diff --git a/src/Routes/RouteUserDirectory.c b/src/Routes/RouteUserDirectory.c
index c1040ff..be51f04 100644
--- a/src/Routes/RouteUserDirectory.c
+++ b/src/Routes/RouteUserDirectory.c
@@ -52,6 +52,8 @@ ROUTE_IMPL(RouteUserDirectory, path, argp)
     char *searchTerm = NULL;
     char *requesterName = NULL;
 
+    char *error;
+
     size_t limit = 10;
 
     size_t i, included;
@@ -62,7 +64,7 @@ ROUTE_IMPL(RouteUserDirectory, path, argp)
     if (HttpRequestMethodGet(args->context) != HTTP_POST)
     {
         HttpResponseStatus(args->context, HTTP_BAD_REQUEST);
-        response = MatrixErrorCreate(M_UNRECOGNIZED);
+        response = MatrixErrorCreate(M_UNRECOGNIZED, NULL);
         goto finish;
     }
 
@@ -70,7 +72,7 @@ ROUTE_IMPL(RouteUserDirectory, path, argp)
     if (!request)
     {
         HttpResponseStatus(args->context, HTTP_BAD_REQUEST);
-        response = MatrixErrorCreate(M_NOT_JSON);
+        response = MatrixErrorCreate(M_NOT_JSON, NULL);
         goto finish;
     }
 
@@ -85,7 +87,7 @@ ROUTE_IMPL(RouteUserDirectory, path, argp)
     if (!user)
     {
         HttpResponseStatus(args->context, HTTP_BAD_REQUEST);
-        response = MatrixErrorCreate(M_UNKNOWN_TOKEN);
+        response = MatrixErrorCreate(M_UNKNOWN_TOKEN, NULL);
         goto finish;
     }
     requesterName = UserGetName(user);
@@ -96,7 +98,8 @@ ROUTE_IMPL(RouteUserDirectory, path, argp)
     {
         /* The Spec requires search_term to be set to a string. */
         HttpResponseStatus(args->context, HTTP_BAD_REQUEST);
-        response = MatrixErrorCreate(M_BAD_JSON);
+        error = "search_term is not a string, or is non-existent";
+        response = MatrixErrorCreate(M_BAD_JSON, error);
         goto finish;
     }
     searchTerm = StrLower(JsonValueAsString(val));
@@ -120,9 +123,10 @@ ROUTE_IMPL(RouteUserDirectory, path, argp)
     config = ConfigLock(db);
     if (!config)
     {
-        Log(LOG_ERR, "Directory endpoint failed to lock configuration.");
+        error = "Directory endpoint failed to lock configuration.";
+        Log(LOG_ERR, error);
         HttpResponseStatus(args->context, HTTP_INTERNAL_SERVER_ERROR);
-        response = MatrixErrorCreate(M_UNKNOWN);
+        response = MatrixErrorCreate(M_UNKNOWN, error);
 
         goto finish;
     }