diff --git a/src/Jx9Manager.cpp b/src/Jx9Manager.cpp
index c16f41d..944d481 100644
--- a/src/Jx9Manager.cpp
+++ b/src/Jx9Manager.cpp
@@ -76,6 +76,11 @@ std::string Jx9Manager::executeQuery(
         comm_world = json::object();
         comm_world["rank"] = self->m_mpi.globalRank();
         comm_world["size"] = self->m_mpi.globalSize();
+        comm_world["addresses"] = json::array();
+        for(int i = 0; i < self->m_mpi.globalSize(); ++i) {
+            comm_world["addresses"].push_back(
+                self->m_mpi.addressOfRank(i));
+        }
     }
 #endif
     jx9_value* jx9_comm_world = nullptr;
diff --git a/src/MPIEnv.cpp b/src/MPIEnv.cpp
index 76cd284..470be3a 100644
--- a/src/MPIEnv.cpp
+++ b/src/MPIEnv.cpp
@@ -50,6 +50,8 @@ const std::string& MPIEnv::addressOfRank(int rank) const {
     if(rank < 0 || rank >= globalSize()) {
         throw Exception{"Requesting address of an invalid rank ({})", rank};
     }
+    static const std::string uninitialized = "<uninitialized>";
+    if(self->m_addresses.empty()) return uninitialized;
     return self->m_addresses[rank];
 }