diff --git a/examples/server/server.cpp b/examples/server/server.cpp
index ee0ababb1d5ce..b1a6aed274d20 100644
--- a/examples/server/server.cpp
+++ b/examples/server/server.cpp
@@ -436,31 +436,34 @@ struct llama_server_context
         }
         params.n_keep = std::min(n_ctx - 4, params.n_keep);
 
-        // if input prompt is too big, truncate like normal
+        // if input prompt is too big, we will truncate in the same way when the embd becomes too big when generating tokens
         if (num_prompt_tokens >= (size_t)n_ctx)
         {
-            const int n_left = (n_ctx - params.n_keep) / 2;
+            const int n_left = n_ctx - params.n_keep;
+
+            // Keep n_keep tokens of start of prompt (at most n_ctx - 4)
             std::vector<llama_token> new_tokens(prompt_tokens.begin(), prompt_tokens.begin() + params.n_keep);
-            const int erased_blocks = (num_prompt_tokens - params.n_keep - n_left - 1) / n_left;
-            new_tokens.insert(new_tokens.end(), prompt_tokens.begin() + params.n_keep + erased_blocks * n_left, prompt_tokens.end());
-            std::copy(prompt_tokens.end() - n_ctx, prompt_tokens.end(), last_n_tokens.begin());
+
+            // Use half the left-over space in the context for the prompt
+            new_tokens.insert(new_tokens.end(), prompt_tokens.end() - n_left / 2, prompt_tokens.end());
 
             LOG_VERBOSE("input truncated", {
                                                {"n_ctx", n_ctx},
                                                {"n_keep", params.n_keep},
                                                {"n_left", n_left},
                                                {"new_tokens", tokens_to_str(ctx, new_tokens.cbegin(), new_tokens.cend())},
+                                               {"num_prompt_tokens", new_tokens.size()}
                                            });
 
             truncated = true;
             prompt_tokens = new_tokens;
+            num_prompt_tokens = prompt_tokens.size();
         }
-        else
-        {
-            const size_t ps = num_prompt_tokens;
-            std::fill(last_n_tokens.begin(), last_n_tokens.end() - ps, 0);
-            std::copy(prompt_tokens.begin(), prompt_tokens.end(), last_n_tokens.end() - ps);
-        }
+
+        // Initialize last_n_tokens
+        const size_t ps = num_prompt_tokens;
+        std::fill(last_n_tokens.begin(), last_n_tokens.end() - ps, 0);
+        std::copy(prompt_tokens.begin(), prompt_tokens.end(), last_n_tokens.end() - ps);
 
         // compare the evaluated prompt with the new prompt
         n_past = common_part(embd, prompt_tokens);