diff --git a/internal/translator/codex/openai/chat-completions/codex_openai_request.go b/internal/translator/codex/openai/chat-completions/codex_openai_request.go
index 7d24d60e..6cc701e7 100644
--- a/internal/translator/codex/openai/chat-completions/codex_openai_request.go
+++ b/internal/translator/codex/openai/chat-completions/codex_openai_request.go
@@ -65,9 +65,6 @@ func ConvertOpenAIRequestToCodex(modelName string, inputRawJSON []byte, stream b
 
 	// Model
 	out, _ = sjson.SetBytes(out, "model", modelName)
-	if v := gjson.GetBytes(rawJSON, "prompt_cache_retention"); v.Exists() {
-		out, _ = sjson.SetBytes(out, "prompt_cache_retention", v.Value())
-	}
 
 	// Build tool name shortening map from original tools (if any)
 	originalToolNameMap := map[string]string{}
diff --git a/internal/translator/codex/openai/chat-completions/codex_openai_request_test.go b/internal/translator/codex/openai/chat-completions/codex_openai_request_test.go
index 1202980f..84c8dad2 100644
--- a/internal/translator/codex/openai/chat-completions/codex_openai_request_test.go
+++ b/internal/translator/codex/openai/chat-completions/codex_openai_request_test.go
@@ -633,19 +633,3 @@ func TestToolsDefinitionTranslated(t *testing.T) {
 		t.Errorf("tool 'search' not found in output tools: %s", gjson.Get(result, "tools").Raw)
 	}
 }
-
-func TestPromptCacheRetentionPreserved(t *testing.T) {
-	input := []byte(`{
-		"model": "gpt-4o",
-		"prompt_cache_retention": "persistent",
-		"messages": [
-			{"role": "user", "content": "Hello"}
-		]
-	}`)
-
-	out := ConvertOpenAIRequestToCodex("gpt-4o", input, true)
-
-	if got := gjson.GetBytes(out, "prompt_cache_retention").String(); got != "persistent" {
-		t.Fatalf("prompt_cache_retention = %q, want %q", got, "persistent")
-	}
-}