'callsign');
+    }
+
     $path     = idx($params, 'path');
     $branch   = idx($params, 'branch');
     $commit   = idx($params, 'commit');
diff --git a/src/applications/harbormaster/step/HarbormasterWaitForPreviousBuildStepImplementation.php b/src/applications/harbormaster/step/HarbormasterWaitForPreviousBuildStepImplementation.php
--- a/src/applications/harbormaster/step/HarbormasterWaitForPreviousBuildStepImplementation.php
+++ b/src/applications/harbormaster/step/HarbormasterWaitForPreviousBuildStepImplementation.php
@@ -63,8 +63,8 @@
     $call = new ConduitCall(
       'diffusion.commitparentsquery',
       array(
-        'commit'   => $commit->getCommitIdentifier(),
-        'callsign' => $commit->getRepository()->getCallsign(),
+        'commit' => $commit->getCommitIdentifier(),
+        'repository' => $commit->getRepository()->getPHID(),
       ));
     $call->setUser(PhabricatorUser::getOmnipotentUser());
     $parents = $call->execute();
diff --git a/src/applications/owners/controller/PhabricatorOwnersDetailController.php b/src/applications/owners/controller/PhabricatorOwnersDetailController.php
--- a/src/applications/owners/controller/PhabricatorOwnersDetailController.php
+++ b/src/applications/owners/controller/PhabricatorOwnersDetailController.php
@@ -270,7 +270,7 @@
       }
       $href = DiffusionRequest::generateDiffusionURI(
         array(
-          'callsign' => $repo->getCallsign(),
+          'repository' => $repo,
           'branch'   => $repo->getDefaultBranch(),
           'path'     => $path->getPath(),
           'action'   => 'browse',
diff --git a/src/applications/repository/customfield/PhabricatorCommitBranchesField.php b/src/applications/repository/customfield/PhabricatorCommitBranchesField.php
--- a/src/applications/repository/customfield/PhabricatorCommitBranchesField.php
+++ b/src/applications/repository/customfield/PhabricatorCommitBranchesField.php
@@ -26,7 +26,7 @@
 
     $params = array(
       'contains' => $this->getObject()->getCommitIdentifier(),
-      'callsign' => $this->getObject()->getRepository()->getCallsign(),
+      'repository' => $this->getObject()->getRepository()->getPHID(),
     );
 
     try {
diff --git a/src/applications/repository/customfield/PhabricatorCommitMergedCommitsField.php b/src/applications/repository/customfield/PhabricatorCommitMergedCommitsField.php
--- a/src/applications/repository/customfield/PhabricatorCommitMergedCommitsField.php
+++ b/src/applications/repository/customfield/PhabricatorCommitMergedCommitsField.php
@@ -39,7 +39,7 @@
         id(new ConduitCall('diffusion.mergedcommitsquery', array(
           'commit' => $commit->getCommitIdentifier(),
           'limit' => $limit + 1,
-          'callsign' => $commit->getRepository()->getCallsign(),
+          'repository' => $commit->getRepository()->getPHID(),
         )))
         ->setUser($this->getViewer())
         ->execute());
diff --git a/src/applications/repository/customfield/PhabricatorCommitTagsField.php b/src/applications/repository/customfield/PhabricatorCommitTagsField.php
--- a/src/applications/repository/customfield/PhabricatorCommitTagsField.php
+++ b/src/applications/repository/customfield/PhabricatorCommitTagsField.php
@@ -26,7 +26,7 @@
 
     $params = array(
       'commit' => $this->getObject()->getCommitIdentifier(),
-      'callsign' => $this->getObject()->getRepository()->getCallsign(),
+      'repository' => $this->getObject()->getRepository()->getPHID(),
     );
 
     try {
diff --git a/src/applications/repository/query/PhabricatorRepositorySearchEngine.php b/src/applications/repository/query/PhabricatorRepositorySearchEngine.php
--- a/src/applications/repository/query/PhabricatorRepositorySearchEngine.php
+++ b/src/applications/repository/query/PhabricatorRepositorySearchEngine.php
@@ -177,7 +177,7 @@
       if ($size) {
         $history_uri = DiffusionRequest::generateDiffusionURI(
           array(
-            'callsign' => $repository->getCallsign(),
+            'repository' => $repository,
             'action' => 'history',
           ));
 
diff --git a/src/applications/repository/storage/PhabricatorRepository.php b/src/applications/repository/storage/PhabricatorRepository.php
--- a/src/applications/repository/storage/PhabricatorRepository.php
+++ b/src/applications/repository/storage/PhabricatorRepository.php
@@ -601,6 +601,10 @@
     return '/diffusion/'.$this->getCallsign().'/';
   }
 
+  public function getPathURI($path) {
+    return $this->getURI().$path;
+  }
+
   public function getCommitURI($identifier) {
     $callsign = $this->getCallsign();
     return "/r{$callsign}{$identifier}";