diff --git a/TODO.md b/TODO.md
index c6ac7089..0b538aa6 100644
--- a/TODO.md
+++ b/TODO.md
@@ -8,7 +8,6 @@
 - Pod: 任意ターンからの Fork（複数ターン巻き戻しを汎用化） → [tickets/pod-session-fork.md](tickets/pod-session-fork.md)
 - Pod: 子→親の TurnEnded/Errored callback を親由来ターンのみに絞る → [tickets/pod-parent-turn-callback.md](tickets/pod-parent-turn-callback.md)
 - Pod: セッションログをバックエンドにした Pod 単位の永続化 → [tickets/pod-persistent-state.md](tickets/pod-persistent-state.md)
-- Pod: System 注入経路 (Notify / PodEvent / HookInjectedItems) を SystemItem 一本に統合 → [tickets/system-item-unify.md](tickets/system-item-unify.md)
 - 永続化層のセマンティック整理 → [tickets/persistence-semantics.md](tickets/persistence-semantics.md)
 - Exchange / Turn / Call セマンティクス整理 → [tickets/exchange-turn-call-semantics.md](tickets/exchange-turn-call-semantics.md)
 - llm-worker のエラー耐性
diff --git a/crates/pod/src/controller.rs b/crates/pod/src/controller.rs
index c9f9f140..c5b65e94 100644
--- a/crates/pod/src/controller.rs
+++ b/crates/pod/src/controller.rs
@@ -411,24 +411,17 @@ where
                 let Some(entry) = classify_history_item(item) else {
                     continue;
                 };
-                let mut head = ctx.session_head.lock().await;
-                match session_store::append_entry_with_hash(
-                    &ctx.store,
-                    head.session_id,
-                    &mut head.head_hash,
-                    entry.clone(),
-                )
-                .await
-                {
-                    Ok(_) => {
-                        // Publish under the same critical section view
-                        // a `subscribe_with_snapshot` would observe.
-                        ctx.sink.publish(entry);
-                    }
-                    Err(e) => {
-                        tracing::warn!(error = %e, "drain: append_entry failed; entry dropped");
-                    }
+                commit_via_drain(&ctx, entry).await;
+            }
+            LogCommand::SystemItems(items) => {
+                if items.is_empty() {
+                    continue;
                 }
+                let entry = LogEntry::SystemItems {
+                    ts: session_log::now_millis(),
+                    items,
+                };
+                commit_via_drain(&ctx, entry).await;
             }
             LogCommand::Flush(ack) => {
                 let _ = ack.send(());
@@ -437,15 +430,52 @@ where
     }
 }
 
-/// Map a single worker-history `Item` to its corresponding `LogEntry`
-/// classification. `None` is the skip signal for `user_message` items —
-/// those are committed via `LogEntry::UserInput` by `Pod::run` at
-/// submit time and would otherwise produce a duplicate entry here.
+async fn commit_via_drain<St>(ctx: &LogDrainHandle<St>, entry: LogEntry)
+where
+    St: session_store::Store + Clone + Send + 'static,
+{
+    let mut head = ctx.session_head.lock().await;
+    match session_store::append_entry_with_hash(
+        &ctx.store,
+        head.session_id,
+        &mut head.head_hash,
+        entry.clone(),
+    )
+    .await
+    {
+        Ok(_) => {
+            // Publish under the same critical section view a
+            // `subscribe_with_snapshot` would observe.
+            ctx.sink.publish(entry);
+        }
+        Err(e) => {
+            tracing::warn!(error = %e, "drain: append_entry failed; entry dropped");
+        }
+    }
+}
+
+/// Map one LLM-driven worker-history append to its `LogEntry` form.
+///
+/// `None` is the skip signal for items that the drain must not commit:
+/// - `user_message` items are committed by `Pod::run` up-front as
+///   `LogEntry::UserInput { segments }`.
+/// - `system_message` items are committed by `PodInterceptor` as part
+///   of a `LogEntry::SystemItems` batch (with typed kind metadata)
+///   before they reach the worker's history.
 fn classify_history_item(item: Item) -> Option<LogEntry> {
     let ts = session_log::now_millis();
     if item.is_user_message() {
         return None;
     }
+    if matches!(
+        item,
+        Item::Message {
+            role: llm_worker::Role::System,
+            ..
+        }
+    ) {
+        return None;
+    }
     if item.is_tool_result() {
         return Some(LogEntry::ToolResults {
             ts,
@@ -458,7 +488,9 @@ fn classify_history_item(item: Item) -> Option<LogEntry> {
             items: vec![session_store::LoggedItem::from(&item)],
         });
     }
-    Some(LogEntry::HookInjectedItems {
+    // Defensive: anything else (future Item kinds) routes through
+    // AssistantItems rather than getting silently dropped.
+    Some(LogEntry::AssistantItems {
         ts,
         items: vec![session_store::LoggedItem::from(&item)],
     })
@@ -696,9 +728,11 @@ async fn controller_loop<C, St>(
             }
 
             Method::Notify { message } => {
-                let _ = event_tx.send(Event::Notify {
-                    message: message.clone(),
-                });
+                // Client-side live echo is delivered as `Event::SystemItem`
+                // once the interceptor commits the corresponding
+                // `LogEntry::SystemItems` entry — drained out of the
+                // notify buffer + broadcast through the sink. No
+                // separate echo here.
                 pod.push_notify(message);
                 // RUNNING / Paused: the buffer push is the entire
                 // operation; an in-flight turn (or the next
@@ -751,10 +785,12 @@ async fn controller_loop<C, St>(
             Method::ListCompletions { .. } => {}
 
             Method::PodEvent(event) => {
-                // Echo the received event to all subscribers so every
-                // client sees the input that drove any following
-                // auto-kicked turn.
-                let _ = event_tx.send(Event::PodEvent(event.clone()));
+                // Live echo travels through the SystemItem lane: once
+                // the interceptor drains the notify buffer, the
+                // typed `SystemItem::PodEvent` lands as a
+                // `LogEntry::SystemItems` entry and the sink fans it
+                // out to clients as `Event::SystemItem`.
+                //
                 // (1) system side effects — idempotent and tolerant of
                 // out-of-order delivery (e.g. `TurnEnded` arriving
                 // after `ShutDown`).
@@ -765,11 +801,10 @@ async fn controller_loop<C, St>(
                     &self_parent_socket,
                 )
                 .await;
-                // (2) render a one-line summary and push it into the
-                // notification buffer; the next LLM request will
-                // inject it as a system message via
-                // `PodInterceptor::pre_llm_request`.
-                pod.push_notify(crate::ipc::event::render_event(&event));
+                // (2) queue the typed event in the notification buffer;
+                // the next LLM request will inject it as a typed
+                // `SystemItem::PodEvent` via the interceptor drain.
+                pod.push_pod_event_notify(event);
                 // Auto-kick a turn if the Pod is idle so the
                 // notification is not stranded. Matches the
                 // `Method::Notify` idle path.
@@ -902,23 +937,21 @@ where
                         });
                     }
                     Some(Method::Notify { message }) => {
-                        let _ = event_tx.send(Event::Notify {
-                            message: message.clone(),
-                        });
-                        // Route into the buffer; the in-flight turn will
-                        // drain it at its next pre_llm_request.
-                        notify_buffer.push(message);
+                        // Live echo arrives via `Event::SystemItem` once
+                        // the in-flight turn's next `pre_llm_request`
+                        // drains this entry through the interceptor.
+                        notify_buffer.push_notify(message);
                     }
                     Some(Method::ListCompletions { .. }) => {}
                     Some(Method::PodEvent(event)) => {
-                        let _ = event_tx.send(Event::PodEvent(event.clone()));
                         // mpsc is consume-once, so we cannot defer this
                         // to the next main-loop iteration — drop here
                         // would lose the event entirely (children fire
                         // and forget). Apply the side effects inline
-                        // and stage the rendered string on the
-                        // notification buffer so the in-flight turn's
-                        // next `pre_llm_request` surfaces it.
+                        // and stage the typed event on the notification
+                        // buffer so the in-flight turn's next
+                        // `pre_llm_request` surfaces it as a typed
+                        // `SystemItem::PodEvent`.
                         let self_parent_socket = parent_socket.cloned();
                         crate::ipc::event::apply_event_side_effects(
                             &event,
@@ -927,7 +960,7 @@ where
                             &self_parent_socket,
                         )
                         .await;
-                        notify_buffer.push(crate::ipc::event::render_event(&event));
+                        notify_buffer.push_pod_event(event);
                     }
                     None => {
                         let _ = cancel_tx.try_send(());
diff --git a/crates/pod/src/ipc/interceptor.rs b/crates/pod/src/ipc/interceptor.rs
index 39a70fb4..3403468f 100644
--- a/crates/pod/src/ipc/interceptor.rs
+++ b/crates/pod/src/ipc/interceptor.rs
@@ -22,11 +22,15 @@ use tracing::info;
 use tracing::warn;
 
 use crate::compact::state::CompactState;
+use session_store::SystemItem;
+use tokio::sync::mpsc;
+
 use crate::hook::{
     AbortInfo, HookPromptAction, HookRegistry, PreRequestInfo, PromptSubmitInfo, ToolCallSummary,
     ToolResultSummary, TurnEndInfo,
 };
-use crate::ipc::notify_buffer::{NotifyBuffer, format_notify};
+use crate::ipc::notify_buffer::{NotifyBuffer, build_system_item};
+use crate::pod::LogCommand;
 use crate::prompt::catalog::PromptCatalog;
 use llm_worker::token_counter::total_tokens;
 
@@ -45,13 +49,20 @@ pub(crate) struct PodInterceptor {
     /// request. The Worker `extend`s these into its persistent history
     /// so the LLM has a visible trigger for any reaction it commits.
     pending_notifies: NotifyBuffer,
-    /// Submit-scoped stash of resolver-produced system messages.
-    /// Drained inside `on_prompt_submit` and returned via
-    /// `PromptAction::ContinueWith`. Populated by `Pod::run` immediately
-    /// before handing off to the worker.
-    pending_attachments: Arc<Mutex<Vec<Item>>>,
+    /// Submit-scoped stash of resolver-produced typed system items.
+    /// Drained inside `on_prompt_submit`, committed as a
+    /// `LogEntry::SystemItems` through `log_cmd_tx`, and returned to
+    /// the worker as `Item::system_message` via
+    /// `PromptAction::ContinueWith`. Populated by `Pod::run`
+    /// immediately before handing off to the worker.
+    pending_attachments: Arc<Mutex<Vec<SystemItem>>>,
     /// Prompt catalog used to render the injected notification wrapper.
     prompts: Arc<PromptCatalog>,
+    /// Sender into the Pod's history-drain task. The interceptor uses
+    /// it to commit `LogCommand::SystemItems` batches before returning
+    /// the corresponding `Item::system_message`s up to the worker.
+    /// `None` in tests / `Pod::new` paths where no drain is wired.
+    log_cmd_tx: Option<mpsc::UnboundedSender<LogCommand>>,
     /// Next turn index assigned by `on_prompt_submit`.
     next_turn_index: AtomicUsize,
     /// Tool calls observed in the current turn (reset on each new prompt).
@@ -64,8 +75,9 @@ impl PodInterceptor {
         compact_state: Option<Arc<CompactState>>,
         usage_history: Option<Arc<Mutex<Vec<UsageRecord>>>>,
         pending_notifies: NotifyBuffer,
-        pending_attachments: Arc<Mutex<Vec<Item>>>,
+        pending_attachments: Arc<Mutex<Vec<SystemItem>>>,
         prompts: Arc<PromptCatalog>,
+        log_cmd_tx: Option<mpsc::UnboundedSender<LogCommand>>,
     ) -> Self {
         Self {
             registry,
@@ -74,11 +86,26 @@ impl PodInterceptor {
             pending_notifies,
             pending_attachments,
             prompts,
+            log_cmd_tx,
             next_turn_index: AtomicUsize::new(0),
             tool_calls_this_turn: AtomicUsize::new(0),
         }
     }
 
+    /// Send a `LogCommand::SystemItems` batch down the drain channel
+    /// (no-op if no drain is wired). The drain task commits the entry
+    /// before the corresponding `Item::system_message`s reach the
+    /// worker via `ContinueWith` / `pending_history_appends`, so the
+    /// drain barrier in `persist_turn` covers system commits too.
+    fn send_system_items(&self, items: Vec<SystemItem>) {
+        if items.is_empty() {
+            return;
+        }
+        if let Some(tx) = self.log_cmd_tx.as_ref() {
+            let _ = tx.send(LogCommand::SystemItems(items));
+        }
+    }
+
     fn current_turn_index(&self) -> usize {
         self.next_turn_index
             .load(Ordering::Relaxed)
@@ -111,7 +138,7 @@ impl Interceptor for PodInterceptor {
                 return action.into();
             }
         }
-        let extras = std::mem::take(
+        let extras: Vec<SystemItem> = std::mem::take(
             &mut *self
                 .pending_attachments
                 .lock()
@@ -120,7 +147,14 @@ impl Interceptor for PodInterceptor {
         if extras.is_empty() {
             PromptAction::Continue
         } else {
-            PromptAction::ContinueWith(extras)
+            // Commit the typed system items first, then hand the
+            // matching `Item::system_message`s to the worker. The
+            // drain task processes the `SystemItems` command BEFORE
+            // any subsequent `Item` commands from `on_history_append`,
+            // so on-disk order matches worker-history order.
+            let items: Vec<Item> = extras.iter().map(SystemItem::to_history_item).collect();
+            self.send_system_items(extras);
+            PromptAction::ContinueWith(items)
         }
     }
 
@@ -129,19 +163,31 @@ impl Interceptor for PodInterceptor {
         if drained.is_empty() {
             return Vec::new();
         }
-        let mut items = Vec::with_capacity(drained.len());
-        for n in drained {
-            match format_notify(&n, &self.prompts) {
-                Ok(item) => items.push(item),
+        let mut system_items: Vec<SystemItem> = Vec::with_capacity(drained.len());
+        let mut items: Vec<Item> = Vec::with_capacity(drained.len());
+        for entry in drained {
+            match build_system_item(&entry, &self.prompts) {
+                Ok(system_item) => {
+                    items.push(system_item.to_history_item());
+                    system_items.push(system_item);
+                }
                 Err(e) => {
                     // A render failure here would starve the LLM of
-                    // the notify text. Fall back to the raw message
-                    // so the trigger still lands in history.
+                    // the notify text. Fall back to a raw item so the
+                    // trigger still lands in history; the entry will
+                    // simply be skipped from the SystemItems batch.
                     warn!(error = %e, "failed to render notify_wrapper; using raw message");
-                    items.push(Item::system_message(n.message.clone()));
+                    let fallback = match &entry {
+                        super::notify_buffer::PendingNotify::Notify { message } => message.clone(),
+                        super::notify_buffer::PendingNotify::PodEvent { event } => {
+                            session_store::render_pod_event(event)
+                        }
+                    };
+                    items.push(Item::system_message(fallback));
                 }
             }
         }
+        self.send_system_items(system_items);
         items
     }
 
@@ -321,6 +367,7 @@ mod tests {
             NotifyBuffer::new(),
             Arc::new(Mutex::new(Vec::new())),
             PromptCatalog::builtins_only().unwrap(),
+            None,
         );
         let mut ctx = ctx_items;
         let action = interceptor.pre_llm_request(&mut ctx).await;
@@ -346,6 +393,7 @@ mod tests {
             NotifyBuffer::new(),
             Arc::new(Mutex::new(Vec::new())),
             PromptCatalog::builtins_only().unwrap(),
+            None,
         );
         let mut ctx = ctx_items;
         let action = interceptor.pre_llm_request(&mut ctx).await;
@@ -372,6 +420,7 @@ mod tests {
             NotifyBuffer::new(),
             Arc::new(Mutex::new(Vec::new())),
             PromptCatalog::builtins_only().unwrap(),
+            None,
         );
         let mut ctx = ctx_items;
         let action = interceptor.pre_llm_request(&mut ctx).await;
@@ -392,6 +441,7 @@ mod tests {
             NotifyBuffer::new(),
             Arc::new(Mutex::new(Vec::new())),
             PromptCatalog::builtins_only().unwrap(),
+            None,
         );
         let mut ctx: Vec<Item> = Vec::new();
         let action = interceptor.pre_llm_request(&mut ctx).await;
@@ -414,8 +464,8 @@ mod tests {
     async fn pending_history_appends_drains_buffer_into_items() {
         let registry = Arc::new(HookRegistryBuilder::new().build());
         let buffer = NotifyBuffer::new();
-        buffer.push("first".into());
-        buffer.push("second".into());
+        buffer.push_notify("first".into());
+        buffer.push_notify("second".into());
 
         let interceptor = PodInterceptor::new(
             registry,
@@ -424,6 +474,7 @@ mod tests {
             buffer.clone(),
             Arc::new(Mutex::new(Vec::new())),
             PromptCatalog::builtins_only().unwrap(),
+            None,
         );
 
         let items = interceptor.pending_history_appends().await;
@@ -451,7 +502,7 @@ mod tests {
         // anything itself.
         let registry = Arc::new(HookRegistryBuilder::new().build());
         let buffer = NotifyBuffer::new();
-        buffer.push("msg".into());
+        buffer.push_notify("msg".into());
 
         let interceptor = PodInterceptor::new(
             registry,
@@ -460,6 +511,7 @@ mod tests {
             buffer.clone(),
             Arc::new(Mutex::new(Vec::new())),
             PromptCatalog::builtins_only().unwrap(),
+            None,
         );
         let mut ctx: Vec<Item> = vec![Item::user_message("hi")];
         let action = interceptor.pre_llm_request(&mut ctx).await;
@@ -489,6 +541,7 @@ mod tests {
             NotifyBuffer::new(),
             Arc::new(Mutex::new(Vec::new())),
             PromptCatalog::builtins_only().unwrap(),
+            None,
         );
         let mut ctx: Vec<Item> = Vec::new();
         let action = interceptor.pre_llm_request(&mut ctx).await;
diff --git a/crates/pod/src/ipc/notify_buffer.rs b/crates/pod/src/ipc/notify_buffer.rs
index 2700f2eb..f5e50477 100644
--- a/crates/pod/src/ipc/notify_buffer.rs
+++ b/crates/pod/src/ipc/notify_buffer.rs
@@ -3,39 +3,48 @@
 //! Entries are queued here by the Controller (on receipt of the
 //! corresponding IPC method) and drained by
 //! `PodInterceptor::pending_history_appends`, which the Worker calls
-//! at the head of each turn loop iteration to `extend` them into the
-//! persistent `worker.history`. Each queued entry becomes one
-//! `Item::system_message`.
+//! at the head of each turn loop iteration. The drain renders each
+//! pending entry into a typed `SystemItem` (with the `notify_wrapper`
+//! prompt applied), commits a `LogEntry::SystemItems` through the
+//! session-log sink, and returns the corresponding
+//! `Item::system_message`s for the worker to append to its
+//! persistent history.
 //!
 //! This is the **single lane** for "system messages produced by Pod
 //! state that should land in the next LLM request": Notify, PodEvent,
-//! and any future `<system-reminder>` injection all ride this queue
-//! (or a sibling queue with the same lifecycle). Per
-//! `tickets/notify-history-persist.md` and `AGENTS.md` (LLM コンテキスト
-//! の加工原則), there is **no** "transient, history-skipping" lane —
-//! everything injected into a request is also committed to history so
-//! that any LLM reaction has a visible trigger across turns, resume,
-//! and compaction, and so the Anthropic prompt cache prefix stays
-//! stable across requests.
+//! and any future `<system-reminder>` injection all ride this queue.
+//! Per `tickets/notify-history-persist.md` and `AGENTS.md` (LLM
+//! context の加工原則), there is **no** "transient, history-skipping"
+//! lane — everything injected into a request is also committed to
+//! history so any LLM reaction has a visible trigger across turns,
+//! resume, and compaction, and so the Anthropic prompt cache prefix
+//! stays stable across requests.
 
 use std::collections::VecDeque;
 use std::sync::{Arc, Mutex};
 
-use llm_worker::Item;
+use protocol::PodEvent;
+use session_store::SystemItem;
 use tracing::warn;
 
 use crate::prompt::catalog::{CatalogError, PromptCatalog};
 
-/// Maximum queued notify entries. Oldest entries are dropped beyond this.
+/// Maximum queued pending entries. Oldest entries are dropped beyond this.
 const CAPACITY: usize = 128;
 
-/// One pending notify entry awaiting injection into the next LLM request.
+/// One pending entry awaiting drain into the next LLM request.
+///
+/// The buffer keeps the raw input shape so the drain step can decide
+/// the right `SystemItem` kind (and apply `notify_wrapper` to the
+/// rendered body) at the moment of commit, when the prompt catalog
+/// is available.
 #[derive(Debug, Clone)]
-pub struct PendingNotify {
-    pub message: String,
+pub enum PendingNotify {
+    Notify { message: String },
+    PodEvent { event: PodEvent },
 }
 
-/// Shared, mutex-guarded buffer of pending notify entries.
+/// Shared, mutex-guarded buffer of pending entries.
 ///
 /// Cloned between the Pod (producer) and PodInterceptor (consumer).
 #[derive(Clone, Default)]
@@ -51,26 +60,35 @@ impl NotifyBuffer {
     /// Push a notify entry onto the queue. If the queue is full, the
     /// oldest entry is dropped and a `tracing::warn` is emitted — the
     /// caller should never hit this in normal operation.
-    pub fn push(&self, message: String) {
+    pub fn push_notify(&self, message: String) {
+        self.push_entry(PendingNotify::Notify { message });
+    }
+
+    /// Push a typed pod-event entry onto the queue.
+    pub fn push_pod_event(&self, event: PodEvent) {
+        self.push_entry(PendingNotify::PodEvent { event });
+    }
+
+    fn push_entry(&self, entry: PendingNotify) {
         let mut q = self.inner.lock().expect("notify buffer poisoned");
         if q.len() >= CAPACITY {
             let dropped = q.pop_front();
             warn!(
                 capacity = CAPACITY,
-                dropped_message = dropped.as_ref().map(|n| n.message.as_str()),
+                dropped = ?dropped,
                 "notify buffer overflow; dropped oldest"
             );
         }
-        q.push_back(PendingNotify { message });
+        q.push_back(entry);
     }
 
-    /// Remove and return all pending notify entries in FIFO order.
+    /// Remove and return all pending entries in FIFO order.
     pub fn drain(&self) -> Vec<PendingNotify> {
         let mut q = self.inner.lock().expect("notify buffer poisoned");
         q.drain(..).collect()
     }
 
-    /// Number of pending notify entries. Primarily for tests.
+    /// Number of pending entries. Primarily for tests.
     pub fn len(&self) -> usize {
         self.inner.lock().expect("notify buffer poisoned").len()
     }
@@ -80,17 +98,30 @@ impl NotifyBuffer {
     }
 }
 
-/// Format a single pending notify entry into the `Item::system_message`
-/// that gets appended to `worker.history` just before the next LLM
-/// request. The wrapper body comes from `PodPrompt::NotifyWrapper` so
-/// the surrounding phrasing can be customised via a prompt pack
-/// (translation, tone, ...).
-pub(crate) fn format_notify(
-    n: &PendingNotify,
+/// Render one pending entry into a typed `SystemItem`. The
+/// `notify_wrapper` prompt produces the LLM-context body for both
+/// `Notify` (raw message) and `PodEvent` (rendered event line).
+pub(crate) fn build_system_item(
+    entry: &PendingNotify,
     prompts: &PromptCatalog,
-) -> Result<Item, CatalogError> {
-    let text = prompts.notify_wrapper(&n.message)?;
-    Ok(Item::system_message(text))
+) -> Result<SystemItem, CatalogError> {
+    match entry {
+        PendingNotify::Notify { message } => {
+            let body = prompts.notify_wrapper(message)?;
+            Ok(SystemItem::Notification {
+                message: message.clone(),
+                body,
+            })
+        }
+        PendingNotify::PodEvent { event } => {
+            let rendered = session_store::render_pod_event(event);
+            let body = prompts.notify_wrapper(&rendered)?;
+            Ok(SystemItem::PodEvent {
+                event: event.clone(),
+                body,
+            })
+        }
+    }
 }
 
 #[cfg(test)]
@@ -100,12 +131,14 @@ mod tests {
     #[test]
     fn push_then_drain_preserves_order() {
         let buf = NotifyBuffer::new();
-        buf.push("one".into());
-        buf.push("two".into());
+        buf.push_notify("one".into());
+        buf.push_notify("two".into());
         let drained = buf.drain();
         assert_eq!(drained.len(), 2);
-        assert_eq!(drained[0].message, "one");
-        assert_eq!(drained[1].message, "two");
+        match &drained[0] {
+            PendingNotify::Notify { message } => assert_eq!(message, "one"),
+            other => panic!("unexpected: {other:?}"),
+        }
         assert!(buf.is_empty());
     }
 
@@ -113,28 +146,50 @@ mod tests {
     fn capacity_drops_oldest() {
         let buf = NotifyBuffer::new();
         for i in 0..(CAPACITY + 5) {
-            buf.push(format!("msg{i}"));
+            buf.push_notify(format!("msg{i}"));
         }
         let drained = buf.drain();
         assert_eq!(drained.len(), CAPACITY);
-        // Oldest 5 were dropped; first retained is msg5.
-        assert_eq!(drained[0].message, "msg5");
-        assert_eq!(
-            drained[CAPACITY - 1].message,
-            format!("msg{}", CAPACITY + 4)
-        );
+        match &drained[0] {
+            PendingNotify::Notify { message } => assert_eq!(message, "msg5"),
+            other => panic!("unexpected: {other:?}"),
+        }
     }
 
     #[test]
-    fn format_notify_includes_message_and_nonblocking_hint() {
-        let n = PendingNotify {
+    fn build_system_item_for_notify_carries_wrapper_body() {
+        let entry = PendingNotify::Notify {
             message: "hello".into(),
         };
         let catalog = PromptCatalog::builtins_only().unwrap();
-        let item = format_notify(&n, &catalog).unwrap();
-        let text = item.as_text().unwrap_or_default().to_string();
-        assert!(text.contains("[Notification]"));
-        assert!(text.contains("hello"));
-        assert!(text.contains("not a blocking request"));
+        let item = build_system_item(&entry, &catalog).unwrap();
+        match item {
+            SystemItem::Notification { message, body } => {
+                assert_eq!(message, "hello");
+                assert!(body.contains("[Notification]"));
+                assert!(body.contains("hello"));
+                assert!(body.contains("not a blocking request"));
+            }
+            other => panic!("unexpected: {other:?}"),
+        }
+    }
+
+    #[test]
+    fn build_system_item_for_pod_event_wraps_rendered_event_text() {
+        let entry = PendingNotify::PodEvent {
+            event: PodEvent::TurnEnded {
+                pod_name: "child".into(),
+            },
+        };
+        let catalog = PromptCatalog::builtins_only().unwrap();
+        let item = build_system_item(&entry, &catalog).unwrap();
+        match item {
+            SystemItem::PodEvent { event, body } => {
+                assert!(matches!(event, PodEvent::TurnEnded { ref pod_name } if pod_name == "child"));
+                assert!(body.contains("[Notification]"));
+                assert!(body.contains("`child`"));
+            }
+            other => panic!("unexpected: {other:?}"),
+        }
     }
 }
diff --git a/crates/pod/src/ipc/server.rs b/crates/pod/src/ipc/server.rs
index 23b29825..3f2a03e4 100644
--- a/crates/pod/src/ipc/server.rs
+++ b/crates/pod/src/ipc/server.rs
@@ -104,22 +104,39 @@ async fn handle_connection(stream: tokio::net::UnixStream, handle: PodHandle) {
             entry = entry_rx.recv() => {
                 match entry {
                     Ok(entry) => {
-                        let value = serde_json::to_value(&entry)
-                            .expect("LogEntry is Serialize");
-                        let outbound = match &entry {
+                        let outbound = match entry {
                             session_store::LogEntry::SessionStart { .. } => {
-                                Some(Event::SessionRotated { entry: value })
+                                let value = serde_json::to_value(&entry)
+                                    .expect("LogEntry is Serialize");
+                                vec![Event::SessionRotated { entry: value }]
                             }
-                            session_store::LogEntry::HookInjectedItems { .. } => {
-                                Some(Event::HookInjectedItems { entry: value })
+                            session_store::LogEntry::SystemItems { items, .. } => {
+                                // Fan out per-item so each `SystemItem`
+                                // arrives as its own `Event::SystemItem`
+                                // on the wire. Batching on disk is an
+                                // implementation detail of the drain
+                                // task; clients see them one at a time.
+                                items
+                                    .into_iter()
+                                    .map(|si| {
+                                        let value = serde_json::to_value(&si)
+                                            .expect("SystemItem is Serialize");
+                                        Event::SystemItem { item: value }
+                                    })
+                                    .collect()
                             }
                             // Defensive: should never reach here per
                             // `SessionLogSink::is_live_relevant`.
-                            _ => None,
+                            _ => Vec::new(),
                         };
-                        if let Some(event) = outbound
-                            && writer.write(&event).await.is_err()
-                        {
+                        let mut hit_error = false;
+                        for event in outbound {
+                            if writer.write(&event).await.is_err() {
+                                hit_error = true;
+                                break;
+                            }
+                        }
+                        if hit_error {
                             break;
                         }
                     }
diff --git a/crates/pod/src/pod.rs b/crates/pod/src/pod.rs
index 674efee0..c4e35c64 100644
--- a/crates/pod/src/pod.rs
+++ b/crates/pod/src/pod.rs
@@ -9,8 +9,8 @@ use llm_worker::llm_client::client::LlmClient;
 use llm_worker::state::Mutable;
 use llm_worker::{ToolOutputLimits, UsageRecord, Worker, WorkerError, WorkerResult};
 use session_store::{
-    EntryHash, HashedEntry, LogEntry, PodScopeSnapshot, SessionId, Store, StoreError, session_log,
-    to_logged,
+    EntryHash, HashedEntry, LogEntry, PodScopeSnapshot, SessionId, Store, StoreError, SystemItem,
+    session_log, to_logged,
 };
 use tracing::{info, warn};
 
@@ -18,16 +18,21 @@ use crate::session_log_sink::SessionLogSink;
 
 /// Command sent to the per-Pod history-drain task.
 ///
-/// `Item` carries one worker-history append observed via
-/// `Worker::on_history_append`; the drain classifies it into a
-/// `LogEntry::AssistantItems` / `LogEntry::ToolResults` /
-/// `LogEntry::HookInjectedItems` and commits it through the sink.
-/// `Flush(ack)` is the barrier used by `persist_turn` to ensure every
-/// in-flight item is committed before the trailing `TurnEnd` entry
-/// lands.
+/// - `Item`: one worker-history append observed via
+///   `Worker::on_history_append`; the drain classifies it into
+///   `LogEntry::AssistantItems` / `LogEntry::ToolResults` and commits
+///   through the sink. `role:system` items are explicitly skipped
+///   because they are committed up-front through `SystemItems`.
+/// - `SystemItems`: typed agent-injected items committed as a single
+///   `LogEntry::SystemItems` entry. Used by the interceptor when it
+///   drains the notify buffer or pending attachments.
+/// - `Flush(ack)`: barrier used by `persist_turn` to ensure every
+///   queued command has been processed before the trailing `TurnEnd`
+///   entry lands.
 #[derive(Debug)]
 pub enum LogCommand {
     Item(Item),
+    SystemItems(Vec<SystemItem>),
     Flush(tokio::sync::oneshot::Sender<()>),
 }
 
@@ -158,7 +163,7 @@ pub struct Pod<C: LlmClient, St: Store> {
     /// before handing off to the worker; `PodInterceptor::on_prompt_submit`
     /// drains it and returns `ContinueWith` so the items land in
     /// history right after the user message that referenced them.
-    pending_attachments: Arc<Mutex<Vec<Item>>>,
+    pending_attachments: Arc<Mutex<Vec<SystemItem>>>,
     /// Scope allocation in the machine-wide lock file. `Some` for
     /// Pods built via `from_manifest` / `from_manifest_spawned` /
     /// `restore_from_manifest` (production paths); `None` for the
@@ -279,7 +284,7 @@ impl<C: LlmClient + Clone + 'static, St: Store + Clone + 'static> Pod<C, St> {
             alerter: self.alerter.clone(),
             event_tx: self.event_tx.clone(),
             pending_notifies: NotifyBuffer::new(),
-            pending_attachments: Arc::new(Mutex::new(Vec::new())),
+            pending_attachments: Arc::new(Mutex::new(Vec::<SystemItem>::new())),
             scope_allocation: None,
             callback_socket: None,
             prompts: self.prompts.clone(),
@@ -378,7 +383,7 @@ impl<C: LlmClient, St: Store> Pod<C, St> {
             alerter: None,
             event_tx: None,
             pending_notifies: NotifyBuffer::new(),
-            pending_attachments: Arc::new(Mutex::new(Vec::new())),
+            pending_attachments: Arc::new(Mutex::new(Vec::<SystemItem>::new())),
             scope_allocation: None,
             callback_socket: None,
             prompts,
@@ -760,7 +765,17 @@ impl<C: LlmClient, St: Store> Pod<C, St> {
     /// `PodInterceptor::pending_history_appends`. See [`NotifyBuffer`]
     /// for overflow behaviour and the lane-of-record rationale.
     pub fn push_notify(&self, message: String) {
-        self.pending_notifies.push(message);
+        self.pending_notifies.push_notify(message);
+    }
+
+    /// Push a typed `PodEvent` entry onto the pending buffer.
+    ///
+    /// Same lifecycle as [`push_notify`](Self::push_notify) but
+    /// preserves the typed `PodEvent` payload so the IPC layer can
+    /// emit `SystemItem::PodEvent { event, body }` with structured
+    /// data for clients.
+    pub fn push_pod_event_notify(&self, event: protocol::PodEvent) {
+        self.pending_notifies.push_pod_event(event);
     }
 
     /// Shared handle to the pending notification buffer.
@@ -892,6 +907,7 @@ impl<C: LlmClient, St: Store> Pod<C, St> {
                 self.pending_notifies.clone(),
                 self.pending_attachments.clone(),
                 self.prompts.clone(),
+                self.log_cmd_tx.clone(),
             );
             self.worker_mut().set_interceptor(interceptor);
             self.interceptor_installed = true;
@@ -1099,7 +1115,7 @@ impl<C: LlmClient, St: Store> Pod<C, St> {
     /// directory) surface as `AlertLevel::Warn` Alerts and are skipped — the
     /// unresolved placeholder stays in the flattened user message so the LLM
     /// still sees the intent.
-    fn resolve_file_refs(&self, segments: &[Segment]) -> Vec<Item> {
+    fn resolve_file_refs(&self, segments: &[Segment]) -> Vec<SystemItem> {
         let view = crate::fs_view::PodFsView::new(tools::ScopedFs::with_shared_scope(
             self.scope.clone(),
             self.pwd.clone(),
@@ -1110,7 +1126,19 @@ impl<C: LlmClient, St: Store> Pod<C, St> {
                 continue;
             };
             match view.resolve_file_ref(path, self.manifest.worker.file_upload.max_bytes) {
-                Ok(item) => out.push(item),
+                Ok(item) => {
+                    // `resolve_file_ref` returns an `Item::system_message`
+                    // whose text already carries the `[File: <path>]` or
+                    // `[Dir: <path>]` header (plus any truncation hint).
+                    // Persist that body verbatim — it is what the LLM
+                    // actually saw, so resume produces byte-identical
+                    // history.
+                    let body = item.as_text().unwrap_or_default().to_string();
+                    out.push(SystemItem::FileAttachment {
+                        path: path.clone(),
+                        body,
+                    });
+                }
                 Err(e) => {
                     self.alert(
                         AlertLevel::Warn,
@@ -1123,7 +1151,7 @@ impl<C: LlmClient, St: Store> Pod<C, St> {
         out
     }
 
-    fn resolve_knowledge_refs(&self, segments: &[Segment]) -> Vec<Item> {
+    fn resolve_knowledge_refs(&self, segments: &[Segment]) -> Vec<SystemItem> {
         let Some(layout) = self.memory_layout.as_ref() else {
             return Vec::new();
         };
@@ -1156,7 +1184,7 @@ impl<C: LlmClient, St: Store> Pod<C, St> {
                 }
             };
             let raw = String::from_utf8_lossy(&bytes).into_owned();
-            let body = match memory::schema::split_frontmatter(&raw) {
+            let body_text = match memory::schema::split_frontmatter(&raw) {
                 Ok((_yaml, body)) => body,
                 Err(e) => {
                     self.alert(
@@ -1173,11 +1201,11 @@ impl<C: LlmClient, St: Store> Pod<C, St> {
                 &bytes,
             );
             self.append_memory_use_event(memory::UsageSource::KnowledgeRef, vec![snapshot]);
-            out.push(Item::system_message(format!(
-                "[Knowledge #{}]\n{}",
-                slug,
-                body.trim_end()
-            )));
+            let body = format!("[Knowledge #{}]\n{}", slug, body_text.trim_end());
+            out.push(SystemItem::Knowledge {
+                slug: slug.clone(),
+                body,
+            });
         }
         out
     }
@@ -1247,7 +1275,7 @@ impl<C: LlmClient, St: Store> Pod<C, St> {
     fn resolve_workflow_invocations(
         &self,
         segments: &[Segment],
-    ) -> Result<Vec<Item>, WorkflowResolveError> {
+    ) -> Result<Vec<SystemItem>, WorkflowResolveError> {
         let Some(layout) = self.memory_layout.as_ref() else {
             if let Some(slug) = segments.iter().find_map(|seg| match seg {
                 Segment::WorkflowInvoke { slug } => Some(slug.clone()),
@@ -1282,7 +1310,17 @@ impl<C: LlmClient, St: Store> Pod<C, St> {
                     warn!(workflow = %slug, error = %err, "failed to snapshot workflow usage");
                 }
             }
-            out.extend(items);
+            // `resolve_workflow_invocation` returns Item::system_message
+            // entries (potentially multiple — body + dependency knowledge
+            // bodies). Persist each as a SystemItem::Workflow keyed on
+            // the invocation slug.
+            for item in items {
+                let body = item.as_text().unwrap_or_default().to_string();
+                out.push(SystemItem::Workflow {
+                    slug: slug.clone(),
+                    body,
+                });
+            }
         }
         Ok(out)
     }
@@ -2635,7 +2673,7 @@ impl<St: Store> Pod<Box<dyn LlmClient>, St> {
             alerter: None,
             event_tx: None,
             pending_notifies: NotifyBuffer::new(),
-            pending_attachments: Arc::new(Mutex::new(Vec::new())),
+            pending_attachments: Arc::new(Mutex::new(Vec::<SystemItem>::new())),
             scope_allocation: Some(scope_allocation),
             callback_socket: None,
             prompts: common.prompts,
@@ -2708,7 +2746,7 @@ impl<St: Store> Pod<Box<dyn LlmClient>, St> {
             alerter: None,
             event_tx: None,
             pending_notifies: NotifyBuffer::new(),
-            pending_attachments: Arc::new(Mutex::new(Vec::new())),
+            pending_attachments: Arc::new(Mutex::new(Vec::<SystemItem>::new())),
             scope_allocation: Some(scope_allocation),
             callback_socket: Some(callback_socket),
             prompts: common.prompts,
@@ -2852,7 +2890,7 @@ impl<St: Store> Pod<Box<dyn LlmClient>, St> {
             alerter: None,
             event_tx: None,
             pending_notifies: NotifyBuffer::new(),
-            pending_attachments: Arc::new(Mutex::new(Vec::new())),
+            pending_attachments: Arc::new(Mutex::new(Vec::<SystemItem>::new())),
             scope_allocation: Some(scope_allocation),
             callback_socket: None,
             prompts: common.prompts,
diff --git a/crates/pod/src/session_log_sink.rs b/crates/pod/src/session_log_sink.rs
index 4e35a046..1f72deaf 100644
--- a/crates/pod/src/session_log_sink.rs
+++ b/crates/pod/src/session_log_sink.rs
@@ -120,7 +120,7 @@ impl SessionLogSink {
     fn is_live_relevant(entry: &LogEntry) -> bool {
         matches!(
             entry,
-            LogEntry::SessionStart { .. } | LogEntry::HookInjectedItems { .. }
+            LogEntry::SessionStart { .. } | LogEntry::SystemItems { .. }
         )
     }
 
@@ -427,12 +427,13 @@ mod tests {
         assert!(rx.try_recv().is_err());
     }
 
-    fn hook_injected(text: &str) -> LogEntry {
-        LogEntry::HookInjectedItems {
+    fn notification_entry(text: &str) -> LogEntry {
+        LogEntry::SystemItems {
             ts: now_millis(),
-            items: vec![session_store::LoggedItem::from(
-                &llm_worker::Item::system_message(text),
-            )],
+            items: vec![session_store::SystemItem::Notification {
+                message: text.to_owned(),
+                body: format!("[Notification] {text}"),
+            }],
         }
     }
 
@@ -448,11 +449,11 @@ mod tests {
         sink.publish(turn_end(1));
         assert!(rx.try_recv().is_err(), "TurnEnd must not be broadcast live");
 
-        // HookInjectedItems is live-relevant.
-        sink.publish(hook_injected("[Notify] hi"));
+        // SystemItems is live-relevant.
+        sink.publish(notification_entry("hi"));
         match rx.try_recv() {
-            Ok(LogEntry::HookInjectedItems { .. }) => {}
-            other => panic!("expected HookInjectedItems, got {other:?}"),
+            Ok(LogEntry::SystemItems { .. }) => {}
+            other => panic!("expected SystemItems, got {other:?}"),
         }
 
         // Mirror still grew with both entries (snapshot completeness).
@@ -465,11 +466,11 @@ mod tests {
         let sink = SessionLogSink::new();
         sink.publish(session_start());
         let (snapshot, mut rx) = sink.subscribe_with_snapshot();
-        sink.publish(hook_injected("post-snapshot"));
+        sink.publish(notification_entry("post-snapshot"));
 
         assert_eq!(snapshot.len(), 1);
         match rx.try_recv() {
-            Ok(LogEntry::HookInjectedItems { .. }) => {}
+            Ok(LogEntry::SystemItems { .. }) => {}
             other => panic!("unexpected: {other:?}"),
         }
         assert!(rx.try_recv().is_err());
diff --git a/crates/pod/tests/controller_test.rs b/crates/pod/tests/controller_test.rs
index af1fb9c2..b4859641 100644
--- a/crates/pod/tests/controller_test.rs
+++ b/crates/pod/tests/controller_test.rs
@@ -34,6 +34,9 @@ fn history_from_sink(handle: &PodHandle) -> Vec<Item> {
             | LogEntry::HookInjectedItems { items: i, .. } => {
                 items.extend(i.into_iter().map(Item::from));
             }
+            LogEntry::SystemItems { items: si, .. } => {
+                items.extend(si.iter().map(|s| s.to_history_item()));
+            }
             _ => {}
         }
     }
@@ -745,16 +748,12 @@ async fn notify_while_idle_auto_starts_turn_and_injects_system_message() {
         .unwrap();
 
     // Wait for the auto-started turn to complete.
-    let mut saw_notify_echo = false;
     let mut saw_turn_end = false;
     let deadline = tokio::time::Instant::now() + std::time::Duration::from_secs(2);
     loop {
         tokio::select! {
             event = rx.recv() => {
                 match event {
-                    Ok(Event::Notify { ref message }) if message == "turn finished" => {
-                        saw_notify_echo = true;
-                    }
                     Ok(Event::TurnEnd { .. }) => { saw_turn_end = true; break; }
                     Err(_) => break,
                     _ => {}
@@ -763,14 +762,28 @@ async fn notify_while_idle_auto_starts_turn_and_injects_system_message() {
             _ = tokio::time::sleep_until(deadline) => break,
         }
     }
-    assert!(
-        saw_notify_echo,
-        "Method::Notify on idle Pod should be echoed as Event::Notify"
-    );
     assert!(saw_turn_end, "auto-triggered turn should complete");
-    // Status flips back to Idle on the controller thread after RunEnd.
-    tokio::time::sleep(std::time::Duration::from_millis(50)).await;
-    assert_eq!(handle.shared_state.get_status(), PodStatus::Idle);
+    // Wait for the post-run persist_turn (Flush + TurnEnd + RunCompleted
+    // commits) to finish; the controller flips status to Idle right
+    // after that.
+    wait_for_status(&handle, PodStatus::Idle).await;
+    // The live echo arrives via the sink's `Event::SystemItem` lane,
+    // not on the `event_tx` broadcast that `handle.subscribe()` taps.
+    // Verify the notification landed on the sink mirror instead.
+    let (entries, _) = handle.sink.subscribe_with_snapshot();
+    let saw_notify_in_mirror = entries.iter().any(|e| matches!(
+        e,
+        session_store::LogEntry::SystemItems { items, .. }
+            if items.iter().any(|si| matches!(
+                si,
+                session_store::SystemItem::Notification { message, .. }
+                    if message == "turn finished"
+            ))
+    ));
+    assert!(
+        saw_notify_in_mirror,
+        "Method::Notify should commit a SystemItem::Notification entry; mirror = {entries:?}"
+    );
 
     // Exactly one request was made; it must contain the formatted
     // notification as one of the items (committed to history by
@@ -825,18 +838,12 @@ async fn pod_event_turn_ended_while_idle_auto_starts_turn_and_injects_system_mes
         .await
         .unwrap();
 
-    let mut saw_pod_event_echo = false;
     let mut saw_turn_end = false;
     let deadline = tokio::time::Instant::now() + std::time::Duration::from_secs(2);
     loop {
         tokio::select! {
             event = rx.recv() => {
                 match event {
-                    Ok(Event::PodEvent(protocol::PodEvent::TurnEnded { ref pod_name }))
-                        if pod_name == "child" =>
-                    {
-                        saw_pod_event_echo = true;
-                    }
                     Ok(Event::TurnEnd { .. }) => { saw_turn_end = true; break; }
                     Err(_) => break,
                     _ => {}
@@ -845,15 +852,28 @@ async fn pod_event_turn_ended_while_idle_auto_starts_turn_and_injects_system_mes
             _ = tokio::time::sleep_until(deadline) => break,
         }
     }
-    assert!(
-        saw_pod_event_echo,
-        "Method::PodEvent on idle Pod should be echoed as Event::PodEvent"
-    );
     assert!(
         saw_turn_end,
         "PodEvent::TurnEnded on idle Pod should auto-start a turn"
     );
-    tokio::time::sleep(std::time::Duration::from_millis(50)).await;
+    // Wait for the post-run persist_turn to complete before reading the
+    // mirror — TurnEnd fires inside the worker loop, persist_turn (and
+    // its Flush of the drain queue) runs afterwards.
+    wait_for_status(&handle, PodStatus::Idle).await;
+    let (entries, _) = handle.sink.subscribe_with_snapshot();
+    let saw_pod_event_in_mirror = entries.iter().any(|e| matches!(
+        e,
+        session_store::LogEntry::SystemItems { items, .. }
+            if items.iter().any(|si| matches!(
+                si,
+                session_store::SystemItem::PodEvent { event: protocol::PodEvent::TurnEnded { pod_name }, .. }
+                    if pod_name == "child"
+            ))
+    ));
+    assert!(
+        saw_pod_event_in_mirror,
+        "Method::PodEvent should commit a SystemItem::PodEvent entry"
+    );
     assert_eq!(handle.shared_state.get_status(), PodStatus::Idle);
 
     let requests = client_for_assert.captured_requests();
@@ -911,8 +931,6 @@ async fn notify_while_running_does_not_emit_already_running_error() {
         .unwrap();
 
     // Drain events until the run ends; AlreadyRunning must never appear.
-    // The in-flight branch must still echo the Notify as a log element.
-    let mut saw_notify_echo = false;
     let deadline = tokio::time::Instant::now() + std::time::Duration::from_secs(2);
     loop {
         tokio::select! {
@@ -921,9 +939,6 @@ async fn notify_while_running_does_not_emit_already_running_error() {
                     Ok(Event::Error { code, .. }) if code == pod::ErrorCode::AlreadyRunning => {
                         panic!("Notify while running must not produce AlreadyRunning");
                     }
-                    Ok(Event::Notify { ref message }) if message == "ping" => {
-                        saw_notify_echo = true;
-                    }
                     Ok(Event::TurnEnd { .. }) => break,
                     Err(_) => break,
                     _ => {}
@@ -932,10 +947,13 @@ async fn notify_while_running_does_not_emit_already_running_error() {
             _ = tokio::time::sleep_until(deadline) => break,
         }
     }
-    assert!(
-        saw_notify_echo,
-        "in-flight Notify must still be echoed as Event::Notify"
-    );
+    // The core property of this test is "no AlreadyRunning error fires
+    // when Notify arrives mid-run". The notify's `SystemItem` commit
+    // is racy here (depends on whether the in-flight turn's next
+    // `pending_history_appends` runs before vs after the buffer push)
+    // and has dedicated coverage in
+    // `notify_while_idle_auto_starts_turn_and_injects_system_message`.
+    wait_for_status(&handle, PodStatus::Idle).await;
 }
 
 #[tokio::test]
@@ -1032,19 +1050,29 @@ async fn socket_pod_event_turn_ended_while_idle_auto_starts_turn() {
     let mut saw_turn_end = false;
 
     let deadline = tokio::time::Instant::now() + std::time::Duration::from_secs(2);
+    // The SystemItem and TurnEnd events arrive through independent
+    // broadcast lanes (sink fan-out vs `event_tx`), so their relative
+    // order on the wire is non-deterministic. Keep reading until both
+    // are observed (or the deadline trips), rather than breaking on
+    // the first TurnEnd.
     loop {
+        if saw_pod_event_echo && saw_turn_end {
+            break;
+        }
         tokio::select! {
             event = reader.next::<Event>() => {
                 match event {
-                    Ok(Some(Event::PodEvent(protocol::PodEvent::TurnEnded { pod_name })))
-                        if pod_name == "child" =>
+                    Ok(Some(Event::SystemItem { ref item }))
+                        if item.get("kind").and_then(|k| k.as_str()) == Some("pod_event")
+                            && item
+                                .pointer("/event/pod_name")
+                                .and_then(|v| v.as_str()) == Some("child") =>
                     {
                         saw_pod_event_echo = true;
                     }
                     Ok(Some(Event::TurnStart { .. })) => saw_turn_start = true,
                     Ok(Some(Event::TurnEnd { .. })) => {
                         saw_turn_end = true;
-                        break;
                     }
                     Ok(None) | Err(_) => break,
                     _ => {}
@@ -1056,7 +1084,7 @@ async fn socket_pod_event_turn_ended_while_idle_auto_starts_turn() {
 
     assert!(
         saw_pod_event_echo,
-        "PodEvent::TurnEnded via socket should be echoed as Event::PodEvent"
+        "PodEvent::TurnEnded via socket should be echoed as Event::SystemItem(PodEvent)"
     );
     assert!(
         saw_turn_start,
diff --git a/crates/protocol/src/lib.rs b/crates/protocol/src/lib.rs
index 262a6a7b..eb51e148 100644
--- a/crates/protocol/src/lib.rs
+++ b/crates/protocol/src/lib.rs
@@ -214,20 +214,23 @@ pub enum Event {
     UserMessage {
         segments: Vec<Segment>,
     },
-    /// Echo of `Method::Notify` received by this Pod. Broadcast on
-    /// receipt so subscribers can render the external input as a log
-    /// element. The same `message` is independently pushed into the
-    /// notification buffer for LLM injection (with prompt-pack
-    /// wrapping); this echo carries the raw payload and does not
-    /// imply any turn-boundary semantics.
-    Notify {
-        message: String,
+    /// One agent-injected system item committed to history.
+    ///
+    /// Carries the JSON form of `session_store::SystemItem`. Covers
+    /// `Method::Notify` echoes, child-Pod lifecycle events from
+    /// `Method::PodEvent`, `@<path>` / `#<slug>` / `/<slug>`
+    /// resolution payloads, and any future agent-side injection kind.
+    /// Clients dispatch on the `kind` tag for typed rendering instead
+    /// of parsing free-text prefixes like `[Notification] …` or
+    /// `[File: …]`.
+    ///
+    /// Fired per-item, even when the underlying
+    /// `LogEntry::SystemItems` entry batched several together — the
+    /// IPC layer fans the batch out at broadcast time so subscribers
+    /// observe one event per item.
+    SystemItem {
+        item: serde_json::Value,
     },
-    /// Echo of `Method::PodEvent` received by this Pod. Same rationale
-    /// as `Notify`: subscribers render the event as a log element,
-    /// while a rendered summary is independently injected into the LLM
-    /// context via the notification buffer.
-    PodEvent(PodEvent),
     TurnStart {
         turn: usize,
     },
@@ -335,17 +338,6 @@ pub enum Event {
     SessionRotated {
         entry: serde_json::Value,
     },
-    /// A non-LLM-driven history append landed in the worker history.
-    ///
-    /// Carries the JSON form of `session_store::LogEntry::HookInjectedItems`.
-    /// This is the live counterpart of items that the streaming lane
-    /// never broadcasts — `Method::Notify` echoes, `@<path>` attachment
-    /// resolutions, `<system-reminder>` injections — so a connected
-    /// client can render them in time order without waiting for the
-    /// next reconnect's `Snapshot`.
-    HookInjectedItems {
-        entry: serde_json::Value,
-    },
     /// Current Pod controller status. Broadcast on every controller-level
     /// transition and included in `History` snapshots for late attach.
     Status {
@@ -791,20 +783,18 @@ mod tests {
     }
 
     #[test]
-    fn event_hook_injected_items_roundtrip() {
-        let event = Event::HookInjectedItems {
-            entry: serde_json::json!({"kind": "hook_injected_items", "ts": 42, "items": []}),
+    fn event_system_item_roundtrip() {
+        let event = Event::SystemItem {
+            item: serde_json::json!({"kind": "notification", "message": "hello"}),
         };
         let json = serde_json::to_string(&event).unwrap();
         let parsed: serde_json::Value = serde_json::from_str(&json).unwrap();
-        assert_eq!(parsed["event"], "hook_injected_items");
-        assert_eq!(parsed["data"]["entry"]["kind"], "hook_injected_items");
+        assert_eq!(parsed["event"], "system_item");
+        assert_eq!(parsed["data"]["item"]["kind"], "notification");
         let decoded: Event = serde_json::from_str(&json).unwrap();
         match decoded {
-            Event::HookInjectedItems { entry } => {
-                assert_eq!(entry["kind"], "hook_injected_items")
-            }
-            other => panic!("expected HookInjectedItems, got {other:?}"),
+            Event::SystemItem { item } => assert_eq!(item["kind"], "notification"),
+            other => panic!("expected SystemItem, got {other:?}"),
         }
     }
 
@@ -1066,43 +1056,6 @@ mod tests {
         assert_eq!(parsed["data"]["code"], "already_running");
     }
 
-    #[test]
-    fn event_notify_roundtrip() {
-        let event = Event::Notify {
-            message: "child-pod finished".into(),
-        };
-        let json = serde_json::to_string(&event).unwrap();
-        let parsed: serde_json::Value = serde_json::from_str(&json).unwrap();
-        assert_eq!(parsed["event"], "notify");
-        assert_eq!(parsed["data"]["message"], "child-pod finished");
-
-        let decoded: Event = serde_json::from_str(&json).unwrap();
-        match decoded {
-            Event::Notify { message } => assert_eq!(message, "child-pod finished"),
-            other => panic!("expected Notify, got {other:?}"),
-        }
-    }
-
-    #[test]
-    fn event_pod_event_roundtrip() {
-        let event = Event::PodEvent(PodEvent::TurnEnded {
-            pod_name: "child".into(),
-        });
-        let json = serde_json::to_string(&event).unwrap();
-        let parsed: serde_json::Value = serde_json::from_str(&json).unwrap();
-        assert_eq!(parsed["event"], "pod_event");
-        assert_eq!(parsed["data"]["kind"], "turn_ended");
-        assert_eq!(parsed["data"]["pod_name"], "child");
-
-        let decoded: Event = serde_json::from_str(&json).unwrap();
-        match decoded {
-            Event::PodEvent(PodEvent::TurnEnded { pod_name }) => {
-                assert_eq!(pod_name, "child");
-            }
-            other => panic!("expected PodEvent::TurnEnded, got {other:?}"),
-        }
-    }
-
     #[test]
     fn event_user_message_roundtrip() {
         let event = Event::UserMessage {
diff --git a/crates/session-store/src/lib.rs b/crates/session-store/src/lib.rs
index 697c0ae6..62f0d872 100644
--- a/crates/session-store/src/lib.rs
+++ b/crates/session-store/src/lib.rs
@@ -32,6 +32,7 @@ pub mod logged_item;
 pub mod session;
 pub mod session_log;
 pub mod store;
+pub mod system_item;
 
 pub use event_trace::TraceEntry;
 pub use fs_store::FsStore;
@@ -48,6 +49,7 @@ pub use session_log::{
     EntryHash, HashedEntry, LogEntry, POD_SCOPE_EXTENSION_DOMAIN, PodScopeSnapshot, RestoredState,
     SessionOrigin, build_chain, collect_state, compute_hash,
 };
+pub use system_item::{SystemItem, render_pod_event};
 pub use store::{Store, StoreError};
 
 /// Session identifier. UUID v7 (time-ordered, lexicographically sortable).
diff --git a/crates/session-store/src/session_log.rs b/crates/session-store/src/session_log.rs
index 4e6dcae7..056ef115 100644
--- a/crates/session-store/src/session_log.rs
+++ b/crates/session-store/src/session_log.rs
@@ -15,6 +15,7 @@ use serde::{Deserialize, Serialize};
 use sha2::{Digest, Sha256};
 
 use crate::logged_item::LoggedItem;
+use crate::system_item::SystemItem;
 
 /// SHA-256 hash identifying a specific log entry in the chain.
 ///
@@ -125,7 +126,18 @@ pub enum LogEntry {
     /// Tool execution results added to history (worker.rs:897-900, 1072-1076).
     ToolResults { ts: u64, items: Vec<LoggedItem> },
 
-    /// Items injected by `on_turn_end` hook via `ContinueWithMessages` (worker.rs:1055).
+    /// Typed agent-injected system items: notifications, child-Pod
+    /// lifecycle events, `@<path>` / `#<slug>` / `/<slug>` resolution
+    /// payloads. Each `SystemItem` carries kind metadata that the LLM
+    /// itself never sees (the LLM gets `Item::system_message` with the
+    /// item's `history_text()`), but live clients and replay paths
+    /// dispatch on `kind` for typed rendering.
+    SystemItems { ts: u64, items: Vec<SystemItem> },
+
+    /// Legacy pre-`SystemItems` form. Deserialize-only — new writes
+    /// always use `SystemItems`. Items are flattened to
+    /// `Item::system_message` on replay, matching how the original
+    /// path worked.
     HookInjectedItems { ts: u64, items: Vec<LoggedItem> },
 
     /// Turn boundary. Records the turn count after increment.
@@ -276,6 +288,11 @@ pub fn collect_state(entries: &[HashedEntry]) -> RestoredState {
             LogEntry::ToolResults { items, .. } => {
                 state.history.extend(items.iter().cloned().map(Item::from));
             }
+            LogEntry::SystemItems { items, .. } => {
+                state
+                    .history
+                    .extend(items.iter().map(|si| si.to_history_item()));
+            }
             LogEntry::HookInjectedItems { items, .. } => {
                 state.history.extend(items.iter().cloned().map(Item::from));
             }
diff --git a/crates/session-store/src/system_item.rs b/crates/session-store/src/system_item.rs
new file mode 100644
index 00000000..8849f2b8
--- /dev/null
+++ b/crates/session-store/src/system_item.rs
@@ -0,0 +1,198 @@
+//! Typed system-message items injected by the agent system.
+//!
+//! Items in worker history with `role:system` are never produced by the
+//! LLM — they are always inserted by the Pod itself (notifications,
+//! file/knowledge/workflow ref resolutions, child-pod lifecycle events,
+//! future `<system-reminder>` tags, …). [`SystemItem`] carries the
+//! typed shape of each such injection so clients can dispatch on
+//! `kind` instead of parsing text prefixes like `[Notification] …` or
+//! `[File: …]`.
+//!
+//! Persisted as the payload of [`crate::LogEntry::SystemItems`], and
+//! broadcast live as the payload of `Event::SystemItem` on the wire.
+//!
+//! For LLM context replay, each `SystemItem` reduces to an
+//! `Item::system_message(...)` whose body matches the legacy free-text
+//! shape (see [`SystemItem::history_text`]). The kind metadata is
+//! preserved only on the log/wire side; the LLM still sees plain
+//! system-message text.
+
+use llm_worker::llm_client::types::Item;
+use protocol::PodEvent;
+use serde::{Deserialize, Serialize};
+
+/// One agent-injected system item, tagged by origin.
+///
+/// Each variant carries the kind-specific raw data clients use for
+/// typed rendering (`Notification.message`, `PodEvent.event`, file
+/// path / knowledge slug / workflow slug / etc.), plus a pre-rendered
+/// `body` (where applicable) that is the exact `role:system` text the
+/// LLM actually saw at commit time. `body` is denormalised so that
+/// session log replay reconstructs worker history byte-identical to
+/// what was on the wire — even when prompt overrides (e.g. custom
+/// `notify_wrapper` template) re-shape the live rendering on a later
+/// resume.
+///
+/// New variants get added here as fresh injection kinds come online
+/// (e.g. `Reminder`). The `kind` JSON tag is the snake_case form of
+/// the variant name.
+#[derive(Debug, Clone, Serialize, Deserialize)]
+#[serde(tag = "kind", rename_all = "snake_case")]
+pub enum SystemItem {
+    /// Free-form notification sent in by an external caller via
+    /// `Method::Notify`. `message` is the raw caller-supplied text;
+    /// `body` is the wrapped LLM-context form (Pod renders it via
+    /// `notify_wrapper` at commit time).
+    Notification { message: String, body: String },
+
+    /// Lifecycle event reported by a child Pod via `Method::PodEvent`.
+    /// `event` is the typed payload (so the TUI can render per-child
+    /// banners without re-parsing); `body` is the wrapped LLM-context
+    /// form (same `notify_wrapper` path as `Notification`).
+    PodEvent { event: PodEvent, body: String },
+
+    /// `@<path>` file reference resolution. `body` is the rendered
+    /// LLM-context text (`[File: <path>]\n…` for regular files,
+    /// `[Dir: <path>]\n…` for directory listings, possibly with a
+    /// truncation hint) so replay reconstructs worker history
+    /// byte-identical to what was sent.
+    FileAttachment { path: String, body: String },
+
+    /// `#<slug>` Knowledge reference resolution. `body` is the
+    /// rendered text the LLM saw (Pod composes the `[Knowledge: …]`
+    /// header + body).
+    Knowledge { slug: String, body: String },
+
+    /// `/<slug>` Workflow invocation. `body` is the workflow's
+    /// prompt body materialized into the LLM context.
+    Workflow { slug: String, body: String },
+}
+
+impl SystemItem {
+    /// Free-text body the LLM sees inside its `role:system` message
+    /// for this item. Returns the variant's stored `body` verbatim.
+    pub fn history_text(&self) -> String {
+        match self {
+            SystemItem::Notification { body, .. } => body.clone(),
+            SystemItem::PodEvent { body, .. } => body.clone(),
+            SystemItem::FileAttachment { body, .. } => body.clone(),
+            SystemItem::Knowledge { body, .. } => body.clone(),
+            SystemItem::Workflow { body, .. } => body.clone(),
+        }
+    }
+
+    /// Materialize this `SystemItem` as the `Item::system_message`
+    /// form that lands in worker history.
+    pub fn to_history_item(&self) -> Item {
+        Item::system_message(self.history_text())
+    }
+
+    /// Short human-readable label used for diagnostics. Not on the
+    /// wire — keep flexible.
+    pub fn kind_label(&self) -> &'static str {
+        match self {
+            SystemItem::Notification { .. } => "notification",
+            SystemItem::PodEvent { .. } => "pod_event",
+            SystemItem::FileAttachment { .. } => "file_attachment",
+            SystemItem::Knowledge { .. } => "knowledge",
+            SystemItem::Workflow { .. } => "workflow",
+        }
+    }
+}
+
+/// Render a `PodEvent` as the one-line notification text the agent
+/// sees. Centralised here (rather than at the controller's render
+/// site) so persistence and broadcast share the same rendering.
+pub fn render_pod_event(event: &PodEvent) -> String {
+    match event {
+        PodEvent::TurnEnded { pod_name } => format!("pod `{pod_name}` finished a turn"),
+        PodEvent::Errored { pod_name, message } => {
+            format!("pod `{pod_name}` errored: {message}")
+        }
+        PodEvent::ShutDown { pod_name } => format!("pod `{pod_name}` shut down"),
+        PodEvent::ScopeSubDelegated {
+            parent_pod,
+            sub_pod,
+            ..
+        } => {
+            format!("pod `{parent_pod}` sub-delegated scope to `{sub_pod}`")
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn notification_history_text_returns_stored_body() {
+        let item = SystemItem::Notification {
+            message: "child done".into(),
+            body: "[Notification]\nchild done\n\n(non-blocking hint…)".into(),
+        };
+        assert_eq!(
+            item.history_text(),
+            "[Notification]\nchild done\n\n(non-blocking hint…)"
+        );
+    }
+
+    #[test]
+    fn pod_event_history_text_returns_stored_body() {
+        let item = SystemItem::PodEvent {
+            event: PodEvent::TurnEnded {
+                pod_name: "child".into(),
+            },
+            body: "[Notification]\npod `child` finished a turn\n\n(non-blocking hint…)".into(),
+        };
+        assert!(item.history_text().starts_with("[Notification]\n"));
+        assert!(item.history_text().contains("`child`"));
+    }
+
+    #[test]
+    fn file_attachment_history_text_returns_stored_body() {
+        let item = SystemItem::FileAttachment {
+            path: "src/main.rs".into(),
+            body: "[File: src/main.rs]\nfn main() {}".into(),
+        };
+        assert_eq!(item.history_text(), "[File: src/main.rs]\nfn main() {}");
+    }
+
+    #[test]
+    fn round_trip_via_json() {
+        let item = SystemItem::FileAttachment {
+            path: "src/main.rs".into(),
+            body: "[File: src/main.rs]\nfn main() {}".into(),
+        };
+        let json = serde_json::to_string(&item).unwrap();
+        let parsed: SystemItem = serde_json::from_str(&json).unwrap();
+        match parsed {
+            SystemItem::FileAttachment { path, body } => {
+                assert_eq!(path, "src/main.rs");
+                assert_eq!(body, "[File: src/main.rs]\nfn main() {}");
+            }
+            other => panic!("unexpected: {other:?}"),
+        }
+    }
+
+    #[test]
+    fn round_trip_pod_event() {
+        let item = SystemItem::PodEvent {
+            event: PodEvent::TurnEnded {
+                pod_name: "child".into(),
+            },
+            body: "[Notification] pod `child` finished a turn".into(),
+        };
+        let json = serde_json::to_string(&item).unwrap();
+        let parsed: SystemItem = serde_json::from_str(&json).unwrap();
+        match parsed {
+            SystemItem::PodEvent {
+                event: PodEvent::TurnEnded { pod_name },
+                body,
+            } => {
+                assert_eq!(pod_name, "child");
+                assert!(body.contains("`child`"));
+            }
+            other => panic!("unexpected: {other:?}"),
+        }
+    }
+}
diff --git a/crates/tui/src/app.rs b/crates/tui/src/app.rs
index 2eb75ce5..607ef82c 100644
--- a/crates/tui/src/app.rs
+++ b/crates/tui/src/app.rs
@@ -483,21 +483,13 @@ impl App {
                 self.blocks.push(Block::UserMessage { segments });
                 self.assistant_streaming = false;
             }
-            Event::Notify { message } => {
-                self.blocks.push(Block::Notify { message });
-                self.assistant_streaming = false;
-            }
-            Event::PodEvent(event) => {
-                self.blocks.push(Block::PodEvent { event });
-                self.assistant_streaming = false;
-            }
             Event::SessionRotated { entry } => {
                 self.reset_for_rotation();
                 self.apply_log_entry_raw(&entry);
                 self.assistant_streaming = false;
             }
-            Event::HookInjectedItems { entry } => {
-                self.apply_log_entry_raw(&entry);
+            Event::SystemItem { item } => {
+                self.apply_system_item(&item);
                 self.assistant_streaming = false;
             }
             Event::TurnStart { .. } => {
@@ -984,11 +976,51 @@ impl App {
                     self.push_history_item(&item_value);
                 }
             }
+            session_store::LogEntry::SystemItems { items, .. } => {
+                for system_item in items {
+                    let value =
+                        serde_json::to_value(&system_item).expect("SystemItem is Serialize");
+                    self.apply_system_item(&value);
+                }
+            }
             // Non-history-bearing variants don't affect the block view.
             _ => {}
         }
     }
 
+    /// Dispatch one `SystemItem` JSON value into the appropriate block.
+    ///
+    /// Kind-based routing replaces the old free-text `[Notification]` /
+    /// `[File: …]` parsing path: each kind maps directly to a typed
+    /// block (`Block::Notify`, `Block::PodEvent`, …).
+    fn apply_system_item(&mut self, value: &serde_json::Value) {
+        let Ok(item) = serde_json::from_value::<session_store::SystemItem>(value.clone()) else {
+            // Unknown / forward-compat shape: fall back to rendering the
+            // raw text payload (if any) as a generic system message.
+            if let Some(text) = value.get("body").and_then(|b| b.as_str()) {
+                self.task_store.apply_system_message_text(text);
+                self.blocks.push(Block::SystemMessage {
+                    text: text.to_owned(),
+                });
+            }
+            return;
+        };
+        match item {
+            session_store::SystemItem::Notification { message, .. } => {
+                self.blocks.push(Block::Notify { message });
+            }
+            session_store::SystemItem::PodEvent { event, .. } => {
+                self.blocks.push(Block::PodEvent { event });
+            }
+            session_store::SystemItem::FileAttachment { body, .. }
+            | session_store::SystemItem::Knowledge { body, .. }
+            | session_store::SystemItem::Workflow { body, .. } => {
+                self.task_store.apply_system_message_text(&body);
+                self.blocks.push(Block::SystemMessage { text: body });
+            }
+        }
+    }
+
     /// Sweep all current tool-call blocks: any that never resolved into
     /// a Done / Error state get marked Incomplete. Called after a
     /// snapshot replay so dangling in-flight tool calls in the seed
@@ -1422,18 +1454,14 @@ mod completion_flow_tests {
     }
 
     #[test]
-    fn live_hook_injected_items_event_appends_system_message_block() {
+    fn live_system_item_workflow_appends_system_message_block() {
         let mut app = App::new("test".into());
-        let entry = serde_json::json!({
-            "kind": "hook_injected_items",
-            "ts": 1,
-            "items": [{
-                "kind": "message",
-                "role": "system",
-                "content": [{ "kind": "text", "text": "[Workflow /build]\nRun the build" }],
-            }],
+        let item = serde_json::json!({
+            "kind": "workflow",
+            "slug": "build",
+            "body": "[Workflow /build]\nRun the build",
         });
-        app.handle_pod_event(Event::HookInjectedItems { entry });
+        app.handle_pod_event(Event::SystemItem { item });
 
         assert!(matches!(
             app.blocks.as_slice(),
@@ -1441,6 +1469,39 @@ mod completion_flow_tests {
         ));
     }
 
+    #[test]
+    fn live_system_item_notification_appends_notify_block() {
+        let mut app = App::new("test".into());
+        let item = serde_json::json!({
+            "kind": "notification",
+            "message": "hi",
+            "body": "[Notification] hi",
+        });
+        app.handle_pod_event(Event::SystemItem { item });
+        assert!(matches!(
+            app.blocks.as_slice(),
+            [Block::Notify { message }] if message == "hi"
+        ));
+    }
+
+    #[test]
+    fn live_system_item_pod_event_appends_pod_event_block() {
+        let mut app = App::new("test".into());
+        let item = serde_json::json!({
+            "kind": "pod_event",
+            "event": { "kind": "turn_ended", "pod_name": "child" },
+            "body": "[Notification] pod `child` finished a turn",
+        });
+        app.handle_pod_event(Event::SystemItem { item });
+        assert_eq!(app.blocks.len(), 1);
+        match &app.blocks[0] {
+            Block::PodEvent {
+                event: protocol::PodEvent::TurnEnded { pod_name },
+            } => assert_eq!(pod_name, "child"),
+            _ => panic!("expected a PodEvent block"),
+        }
+    }
+
     #[test]
     fn compact_done_replaces_live_block() {
         let mut app = App::new("test".into());
@@ -1577,15 +1638,13 @@ mod completion_flow_tests {
             ```json\n{\n  \"tasks\": [\n    {\n      \"taskid\": 4,\n      \
             \"status\": \"inprogress\",\n      \"subject\": \"from snapshot\",\n      \
             \"description\": \"d\"\n    }\n  ]\n}\n```\n";
-        app.handle_pod_event(Event::HookInjectedItems {
-            entry: serde_json::json!({
-                "kind": "hook_injected_items",
-                "ts": 1,
-                "items": [{
-                    "kind": "message",
-                    "role": "system",
-                    "content": [{ "kind": "text", "text": snapshot }],
-                }],
+        // Snapshot text injected as a workflow body (kind doesn't matter
+        // for task-store parsing, only the text contents do).
+        app.handle_pod_event(Event::SystemItem {
+            item: serde_json::json!({
+                "kind": "workflow",
+                "slug": "task-snapshot",
+                "body": snapshot,
             }),
         });
 
diff --git a/tickets/system-item-unify.md b/tickets/system-item-unify.md
deleted file mode 100644
index 6b1f539a..00000000
--- a/tickets/system-item-unify.md
+++ /dev/null
@@ -1,80 +0,0 @@
-# Event / LogEntry: System 注入経路を SystemItem 一本に統合する
-
-## 背景
-
-エージェントシステム (= ユーザー由来でも LLM 由来でもない、Pod 自身) が LLM context に注入する `role:system` の `Item::Message` は、現状 3 系統の ad-hoc 経路で並走している:
-
-1. **`Method::Notify`** — 外部からの非同期メッセージ
-   - controller → `Event::Notify { message }` (生 message echo)
-   - `pod.push_notify(message)` → `NotifyBuffer` → `pending_history_appends` で `[Notification] <msg>` の system_message として history に commit
-2. **`Method::PodEvent`** — 子 pod のライフサイクル通知
-   - controller → `Event::PodEvent(event)` (typed echo)
-   - `render_event` で 1 行整形 → `NotifyBuffer` (Notify と合流) → 同じく `[Notification] <rendered>` として commit
-3. **Interceptor 内部注入** — `@<path>` / `#<slug>` / `/<slug>` の解決結果
-   - `PodInterceptor::on_prompt_submit` の `ContinueWith` で `[File: <path>]` / `[Knowledge: <slug>]` / workflow 本文の system_message を history に append
-   - wire echo は無し
-
-これらは全部 「**人でも LLM でもなく、エージェントシステムが LLM に与えた情報**」 という同一カテゴリで、history への commit 形 (`role:system` の `Item::Message`) もほぼ同じだが、wire event 側は echo/typed/未送信が混在し、TUI 側のブロックも `Block::Notify` / `Block::PodEvent` / `Block::SystemMessage` の 3 つに分かれている。
-
-加えて `LogEntry::HookInjectedItems` という命名が誤称: 実際に注入しているのは公開 `Hook` ではなく **`Interceptor`** で、内部機構専用の経路。`hook.rs` モジュール doc でも 「Hook は read-only な公開 extension surface」 「内部機構は Interceptor を使う」 と明確に分離されている。
-
-このばらつきの結果:
-- wire 上、同じ通知が `Event::Notify` (生) + `Event::HookInjectedItems` (整形版) の 2 重に流れて TUI が重複描画した (`pod-state-from-session-log` 改修中に表面化)
-- kind 判別がテキストプレフィックス (`[Notification] ...` / `[File: ...]`) 頼みで脆い
-- 新しい注入種 (`<system-reminder>` 等) を足すたびに 1 系統増える設計圧力
-- `Method::Notify` の "Notify" 語感が view-only な `Alerter` (本来 "Notification" 寄り) とぶつかっている
-
-LLM は `role:system` を生成しないため、worker.history 中の `role:system` 項目は構造的にすべてこのエージェント注入経路に由来する。この性質を型として表に出す。
-
-## 方針
-
-`Tool` パターンに倣って 「**1 つの concept + kind ベース dispatch**」 に統合する。
-
-- wire event は 1 種類: `Event::SystemItem { kind, payload }` (1 件ずつライブ配信)
-- LogEntry は kind 揃いで batch する単一バリアントに置き換え、`Hook` 命名を捨てる: `LogEntry::SystemItems { ts, items: Vec<SystemItem> }`
-- Pod 内部の注入路 (NotifyBuffer / `format_notify` / `render_event` / Interceptor.ContinueWith) は **全部「kind 付き `SystemItem` を作って worker.history に commit」 という単一形式に合流**
-- TUI は kind 別に Block を出し分け (現 `ToolCallBlock` がツール別に見た目を出すのと同じ構造)
-
-単数/複数の使い分けは既存パターンに揃える:
-- 1 件単位の wire event は `Event::SystemItem` (`Event::TextDelta` と同じ呼吸)
-- 永続バッチは `LogEntry::SystemItems` で `Vec<SystemItem>` を内包 (`LogEntry::AssistantItems` / `ToolResults` と同じ呼吸)
-
-`Method::Notify` / `Method::PodEvent` は外部 API としてはそのまま残す (入口の意味付けは別)。 中で `SystemItem::Notification` / `SystemItem::PodEvent` に変換されて以後は単一経路、という整理。
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-`Event::Alert` (= LLM context に乗らない純 UI 通知) は **別経路として明確に残す**。 view-only な persistent stream (Alerter の subscribe_with_snapshot) としてすでに正しく機能している。 "Notification" 語感の衝突は、本チケットで context 注入側を `SystemItem` に rename することで解消する (Notification は `SystemItem` の一 kind に格下げ、`Alerter` が "Notification" 語感の本来のオーナーに戻る)。
-
-## 要件
-
-- wire event は 1 種類: `Event::SystemItem { kind, payload }` で全注入が乗る。 `Event::Notify` / `Event::PodEvent` / `Event::HookInjectedItems` は protocol から削除
-- LogEntry は `HookInjectedItems` を rename + items を kind 付き typed shape に置換。 新名 `LogEntry::SystemItems { ts, items: Vec<SystemItem> }` で wire tag は `system_items`
-- `SystemItem` の kind 列挙は最低限以下を含む:
-  - `Notification { message }` (`Method::Notify` 由来)
-  - `PodEvent { event: PodEvent }` (子 pod ライフサイクル)
-  - `FileAttachment { path, content }` (`@<path>` 解決)
-  - `Knowledge { slug, body }` (`#<slug>` 解決)
-  - `Workflow { slug, body }` (`/<slug>` 解決)
-  - 将来追加可能 (`Reminder` 等) を見越した拡張点
-- Pod 側の `NotifyBuffer` / `format_notify` / `render_event` / `Interceptor::on_prompt_submit ContinueWith` は `SystemItem` を中間表現として通る。 worker.history への append は最終的に `Item::system_message` + 対応する `SystemItem` 1 件を `LogEntry::SystemItems` として commit
-- TUI は `Event::SystemItem` を kind で dispatch して描画する。 既存 `Block::Notify` / `Block::PodEvent` / `Block::SystemMessage` を `Block::SystemItem(SystemItemBlock)` に集約 (or 既存 Block を再利用しつつ駆動イベントだけ統一)
-- `Method::Notify` / `Method::PodEvent` (外部入口 API) は名前を維持し、内部で `SystemItem::Notification` / `SystemItem::PodEvent` に変換される
-- `Event::Alert` / `Alerter` は無変更
-
-## 完了条件
-
-- `Event::Notify` / `Event::PodEvent` / `Event::HookInjectedItems` が protocol から削除されている
-- `LogEntry::HookInjectedItems` が削除され、`LogEntry::SystemItems` に置き換わっている (旧 wire tag を deserialize alias で残すかは実装判断)
-- TUI が `Event::SystemItem` 駆動で system 系ブロックを構築している。 ライブ通知の二重描画が起きない
-- `Method::Notify` と `Method::PodEvent` は外部 API としては変わらず動く
-- `Event::Alert` / `Alerter` 経路は無変更
-
-## 範囲外
-
-- `Method::Notify` / `Method::PodEvent` の rename (入口名の整理は別の話)
-- `Event::Alert` / `Alerter` 系の変更
-- 旧 session log (`hook_injected_items` を含む) のファイル変換: deserialize alias で読めるところまでで、ファイル書き換えは行わない
-- TUI 内の `Block::SystemItem` 詳細な視覚設計
-
-## 関連
-
-- 前提となる `tickets/pod-state-from-session-log.md` (state 正本を session log に統合) の後続。 同チケット内で `Event::HookInjectedItems` を導入したが、 直後に「Hook 命名は誤り」「Notify/PodEvent と二重」と判明したため本チケットで整理する
-- CLAUDE.md の 「context に乗せる前に history に commit する」 加工原則に整合する整理 (現実装の経路を統一形にするだけで、原則自体は変わらない)