diff --git a/clang-tools-extra/clangd/unittests/ClangdLSPServerTests.cpp b/clang-tools-extra/clangd/unittests/ClangdLSPServerTests.cpp
--- a/clang-tools-extra/clangd/unittests/ClangdLSPServerTests.cpp
+++ b/clang-tools-extra/clangd/unittests/ClangdLSPServerTests.cpp
@@ -13,8 +13,11 @@
 #include "Protocol.h"
 #include "TestFS.h"
 #include "refactor/Rename.h"
+#include "support/Context.h"
 #include "support/Logger.h"
 #include "support/TestTracer.h"
+#include "support/Threading.h"
+#include "llvm/ADT/ScopeExit.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/Support/Error.h"
 #include "llvm/Support/JSON.h"
diff --git a/clang-tools-extra/clangd/unittests/LSPClient.cpp b/clang-tools-extra/clangd/unittests/LSPClient.cpp
--- a/clang-tools-extra/clangd/unittests/LSPClient.cpp
+++ b/clang-tools-extra/clangd/unittests/LSPClient.cpp
@@ -5,6 +5,7 @@
 #include "Protocol.h"
 #include "TestFS.h"
 #include "Transport.h"
+#include "support/Context.h"
 #include "support/Threading.h"
 #include "llvm/Support/Path.h"
 #include "llvm/Support/raw_ostream.h"
@@ -68,7 +69,7 @@
   // A null action causes the transport to shut down.
   void enqueue(std::function<void(MessageHandler &)> Action) {
     std::lock_guard<std::mutex> Lock(Mu);
-    Actions.push(std::move(Action));
+    Requests.push({Context::current().clone(), std::move(Action)});
     CV.notify_all();
   }
 
@@ -112,20 +113,28 @@
   llvm::Error loop(MessageHandler &H) override {
     std::unique_lock<std::mutex> Lock(Mu);
     while (true) {
-      CV.wait(Lock, [&] { return !Actions.empty(); });
-      if (!Actions.front()) // Stop!
+      CV.wait(Lock, [&] { return !Requests.empty(); });
+      if (!Requests.front().Action) // Stop!
         return llvm::Error::success();
-      auto Action = std::move(Actions.front());
-      Actions.pop();
+      auto Req = std::move(Requests.front());
+      Requests.pop();
       Lock.unlock();
-      Action(H);
+      {
+        WithContext Ctx(std::move(Req.Ctx));
+        Req.Action(H);
+      }
       Lock.lock();
     }
   }
 
+  struct Request {
+    Context Ctx;
+    std::function<void(Transport::MessageHandler &)> Action;
+  };
+
   std::mutex Mu;
   std::deque<CallResult> CallResults;
-  std::queue<std::function<void(Transport::MessageHandler &)>> Actions;
+  std::queue<Request> Requests;
   std::condition_variable CV;
   llvm::StringMap<std::vector<llvm::json::Value>> Notifications;
 };