diff --git a/clang-tools-extra/clangd/Config.h b/clang-tools-extra/clangd/Config.h
--- a/clang-tools-extra/clangd/Config.h
+++ b/clang-tools-extra/clangd/Config.h
@@ -85,7 +85,7 @@
     /// Whether this TU should be background-indexed.
     BackgroundPolicy Background = BackgroundPolicy::Build;
     ExternalIndexSpec External;
-    bool StandardLibrary = false;
+    bool StandardLibrary = true;
   } Index;
 
   enum UnusedIncludesPolicy { Strict, None };
diff --git a/clang-tools-extra/clangd/tool/ClangdMain.cpp b/clang-tools-extra/clangd/tool/ClangdMain.cpp
--- a/clang-tools-extra/clangd/tool/ClangdMain.cpp
+++ b/clang-tools-extra/clangd/tool/ClangdMain.cpp
@@ -360,6 +360,7 @@
     cat(Misc),
     desc("Abbreviation for -input-style=delimited -pretty -sync "
          "-enable-test-scheme -enable-config=0 -log=verbose -crash-pragmas. "
+         "Also sets config options: Index.StandardLibrary=false. "
          "Intended to simplify lit tests"),
     init(false),
     Hidden,
@@ -697,6 +698,9 @@
         C.Index.Background = *BGPolicy;
       if (AllScopesCompletion.getNumOccurrences())
         C.Completion.AllScopes = AllScopesCompletion;
+
+      if (Test)
+        C.Index.StandardLibrary = false;
       return true;
     };
   }