diff --git a/codex-rs/core/src/codex.rs b/codex-rs/core/src/codex.rs
index c17849d0f8..3a8faac441 100644
--- a/codex-rs/core/src/codex.rs
+++ b/codex-rs/core/src/codex.rs
@@ -3649,8 +3649,11 @@ impl Session {
         &self,
         turn_context: &TurnContext,
     ) {
-        self.record_context_updates_with_additional_developer_sections(turn_context, Vec::new())
-            .await;
+        self.record_context_updates_with_additional_developer_sections(
+            turn_context,
+            /*additional_developer_sections*/ Vec::new(),
+        )
+        .await;
     }
 
     // Some turn-local guidance, such as explicit plugin mention hints, belongs in the canonical
diff --git a/codex-rs/core/src/codex_tests.rs b/codex-rs/core/src/codex_tests.rs
index 0c7e1d5610..c7d29ea9f7 100644
--- a/codex-rs/core/src/codex_tests.rs
+++ b/codex-rs/core/src/codex_tests.rs
@@ -961,7 +961,10 @@ async fn resumed_history_injects_initial_context_on_first_context_update_only()
         .await;
     expected.extend(
         session
-            .build_initial_context(&turn_context, Vec::new())
+            .build_initial_context(
+                &turn_context,
+                /*additional_developer_sections*/ Vec::new(),
+            )
             .await,
     );
     let history_after_seed = session.clone_history().await;
@@ -1342,7 +1345,12 @@ async fn thread_rollback_drops_last_turn_from_history() {
     let (sess, tc, rx) = make_session_and_context_with_rx().await;
     let rollout_path = attach_rollout_recorder(&sess).await;
 
-    let initial_context = sess.build_initial_context(tc.as_ref(), Vec::new()).await;
+    let initial_context = sess
+        .build_initial_context(
+            tc.as_ref(),
+            /*additional_developer_sections*/ Vec::new(),
+        )
+        .await;
     let turn_1 = vec![
         user_message("turn 1 user"),
         assistant_message("turn 1 assistant"),
@@ -1406,7 +1414,12 @@ async fn thread_rollback_clears_history_when_num_turns_exceeds_existing_turns()
     let (sess, tc, rx) = make_session_and_context_with_rx().await;
     attach_rollout_recorder(&sess).await;
 
-    let initial_context = sess.build_initial_context(tc.as_ref(), Vec::new()).await;
+    let initial_context = sess
+        .build_initial_context(
+            tc.as_ref(),
+            /*additional_developer_sections*/ Vec::new(),
+        )
+        .await;
     let turn_1 = vec![user_message("turn 1 user")];
     let mut full_history = Vec::new();
     full_history.extend(initial_context.clone());
@@ -1432,7 +1445,12 @@ async fn thread_rollback_clears_history_when_num_turns_exceeds_existing_turns()
 async fn thread_rollback_fails_without_persisted_rollout_path() {
     let (sess, tc, rx) = make_session_and_context_with_rx().await;
 
-    let initial_context = sess.build_initial_context(tc.as_ref(), Vec::new()).await;
+    let initial_context = sess
+        .build_initial_context(
+            tc.as_ref(),
+            /*additional_developer_sections*/ Vec::new(),
+        )
+        .await;
     sess.record_into_history(&initial_context, tc.as_ref())
         .await;
 
@@ -1749,7 +1767,12 @@ async fn thread_rollback_persists_marker_and_replays_cumulatively() {
 async fn thread_rollback_fails_when_turn_in_progress() {
     let (sess, tc, rx) = make_session_and_context_with_rx().await;
 
-    let initial_context = sess.build_initial_context(tc.as_ref(), Vec::new()).await;
+    let initial_context = sess
+        .build_initial_context(
+            tc.as_ref(),
+            /*additional_developer_sections*/ Vec::new(),
+        )
+        .await;
     sess.record_into_history(&initial_context, tc.as_ref())
         .await;
 
@@ -1770,7 +1793,12 @@ async fn thread_rollback_fails_when_turn_in_progress() {
 async fn thread_rollback_fails_when_num_turns_is_zero() {
     let (sess, tc, rx) = make_session_and_context_with_rx().await;
 
-    let initial_context = sess.build_initial_context(tc.as_ref(), Vec::new()).await;
+    let initial_context = sess
+        .build_initial_context(
+            tc.as_ref(),
+            /*additional_developer_sections*/ Vec::new(),
+        )
+        .await;
     sess.record_into_history(&initial_context, tc.as_ref())
         .await;
 
@@ -3703,7 +3731,11 @@ async fn build_settings_update_items_emits_environment_item_for_network_changes(
 
     let reference_context_item = previous_context.to_turn_context_item();
     let update_items = session
-        .build_settings_update_items(Some(&reference_context_item), &current_context, Vec::new())
+        .build_settings_update_items(
+            Some(&reference_context_item),
+            &current_context,
+            /*additional_developer_sections*/ Vec::new(),
+        )
         .await;
 
     let environment_update = update_items
@@ -3738,7 +3770,11 @@ async fn build_settings_update_items_emits_environment_item_for_time_changes() {
 
     let reference_context_item = previous_context.to_turn_context_item();
     let update_items = session
-        .build_settings_update_items(Some(&reference_context_item), &current_context, Vec::new())
+        .build_settings_update_items(
+            Some(&reference_context_item),
+            &current_context,
+            /*additional_developer_sections*/ Vec::new(),
+        )
         .await;
 
     let environment_update = update_items
@@ -3773,7 +3809,7 @@ async fn build_settings_update_items_emits_realtime_start_when_session_becomes_l
         .build_settings_update_items(
             Some(&previous_context.to_turn_context_item()),
             &current_context,
-            Vec::new(),
+            /*additional_developer_sections*/ Vec::new(),
         )
         .await;
 
@@ -3802,7 +3838,7 @@ async fn build_settings_update_items_emits_realtime_end_when_session_stops_being
         .build_settings_update_items(
             Some(&previous_context.to_turn_context_item()),
             &current_context,
-            Vec::new(),
+            /*additional_developer_sections*/ Vec::new(),
         )
         .await;
 
@@ -3836,7 +3872,11 @@ async fn build_settings_update_items_uses_previous_turn_settings_for_realtime_en
         .set_previous_turn_settings(Some(previous_turn_settings))
         .await;
     let update_items = session
-        .build_settings_update_items(Some(&previous_context_item), &current_context, Vec::new())
+        .build_settings_update_items(
+            Some(&previous_context_item),
+            &current_context,
+            /*additional_developer_sections*/ Vec::new(),
+        )
         .await;
 
     let developer_texts = developer_input_texts(&update_items);
@@ -3854,7 +3894,10 @@ async fn build_initial_context_uses_previous_realtime_state() {
     turn_context.realtime_active = true;
 
     let initial_context = session
-        .build_initial_context(&turn_context, Vec::new())
+        .build_initial_context(
+            &turn_context,
+            /*additional_developer_sections*/ Vec::new(),
+        )
         .await;
     let developer_texts = developer_input_texts(&initial_context);
     assert!(
@@ -3870,7 +3913,10 @@ async fn build_initial_context_uses_previous_realtime_state() {
         state.set_reference_context_item(Some(previous_context_item));
     }
     let resumed_context = session
-        .build_initial_context(&turn_context, Vec::new())
+        .build_initial_context(
+            &turn_context,
+            /*additional_developer_sections*/ Vec::new(),
+        )
         .await;
     let resumed_developer_texts = developer_input_texts(&resumed_context);
     assert!(
@@ -3897,7 +3943,10 @@ async fn build_initial_context_omits_default_image_save_location_with_image_hist
         .await;
 
     let initial_context = session
-        .build_initial_context(&turn_context, Vec::new())
+        .build_initial_context(
+            &turn_context,
+            /*additional_developer_sections*/ Vec::new(),
+        )
         .await;
     let developer_texts = developer_input_texts(&initial_context);
     assert!(
@@ -3913,7 +3962,10 @@ async fn build_initial_context_omits_default_image_save_location_without_image_h
     let (session, turn_context) = make_session_and_context().await;
 
     let initial_context = session
-        .build_initial_context(&turn_context, Vec::new())
+        .build_initial_context(
+            &turn_context,
+            /*additional_developer_sections*/ Vec::new(),
+        )
         .await;
     let developer_texts = developer_input_texts(&initial_context);
 
@@ -4028,7 +4080,10 @@ async fn build_initial_context_uses_previous_turn_settings_for_realtime_end() {
         .set_previous_turn_settings(Some(previous_turn_settings))
         .await;
     let initial_context = session
-        .build_initial_context(&turn_context, Vec::new())
+        .build_initial_context(
+            &turn_context,
+            /*additional_developer_sections*/ Vec::new(),
+        )
         .await;
     let developer_texts = developer_input_texts(&initial_context);
     assert!(
@@ -4052,7 +4107,10 @@ async fn build_initial_context_restates_realtime_start_when_reference_context_is
         .set_previous_turn_settings(Some(previous_turn_settings))
         .await;
     let initial_context = session
-        .build_initial_context(&turn_context, Vec::new())
+        .build_initial_context(
+            &turn_context,
+            /*additional_developer_sections*/ Vec::new(),
+        )
         .await;
     let developer_texts = developer_input_texts(&initial_context);
     assert!(
@@ -4072,7 +4130,10 @@ async fn record_context_updates_and_set_reference_context_item_injects_full_cont
         .await;
     let history = session.clone_history().await;
     let initial_context = session
-        .build_initial_context(&turn_context, Vec::new())
+        .build_initial_context(
+            &turn_context,
+            /*additional_developer_sections*/ Vec::new(),
+        )
         .await;
     assert_eq!(history.raw_items().to_vec(), initial_context);
 
@@ -4119,7 +4180,10 @@ async fn record_context_updates_and_set_reference_context_item_reinjects_full_co
     let mut expected_history = vec![compacted_summary];
     expected_history.extend(
         session
-            .build_initial_context(&turn_context, Vec::new())
+            .build_initial_context(
+                &turn_context,
+                /*additional_developer_sections*/ Vec::new(),
+            )
             .await,
     );
     assert_eq!(history.raw_items().to_vec(), expected_history);
@@ -4165,7 +4229,11 @@ async fn record_context_updates_and_set_reference_context_item_persists_baseline
     }
 
     let update_items = session
-        .build_settings_update_items(Some(&previous_context_item), &turn_context, Vec::new())
+        .build_settings_update_items(
+            Some(&previous_context_item),
+            &turn_context,
+            /*additional_developer_sections*/ Vec::new(),
+        )
         .await;
     assert_eq!(update_items, Vec::new());
 
@@ -4216,7 +4284,10 @@ async fn build_initial_context_prepends_model_switch_message() {
         .set_previous_turn_settings(Some(previous_turn_settings))
         .await;
     let initial_context = session
-        .build_initial_context(&turn_context, Vec::new())
+        .build_initial_context(
+            &turn_context,
+            /*additional_developer_sections*/ Vec::new(),
+        )
         .await;
 
     let ResponseItem::Message { role, content, .. } = &initial_context[0] else {
@@ -4898,7 +4969,10 @@ async fn sample_rollout(
     // personality_spec) matches reconstruction.
     let reconstruction_turn = session.new_default_turn().await;
     let mut initial_context = session
-        .build_initial_context(reconstruction_turn.as_ref(), Vec::new())
+        .build_initial_context(
+            reconstruction_turn.as_ref(),
+            /*additional_developer_sections*/ Vec::new(),
+        )
         .await;
     // Ensure personality_spec is present when Personality is enabled, so expected matches
     // what reconstruction produces (build_initial_context may omit it when baked into model).
diff --git a/codex-rs/core/src/compact.rs b/codex-rs/core/src/compact.rs
index 3862f137a9..70958ef659 100644
--- a/codex-rs/core/src/compact.rs
+++ b/codex-rs/core/src/compact.rs
@@ -201,7 +201,10 @@ async fn run_compact_task_inner(
         InitialContextInjection::BeforeLastUserMessage
     ) {
         let initial_context = sess
-            .build_initial_context(turn_context.as_ref(), Vec::new())
+            .build_initial_context(
+                turn_context.as_ref(),
+                /*additional_developer_sections*/ Vec::new(),
+            )
             .await;
         new_history =
             insert_initial_context_before_last_real_user_or_summary(new_history, initial_context);
diff --git a/codex-rs/core/src/compact_remote.rs b/codex-rs/core/src/compact_remote.rs
index 70ac90778d..c24331292f 100644
--- a/codex-rs/core/src/compact_remote.rs
+++ b/codex-rs/core/src/compact_remote.rs
@@ -178,7 +178,11 @@ pub(crate) async fn process_compacted_history(
         initial_context_injection,
         InitialContextInjection::BeforeLastUserMessage
     ) {
-        sess.build_initial_context(turn_context, Vec::new()).await
+        sess.build_initial_context(
+            turn_context,
+            /*additional_developer_sections*/ Vec::new(),
+        )
+        .await
     } else {
         Vec::new()
     };
diff --git a/codex-rs/core/src/compact_tests.rs b/codex-rs/core/src/compact_tests.rs
index 8259caa191..1af4bc4991 100644
--- a/codex-rs/core/src/compact_tests.rs
+++ b/codex-rs/core/src/compact_tests.rs
@@ -10,7 +10,10 @@ async fn process_compacted_history_with_test_session(
         .set_previous_turn_settings(previous_turn_settings.cloned())
         .await;
     let initial_context = session
-        .build_initial_context(&turn_context, Vec::new())
+        .build_initial_context(
+            &turn_context,
+            /*additional_developer_sections*/ Vec::new(),
+        )
         .await;
     let refreshed = crate::compact_remote::process_compacted_history(
         &session,
diff --git a/codex-rs/core/src/thread_manager_tests.rs b/codex-rs/core/src/thread_manager_tests.rs
index 167dfe9d6d..09b99b852d 100644
--- a/codex-rs/core/src/thread_manager_tests.rs
+++ b/codex-rs/core/src/thread_manager_tests.rs
@@ -196,7 +196,10 @@ fn out_of_range_truncation_drops_pre_user_active_turn_prefix() {
 async fn ignores_session_prefix_messages_when_truncating() {
     let (session, turn_context) = make_session_and_context().await;
     let mut items = session
-        .build_initial_context(&turn_context, Vec::new())
+        .build_initial_context(
+            &turn_context,
+            /*additional_developer_sections*/ Vec::new(),
+        )
         .await;
     items.push(user_msg("feature request"));
     items.push(assistant_msg("ack"));
diff --git a/codex-rs/core/src/thread_rollout_truncation_tests.rs b/codex-rs/core/src/thread_rollout_truncation_tests.rs
index 8e18a36a79..5bb14cb2f8 100644
--- a/codex-rs/core/src/thread_rollout_truncation_tests.rs
+++ b/codex-rs/core/src/thread_rollout_truncation_tests.rs
@@ -125,7 +125,10 @@ fn truncates_rollout_from_start_applies_thread_rollback_markers() {
 async fn ignores_session_prefix_messages_when_truncating_rollout_from_start() {
     let (session, turn_context) = make_session_and_context().await;
     let mut items = session
-        .build_initial_context(&turn_context, Vec::new())
+        .build_initial_context(
+            &turn_context,
+            /*additional_developer_sections*/ Vec::new(),
+        )
         .await;
     items.push(user_msg("feature request"));
     items.push(assistant_msg("ack"));