diff --git a/codex-rs/core/src/client.rs b/codex-rs/core/src/client.rs
index 853f693a8f..dc31174bdf 100644
--- a/codex-rs/core/src/client.rs
+++ b/codex-rs/core/src/client.rs
@@ -578,13 +578,6 @@ impl ModelClientSession {
             .inline_compaction_threshold
             .map(ApiContextManagement::compaction)
             .map(|entry| vec![entry]);
-        if let Some(threshold) = prompt.inline_compaction_threshold {
-            trace!(
-                model = %model_info.slug,
-                compact_threshold = threshold,
-                "attaching inline server-side compaction to responses request"
-            );
-        }
         let request = ResponsesApiRequest {
             model: model_info.slug.clone(),
             instructions: instructions.clone(),
diff --git a/codex-rs/core/src/stream_events_utils.rs b/codex-rs/core/src/stream_events_utils.rs
index 8ae516ff9c..de766133c7 100644
--- a/codex-rs/core/src/stream_events_utils.rs
+++ b/codex-rs/core/src/stream_events_utils.rs
@@ -152,6 +152,9 @@ pub(crate) struct OutputItemResult {
 }
 
 pub(crate) struct PendingServerSideCompactionCheckpoint {
+    // Snapshot the raw history at the moment the compaction item streamed. We cannot build
+    // replacement history yet because later same-turn output may still arrive before
+    // `response.completed`.
     pub history_at_checkpoint: Vec<ResponseItem>,
     pub item: ResponseItem,
     pub turn_item: TurnItem,
@@ -191,6 +194,8 @@ pub(crate) async fn handle_output_item_done(
                 EventMsg::RawResponseItem(RawResponseItemEvent { item: item.clone() }),
             )
             .await;
+        // Replacement history is derived on `response.completed` from this snapshot plus whatever
+        // else the model streamed afterward.
         output.pending_server_side_compaction = Some(PendingServerSideCompactionCheckpoint {
             history_at_checkpoint: ctx.sess.clone_history().await.raw_items().to_vec(),
             item,