tests

codex-rs/core/src/codex.rs

@@ -9,6 +9,7 @@ use std::sync::atomic::AtomicU64;
 use std::time::Duration;
 
 use crate::AuthManager;
+use crate::conversation_history::EventMsgsHistory;
 use crate::event_mapping::map_response_item_to_event_messages;
 use async_channel::Receiver;
 use async_channel::Sender;
@@ -44,7 +45,7 @@ use crate::client_common::Prompt;
 use crate::client_common::ResponseEvent;
 use crate::config::Config;
 use crate::config_types::ShellEnvironmentPolicy;
-use crate::conversation_history::ConversationHistory;
+use crate::conversation_history::ResponseItemsHistory;
 use crate::environment_context::EnvironmentContext;
 use crate::error::CodexErr;
 use crate::error::Result as CodexResult;
@@ -263,7 +264,8 @@ struct State {
     current_task: Option<AgentTask>,
     pending_approvals: HashMap<String, oneshot::Sender<ReviewDecision>>,
     pending_input: Vec<ResponseInputItem>,
-    history: ConversationHistory,
+    response_items: ResponseItemsHistory,
+    event_msgs: EventMsgsHistory,
     token_info: Option<TokenUsageInfo>,
 }
 
@@ -417,7 +419,7 @@ impl Session {
         let rollout_path = rollout_recorder.rollout_path.clone();
         // Create the mutable state for the Session.
         let state = State {
-            history: ConversationHistory::new(),
+            response_items: ResponseItemsHistory::new(),
             ..Default::default()
         };
 
@@ -541,7 +543,7 @@ impl Session {
             InitialHistory::New => {
                 // Build and record initial items (user instructions + environment context)
                 let items = self.build_initial_context(turn_context);
-                self.record_conversation_items(&items).await;
+                self.record_response_items(&items).await;
             }
             InitialHistory::Resumed(_) | InitialHistory::Forked(_) => {
                 let rollout_items = conversation_history.get_rollout_items();
@@ -550,7 +552,13 @@ impl Session {
                 // Always add response items to conversation history
                 let response_items = conversation_history.get_response_items();
                 if !response_items.is_empty() {
-                    self.record_into_history(&response_items);
+                    self.record_into_history_response_items(&response_items);
+                }
+
+                // Always add event msgs to conversation history
+                let event_msgs = conversation_history.get_event_msgs();
+                if let Some(event_msgs) = event_msgs {
+                    self.record_into_history_event_msgs(&event_msgs);
                 }
 
                 // If persisting, persist all rollout items as-is (recorder filters)
@@ -563,9 +571,9 @@ impl Session {
 
     /// Persist the event to rollout and send it to clients.
     pub(crate) async fn send_event(&self, event: Event) {
-        // Persist the event into rollout (recorder filters as needed)
-        let rollout_items = vec![RolloutItem::EventMsg(event.msg.clone())];
-        self.persist_rollout_items(&rollout_items).await;
+        // Persist the event into event_msgs in memory
+        self.record_conversation_event_msgs(std::slice::from_ref(&event.msg))
+            .await;
         if let Err(e) = self.tx_event.send(event).await {
             error!("failed to send tool call event: {e}");
         }
@@ -655,18 +663,31 @@ impl Session {
         state.approved_commands.insert(cmd);
     }
 
+    async fn record_conversation_event_msgs(&self, items: &[EventMsg]) {
+        self.record_into_history_event_msgs(items);
+        self.persist_rollout_event_msgs(items).await;
+    }
+
     /// Records input items: always append to conversation history and
     /// persist these response items to rollout.
-    async fn record_conversation_items(&self, items: &[ResponseItem]) {
-        self.record_into_history(items);
+    async fn record_response_items(&self, items: &[ResponseItem]) {
+        self.record_into_history_response_items(items);
         self.persist_rollout_response_items(items).await;
     }
 
     /// Append ResponseItems to the in-memory conversation history only.
-    fn record_into_history(&self, items: &[ResponseItem]) {
+    fn record_into_history_response_items(&self, items: &[ResponseItem]) {
         self.state
             .lock_unchecked()
-            .history
+            .response_items
+            .record_items(items.iter());
+    }
+
+    /// Append EventMsgs to the in-memory conversation history only.
+    fn record_into_history_event_msgs(&self, items: &[EventMsg]) {
+        self.state
+            .lock_unchecked()
+            .event_msgs
             .record_items(items.iter());
     }
 
@@ -679,6 +700,12 @@ impl Session {
         self.persist_rollout_items(&rollout_items).await;
     }
 
+    async fn persist_rollout_event_msgs(&self, items: &[EventMsg]) {
+        let rollout_items: Vec<RolloutItem> =
+            items.iter().cloned().map(RolloutItem::EventMsg).collect();
+        self.persist_rollout_items(&rollout_items).await;
+    }
+
     fn build_initial_context(&self, turn_context: &TurnContext) -> Vec<ResponseItem> {
         let mut items = Vec::<ResponseItem>::with_capacity(2);
         if let Some(user_instructions) = turn_context.user_instructions.as_deref() {
@@ -710,13 +737,14 @@ impl Session {
     async fn record_input_and_rollout_usermsg(&self, response_input: &ResponseInputItem) {
         let response_item: ResponseItem = response_input.clone().into();
         // Add to conversation history and persist response item to rollout
-        self.record_conversation_items(std::slice::from_ref(&response_item))
+        self.record_response_items(std::slice::from_ref(&response_item))
             .await;
 
         // Derive user message events and persist only UserMessage to rollout
         let msgs =
             map_response_item_to_event_messages(&response_item, self.show_raw_agent_reasoning);
         let user_msgs: Vec<RolloutItem> = msgs
+            .clone()
             .into_iter()
             .filter_map(|m| match m {
                 EventMsg::UserMessage(ev) => Some(RolloutItem::EventMsg(EventMsg::UserMessage(ev))),
@@ -726,6 +754,7 @@ impl Session {
         if !user_msgs.is_empty() {
             self.persist_rollout_items(&user_msgs).await;
         }
+        self.state.lock_unchecked().event_msgs.record_items(&msgs);
     }
 
     async fn on_exec_command_begin(
@@ -908,7 +937,7 @@ impl Session {
     /// Build the full turn input by concatenating the current conversation
     /// history with additional items for this turn.
     pub fn turn_input_with_history(&self, extra: Vec<ResponseItem>) -> Vec<ResponseItem> {
-        [self.state.lock_unchecked().history.contents(), extra].concat()
+        [self.state.lock_unchecked().response_items.contents(), extra].concat()
     }
 
     /// Returns the input if there was no task running to inject into
@@ -1163,7 +1192,7 @@ async fn submission_loop(
                 // Install the new persistent context for subsequent tasks/turns.
                 turn_context = Arc::new(new_turn_context);
                 if cwd.is_some() || approval_policy.is_some() || sandbox_policy.is_some() {
-                    sess.record_conversation_items(&[ResponseItem::from(EnvironmentContext::new(
+                    sess.record_response_items(&[ResponseItem::from(EnvironmentContext::new(
                         cwd,
                         approval_policy,
                         sandbox_policy,
@@ -1380,12 +1409,17 @@ async fn submission_loop(
             }
             Op::GetHistory => {
                 let sub_id = sub.id.clone();
-
+                let entries = {
+                    let state = sess.state.lock_unchecked();
+                    let rolled_response_items: Vec<RolloutItem> = (&state.response_items).into();
+                    let rolled_event_msgs: Vec<RolloutItem> = (&state.event_msgs).into();
+                    [rolled_response_items, rolled_event_msgs].concat()
+                };
                 let event = Event {
                     id: sub_id.clone(),
                     msg: EventMsg::ConversationHistory(ConversationHistoryResponseEvent {
                         conversation_id: sess.conversation_id,
-                        entries: sess.state.lock_unchecked().history.contents(),
+                        history: InitialHistory::Forked(entries),
                     }),
                 };
                 sess.send_event(event).await;
@@ -1446,7 +1480,7 @@ async fn run_task(
             .into_iter()
             .map(ResponseItem::from)
             .collect::<Vec<ResponseItem>>();
-        sess.record_conversation_items(&pending_input).await;
+        sess.record_response_items(&pending_input).await;
 
         // Construct the input that we will send to the model. When using the
         // Chat completions API (or ZDR clients), the model needs the full
@@ -1573,7 +1607,7 @@ async fn run_task(
 
                 // Only attempt to take the lock if there is something to record.
                 if !items_to_record_in_conversation_history.is_empty() {
-                    sess.record_conversation_items(&items_to_record_in_conversation_history)
+                    sess.record_response_items(&items_to_record_in_conversation_history)
                         .await;
                 }
 
@@ -1928,7 +1962,7 @@ async fn run_compact_task(
 
     {
         let mut state = sess.state.lock_unchecked();
-        state.history.keep_last_messages(1);
+        state.response_items.keep_last_messages(1);
     }
 
     let event = Event {
@@ -2882,7 +2916,9 @@ async fn drain_to_completed(
             Ok(ResponseEvent::OutputItemDone(item)) => {
                 // Record only to in-memory conversation history; avoid state snapshot.
                 let mut state = sess.state.lock_unchecked();
-                state.history.record_items(std::slice::from_ref(&item));
+                state
+                    .response_items
+                    .record_items(std::slice::from_ref(&item));
             }
             Ok(ResponseEvent::Completed {
                 response_id: _,

codex-rs/core/src/conversation_history.rs

@@ -1,13 +1,16 @@
+use crate::rollout::policy::should_persist_event_msg;
 use codex_protocol::models::ResponseItem;
+use codex_protocol::protocol::EventMsg;
+use codex_protocol::protocol::RolloutItem;
 
 /// Transcript of conversation history
 #[derive(Debug, Clone, Default)]
-pub(crate) struct ConversationHistory {
+pub(crate) struct ResponseItemsHistory {
     /// The oldest items are at the beginning of the vector.
     items: Vec<ResponseItem>,
 }
 
-impl ConversationHistory {
+impl ResponseItemsHistory {
     pub(crate) fn new() -> Self {
         Self { items: Vec::new() }
     }
@@ -61,6 +64,51 @@ impl ConversationHistory {
     }
 }
 
+#[derive(Debug, Clone, Default)]
+pub(crate) struct EventMsgsHistory {
+    items: Vec<EventMsg>,
+}
+
+impl EventMsgsHistory {
+    pub(crate) fn record_items<I>(&mut self, items: I)
+    where
+        I: IntoIterator,
+        I::Item: std::ops::Deref<Target = EventMsg>,
+    {
+        for item in items {
+            if self.should_record_item(&item) {
+                self.items.push(item.clone());
+            }
+        }
+    }
+
+    fn should_record_item(&self, item: &EventMsg) -> bool {
+        should_persist_event_msg(item)
+    }
+}
+
+impl From<&ResponseItemsHistory> for Vec<RolloutItem> {
+    fn from(history: &ResponseItemsHistory) -> Self {
+        history
+            .items
+            .iter()
+            .cloned()
+            .map(RolloutItem::ResponseItem)
+            .collect()
+    }
+}
+
+impl From<&EventMsgsHistory> for Vec<RolloutItem> {
+    fn from(history: &EventMsgsHistory) -> Self {
+        history
+            .items
+            .iter()
+            .cloned()
+            .map(RolloutItem::EventMsg)
+            .collect()
+    }
+}
+
 /// Anything that is not a system message or "reasoning" message is considered
 /// an API message.
 fn is_api_message(message: &ResponseItem) -> bool {
@@ -103,7 +151,7 @@ mod tests {
 
     #[test]
     fn filters_non_api_messages() {
-        let mut h = ConversationHistory::default();
+        let mut h = ResponseItemsHistory::default();
         // System message is not an API message; Other is ignored.
         let system = ResponseItem::Message {
             id: None,

codex-rs/core/src/conversation_manager.rs

@@ -150,7 +150,7 @@ impl ConversationManager {
     /// caller's `config`). The new conversation will have a fresh id.
     pub async fn fork_conversation(
         &self,
-        conversation_history: Vec<ResponseItem>,
+        conversation_history: InitialHistory,
         num_messages_to_drop: usize,
         config: Config,
     ) -> CodexResult<NewConversation> {
@@ -171,43 +171,117 @@ impl ConversationManager {
 
 /// Return a prefix of `items` obtained by dropping the last `n` user messages
 /// and all items that follow them.
-fn truncate_after_dropping_last_messages(items: Vec<ResponseItem>, n: usize) -> InitialHistory {
+fn truncate_after_dropping_last_messages(history: InitialHistory, n: usize) -> InitialHistory {
     if n == 0 {
-        let rolled: Vec<RolloutItem> = items.into_iter().map(RolloutItem::ResponseItem).collect();
-        return InitialHistory::Forked(rolled);
+        return history;
     }
 
-    // Walk backwards counting only `user` Message items, find cut index.
-    let mut count = 0usize;
-    let mut cut_index = 0usize;
-    for (idx, item) in items.iter().enumerate().rev() {
+    // Compute event prefix by dropping the last `n` user events (counted from the end).
+    let event_msgs_prefix: Vec<EventMsg> =
+        build_event_prefix_excluding_last_n_user_turns(&history, n);
+
+    // Keep only response items strictly before the cut (drop last `n` user messages).
+    let response_prefix: Vec<ResponseItem> =
+        build_response_prefix_excluding_last_n_user_turns(&history, n);
+
+    let rolled = build_truncated_rollout(&event_msgs_prefix, &response_prefix);
+    if rolled.is_empty() {
+        InitialHistory::New
+    } else {
+        InitialHistory::Forked(rolled)
+    }
+}
+
+/// Build the event messages prefix from `history` by dropping the last `n` user
+/// turns (counted from the end) and taking everything before that cut.
+fn build_event_prefix_excluding_last_n_user_turns(
+    history: &InitialHistory,
+    n: usize,
+) -> Vec<EventMsg> {
+    match history.get_event_msgs() {
+        Some(all_events) => {
+            take_prefix_before_index(&all_events, find_cut_event_index(&all_events, n))
+        }
+        None => Vec::new(),
+    }
+}
+
+/// Build the response items prefix from `history` by dropping the last `n` user
+/// turns (counted from the end) and taking everything before that cut.
+fn build_response_prefix_excluding_last_n_user_turns(
+    history: &InitialHistory,
+    n: usize,
+) -> Vec<ResponseItem> {
+    let all_items: Vec<ResponseItem> = history.get_response_items();
+    take_prefix_before_index(&all_items, find_cut_response_index(&all_items, n))
+}
+
+/// Return a cloned prefix of `items` up to (but not including) `idx`.
+/// If `idx` is `None`, returns an empty vector.
+fn take_prefix_before_index<T: Clone>(items: &[T], idx: Option<usize>) -> Vec<T> {
+    match idx {
+        Some(i) => items[..i].to_vec(),
+        None => Vec::new(),
+    }
+}
+
+/// Find the index (into response items) of the Nth user message from the end.
+fn find_cut_response_index(response_items: &[ResponseItem], n: usize) -> Option<usize> {
+    if n == 0 {
+        return None;
+    }
+    let mut remaining = n;
+    for (idx, item) in response_items.iter().enumerate().rev() {
         if let ResponseItem::Message { role, .. } = item
             && role == "user"
         {
-            count += 1;
-            if count == n {
-                // Cut everything from this user message to the end.
-                cut_index = idx;
-                break;
+            remaining -= 1;
+            if remaining == 0 {
+                return Some(idx);
             }
         }
     }
-    if cut_index == 0 {
-        // No prefix remains after dropping; start a new conversation.
-        InitialHistory::New
-    } else {
-        let rolled: Vec<RolloutItem> = items
-            .into_iter()
-            .take(cut_index)
-            .map(RolloutItem::ResponseItem)
-            .collect();
-        InitialHistory::Forked(rolled)
+    None
+}
+
+/// Find the index (into event messages) of the Nth user event from the end.
+fn find_cut_event_index(event_msgs: &[EventMsg], n: usize) -> Option<usize> {
+    if n == 0 {
+        return None;
     }
+    let mut remaining = n;
+    for (idx, ev) in event_msgs.iter().enumerate().rev() {
+        if matches!(ev, EventMsg::UserMessage(_)) {
+            remaining -= 1;
+            if remaining == 0 {
+                return Some(idx);
+            }
+        }
+    }
+    None
+}
+
+/// Build a truncated rollout by concatenating the (already-sliced) event messages and response items.
+fn build_truncated_rollout(
+    event_msgs: &[EventMsg],
+    response_items: &[ResponseItem],
+) -> Vec<RolloutItem> {
+    let mut rolled: Vec<RolloutItem> = Vec::with_capacity(event_msgs.len() + response_items.len());
+    rolled.extend(event_msgs.iter().cloned().map(RolloutItem::EventMsg));
+    rolled.extend(
+        response_items
+            .iter()
+            .cloned()
+            .map(RolloutItem::ResponseItem),
+    );
+    rolled
 }
 
 #[cfg(test)]
 mod tests {
     use super::*;
+    use crate::event_mapping::map_response_item_to_event_messages;
+    use crate::protocol::EventMsg;
     use codex_protocol::models::ContentItem;
     use codex_protocol::models::ReasoningItemReasoningSummary;
     use codex_protocol::models::ResponseItem;
@@ -221,6 +295,15 @@ mod tests {
             }],
         }
     }
+    fn user_input(text: &str) -> ResponseItem {
+        ResponseItem::Message {
+            id: None,
+            role: "user".to_string(),
+            content: vec![ContentItem::InputText {
+                text: text.to_string(),
+            }],
+        }
+    }
     fn assistant_msg(text: &str) -> ResponseItem {
         ResponseItem::Message {
             id: None,
@@ -256,7 +339,13 @@ mod tests {
             assistant_msg("a4"),
         ];
 
-        let truncated = truncate_after_dropping_last_messages(items.clone(), 1);
+        // Wrap as InitialHistory::Forked with response items only.
+        let initial: Vec<RolloutItem> = items
+            .iter()
+            .cloned()
+            .map(RolloutItem::ResponseItem)
+            .collect();
+        let truncated = truncate_after_dropping_last_messages(InitialHistory::Forked(initial), 1);
         let got_items = truncated.get_rollout_items();
         let expected_items = vec![
             RolloutItem::ResponseItem(items[0].clone()),
@@ -268,7 +357,62 @@ mod tests {
             serde_json::to_value(&expected_items).unwrap()
         );
 
-        let truncated2 = truncate_after_dropping_last_messages(items, 2);
+        let initial2: Vec<RolloutItem> = items
+            .iter()
+            .cloned()
+            .map(RolloutItem::ResponseItem)
+            .collect();
+        let truncated2 = truncate_after_dropping_last_messages(InitialHistory::Forked(initial2), 2);
         assert!(matches!(truncated2, InitialHistory::New));
     }
+
+    #[test]
+    fn event_prefix_counts_from_end_with_duplicate_user_prompts() {
+        // Two identical user prompts with assistant replies between them.
+        let responses = vec![
+            user_input("same"),
+            assistant_msg("a1"),
+            user_input("same"),
+            assistant_msg("a2"),
+        ];
+
+        // Derive event messages in order from responses (user → UserMessage, assistant → AgentMessage).
+        let mut events: Vec<EventMsg> = Vec::new();
+        for r in &responses {
+            events.extend(map_response_item_to_event_messages(r, false));
+        }
+
+        // Build initial history containing both events and responses.
+        let mut initial: Vec<RolloutItem> = Vec::new();
+        initial.extend(events.iter().cloned().map(RolloutItem::EventMsg));
+        initial.extend(responses.iter().cloned().map(RolloutItem::ResponseItem));
+
+        // Drop the last user turn.
+        let truncated = truncate_after_dropping_last_messages(InitialHistory::Forked(initial), 1);
+
+        // Expect the event prefix to include the first user + first assistant only,
+        // and the response prefix to include the first user + first assistant only.
+        let got_items = truncated.get_rollout_items();
+
+        // Compute expected events and responses after cut.
+        let expected_event_prefix: Vec<RolloutItem> = events[..2]
+            .iter()
+            .cloned()
+            .map(RolloutItem::EventMsg)
+            .collect();
+        let expected_response_prefix: Vec<RolloutItem> = responses[..2]
+            .iter()
+            .cloned()
+            .map(RolloutItem::ResponseItem)
+            .collect();
+
+        let mut expected: Vec<RolloutItem> = Vec::new();
+        expected.extend(expected_event_prefix);
+        expected.extend(expected_response_prefix);
+
+        assert_eq!(
+            serde_json::to_value(&got_items).unwrap(),
+            serde_json::to_value(&expected).unwrap()
+        );
+    }
 }

codex-rs/core/tests/suite/fork_conversation.rs

@@ -77,12 +77,13 @@ async fn fork_conversation_twice_drops_to_first_message() {
         wait_for_event(&codex, |ev| matches!(ev, EventMsg::ConversationHistory(_))).await;
 
     // Capture entries from the base history and compute expected prefixes after each fork.
-    let entries_after_three = match &base_history {
-        EventMsg::ConversationHistory(ConversationHistoryResponseEvent { entries, .. }) => {
-            entries.clone()
+    let history_after_three = match &base_history {
+        EventMsg::ConversationHistory(ConversationHistoryResponseEvent { history, .. }) => {
+            history.clone()
         }
         _ => panic!("expected ConversationHistory event"),
     };
+    let entries_after_three = history_after_three.get_rollout_items();
     // History layout for this test:
     // [0] user instructions,
     // [1] environment context,
@@ -113,7 +114,7 @@ async fn fork_conversation_twice_drops_to_first_message() {
         conversation: codex_fork1,
         ..
     } = conversation_manager
-        .fork_conversation(entries_after_three.clone(), 1, config_for_fork.clone())
+        .fork_conversation(history_after_three.clone(), 1, config_for_fork.clone())
         .await
         .expect("fork 1");
 
@@ -122,13 +123,14 @@ async fn fork_conversation_twice_drops_to_first_message() {
         matches!(ev, EventMsg::ConversationHistory(_))
     })
     .await;
-    let entries_after_first_fork = match &fork1_history {
-        EventMsg::ConversationHistory(ConversationHistoryResponseEvent { entries, .. }) => {
-            assert!(matches!(
-                fork1_history,
-                EventMsg::ConversationHistory(ConversationHistoryResponseEvent { ref entries, .. }) if *entries == expected_after_first
-            ));
-            entries.clone()
+    let history_after_first_fork = match &fork1_history {
+        EventMsg::ConversationHistory(ConversationHistoryResponseEvent { history, .. }) => {
+            let got = history.get_rollout_items();
+            assert_eq!(
+                serde_json::to_value(&got).unwrap(),
+                serde_json::to_value(&expected_after_first).unwrap()
+            );
+            history.clone()
         }
         _ => panic!("expected ConversationHistory event after first fork"),
     };
@@ -138,7 +140,7 @@ async fn fork_conversation_twice_drops_to_first_message() {
         conversation: codex_fork2,
         ..
     } = conversation_manager
-        .fork_conversation(entries_after_first_fork.clone(), 1, config_for_fork.clone())
+        .fork_conversation(history_after_first_fork.clone(), 1, config_for_fork.clone())
         .await
         .expect("fork 2");
 
@@ -147,8 +149,14 @@ async fn fork_conversation_twice_drops_to_first_message() {
         matches!(ev, EventMsg::ConversationHistory(_))
     })
     .await;
-    assert!(matches!(
-        fork2_history,
-        EventMsg::ConversationHistory(ConversationHistoryResponseEvent { ref entries, .. }) if *entries == expected_after_second
-    ));
+    match &fork2_history {
+        EventMsg::ConversationHistory(ConversationHistoryResponseEvent { history, .. }) => {
+            let got = history.get_rollout_items();
+            assert_eq!(
+                serde_json::to_value(&got).unwrap(),
+                serde_json::to_value(&expected_after_second).unwrap()
+            );
+        }
+        _ => panic!("expected ConversationHistory event after second fork"),
+    }
 }

codex-rs/protocol/src/protocol.rs

@@ -803,7 +803,7 @@ pub struct WebSearchEndEvent {
 #[derive(Debug, Clone, Deserialize, Serialize, TS)]
 pub struct ConversationHistoryResponseEvent {
     pub conversation_id: ConversationId,
-    pub entries: Vec<ResponseItem>,
+    pub history: InitialHistory,
 }
 
 #[derive(Debug, Clone, Deserialize, Serialize, TS)]

codex-rs/tui/src/app_backtrack.rs

@@ -3,6 +3,7 @@ use crate::backtrack_helpers;
 use crate::pager_overlay::Overlay;
 use crate::tui;
 use crate::tui::TuiEvent;
+use codex_core::InitialHistory;
 use codex_core::protocol::ConversationHistoryResponseEvent;
 use codex_protocol::mcp_protocol::ConversationId;
 use color_eyre::eyre::Result;
@@ -288,7 +289,7 @@ impl App {
         let cfg = self.chat_widget.config_ref().clone();
         // Perform the fork via a thin wrapper for clarity/testability.
         let result = self
-            .perform_fork(ev.entries.clone(), drop_count, cfg.clone())
+            .perform_fork(ev.history.clone(), drop_count, cfg.clone())
             .await;
         match result {
             Ok(new_conv) => {
@@ -301,7 +302,7 @@ impl App {
     /// Thin wrapper around ConversationManager::fork_conversation.
     async fn perform_fork(
         &self,
-        entries: Vec<codex_protocol::models::ResponseItem>,
+        entries: InitialHistory,
         drop_count: usize,
         cfg: codex_core::config::Config,
     ) -> codex_core::error::Result<codex_core::NewConversation> {