diff --git a/codex-rs/app-server-protocol/src/protocol/thread_history.rs b/codex-rs/app-server-protocol/src/protocol/thread_history.rs
index e6c679b418..f6eee656c3 100644
--- a/codex-rs/app-server-protocol/src/protocol/thread_history.rs
+++ b/codex-rs/app-server-protocol/src/protocol/thread_history.rs
@@ -3,6 +3,7 @@ use crate::protocol::v2::Turn;
 use crate::protocol::v2::TurnError;
 use crate::protocol::v2::TurnStatus;
 use crate::protocol::v2::UserInput;
+use codex_protocol::config_types::ModeKind;
 use codex_protocol::protocol::AgentReasoningEvent;
 use codex_protocol::protocol::AgentReasoningRawContentEvent;
 use codex_protocol::protocol::EventMsg;
@@ -164,6 +165,7 @@ impl ThreadHistoryBuilder {
             items: Vec::new(),
             error: None,
             status: TurnStatus::Completed,
+            collaboration_mode_kind: None,
         }
     }
 
@@ -222,6 +224,7 @@ struct PendingTurn {
     items: Vec<ThreadItem>,
     error: Option<TurnError>,
     status: TurnStatus,
+    collaboration_mode_kind: Option<ModeKind>,
 }
 
 impl From<PendingTurn> for Turn {
@@ -231,6 +234,7 @@ impl From<PendingTurn> for Turn {
             items: value.items,
             error: value.error,
             status: value.status,
+            collaboration_mode_kind: value.collaboration_mode_kind,
         }
     }
 }
@@ -493,6 +497,7 @@ mod tests {
                 id: "turn-1".into(),
                 status: TurnStatus::Completed,
                 error: None,
+                collaboration_mode_kind: None,
                 items: vec![
                     ThreadItem::UserMessage {
                         id: "item-1".into(),
@@ -511,6 +516,7 @@ mod tests {
                 id: "turn-2".into(),
                 status: TurnStatus::Completed,
                 error: None,
+                collaboration_mode_kind: None,
                 items: vec![
                     ThreadItem::UserMessage {
                         id: "item-3".into(),
diff --git a/codex-rs/app-server-protocol/src/protocol/v2.rs b/codex-rs/app-server-protocol/src/protocol/v2.rs
index 9eddf28148..9c39ab0ee3 100644
--- a/codex-rs/app-server-protocol/src/protocol/v2.rs
+++ b/codex-rs/app-server-protocol/src/protocol/v2.rs
@@ -6,6 +6,7 @@ use codex_protocol::account::PlanType;
 use codex_protocol::approvals::ExecPolicyAmendment as CoreExecPolicyAmendment;
 use codex_protocol::config_types::CollaborationMode;
 use codex_protocol::config_types::ForcedLoginMethod;
+use codex_protocol::config_types::ModeKind;
 use codex_protocol::config_types::Personality;
 use codex_protocol::config_types::ReasoningSummary;
 use codex_protocol::config_types::SandboxMode as CoreSandboxMode;
@@ -1563,6 +1564,10 @@ pub struct Turn {
     pub status: TurnStatus,
     /// Only populated when the Turn's status is failed.
     pub error: Option<TurnError>,
+    /// Collaboration mode kind captured at the start of the turn, when known.
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    #[ts(optional)]
+    pub collaboration_mode_kind: Option<ModeKind>,
 }
 
 #[derive(Serialize, Deserialize, Debug, Clone, PartialEq, JsonSchema, TS, Error)]
diff --git a/codex-rs/app-server/README.md b/codex-rs/app-server/README.md
index 659e2bf72c..cf6c217be7 100644
--- a/codex-rs/app-server/README.md
+++ b/codex-rs/app-server/README.md
@@ -385,7 +385,7 @@ Event notifications are the server-initiated event stream for thread lifecycles,
 
 The app-server streams JSON-RPC notifications while a turn is running. Each turn starts with `turn/started` (initial `turn`) and ends with `turn/completed` (final `turn` status). Token usage events stream separately via `thread/tokenUsage/updated`. Clients subscribe to the events they care about, rendering each item incrementally as updates arrive. The per-item lifecycle is always: `item/started` → zero or more item-specific deltas → `item/completed`.
 
-- `turn/started` — `{ turn }` with the turn id, empty `items`, and `status: "inProgress"`.
+- `turn/started` — `{ turn }` with the turn id, empty `items`, `status: "inProgress"`, and (when known) `collaborationModeKind`.
 - `turn/completed` — `{ turn }` where `turn.status` is `completed`, `interrupted`, or `failed`; failures carry `{ error: { message, codexErrorInfo?, additionalDetails? } }`.
 - `turn/diff/updated` — `{ threadId, turnId, diff }` represents the up-to-date snapshot of the turn-level unified diff, emitted after every FileChange item. `diff` is the latest aggregated unified diff across every file change in the turn. UIs can render this to show the full "what changed" view without stitching individual `fileChange` items.
 - `turn/plan/updated` — `{ turnId, explanation?, plan }` whenever the agent shares or changes its plan; each `plan` entry is `{ step, status }` with `status` in `pending`, `inProgress`, or `completed`.
diff --git a/codex-rs/app-server/src/bespoke_event_handling.rs b/codex-rs/app-server/src/bespoke_event_handling.rs
index 68e233b843..8794765ca0 100644
--- a/codex-rs/app-server/src/bespoke_event_handling.rs
+++ b/codex-rs/app-server/src/bespoke_event_handling.rs
@@ -85,6 +85,7 @@ use codex_core::protocol::TurnDiffEvent;
 use codex_core::review_format::format_review_findings_block;
 use codex_core::review_prompts;
 use codex_protocol::ThreadId;
+use codex_protocol::config_types::ModeKind;
 use codex_protocol::plan_tool::UpdatePlanArgs;
 use codex_protocol::protocol::ReviewOutputEvent;
 use codex_protocol::request_user_input::RequestUserInputAnswer as CoreRequestUserInputAnswer;
@@ -115,6 +116,11 @@ pub(crate) async fn apply_bespoke_event_handling(
         msg,
     } = event;
     match msg {
+        EventMsg::TurnStarted(turn_started_event) => {
+            let mut summaries = turn_summary_store.lock().await;
+            let summary = summaries.entry(conversation_id).or_default();
+            summary.collaboration_mode_kind = Some(turn_started_event.collaboration_mode_kind);
+        }
         EventMsg::TurnComplete(_ev) => {
             handle_turn_complete(
                 conversation_id,
@@ -1132,6 +1138,7 @@ async fn emit_turn_completed_with_status(
     event_turn_id: String,
     status: TurnStatus,
     error: Option<TurnError>,
+    collaboration_mode_kind: Option<ModeKind>,
     outgoing: &OutgoingMessageSender,
 ) {
     let notification = TurnCompletedNotification {
@@ -1141,6 +1148,7 @@ async fn emit_turn_completed_with_status(
             items: vec![],
             error,
             status,
+            collaboration_mode_kind,
         },
     };
     outgoing
@@ -1248,13 +1256,22 @@ async fn handle_turn_complete(
     turn_summary_store: &TurnSummaryStore,
 ) {
     let turn_summary = find_and_remove_turn_summary(conversation_id, turn_summary_store).await;
+    let collaboration_mode_kind = turn_summary.collaboration_mode_kind;
 
     let (status, error) = match turn_summary.last_error {
         Some(error) => (TurnStatus::Failed, Some(error)),
         None => (TurnStatus::Completed, None),
     };
 
-    emit_turn_completed_with_status(conversation_id, event_turn_id, status, error, outgoing).await;
+    emit_turn_completed_with_status(
+        conversation_id,
+        event_turn_id,
+        status,
+        error,
+        collaboration_mode_kind,
+        outgoing,
+    )
+    .await;
 }
 
 async fn handle_turn_interrupted(
@@ -1263,13 +1280,14 @@ async fn handle_turn_interrupted(
     outgoing: &OutgoingMessageSender,
     turn_summary_store: &TurnSummaryStore,
 ) {
-    find_and_remove_turn_summary(conversation_id, turn_summary_store).await;
+    let turn_summary = find_and_remove_turn_summary(conversation_id, turn_summary_store).await;
 
     emit_turn_completed_with_status(
         conversation_id,
         event_turn_id,
         TurnStatus::Interrupted,
         None,
+        turn_summary.collaboration_mode_kind,
         outgoing,
     )
     .await;
diff --git a/codex-rs/app-server/src/codex_message_processor.rs b/codex-rs/app-server/src/codex_message_processor.rs
index d0b8c7f949..1fac2792ce 100644
--- a/codex-rs/app-server/src/codex_message_processor.rs
+++ b/codex-rs/app-server/src/codex_message_processor.rs
@@ -170,6 +170,7 @@ use codex_login::ShutdownHandle;
 use codex_login::run_login_server;
 use codex_protocol::ThreadId;
 use codex_protocol::config_types::ForcedLoginMethod;
+use codex_protocol::config_types::ModeKind;
 use codex_protocol::config_types::Personality;
 use codex_protocol::items::TurnItem;
 use codex_protocol::models::ResponseItem;
@@ -213,6 +214,7 @@ pub(crate) type PendingRollbacks = Arc<Mutex<HashMap<ThreadId, RequestId>>>;
 pub(crate) struct TurnSummary {
     pub(crate) file_change_started: HashSet<String>,
     pub(crate) last_error: Option<TurnError>,
+    pub(crate) collaboration_mode_kind: Option<ModeKind>,
 }
 
 pub(crate) type TurnSummaryStore = Arc<Mutex<HashMap<ThreadId, TurnSummary>>>;
@@ -3641,13 +3643,14 @@ impl CodexMessageProcessor {
     }
 
     async fn turn_start(&self, request_id: RequestId, params: TurnStartParams) {
-        let (_, thread) = match self.load_thread(&params.thread_id).await {
+        let (thread_id, thread) = match self.load_thread(&params.thread_id).await {
             Ok(v) => v,
             Err(error) => {
                 self.outgoing.send_error(request_id, error).await;
                 return;
             }
         };
+        let thread_id_str = params.thread_id.clone();
 
         // Map v2 input items to core input items.
         let mapped_items: Vec<CoreInputItem> = params
@@ -3655,6 +3658,15 @@ impl CodexMessageProcessor {
             .into_iter()
             .map(V2UserInput::into_core)
             .collect();
+        let collaboration_mode_kind = params.collaboration_mode.as_ref().map(|mode| mode.mode);
+        let config_snapshot = thread.config_snapshot().await;
+        let collaboration_mode_kind =
+            collaboration_mode_kind.or(Some(config_snapshot.collaboration_mode_kind));
+        {
+            let mut summaries = self.turn_summary_store.lock().await;
+            let summary = summaries.entry(thread_id).or_default();
+            summary.collaboration_mode_kind = collaboration_mode_kind;
+        }
 
         let has_any_overrides = params.cwd.is_some()
             || params.approval_policy.is_some()
@@ -3696,6 +3708,7 @@ impl CodexMessageProcessor {
                     items: vec![],
                     error: None,
                     status: TurnStatus::InProgress,
+                    collaboration_mode_kind,
                 };
 
                 let response = TurnStartResponse { turn: turn.clone() };
@@ -3703,7 +3716,7 @@ impl CodexMessageProcessor {
 
                 // Emit v2 turn/started notification.
                 let notif = TurnStartedNotification {
-                    thread_id: params.thread_id,
+                    thread_id: thread_id_str,
                     turn,
                 };
                 self.outgoing
@@ -3740,6 +3753,7 @@ impl CodexMessageProcessor {
             items,
             error: None,
             status: TurnStatus::InProgress,
+            collaboration_mode_kind: None,
         }
     }
 
diff --git a/codex-rs/core/src/agent/control.rs b/codex-rs/core/src/agent/control.rs
index 611c0d164c..151c6fa0fb 100644
--- a/codex-rs/core/src/agent/control.rs
+++ b/codex-rs/core/src/agent/control.rs
@@ -146,6 +146,7 @@ mod tests {
     use crate::config::Config;
     use crate::config::ConfigBuilder;
     use assert_matches::assert_matches;
+    use codex_protocol::config_types::ModeKind;
     use codex_protocol::protocol::ErrorEvent;
     use codex_protocol::protocol::EventMsg;
     use codex_protocol::protocol::TurnAbortReason;
@@ -231,6 +232,7 @@ mod tests {
     async fn on_event_updates_status_from_task_started() {
         let status = agent_status_from_event(&EventMsg::TurnStarted(TurnStartedEvent {
             model_context_window: None,
+            collaboration_mode_kind: ModeKind::Custom,
         }));
         assert_eq!(status, Some(AgentStatus::Running));
     }
diff --git a/codex-rs/core/src/codex.rs b/codex-rs/core/src/codex.rs
index 9fc2bae165..004563260c 100644
--- a/codex-rs/core/src/codex.rs
+++ b/codex-rs/core/src/codex.rs
@@ -433,6 +433,7 @@ pub(crate) struct TurnContext {
     pub(crate) developer_instructions: Option<String>,
     pub(crate) compact_prompt: Option<String>,
     pub(crate) user_instructions: Option<String>,
+    pub(crate) collaboration_mode_kind: ModeKind,
     pub(crate) personality: Option<Personality>,
     pub(crate) approval_policy: AskForApproval,
     pub(crate) sandbox_policy: SandboxPolicy,
@@ -513,6 +514,7 @@ impl SessionConfiguration {
             reasoning_effort: self.collaboration_mode.reasoning_effort(),
             personality: self.personality,
             session_source: self.session_source.clone(),
+            collaboration_mode_kind: self.collaboration_mode.mode,
         }
     }
 
@@ -606,6 +608,7 @@ impl Session {
             developer_instructions: session_configuration.developer_instructions.clone(),
             compact_prompt: session_configuration.compact_prompt.clone(),
             user_instructions: session_configuration.user_instructions.clone(),
+            collaboration_mode_kind: session_configuration.collaboration_mode.mode,
             personality: session_configuration.personality,
             approval_policy: session_configuration.approval_policy.value(),
             sandbox_policy: session_configuration.sandbox_policy.get().clone(),
@@ -2818,6 +2821,7 @@ async fn spawn_review_thread(
         developer_instructions: None,
         user_instructions: None,
         compact_prompt: parent_turn_context.compact_prompt.clone(),
+        collaboration_mode_kind: parent_turn_context.collaboration_mode_kind,
         personality: parent_turn_context.personality,
         approval_policy: parent_turn_context.approval_policy,
         sandbox_policy: parent_turn_context.sandbox_policy.clone(),
@@ -2917,6 +2921,7 @@ pub(crate) async fn run_turn(
     }
     let event = EventMsg::TurnStarted(TurnStartedEvent {
         model_context_window: turn_context.client.get_model_context_window(),
+        collaboration_mode_kind: turn_context.collaboration_mode_kind,
     });
     sess.send_event(&turn_context, event).await;
 
diff --git a/codex-rs/core/src/codex_thread.rs b/codex-rs/core/src/codex_thread.rs
index 152679d146..34cfec7bde 100644
--- a/codex-rs/core/src/codex_thread.rs
+++ b/codex-rs/core/src/codex_thread.rs
@@ -4,6 +4,7 @@ use crate::error::Result as CodexResult;
 use crate::protocol::Event;
 use crate::protocol::Op;
 use crate::protocol::Submission;
+use codex_protocol::config_types::ModeKind;
 use codex_protocol::config_types::Personality;
 use codex_protocol::openai_models::ReasoningEffort;
 use codex_protocol::protocol::AskForApproval;
@@ -22,6 +23,7 @@ pub struct ThreadConfigSnapshot {
     pub reasoning_effort: Option<ReasoningEffort>,
     pub personality: Option<Personality>,
     pub session_source: SessionSource,
+    pub collaboration_mode_kind: ModeKind,
 }
 
 pub struct CodexThread {
diff --git a/codex-rs/core/src/compact.rs b/codex-rs/core/src/compact.rs
index c365d2cfda..04eaec321f 100644
--- a/codex-rs/core/src/compact.rs
+++ b/codex-rs/core/src/compact.rs
@@ -61,6 +61,7 @@ pub(crate) async fn run_compact_task(
 ) {
     let start_event = EventMsg::TurnStarted(TurnStartedEvent {
         model_context_window: turn_context.client.get_model_context_window(),
+        collaboration_mode_kind: turn_context.collaboration_mode_kind,
     });
     sess.send_event(&turn_context, start_event).await;
     run_compact_task_inner(sess.clone(), turn_context, input).await;
diff --git a/codex-rs/core/src/compact_remote.rs b/codex-rs/core/src/compact_remote.rs
index aaa7fc68a7..0e47a568ae 100644
--- a/codex-rs/core/src/compact_remote.rs
+++ b/codex-rs/core/src/compact_remote.rs
@@ -21,6 +21,7 @@ pub(crate) async fn run_inline_remote_auto_compact_task(
 pub(crate) async fn run_remote_compact_task(sess: Arc<Session>, turn_context: Arc<TurnContext>) {
     let start_event = EventMsg::TurnStarted(TurnStartedEvent {
         model_context_window: turn_context.client.get_model_context_window(),
+        collaboration_mode_kind: turn_context.collaboration_mode_kind,
     });
     sess.send_event(&turn_context, start_event).await;
 
diff --git a/codex-rs/core/src/tasks/user_shell.rs b/codex-rs/core/src/tasks/user_shell.rs
index 1f1f1eb59e..6d723796e0 100644
--- a/codex-rs/core/src/tasks/user_shell.rs
+++ b/codex-rs/core/src/tasks/user_shell.rs
@@ -67,6 +67,7 @@ impl SessionTask for UserShellCommandTask {
 
         let event = EventMsg::TurnStarted(TurnStartedEvent {
             model_context_window: turn_context.client.get_model_context_window(),
+            collaboration_mode_kind: turn_context.collaboration_mode_kind,
         });
         let session = session.clone_session();
         session.send_event(turn_context.as_ref(), event).await;
diff --git a/codex-rs/exec/tests/event_processor_with_json_output.rs b/codex-rs/exec/tests/event_processor_with_json_output.rs
index 43de1f95f8..9dfbbe0fd9 100644
--- a/codex-rs/exec/tests/event_processor_with_json_output.rs
+++ b/codex-rs/exec/tests/event_processor_with_json_output.rs
@@ -44,6 +44,7 @@ use codex_exec::exec_events::TurnFailedEvent;
 use codex_exec::exec_events::TurnStartedEvent;
 use codex_exec::exec_events::Usage;
 use codex_exec::exec_events::WebSearchItem;
+use codex_protocol::config_types::ModeKind;
 use codex_protocol::plan_tool::PlanItemArg;
 use codex_protocol::plan_tool::StepStatus;
 use codex_protocol::plan_tool::UpdatePlanArgs;
@@ -104,6 +105,7 @@ fn task_started_produces_turn_started_event() {
         "t1",
         EventMsg::TurnStarted(codex_core::protocol::TurnStartedEvent {
             model_context_window: Some(32_000),
+            collaboration_mode_kind: ModeKind::Custom,
         }),
     ));
 
diff --git a/codex-rs/protocol/src/protocol.rs b/codex-rs/protocol/src/protocol.rs
index 7b1c39d061..059f25f8bc 100644
--- a/codex-rs/protocol/src/protocol.rs
+++ b/codex-rs/protocol/src/protocol.rs
@@ -14,6 +14,7 @@ use std::time::Duration;
 use crate::ThreadId;
 use crate::approvals::ElicitationRequestEvent;
 use crate::config_types::CollaborationMode;
+use crate::config_types::ModeKind;
 use crate::config_types::Personality;
 use crate::config_types::ReasoningSummary as ReasoningSummaryConfig;
 use crate::custom_prompts::CustomPrompt;
@@ -1075,6 +1076,7 @@ pub struct TurnCompleteEvent {
 pub struct TurnStartedEvent {
     // TODO(aibrahim): make this not optional
     pub model_context_window: Option<i64>,
+    pub collaboration_mode_kind: ModeKind,
 }
 
 #[derive(Debug, Clone, Deserialize, Serialize, Default, PartialEq, Eq, JsonSchema, TS)]
diff --git a/codex-rs/tui/src/chatwidget/tests.rs b/codex-rs/tui/src/chatwidget/tests.rs
index f4ff932e20..9d5de241ae 100644
--- a/codex-rs/tui/src/chatwidget/tests.rs
+++ b/codex-rs/tui/src/chatwidget/tests.rs
@@ -1983,6 +1983,7 @@ async fn unified_exec_wait_after_final_agent_message_snapshot() {
         id: "turn-1".into(),
         msg: EventMsg::TurnStarted(TurnStartedEvent {
             model_context_window: None,
+            collaboration_mode_kind: ModeKind::Custom,
         }),
     });
 
@@ -2017,6 +2018,7 @@ async fn unified_exec_wait_before_streamed_agent_message_snapshot() {
         id: "turn-1".into(),
         msg: EventMsg::TurnStarted(TurnStartedEvent {
             model_context_window: None,
+            collaboration_mode_kind: ModeKind::Custom,
         }),
     });
 
@@ -2654,6 +2656,7 @@ async fn interrupted_turn_error_message_snapshot() {
         id: "task-1".into(),
         msg: EventMsg::TurnStarted(TurnStartedEvent {
             model_context_window: None,
+            collaboration_mode_kind: ModeKind::Custom,
         }),
     });
 
@@ -3631,6 +3634,7 @@ async fn interrupt_clears_unified_exec_wait_streak_snapshot() {
         id: "turn-1".into(),
         msg: EventMsg::TurnStarted(TurnStartedEvent {
             model_context_window: None,
+            collaboration_mode_kind: ModeKind::Custom,
         }),
     });
 
@@ -3704,6 +3708,7 @@ async fn ui_snapshots_small_heights_task_running() {
         id: "task-1".into(),
         msg: EventMsg::TurnStarted(TurnStartedEvent {
             model_context_window: None,
+            collaboration_mode_kind: ModeKind::Custom,
         }),
     });
     chat.handle_codex_event(Event {
@@ -3735,6 +3740,7 @@ async fn status_widget_and_approval_modal_snapshot() {
         id: "task-1".into(),
         msg: EventMsg::TurnStarted(TurnStartedEvent {
             model_context_window: None,
+            collaboration_mode_kind: ModeKind::Custom,
         }),
     });
     // Provide a deterministic header for the status line.
@@ -3787,6 +3793,7 @@ async fn status_widget_active_snapshot() {
         id: "task-1".into(),
         msg: EventMsg::TurnStarted(TurnStartedEvent {
             model_context_window: None,
+            collaboration_mode_kind: ModeKind::Custom,
         }),
     });
     // Provide a deterministic header via a bold reasoning chunk.
@@ -3836,6 +3843,7 @@ async fn mcp_startup_complete_does_not_clear_running_task() {
         id: "task-1".into(),
         msg: EventMsg::TurnStarted(TurnStartedEvent {
             model_context_window: None,
+            collaboration_mode_kind: ModeKind::Custom,
         }),
     });
 
@@ -4392,6 +4400,7 @@ async fn stream_recovery_restores_previous_status_header() {
         id: "task".into(),
         msg: EventMsg::TurnStarted(TurnStartedEvent {
             model_context_window: None,
+            collaboration_mode_kind: ModeKind::Custom,
         }),
     });
     drain_insert_history(&mut rx);
@@ -4429,6 +4438,7 @@ async fn multiple_agent_messages_in_single_turn_emit_multiple_headers() {
         id: "s1".into(),
         msg: EventMsg::TurnStarted(TurnStartedEvent {
             model_context_window: None,
+            collaboration_mode_kind: ModeKind::Custom,
         }),
     });
 
@@ -4623,6 +4633,7 @@ async fn chatwidget_exec_and_status_layout_vt100_snapshot() {
         id: "t1".into(),
         msg: EventMsg::TurnStarted(TurnStartedEvent {
             model_context_window: None,
+            collaboration_mode_kind: ModeKind::Custom,
         }),
     });
     chat.handle_codex_event(Event {
@@ -4670,6 +4681,7 @@ async fn chatwidget_markdown_code_blocks_vt100_snapshot() {
         id: "t1".into(),
         msg: EventMsg::TurnStarted(TurnStartedEvent {
             model_context_window: None,
+            collaboration_mode_kind: ModeKind::Custom,
         }),
     });
     // Build a vt100 visual from the history insertions only (no UI overlay)
@@ -4759,6 +4771,7 @@ async fn chatwidget_tall() {
         id: "t1".into(),
         msg: EventMsg::TurnStarted(TurnStartedEvent {
             model_context_window: None,
+            collaboration_mode_kind: ModeKind::Custom,
         }),
     });
     for i in 0..30 {