diff --git a/clang-tools-extra/clangd/CodeComplete.cpp b/clang-tools-extra/clangd/CodeComplete.cpp
--- a/clang-tools-extra/clangd/CodeComplete.cpp
+++ b/clang-tools-extra/clangd/CodeComplete.cpp
@@ -403,8 +403,9 @@
       if (C.IndexResult) {
         SetDoc(C.IndexResult->Documentation);
       } else if (C.SemaResult) {
-        SetDoc(getDocComment(*ASTCtx, *C.SemaResult,
-                             /*CommentsFromHeader=*/false));
+        const auto DocComment = getDocComment(*ASTCtx, *C.SemaResult,
+                                              /*CommentsFromHeader=*/false);
+        SetDoc(formatDocumentation(*SemaCCS, DocComment));
       }
     }
     if (Completion.Deprecated) {
diff --git a/clang-tools-extra/clangd/unittests/CodeCompleteTests.cpp b/clang-tools-extra/clangd/unittests/CodeCompleteTests.cpp
--- a/clang-tools-extra/clangd/unittests/CodeCompleteTests.cpp
+++ b/clang-tools-extra/clangd/unittests/CodeCompleteTests.cpp
@@ -907,7 +907,7 @@
   auto Results = completions(
       R"cpp(
       // Non-doxygen comment.
-      int foo();
+      __attribute__((annotate("custom_annotation"))) int foo();
       /// Doxygen comment.
       /// \param int a
       int bar(int a);
@@ -919,7 +919,8 @@
       int x = ^
      )cpp");
   EXPECT_THAT(Results.Completions,
-              Contains(AllOf(Named("foo"), Doc("Non-doxygen comment."))));
+              Contains(AllOf(Named("foo"),
+              Doc("Annotation: custom_annotation\nNon-doxygen comment."))));
   EXPECT_THAT(
       Results.Completions,
       Contains(AllOf(Named("bar"), Doc("Doxygen comment.\n\\param int a"))));