diff --git a/examples/server/server.cpp b/examples/server/server.cpp
index aedfca0d6..79727e68c 100644
--- a/examples/server/server.cpp
+++ b/examples/server/server.cpp
@@ -1897,13 +1897,13 @@ struct server_context {
 
                     // Shift context
                     const int n_keep    = slot.params.n_keep + add_bos_token;
-                    const int n_left    = (int) system_tokens.size() + slot.n_past - n_keep;
+                    const int n_left    = slot.n_past - n_keep;
                     const int n_discard = slot.params.n_discard ? slot.params.n_discard : (n_left / 2);
 
                     SLT_WRN(slot, "slot context shift, n_keep = %d, n_left = %d, n_discard = %d\n", n_keep, n_left, n_discard);
 
-                    llama_kv_cache_seq_rm (ctx, slot.id + 1, n_keep            , n_keep + n_discard);
-                    llama_kv_cache_seq_add(ctx, slot.id + 1, n_keep + n_discard, system_tokens.size() + slot.n_past, -n_discard);
+                    llama_kv_cache_seq_rm (ctx, slot.id + 1, system_tokens.size() + n_keep            , system_tokens.size() + n_keep + n_discard);
+                    llama_kv_cache_seq_add(ctx, slot.id + 1, system_tokens.size() + n_keep + n_discard, system_tokens.size() + slot.n_past, -n_discard);
 
                     if (slot.params.cache_prompt) {
                         for (size_t i = n_keep + n_discard; i < slot.cache_tokens.size(); i++) {
@@ -2068,10 +2068,10 @@ struct server_context {
 
                             // if input prompt is too big, truncate it (if group attention self-extend is disabled)
                             if (slot.ga_n == 1 && slot.n_prompt_tokens >= slot.n_ctx) {
-                                const int n_left = slot.n_ctx - slot.params.n_keep;
+                                const int n_left = slot.n_ctx - slot.params.n_keep - system_tokens.size();
 
                                 const int n_block_size = n_left / 2;
-                                const int erased_blocks = (slot.n_prompt_tokens - slot.params.n_keep - n_block_size) / n_block_size;
+                                const int erased_blocks = (slot.n_prompt_tokens - slot.params.n_keep - system_tokens.size() - n_block_size) / n_block_size;
 
                                 std::vector<llama_token> new_tokens(
                                         prompt_tokens.begin(),
@@ -2079,7 +2079,7 @@ struct server_context {
 
                                 new_tokens.insert(
                                         new_tokens.end(),
-                                        prompt_tokens.begin() + slot.params.n_keep + erased_blocks * n_block_size,
+                                        prompt_tokens.begin() + slot.params.n_keep + system_tokens.size() + erased_blocks * n_block_size,
                                         prompt_tokens.end());
 
                                 prompt_tokens = std::move(new_tokens);