diff --git a/examples/server/server.cpp b/examples/server/server.cpp
index 1ebcb50854d31..329492e29d6f7 100644
--- a/examples/server/server.cpp
+++ b/examples/server/server.cpp
@@ -68,6 +68,7 @@ enum server_task_type {
     SERVER_TASK_TYPE_SLOT_RESTORE,
     SERVER_TASK_TYPE_SLOT_ERASE,
     SERVER_TASK_TYPE_SET_LORA,
+    SERVER_TASK_TYPE_NONE,
 };
 
 enum oaicompat_type {
@@ -480,6 +481,7 @@ struct result_timings {
 struct server_task_result {
     int id           = -1;
     int id_slot      = -1;
+    server_task_type type;
     virtual bool is_error() {
         // only used by server_task_result_error
         return false;
@@ -491,6 +493,7 @@ struct server_task_result {
     virtual int get_index() {
         return -1;
     }
+    virtual server_task_type get_server_task_type() = 0;
     virtual json to_json() = 0;
     virtual ~server_task_result() = default;
 };
@@ -794,6 +797,10 @@ struct server_task_result_cmpl_final : server_task_result {
 
         return ret;
     }
+
+    server_task_type get_server_task_type() override {
+        return SERVER_TASK_TYPE_COMPLETION;
+    }
 };
 
 struct server_task_result_cmpl_partial : server_task_result {
@@ -962,6 +969,10 @@ struct server_task_result_cmpl_partial : server_task_result {
 
         return std::vector<json>({ret});
     }
+
+    server_task_type get_server_task_type() override {
+        return SERVER_TASK_TYPE_NONE;
+    }
 };
 
 struct server_task_result_embd : server_task_result {
@@ -997,6 +1008,10 @@ struct server_task_result_embd : server_task_result {
             {"tokens_evaluated", n_tokens},
         };
     }
+
+    server_task_type get_server_task_type() override {
+        return SERVER_TASK_TYPE_EMBEDDING;
+    }
 };
 
 struct server_task_result_rerank : server_task_result {
@@ -1016,6 +1031,10 @@ struct server_task_result_rerank : server_task_result {
             {"tokens_evaluated", n_tokens},
         };
     }
+
+    server_task_type get_server_task_type() override {
+        return SERVER_TASK_TYPE_RERANK;
+    }
 };
 
 // this function maybe used outside of server_task_result_error
@@ -1071,6 +1090,10 @@ struct server_task_result_error : server_task_result {
     virtual json to_json() override {
         return format_error_response(err_msg, err_type);
     }
+
+    server_task_type get_server_task_type() override {
+        return SERVER_TASK_TYPE_NONE;
+    }
 };
 
 struct server_task_result_metrics : server_task_result {
@@ -1127,6 +1150,10 @@ struct server_task_result_metrics : server_task_result {
             { "slots",                           slots_data },
         };
     }
+
+    server_task_type get_server_task_type() override {
+        return SERVER_TASK_TYPE_METRICS;
+    }
 };
 
 struct server_task_result_slot_save_load : server_task_result {
@@ -1160,6 +1187,10 @@ struct server_task_result_slot_save_load : server_task_result {
             };
         }
     }
+
+    server_task_type get_server_task_type() override {
+        return SERVER_TASK_TYPE_SLOT_SAVE;
+    }
 };
 
 struct server_task_result_slot_erase : server_task_result {
@@ -1171,12 +1202,20 @@ struct server_task_result_slot_erase : server_task_result {
             { "n_erased", n_erased },
         };
     }
+
+    server_task_type get_server_task_type() override {
+        return SERVER_TASK_TYPE_SLOT_ERASE;
+    }
 };
 
 struct server_task_result_apply_lora : server_task_result {
     virtual json to_json() override {
         return json {{ "success", true }};
     }
+
+    server_task_type get_server_task_type() override {
+        return SERVER_TASK_TYPE_NONE;
+    }
 };
 
 struct server_slot {
@@ -2751,6 +2790,11 @@ struct server_context {
                     res->id = task.id;
                     queue_results.send(std::move(res));
                 } break;
+            case SERVER_TASK_TYPE_NONE:
+                {
+                    // do nothing
+                    GGML_ASSERT(false && "Invalid task.type (SERVER_TASK_TYPE_NONE)\n");
+                }
         }
     }
 
@@ -3665,49 +3709,23 @@ int main(int argc, char ** argv) {
         res.status = 200; // HTTP OK
     };
 
-    const auto handle_slots_save = [&ctx_server, &res_error, &res_ok, &params](const httplib::Request & req, httplib::Response & res, int id_slot) {
-        json request_data = json::parse(req.body);
-        std::string filename = request_data.at("filename");
-        if (!fs_validate_filename(filename)) {
-            res_error(res, format_error_response("Invalid filename", ERROR_TYPE_INVALID_REQUEST));
-            return;
-        }
-        std::string filepath = params.slot_save_path + filename;
-
-        server_task task(SERVER_TASK_TYPE_SLOT_SAVE);
+    const auto handle_slot_impl = [&ctx_server, &res_error, &res_ok, &params](const httplib::Request & req,
+            httplib::Response & res, int id_slot, server_task_type type) {
+        server_task task(type);
         task.id = ctx_server.queue_tasks.get_new_id();
         task.slot_action.slot_id  = id_slot;
-        task.slot_action.filename = filename;
-        task.slot_action.filepath = filepath;
-
-        ctx_server.queue_results.add_waiting_task_id(task.id);
-        ctx_server.queue_tasks.post(task);
-
-        server_task_result_ptr result = ctx_server.queue_results.recv(task.id);
-        ctx_server.queue_results.remove_waiting_task_id(task.id);
 
-        if (result->is_error()) {
-            res_error(res, result->to_json());
-            return;
-        }
-
-        res_ok(res, result->to_json());
-    };
-
-    const auto handle_slots_restore = [&ctx_server, &res_error, &res_ok, &params](const httplib::Request & req, httplib::Response & res, int id_slot) {
-        json request_data = json::parse(req.body);
-        std::string filename = request_data.at("filename");
-        if (!fs_validate_filename(filename)) {
-            res_error(res, format_error_response("Invalid filename", ERROR_TYPE_INVALID_REQUEST));
-            return;
+        if (type != SERVER_TASK_TYPE_SLOT_ERASE) {
+            json request_data = json::parse(req.body);
+            std::string filename = request_data.at("filename");
+            if (!fs_validate_filename(filename)) {
+                res_error(res, format_error_response("Invalid filename", ERROR_TYPE_INVALID_REQUEST));
+                return;
+            }
+            std::string filepath = params.slot_save_path + filename;
+            task.slot_action.filename = filename;
+            task.slot_action.filepath = filepath;
         }
-        std::string filepath = params.slot_save_path + filename;
-
-        server_task task(SERVER_TASK_TYPE_SLOT_RESTORE);
-        task.id = ctx_server.queue_tasks.get_new_id();
-        task.slot_action.slot_id  = id_slot;
-        task.slot_action.filename = filename;
-        task.slot_action.filepath = filepath;
 
         ctx_server.queue_results.add_waiting_task_id(task.id);
         ctx_server.queue_tasks.post(task);
@@ -3719,32 +3737,28 @@ int main(int argc, char ** argv) {
             res_error(res, result->to_json());
             return;
         }
-
-        GGML_ASSERT(dynamic_cast<server_task_result_slot_save_load*>(result.get()) != nullptr);
+        GGML_ASSERT(result.get() != nullptr);
+        if (type == SERVER_TASK_TYPE_SLOT_RESTORE) {
+            GGML_ASSERT(result.get()->get_server_task_type() == SERVER_TASK_TYPE_SLOT_SAVE);
+        } else {
+            GGML_ASSERT(result.get()->get_server_task_type() == type);
+        }
         res_ok(res, result->to_json());
     };
 
-    const auto handle_slots_erase = [&ctx_server, &res_error, &res_ok](const httplib::Request & /* req */, httplib::Response & res, int id_slot) {
-        server_task task(SERVER_TASK_TYPE_SLOT_ERASE);
-        task.id = ctx_server.queue_tasks.get_new_id();
-        task.slot_action.slot_id = id_slot;
-
-        ctx_server.queue_results.add_waiting_task_id(task.id);
-        ctx_server.queue_tasks.post(task);
-
-        server_task_result_ptr result = ctx_server.queue_results.recv(task.id);
-        ctx_server.queue_results.remove_waiting_task_id(task.id);
+    const auto handle_slots_save = [&handle_slot_impl](const httplib::Request & req, httplib::Response & res, int id_slot) {
+        handle_slot_impl(req, res, id_slot, SERVER_TASK_TYPE_SLOT_SAVE);
+    };
 
-        if (result->is_error()) {
-            res_error(res, result->to_json());
-            return;
-        }
+    const auto handle_slots_restore = [&handle_slot_impl](const httplib::Request & req, httplib::Response & res, int id_slot) {
+        handle_slot_impl(req, res, id_slot, SERVER_TASK_TYPE_SLOT_RESTORE);
+    };
 
-        GGML_ASSERT(dynamic_cast<server_task_result_slot_erase*>(result.get()) != nullptr);
-        res_ok(res, result->to_json());
+    const auto handle_slots_erase = [&handle_slot_impl](const httplib::Request & req, httplib::Response & res, int id_slot) {
+        handle_slot_impl(req, res, id_slot, SERVER_TASK_TYPE_SLOT_ERASE);
     };
 
-    const auto handle_slots_action = [&params, &res_error, &handle_slots_save, &handle_slots_restore, &handle_slots_erase](const httplib::Request & req, httplib::Response & res) {
+ auto handle_slots_action = [&params, &res_error, &handle_slots_save, &handle_slots_restore, &handle_slots_erase](const httplib::Request & req, httplib::Response & res) {
         if (params.slot_save_path.empty()) {
             res_error(res, format_error_response("This server does not support slots action. Start it with `--slot-save-path`", ERROR_TYPE_NOT_SUPPORTED));
             return;