diff --git a/common/arg.cpp b/common/arg.cpp
index f2c2255c4..2487356fc 100644
--- a/common/arg.cpp
+++ b/common/arg.cpp
@@ -1534,7 +1534,7 @@ common_params_context common_params_parser_init(common_params & params, llama_ex
     ).set_examples({LLAMA_EXAMPLE_MAIN, LLAMA_EXAMPLE_SERVER, LLAMA_EXAMPLE_IMATRIX, LLAMA_EXAMPLE_PERPLEXITY}).set_env("LLAMA_ARG_NO_CONTEXT_SHIFT"));
     add_opt(common_arg(
         {"--context-shift"},
-        string_format("enables context shift on infinite text generation (default: %s)", params.ctx_shift ? "disabled" : "enabled"),
+        string_format("enables context shift on infinite text generation (default: %s)", params.ctx_shift ? "enabled" : "disabled"),
         [](common_params & params) {
             params.ctx_shift = true;
         }
diff --git a/common/chat.cpp b/common/chat.cpp
index cb2f40523..a7e4bb4c7 100644
--- a/common/chat.cpp
+++ b/common/chat.cpp
@@ -147,6 +147,7 @@ struct templates_params {
     json extra_context;
     bool add_bos;
     bool add_eos;
+    bool is_inference = true;
 };
 
 common_chat_tool_choice common_chat_tool_choice_parse_oaicompat(const std::string & tool_choice) {
@@ -1336,6 +1337,17 @@ static common_chat_params common_chat_params_init_gpt_oss(const common_chat_temp
     common_chat_params data;
     auto prompt = apply(tmpl, inputs);
 
+    // Check if we need to replace the return token with end token during
+    // inference and without generation prompt. For more details see:
+    // https://github.com/ggml-org/llama.cpp/issues/15417
+    if (inputs.is_inference && !inputs.add_generation_prompt) {
+        static constexpr std::string_view return_token = "<|return|>";
+        static constexpr std::string_view end_token    = "<|end|>";
+        if (size_t pos = prompt.rfind(return_token); pos != std::string::npos) {
+            prompt.replace(pos, return_token.length(), end_token);
+        }
+    }
+
     data.prompt = prompt;
     data.format = COMMON_CHAT_FORMAT_GPT_OSS;
 
diff --git a/common/common.h b/common/common.h
index 5b0502ac2..4d8111b1b 100644
--- a/common/common.h
+++ b/common/common.h
@@ -371,7 +371,7 @@ struct common_params {
     bool cont_batching     = true;  // insert new sequences for decoding on-the-fly
     bool flash_attn        = false; // flash attention
     bool no_perf           = false; // disable performance metrics
-    bool ctx_shift         = false;  // context shift on inifinite text generation
+    bool ctx_shift         = false;  // context shift on infinite text generation
     bool swa_full          = false; // use full-size SWA cache (https://github.com/ggml-org/llama.cpp/pull/13194#issuecomment-2868343055)
     bool kv_unified        = false; // enable unified KV cache