diff --git a/codex-rs/core/src/compact.rs b/codex-rs/core/src/compact.rs
index 59332d66d2..781c578cd6 100644
--- a/codex-rs/core/src/compact.rs
+++ b/codex-rs/core/src/compact.rs
@@ -519,36 +519,14 @@ pub(crate) fn build_compacted_history(
         user_messages,
         summary_text,
         COMPACT_USER_MESSAGE_MAX_TOKENS,
-        CompactedHistoryMessageIds::New,
     )
 }
 
-pub(crate) fn rebuild_legacy_compacted_history(
-    initial_context: Vec<ResponseItem>,
-    user_messages: &[String],
-    summary_text: &str,
-) -> Vec<ResponseItem> {
-    build_compacted_history_with_limit(
-        initial_context,
-        user_messages,
-        summary_text,
-        COMPACT_USER_MESSAGE_MAX_TOKENS,
-        CompactedHistoryMessageIds::Missing,
-    )
-}
-
-#[derive(Clone, Copy)]
-enum CompactedHistoryMessageIds {
-    New,
-    Missing,
-}
-
 fn build_compacted_history_with_limit(
     mut history: Vec<ResponseItem>,
     user_messages: &[String],
     summary_text: &str,
     max_tokens: usize,
-    message_ids: CompactedHistoryMessageIds,
 ) -> Vec<ResponseItem> {
     let mut selected_messages: Vec<String> = Vec::new();
     if max_tokens > 0 {
@@ -571,7 +549,7 @@ fn build_compacted_history_with_limit(
     }
 
     for message in &selected_messages {
-        history.push(compacted_user_message(message.clone(), message_ids));
+        history.push(compacted_user_message(message.clone()));
     }
 
     let summary_text = if summary_text.is_empty() {
@@ -580,22 +558,14 @@ fn build_compacted_history_with_limit(
         summary_text.to_string()
     };
 
-    history.push(compacted_user_message(summary_text, message_ids));
+    history.push(compacted_user_message(summary_text));
 
     history
 }
 
-fn compacted_user_message(text: String, message_ids: CompactedHistoryMessageIds) -> ResponseItem {
+fn compacted_user_message(text: String) -> ResponseItem {
     let content = vec![ContentItem::InputText { text }];
-    match message_ids {
-        CompactedHistoryMessageIds::New => ResponseItem::new_message("user", content),
-        CompactedHistoryMessageIds::Missing => ResponseItem::Message {
-            id: None,
-            role: "user".to_string(),
-            content,
-            phase: None,
-        },
-    }
+    ResponseItem::new_message("user", content)
 }
 
 async fn drain_to_completed(
diff --git a/codex-rs/core/src/compact_tests.rs b/codex-rs/core/src/compact_tests.rs
index bc3f32e181..7c698b1329 100644
--- a/codex-rs/core/src/compact_tests.rs
+++ b/codex-rs/core/src/compact_tests.rs
@@ -162,7 +162,6 @@ fn build_token_limited_compacted_history_truncates_overlong_user_messages() {
         std::slice::from_ref(&big),
         "SUMMARY",
         max_tokens,
-        super::CompactedHistoryMessageIds::New,
     );
     assert_eq!(history.len(), 2);
 
diff --git a/codex-rs/core/src/session/rollout_reconstruction.rs b/codex-rs/core/src/session/rollout_reconstruction.rs
index 4012d1be61..9e57d5a9d9 100644
--- a/codex-rs/core/src/session/rollout_reconstruction.rs
+++ b/codex-rs/core/src/session/rollout_reconstruction.rs
@@ -254,16 +254,17 @@ impl Session {
                         history.replace(replacement_history.clone());
                     } else {
                         saw_legacy_compaction_without_replacement_history = true;
-                        // Legacy rollouts without `replacement_history` should rebuild the
-                        // historical TurnContext at the correct insertion point from persisted
-                        // `TurnContextItem`s. These are rare enough that we currently just clear
-                        // `reference_context_item`, reinject canonical context at the end of the
-                        // resumed conversation, and accept the temporary out-of-distribution
-                        // prompt shape.
+                        // Legacy rollouts without `replacement_history` rebuild fresh compacted
+                        // replacement messages from the historical user-message text and summary.
+                        // They should also rebuild the historical TurnContext at the correct
+                        // insertion point from persisted `TurnContextItem`s. These are rare enough
+                        // that we currently just clear `reference_context_item`, reinject canonical
+                        // context at the end of the resumed conversation, and accept the temporary
+                        // out-of-distribution prompt shape.
                         // TODO(ccunningham): if we drop support for None replacement_history compaction items,
                         // we can get rid of this second loop entirely and just build `history` directly in the first loop.
                         let user_messages = collect_user_messages(history.raw_items());
-                        let rebuilt = compact::rebuild_legacy_compacted_history(
+                        let rebuilt = compact::build_compacted_history(
                             Vec::new(),
                             &user_messages,
                             &compacted.message,