diff --git a/tools/etcpmon/Makefile b/tools/etcpmon/Makefile
index 7f40e719..524904d3 100644
--- a/tools/etcpmon/Makefile
+++ b/tools/etcpmon/Makefile
@@ -24,6 +24,8 @@ $(TARGET): $(OBJS)
 	@echo Linking $@
 	$(CC) $(LDFLAGS) -o $@ $^ $(LIBS)
 
+$(OBJS): $(wildcard *.h)
+
 %.o: %.c
 	@echo Compiling $<
 	$(CC) $(CFLAGS) -c -o $@ $<
diff --git a/tools/etcpmon/etcpmon_client.c b/tools/etcpmon/etcpmon_client.c
index 5060dfd5..2967fdfd 100644
--- a/tools/etcpmon/etcpmon_client.c
+++ b/tools/etcpmon/etcpmon_client.c
@@ -468,6 +468,9 @@ int etcpmon_client_send_request(struct etcpmon_client* client,
                    (unsigned long long)get_timestamp_ms(), type, sent, total_size, sent == SOCKET_ERROR ? WSAGetLastError() : 0);
             fflush(client->log_file);
         }
+        /* После частичной отправки следующий пакет уже нельзя писать в этот поток. */
+        etcpmon_client_disconnect(client);
+        if (client->on_disconnected) client->on_disconnected(client->user_data);
         return -1;
     }
 
@@ -626,7 +629,8 @@ static void handle_response(struct etcpmon_client* client, uint8_t msg_type,
         }
         
         case ETCPMON_RSP_ERROR: {
-            if (payload_size >= sizeof(struct etcpmon_rsp_error)) {
+            if (payload_size > sizeof(struct etcpmon_rsp_error) &&
+                memchr(payload + sizeof(struct etcpmon_rsp_error), 0, payload_size - sizeof(struct etcpmon_rsp_error))) {
                 struct etcpmon_rsp_error* rsp = (struct etcpmon_rsp_error*)payload;
                 const char* msg = (const char*)(payload + sizeof(*rsp));
 
@@ -639,12 +643,15 @@ static void handle_response(struct etcpmon_client* client, uint8_t msg_type,
                 if (client->on_error) {
                     client->on_error(msg, client->user_data);
                 }
+            } else if (client->log_file) {
+                fprintf(client->log_file, "[ERROR] Invalid RSP_ERROR string: size=%u\n", payload_size);
             }
             break;
         }
 
         case ETCPMON_RSP_ACTION_RESULT: {
-            if (payload_size >= sizeof(struct etcpmon_rsp_action_result)) {
+            if (payload_size > sizeof(struct etcpmon_rsp_action_result) &&
+                memchr(payload + sizeof(struct etcpmon_rsp_action_result), 0, payload_size - sizeof(struct etcpmon_rsp_action_result))) {
                 const char* text = (const char*)(payload + sizeof(struct etcpmon_rsp_action_result));
 
                 if (client->log_file) {
@@ -656,15 +663,23 @@ static void handle_response(struct etcpmon_client* client, uint8_t msg_type,
                 if (client->on_action_result) {
                     client->on_action_result(text, client->user_data);
                 }
+            } else if (client->log_file) {
+                fprintf(client->log_file, "[ERROR] Invalid RSP_ACTION_RESULT string: size=%u\n", payload_size);
             }
             break;
         }
 
         case ETCPMON_RSP_DEBUG_CONFIG: {
-            if (payload_size >= 2) {
+            const uint8_t* names_end = payload_size > 2 ? memchr(payload + 2, 0, payload_size - 2) : NULL;
+            if (!names_end || payload[1] > ETCPMON_MAX_DEBUG_CATEGORIES ||
+                (size_t)(names_end - payload) + 1 + payload[1] != payload_size) {
+                if (client->log_file) fprintf(client->log_file, "[ERROR] Invalid RSP_DEBUG_CONFIG: size=%u\n", payload_size);
+                break;
+            }
+            {
                 client->debug_global_level = payload[0];
                 client->debug_category_count = payload[1];
-                uint16_t names_len = (uint16_t)strlen((const char*)(payload + 2)) + 1;
+                uint16_t names_len = (uint16_t)(names_end - payload - 2) + 1;
                 if (2 + names_len <= payload_size) {
                     size_t copy_len = names_len < sizeof(client->debug_category_names) ? names_len : sizeof(client->debug_category_names) - 1;
                     memcpy(client->debug_category_names, payload + 2, copy_len);
@@ -1000,8 +1015,10 @@ int etcpmon_client_send_debug_config(struct etcpmon_client* client,
     memcpy(payload + 2, levels, count);
     uint16_t payload_size = 2 + count;
 
-    struct etcpmon_msg_header hdr;
-    etcpmon_build_header(&hdr, payload_size, ETCPMON_CMD_SET_DEBUG_CONFIG, 0);
+    uint8_t buffer[sizeof(struct etcpmon_msg_header) + sizeof(payload)];
+    struct etcpmon_msg_header* hdr = (struct etcpmon_msg_header*)buffer;
+    etcpmon_build_header(hdr, payload_size, ETCPMON_CMD_SET_DEBUG_CONFIG, 0);
+    memcpy(buffer + sizeof(*hdr), payload, payload_size);
 
     if (client->log_file) {
         fprintf(client->log_file, "%llu: [LOG] CMD_SET_DEBUG_CONFIG global=%d count=%d\n",
@@ -1009,10 +1026,18 @@ int etcpmon_client_send_debug_config(struct etcpmon_client* client,
         fflush(client->log_file);
     }
 
-    int sent = send(client->sock, (const char*)&hdr, sizeof(hdr), 0);
-    if (sent != sizeof(hdr)) return -1;
-    sent = send(client->sock, (const char*)payload, payload_size, 0);
-    if (sent != payload_size) return -1;
+    int total_size = sizeof(*hdr) + payload_size;
+    int sent = send(client->sock, (const char*)buffer, total_size, 0);
+    if (sent != total_size) {
+        if (client->log_file) {
+            fprintf(client->log_file, "[ERROR] Failed to send debug config: sent=%d/%d error=%d\n",
+                    sent, total_size, sent == SOCKET_ERROR ? WSAGetLastError() : 0);
+            fflush(client->log_file);
+        }
+        etcpmon_client_disconnect(client);
+        if (client->on_disconnected) client->on_disconnected(client->user_data);
+        return -1;
+    }
     client->debug_global_level = global_level;
     for (uint8_t i = 0; i < count; i++) client->debug_category_levels[i] = levels[i];
     return 0;
diff --git a/tools/etcpmon/test_etcpmon.c b/tools/etcpmon/test_etcpmon.c
index b3b2367d..7a8cfe06 100644
--- a/tools/etcpmon/test_etcpmon.c
+++ b/tools/etcpmon/test_etcpmon.c
@@ -129,6 +129,7 @@ int main(void) {
     SendMessage(app.hListConnections, LB_SETCURSEL, 1, 0);
     OnConnectionSelect(&app);
     assert(client.selected_peer_id == list[1].peer_node_id);
+    assert(drain_commands(ETCPMON_CMD_SELECT_CONN) == 2);
     struct etcpmon_conn_info reordered[3] = {list[1], list[2], list[0]};
     strcpy(reordered[0].name, "renamed");
     deliver_list(reordered, 3);
@@ -202,6 +203,34 @@ int main(void) {
     assert(client.pending_head == NULL && !client.connected && app.need_initial_request);
     assert(SendMessage(app.hListConnections, LB_GETCOUNT, 0, 0) == 0);
 
+    puts("Malformed debug responses are rejected and socket snapshots are not capped at 16");
+    client.debug_config_dirty = 0;
+    const uint8_t invalid_names[] = {1, 0, 'x'};
+    handle_response(&client, ETCPMON_RSP_DEBUG_CONFIG, invalid_names, sizeof(invalid_names));
+    assert(!client.debug_config_dirty);
+    const uint8_t missing_levels[] = {1, 2, 'a', ',', 'b', 0, 1};
+    handle_response(&client, ETCPMON_RSP_DEBUG_CONFIG, missing_levels, sizeof(missing_levels));
+    assert(!client.debug_config_dirty);
+    const uint8_t valid_debug[] = {1, 2, 'a', ',', 'b', 0, 1, 2};
+    handle_response(&client, ETCPMON_RSP_DEBUG_CONFIG, valid_debug, sizeof(valid_debug));
+    assert(client.debug_config_dirty && client.debug_category_levels[1] == 2);
+    uint8_t socket_payload[1 + 17 * sizeof(struct etcpmon_socket_info)] = {17};
+    struct etcpmon_socket_info* sockets = (struct etcpmon_socket_info*)(socket_payload + 1);
+    for (int i = 0; i < 17; i++) {
+        strcpy(sockets[i].name, "socket");
+        strcpy(sockets[i].ip, "127.0.0.1");
+    }
+    handle_response(&client, ETCPMON_RSP_SOCKET_LIST, socket_payload, sizeof(socket_payload));
+    assert(client.socket_count == 17 && SendMessage(app.hListSockets, LB_GETCOUNT, 0, 0) == 17);
+
+    puts("A send failure clears pending requests and allows another connection");
+    closesocket(server_sock);
+    connect_client();
+    assert(etcpmon_client_send_request(&client, ETCPMON_CMD_ACTION, NULL, 0, request_callback, NULL) == 0);
+    assert(shutdown(client.sock, SD_SEND) == 0);
+    assert(etcpmon_client_send_request(&client, ETCPMON_CMD_ACTION, NULL, 0, request_callback, NULL) == -1);
+    assert(!client.connected && client.pending_head == NULL && client.pending_tail == NULL && app.need_initial_request);
+
     etcpmon_client_cleanup(&client);
     closesocket(server_sock);
     closesocket(listener);