diff --git a/nixos/tests/all-tests.nix b/nixos/tests/all-tests.nix
index 0b4b244b263b0..c37dd0ca52168 100644
--- a/nixos/tests/all-tests.nix
+++ b/nixos/tests/all-tests.nix
@@ -359,6 +359,7 @@ in
   cinnamon-wayland = runTest ./cinnamon-wayland.nix;
   cjdns = runTest ./cjdns.nix;
   clamav = runTest ./clamav.nix;
+  clangd = runTest ./clangd.nix;
   clatd = runTest ./clatd.nix;
   clickhouse = import ./clickhouse {
     inherit runTest;
diff --git a/nixos/tests/clangd.nix b/nixos/tests/clangd.nix
new file mode 100644
index 0000000000000..d1c2b401cbedc
--- /dev/null
+++ b/nixos/tests/clangd.nix
@@ -0,0 +1,135 @@
+let
+  mainCpp = builtins.toFile "main.cpp" ''
+    #include <iostream>
+    int main() {
+      std::cout << "Hello, World!" << std::endl;
+      return 0;
+    }
+  '';
+  cmakeListsTxt = builtins.toFile "CMakeLists.txt" ''
+    cmake_minimum_required(VERSION 3.20)
+    project(clangd-test VERSION 1.0.0 LANGUAGES CXX)
+    set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
+    execute_process(COMMAND ''${CMAKE_COMMAND} -E create_symlink
+        ''${CMAKE_BINARY_DIR}/compile_commands.json
+        ''${CMAKE_CURRENT_SOURCE_DIR}/compile_commands.json
+    )
+    add_executable(clangd-test main.cpp)
+  '';
+in
+{
+  name = "clangd";
+  nodes = {
+    machine =
+      { pkgs, ... }:
+      {
+        environment.systemPackages = [
+          (pkgs.writeShellApplication {
+            name = "clangd-test";
+            runtimeInputs = [
+              pkgs.clang-tools
+              pkgs.cmake
+              pkgs.gnumake
+              pkgs.stdenv.cc
+            ];
+            text = ''
+              TEST_DIR=$(mktemp -d)
+              cd "$TEST_DIR"
+              cp ${mainCpp} main.cpp
+              cp ${cmakeListsTxt} CMakeLists.txt
+              cmake -B .build .
+              cat compile_commands.json
+
+              rpc_request() {
+                local json="$1"
+                local length=$((''${#json} + 1))
+                printf "Content-Length: %s\r\n\r\n%s\n" "$length" "$json"
+              }
+              json_escape() {
+                local input="$1"
+                local output=""
+                local i char
+                for ((i=0; i<''${#input}; i++)); do
+                  char="''${input:$i:1}"
+                  # shellcheck disable=SC1003
+                  case "$char" in
+                    '"')   output+='\"' ;;
+                    '\')   output+='\\' ;;
+                    $'\b') output+='\b' ;;
+                    $'\f') output+='\f' ;;
+                    $'\n') output+='\n' ;;
+                    $'\r') output+='\r' ;;
+                    $'\t') output+='\t' ;;
+                    *)     output+="$char" ;;
+                  esac
+                done
+                echo "$output"
+              }
+              FIFO_IN=$(mktemp -u)
+              FIFO_OUT=$(mktemp -u)
+              mkfifo "$FIFO_IN"
+              mkfifo "$FIFO_OUT"
+              CLANGD_PID=""
+              DIAGNOSTICS_TIMEOUT=5
+              MAIN_CPP="file://$TEST_DIR/main.cpp"
+
+              # Start clangd in background
+              clangd < "$FIFO_IN" > "$FIFO_OUT" 2>&1 &
+              CLANGD_PID=$!
+              echo "Started clangd (''${CLANGD_PID})"
+              sleep 0.5
+              exec 3>"$FIFO_IN"
+              exec 4<"$FIFO_OUT"
+
+              # Send LSP requests to kick off compilation
+              rpc_request '{"jsonrpc":"2.0","id":0,"method":"initialize","params":{"processId":null,"rootUri":"file://'"$TEST_DIR"'","capabilities":{"textDocument":{"diagnostic":{}}}}}' >&3
+              rpc_request '{"jsonrpc":"2.0","method":"initialized","params":{}}' >&3
+              MAIN_CPP_TEXT=$(json_escape "$(cat main.cpp)")
+              rpc_request '{"jsonrpc":"2.0","method":"textDocument/didOpen","params":{"textDocument":{"uri":"'"$MAIN_CPP"'","languageId":"c++","version":0,"text":"'"$MAIN_CPP_TEXT"'"}}}' >&3
+              rpc_request '{"jsonrpc":"2.0","id":1,"method":"textDocument/documentHighlight","params":{"textDocument":{"uri":"'"$MAIN_CPP"'"},"position":{"line":0,"character":0}}}' >&3
+
+              # Wait for diagnostics to come.
+              echo "Waiting for diagnostics (timeout: ''${DIAGNOSTICS_TIMEOUT}s)..."
+              DIAGNOSTICS_FOUND=""
+              TIMEOUT_EXCEEDED=""
+              ALL_OUTPUT=""
+              SECONDS=0
+
+              while IFS= read -r -t "$DIAGNOSTICS_TIMEOUT" line <&4; do
+                ALL_OUTPUT+="$line"$'\n'
+                if [[ "$line" =~ \"diagnostics\":\[\] ]]; then
+                  break
+                fi
+                if [[ "$line" =~ \"diagnostics\":\[.+\] ]]; then
+                  DIAGNOSTICS_FOUND="yes"
+                  break
+                fi
+                if [[ $SECONDS -ge $DIAGNOSTICS_TIMEOUT ]]; then
+                  TIMEOUT_EXCEEDED="yes"
+                  break
+                fi
+              done
+
+              # Cleanup
+              exec 3>&-
+              exec 4<&-
+              kill "$CLANGD_PID" 2>/dev/null || true
+              wait "$CLANGD_PID" 2>/dev/null || true
+              echo "$ALL_OUTPUT"
+
+              if [[ -n "$DIAGNOSTICS_FOUND" ]]; then
+                echo "Found unexpected diagnostics in main.cpp" && exit 1
+              elif [[ -n "$TIMEOUT_EXCEEDED" ]]; then
+                echo "Timeout exceeded" && exit 1
+              else
+                echo "Success, no diagnostics found" && exit 0
+              fi
+            '';
+          })
+        ];
+      };
+  };
+  testScript = ''
+    machine.succeed("clangd-test");
+  '';
+}
diff --git a/pkgs/development/compilers/llvm/common/clang-tools/default.nix b/pkgs/development/compilers/llvm/common/clang-tools/default.nix
index 7ecf0c5c431de..8f216fa865b39 100644
--- a/pkgs/development/compilers/llvm/common/clang-tools/default.nix
+++ b/pkgs/development/compilers/llvm/common/clang-tools/default.nix
@@ -1,6 +1,7 @@
 {
   lib,
   stdenv,
+  nixosTests,
   clang-unwrapped,
   clang,
   libcxxClang,
@@ -52,6 +53,10 @@ stdenv.mkDerivation {
     runHook postInstall
   '';
 
+  passthru.tests = {
+    nginx = nixosTests.clangd;
+  };
+
   meta = llvm_meta // {
     description = "Standalone command line tools for C++ development";
     maintainers = with lib.maintainers; [ patryk27 ];