diff --git a/highfive/configs/rust-lang/rust.json b/highfive/configs/rust-lang/rust.json
index f6e8eb76..87aa8acc 100644
--- a/highfive/configs/rust-lang/rust.json
+++ b/highfive/configs/rust-lang/rust.json
@@ -23,7 +23,6 @@
             "compiler-team-contributors"
         ],
         "libs": [
-            "@dtolnay",
             "@joshtriplett",
             "@Mark-Simulacrum",
             "@kennytm",
@@ -31,6 +30,12 @@
             "@m-ou-se",
             "@thomcc"
         ],
+        "libs-api": [
+            "@dtolnay",
+            "@joshtriplett",
+            "@yaahc",
+            "@m-ou-se"
+        ],
         "infra-ci": [
             "@Mark-Simulacrum",
             "@kennytm",
@@ -192,6 +197,10 @@
         "src/tools/miri": {
             "message": "Some changes occured to the Miri submodule",
             "reviewers": ["@rust-lang/miri"]
+        },
+        "library": {
+            "message": "Thank you for submitting a new PR for the library teams! If this PR contains a stabilization of a library feature that has not already completed FCP in its tracking issue, introduces new or changes existing unstable library APIs, or changes our public documentation in ways that create new stability guarantees then please comment with `r? rust-lang/libs-api @rustbot label +T-libs-api` to request review from a libs-api team reviewer. If you're unsure where your change falls no worries, just leave it as is and the reviewer will take a look and make a decision to forward on if necessary",
+            "reviewers": []
         }
     },
     "new_pr_labels": ["S-waiting-on-review"]
diff --git a/highfive/newpr.py b/highfive/newpr.py
index 9c966c39..5c23e367 100644
--- a/highfive/newpr.py
+++ b/highfive/newpr.py
@@ -129,11 +129,19 @@ def run_commands(self, to_mention, owner, repo, issue, user):
                 if len(message) > 0:
                     message += '\n\n'
                 msg = mention.get('message')
+                reviewers = [x for x in mention['reviewers'] if x != user]
+
                 if msg is not None:
-                    msg += '\n\n'
+                    if len(reviewers) > 0:
+                        msg += '\n\n'
                 else:
                     msg = ''
-                message += "%scc %s" % (msg, ','.join([x for x in mention['reviewers'] if x != user]))
+
+                if len(reviewers) > 0:
+                    message += "%scc %s" % (msg, ','.join(reviewers))
+                else:
+                    message += msg
+
                 cmd = mention.get('command')
                 if cmd is not None:
                     commands[cmd] = self.payload['pull_request', 'head', 'sha']
diff --git a/highfive/tests/test_newpr.py b/highfive/tests/test_newpr.py
index 255138ac..d0dee85e 100644
--- a/highfive/tests/test_newpr.py
+++ b/highfive/tests/test_newpr.py
@@ -564,12 +564,16 @@ def test_has_to_mention(self):
                 'message': 'Also important',
                 'reviewers': ['@userD'],
             },
+            {
+                'message': 'last message but this one has nobody to mention associated with it',
+                'reviewers': [],
+            },
         ]
         self.set_assignee(to_mention=to_mention)
 
         self.assert_api_req_call()
         self.mocks['post_comment'].assert_called_once_with(
-            'This is important\n\ncc @userA,@userB,@userC\n\nAlso important\n\ncc @userD',
+            'This is important\n\ncc @userA,@userB,@userC\n\nAlso important\n\ncc @userD\n\nlast message but this one has nobody to mention associated with it',
             self.owner, self.repo, self.issue
         )