diff --git a/src/applications/auth/adapter/PhutilGitHubAuthAdapter.php b/src/applications/auth/adapter/PhutilGitHubAuthAdapter.php
--- a/src/applications/auth/adapter/PhutilGitHubAuthAdapter.php
+++ b/src/applications/auth/adapter/PhutilGitHubAuthAdapter.php
@@ -55,7 +55,8 @@
     $future = new HTTPSFuture($uri);
 
     // NOTE: GitHub requires a User-Agent string.
-    $future->addHeader('User-Agent', __CLASS__);
+    $future->addHeader('User-Agent',
+      PhabricatorEnv::getEnvConfig('phabricator.base-uri'));
 
     // See T13485. Circa early 2020, GitHub has deprecated use of the
     // "access_token" URI parameter.
diff --git a/src/applications/auth/adapter/PhutilOAuth1AuthAdapter.php b/src/applications/auth/adapter/PhutilOAuth1AuthAdapter.php
--- a/src/applications/auth/adapter/PhutilOAuth1AuthAdapter.php
+++ b/src/applications/auth/adapter/PhutilOAuth1AuthAdapter.php
@@ -100,6 +100,8 @@
 
   protected function newOAuth1Future($uri, $data = array()) {
     $future = id(new PhutilOAuth1Future($uri, $data))
+      ->addHeader('User-Agent',
+          PhabricatorEnv::getEnvConfig('phabricator.base-uri'))
       ->setMethod('POST')
       ->setSignatureMethod($this->getSignatureMethod());