fix: remove unsupported parameters from Codex model requests

backend/internal/service/openai_codex_transform.go

@@ -112,13 +112,19 @@ func applyCodexOAuthTransform(reqBody map[string]any, isCodexCLI bool) codexTran
 		result.Modified = true
 	}
 
-	if _, ok := reqBody["max_output_tokens"]; ok {
-		delete(reqBody, "max_output_tokens")
-		result.Modified = true
-	}
-	if _, ok := reqBody["max_completion_tokens"]; ok {
-		delete(reqBody, "max_completion_tokens")
-		result.Modified = true
+	// Strip parameters unsupported by codex models via the Responses API.
+	for _, key := range []string{
+		"max_output_tokens",
+		"max_completion_tokens",
+		"temperature",
+		"top_p",
+		"frequency_penalty",
+		"presence_penalty",
+	} {
+		if _, ok := reqBody[key]; ok {
+			delete(reqBody, key)
+			result.Modified = true
+		}
 	}
 
 	if normalizeCodexTools(reqBody) {