Trim double Total output lines (#4787)

codex-rs/core/src/client_common.rs

@@ -159,12 +159,16 @@ fn build_structured_output(parsed: &ExecOutputJson) -> String {
         parsed.metadata.duration_seconds
     ));
 
+    let mut output = parsed.output.clone();
     if let Some(total_lines) = extract_total_output_lines(&parsed.output) {
         sections.push(format!("Total output lines: {total_lines}"));
+        if let Some(stripped) = strip_total_output_header(&output) {
+            output = stripped.to_string();
+        }
     }
 
     sections.push("Output:".to_string());
-    sections.push(parsed.output.clone());
+    sections.push(output);
 
     sections.join("\n")
 }
@@ -177,6 +181,13 @@ fn extract_total_output_lines(output: &str) -> Option<u32> {
     total_segment.parse::<u32>().ok()
 }
 
+fn strip_total_output_header(output: &str) -> Option<&str> {
+    let after_prefix = output.strip_prefix("Total output lines: ")?;
+    let (_, remainder) = after_prefix.split_once('\n')?;
+    let remainder = remainder.strip_prefix('\n').unwrap_or(remainder);
+    Some(remainder)
+}
+
 #[derive(Debug)]
 pub enum ResponseEvent {
     Created,