diff --git a/crates/llm-worker/README.md b/crates/llm-worker/README.md
index 0396e55b..3077f261 100644
--- a/crates/llm-worker/README.md
+++ b/crates/llm-worker/README.md
@@ -16,8 +16,8 @@ LLM との対話を管理する低レベル基盤クレート。会話履歴、
 - `tool` — ツール定義・実行（`Tool` トレイト、`ToolDefinition`, `ToolOutput`, サイズ判定による Inline/Stored 切替）
 - `tool_server` — ツール登録・ルックアップ（`ToolServer`, `ToolServerHandle`）
 - `hook` — 実行フローへの介入ポイント（`Hook` トレイト、`PreToolCall`, `PostToolCall`, `OnTurnEnd` など）
-- `subscriber` — リアルタイムイベント購読（`WorkerSubscriber` トレイト）
-- `timeline` — イベントストリームのディスパッチ（`Handler` トレイト、各ブロックコレクター）
+- クロージャベースイベント購読（`Worker::on_text_block()`, `on_tool_use_block()`, `on_usage()` 等）
+- `timeline` — イベントストリームのディスパッチ（`Handler` トレイト、各ブロックコレクター）。パワーユーザー向けに `timeline_mut()` も提供
 - `event` — ストリーミングイベント型（`Event`, `BlockStart`, `BlockDelta` など）
 - `state` — 型状態パターンによるキャッシュ保護（`Mutable` / `CacheLocked`）
 cratesの整理Add READMEsRE to all crates@@
diff --git a/crates/llm-worker/docs/architecture.md b/crates/llm-worker/docs/architecture.md
index 3114401a..920e917d 100644
--- a/crates/llm-worker/docs/architecture.md
+++ b/crates/llm-worker/docs/architecture.md
@@ -33,7 +33,7 @@ llm-workerは3層構成でLLMとのインタラクションを管理する。
 | `tool` / `tool_server` | ツール定義・登録・実行 | R3 |
 | `timeline` | イベントストリーム処理、Handler dispatch | — |
 | `handler` | Handler/Kind trait、ブロック別ハンドラ | — |
-| `subscriber` | WorkerSubscriber trait、UI向けイベント配信 | — |
+| `callback` | クロージャベースイベント購読（`on_text_block`, `on_usage` 等） | — |
 | `llm_client` | LLMプロバイダへのHTTPリクエスト/ストリーミング | — |
 | `llm_client/scheme` | プロバイダ固有ワイヤーフォーマット変換 | — |
 | `llm_client/providers` | Anthropic, OpenAI, Gemini, Ollama実装 | — |
diff --git a/crates/llm-worker/src/callback.rs b/crates/llm-worker/src/callback.rs
new file mode 100644
index 00000000..a66de95f
--- /dev/null
+++ b/crates/llm-worker/src/callback.rs
@@ -0,0 +1,216 @@
+//! Closure-based event callback API
+//!
+//! Provides a closure-based alternative to implementing `Handler<K>` directly.
+//! Register callbacks on `Worker` via `on_text_block()`, `on_tool_use_block()`,
+//! `on_usage()`, etc.
+
+use std::marker::PhantomData;
+
+use crate::handler::{
+    Handler, Kind, TextBlockEvent, TextBlockKind, ToolUseBlockEvent, ToolUseBlockKind,
+    ToolUseBlockStart,
+};
+use crate::hook::ToolCall;
+
+// =============================================================================
+// TextBlock Closure Handler
+// =============================================================================
+
+/// Callback scope for a text block.
+///
+/// Passed to the setup closure registered with `Worker::on_text_block()`.
+/// Register per-block callbacks via `on_delta()` and `on_stop()`.
+///
+/// # Examples
+///
+/// ```ignore
+/// worker.on_text_block(|block| {
+///     block.on_delta(|text| print!("{}", text));
+///     block.on_stop(|full_text| println!("\n--- {} chars ---", full_text.len()));
+/// });
+/// ```
+pub struct TextBlockScope {
+    pub(crate) on_delta: Option<Box<dyn FnMut(&str) + Send + Sync>>,
+    pub(crate) on_stop: Option<Box<dyn FnMut(&str) + Send + Sync>>,
+}
+
+impl TextBlockScope {
+    fn new() -> Self {
+        Self {
+            on_delta: None,
+            on_stop: None,
+        }
+    }
+
+    /// Register a callback for each text delta (streaming fragment).
+    pub fn on_delta(&mut self, f: impl FnMut(&str) + Send + Sync + 'static) {
+        self.on_delta = Some(Box::new(f));
+    }
+
+    /// Register a callback invoked when the block completes.
+    ///
+    /// Receives the full accumulated text of the block.
+    pub fn on_stop(&mut self, f: impl FnMut(&str) + Send + Sync + 'static) {
+        self.on_stop = Some(Box::new(f));
+    }
+}
+
+/// Per-block state created by Timeline's scope lifecycle.
+#[derive(Default)]
+pub(crate) struct TextBlockClosureState {
+    on_delta: Option<Box<dyn FnMut(&str) + Send + Sync>>,
+    on_stop: Option<Box<dyn FnMut(&str) + Send + Sync>>,
+    buffer: String,
+}
+
+/// Closure-based `Handler<TextBlockKind>` adapter.
+pub(crate) struct ClosureTextBlockHandler {
+    pub(crate) setup: Box<dyn FnMut(&mut TextBlockScope) + Send + Sync>,
+}
+
+impl Handler<TextBlockKind> for ClosureTextBlockHandler {
+    type Scope = TextBlockClosureState;
+
+    fn on_event(&mut self, scope: &mut Self::Scope, event: &TextBlockEvent) {
+        match event {
+            TextBlockEvent::Start(_) => {
+                scope.buffer.clear();
+                let mut builder = TextBlockScope::new();
+                (self.setup)(&mut builder);
+                scope.on_delta = builder.on_delta;
+                scope.on_stop = builder.on_stop;
+            }
+            TextBlockEvent::Delta(text) => {
+                scope.buffer.push_str(text);
+                if let Some(f) = &mut scope.on_delta {
+                    f(text);
+                }
+            }
+            TextBlockEvent::Stop(_) => {
+                if let Some(f) = &mut scope.on_stop {
+                    f(&scope.buffer);
+                }
+            }
+        }
+    }
+}
+
+// =============================================================================
+// ToolUseBlock Closure Handler
+// =============================================================================
+
+/// Callback scope for a tool use block.
+///
+/// Passed to the setup closure registered with `Worker::on_tool_use_block()`.
+/// The setup closure also receives `&ToolUseBlockStart` with `id` and `name`.
+///
+/// # Examples
+///
+/// ```ignore
+/// worker.on_tool_use_block(|start, block| {
+///     println!("Tool: {} ({})", start.name, start.id);
+///     block.on_delta(|json| { /* streaming JSON fragment */ });
+///     block.on_stop(|call| println!("Done: {}", call.name));
+/// });
+/// ```
+pub struct ToolUseBlockScope {
+    pub(crate) on_delta: Option<Box<dyn FnMut(&str) + Send + Sync>>,
+    pub(crate) on_stop: Option<Box<dyn FnMut(&ToolCall) + Send + Sync>>,
+}
+
+impl ToolUseBlockScope {
+    fn new() -> Self {
+        Self {
+            on_delta: None,
+            on_stop: None,
+        }
+    }
+
+    /// Register a callback for each JSON input delta (streaming fragment).
+    pub fn on_delta(&mut self, f: impl FnMut(&str) + Send + Sync + 'static) {
+        self.on_delta = Some(Box::new(f));
+    }
+
+    /// Register a callback invoked when the block completes.
+    ///
+    /// Receives the fully assembled `ToolCall` with parsed JSON input.
+    pub fn on_stop(&mut self, f: impl FnMut(&ToolCall) + Send + Sync + 'static) {
+        self.on_stop = Some(Box::new(f));
+    }
+}
+
+/// Per-block state for tool use closure handler.
+#[derive(Default)]
+pub(crate) struct ToolUseBlockClosureState {
+    on_delta: Option<Box<dyn FnMut(&str) + Send + Sync>>,
+    on_stop: Option<Box<dyn FnMut(&ToolCall) + Send + Sync>>,
+    id: String,
+    name: String,
+    input_json: String,
+}
+
+/// Closure-based `Handler<ToolUseBlockKind>` adapter.
+pub(crate) struct ClosureToolUseBlockHandler {
+    pub(crate) setup: Box<dyn FnMut(&ToolUseBlockStart, &mut ToolUseBlockScope) + Send + Sync>,
+}
+
+impl Handler<ToolUseBlockKind> for ClosureToolUseBlockHandler {
+    type Scope = ToolUseBlockClosureState;
+
+    fn on_event(&mut self, scope: &mut Self::Scope, event: &ToolUseBlockEvent) {
+        match event {
+            ToolUseBlockEvent::Start(start) => {
+                scope.id = start.id.clone();
+                scope.name = start.name.clone();
+                scope.input_json.clear();
+                let mut builder = ToolUseBlockScope::new();
+                (self.setup)(start, &mut builder);
+                scope.on_delta = builder.on_delta;
+                scope.on_stop = builder.on_stop;
+            }
+            ToolUseBlockEvent::InputJsonDelta(json) => {
+                scope.input_json.push_str(json);
+                if let Some(f) = &mut scope.on_delta {
+                    f(json);
+                }
+            }
+            ToolUseBlockEvent::Stop(_) => {
+                let input: serde_json::Value =
+                    serde_json::from_str(&scope.input_json).unwrap_or_default();
+                let tool_call = ToolCall {
+                    id: std::mem::take(&mut scope.id),
+                    name: std::mem::take(&mut scope.name),
+                    input,
+                };
+                if let Some(f) = &mut scope.on_stop {
+                    f(&tool_call);
+                }
+            }
+        }
+    }
+}
+
+// =============================================================================
+// Generic Meta Event Closure Handler
+// =============================================================================
+
+/// Closure-based `Handler<K>` adapter for meta events (Usage, Status, Error).
+pub(crate) struct ClosureMetaHandler<F, K>
+where
+    K: Kind,
+{
+    pub(crate) callback: F,
+    pub(crate) _kind: PhantomData<K>,
+}
+
+impl<F, K> Handler<K> for ClosureMetaHandler<F, K>
+where
+    F: FnMut(&K::Event) + Send + Sync,
+    K: Kind,
+{
+    type Scope = ();
+
+    fn on_event(&mut self, _scope: &mut (), event: &K::Event) {
+        (self.callback)(event);
+    }
+}
diff --git a/crates/llm-worker/src/lib.rs b/crates/llm-worker/src/lib.rs
index a958bfe9..0f0fb052 100644
--- a/crates/llm-worker/src/lib.rs
+++ b/crates/llm-worker/src/lib.rs
@@ -7,7 +7,7 @@
 //! - [`Worker`] - Central component for managing LLM interactions
 //! - [`tool::Tool`] - Tools that can be invoked by the LLM
 //! - [`hook::Hook`] - Hooks for intercepting turn progression
-//! - [`subscriber::WorkerSubscriber`] - Subscribing to streaming events
+//! - Closure-based event callbacks via `Worker::on_text_block()`, `on_tool_use_block()`, etc.
 //!
 //! # Quick Start
 //!
@@ -39,14 +39,16 @@ mod handler;
 mod message;
 mod worker;
 
+pub(crate) mod callback;
 pub mod event;
 pub mod hook;
 pub mod llm_client;
 pub mod state;
-pub mod subscriber;
 pub mod timeline;
 pub mod tool;
 pub mod tool_server;
 
+pub use callback::{TextBlockScope, ToolUseBlockScope};
+pub use handler::ToolUseBlockStart;
 pub use message::{ContentPart, Item, Message, Role};
 pub use worker::{ToolRegistryError, Worker, WorkerConfig, WorkerError, WorkerResult};
diff --git a/crates/llm-worker/src/subscriber.rs b/crates/llm-worker/src/subscriber.rs
deleted file mode 100644
index 3f384930..00000000
--- a/crates/llm-worker/src/subscriber.rs
+++ /dev/null
@@ -1,371 +0,0 @@
-//! Event Subscription
-//!
-//! Trait for receiving streaming events from LLM in real-time.
-//! Used for stream display to UI and progress display.
-
-use std::sync::{Arc, Mutex};
-
-use crate::{
-    handler::{
-        ErrorKind, Handler, StatusKind, TextBlockEvent, TextBlockKind, ToolUseBlockEvent,
-        ToolUseBlockKind, UsageKind,
-    },
-    hook::ToolCall,
-    timeline::event::{ErrorEvent, StatusEvent, UsageEvent},
-};
-
-// =============================================================================
-// WorkerSubscriber Trait
-// =============================================================================
-
-/// Trait for subscribing to streaming events from LLM
-///
-/// When registered with Worker, you can receive events from text generation
-/// and tool calls in real-time. Ideal for stream display to UI.
-///
-/// # Available Events
-///
-/// - **Block events**: Text, tool use (with scope)
-/// - **Meta events**: Usage, status, error
-/// - **Completion events**: Text complete, tool call complete
-/// - **Turn control**: Turn start, turn end
-///
-/// # Examples
-///
-/// ```ignore
-/// use llm_worker::subscriber::WorkerSubscriber;
-/// use llm_worker::timeline::TextBlockEvent;
-///
-/// struct StreamPrinter;
-///
-/// impl WorkerSubscriber for StreamPrinter {
-///     type TextBlockScope = ();
-///     type ToolUseBlockScope = ();
-///
-///     fn on_text_block(&mut self, _: &mut (), event: &TextBlockEvent) {
-///         if let TextBlockEvent::Delta(text) = event {
-///             print!("{}", text);  // Real-time output
-///         }
-///     }
-///
-///     fn on_text_complete(&mut self, text: &str) {
-///         println!("\n--- Complete: {} chars ---", text.len());
-///     }
-/// }
-///
-/// // Register with Worker
-/// worker.subscribe(StreamPrinter);
-/// ```
-pub trait WorkerSubscriber: Send {
-    // =========================================================================
-    // Scope Types (for block events)
-    // =========================================================================
-
-    /// Scope type for text block processing
-    ///
-    /// Generated with Default::default() at block start,
-    /// destroyed at block end.
-    type TextBlockScope: Default + Send + Sync;
-
-    /// Scope type for tool use block processing
-    type ToolUseBlockScope: Default + Send + Sync;
-
-    // =========================================================================
-    // Block Events (with scope management)
-    // =========================================================================
-
-    /// Text block event
-    ///
-    /// Has Start/Delta/Stop lifecycle.
-    /// Scope is generated at block start and destroyed at end.
-    #[allow(unused_variables)]
-    fn on_text_block(&mut self, scope: &mut Self::TextBlockScope, event: &TextBlockEvent) {}
-
-    /// Tool use block event
-    ///
-    /// Has Start/InputJsonDelta/Stop lifecycle.
-    #[allow(unused_variables)]
-    fn on_tool_use_block(
-        &mut self,
-        scope: &mut Self::ToolUseBlockScope,
-        event: &ToolUseBlockEvent,
-    ) {
-    }
-
-    // =========================================================================
-    // Single Events (no scope needed)
-    // =========================================================================
-
-    /// Usage event
-    #[allow(unused_variables)]
-    fn on_usage(&mut self, event: &UsageEvent) {}
-
-    /// Status event
-    #[allow(unused_variables)]
-    fn on_status(&mut self, event: &StatusEvent) {}
-
-    /// Error event
-    #[allow(unused_variables)]
-    fn on_error(&mut self, event: &ErrorEvent) {}
-
-    // =========================================================================
-    // Accumulated Events (added in Worker layer)
-    // =========================================================================
-
-    /// Text complete event
-    ///
-    /// When a text block completes, the entire accumulated text is passed.
-    /// Convenient for receiving the final result after block processing.
-    #[allow(unused_variables)]
-    fn on_text_complete(&mut self, text: &str) {}
-
-    /// Tool call complete event
-    ///
-    /// When a tool use block completes, the complete ToolCall is passed.
-    #[allow(unused_variables)]
-    fn on_tool_call_complete(&mut self, call: &ToolCall) {}
-
-    // =========================================================================
-    // Turn Control
-    // =========================================================================
-
-    /// On turn start
-    ///
-    /// `turn` is a 0-based turn number.
-    #[allow(unused_variables)]
-    fn on_turn_start(&mut self, turn: usize) {}
-
-    /// On turn end
-    #[allow(unused_variables)]
-    fn on_turn_end(&mut self, turn: usize) {}
-}
-
-// =============================================================================
-// SubscriberAdapter - Bridge WorkerSubscriber to Timeline handlers
-// =============================================================================
-
-// =============================================================================
-// TextBlock Handler Adapter
-// =============================================================================
-
-/// Subscriber adapter for TextBlockKind
-pub(crate) struct TextBlockSubscriberAdapter<S: WorkerSubscriber> {
-    subscriber: Arc<Mutex<S>>,
-}
-
-impl<S: WorkerSubscriber> TextBlockSubscriberAdapter<S> {
-    pub fn new(subscriber: Arc<Mutex<S>>) -> Self {
-        Self { subscriber }
-    }
-}
-
-impl<S: WorkerSubscriber> Clone for TextBlockSubscriberAdapter<S> {
-    fn clone(&self) -> Self {
-        Self {
-            subscriber: self.subscriber.clone(),
-        }
-    }
-}
-
-/// Wrapper for TextBlock scope
-pub struct TextBlockScopeWrapper<S: WorkerSubscriber> {
-    inner: S::TextBlockScope,
-    buffer: String, // Buffer for on_text_complete
-}
-
-impl<S: WorkerSubscriber> Default for TextBlockScopeWrapper<S> {
-    fn default() -> Self {
-        Self {
-            inner: S::TextBlockScope::default(),
-            buffer: String::new(),
-        }
-    }
-}
-
-impl<S: WorkerSubscriber + 'static> Handler<TextBlockKind> for TextBlockSubscriberAdapter<S> {
-    type Scope = TextBlockScopeWrapper<S>;
-
-    fn on_event(&mut self, scope: &mut Self::Scope, event: &TextBlockEvent) {
-        // Accumulate deltas into buffer
-        if let TextBlockEvent::Delta(text) = event {
-            scope.buffer.push_str(text);
-        }
-
-        // Call Subscriber's TextBlock event handler
-        if let Ok(mut subscriber) = self.subscriber.lock() {
-            subscriber.on_text_block(&mut scope.inner, event);
-
-            // Also call on_text_complete on Stop
-            if matches!(event, TextBlockEvent::Stop(_)) {
-                subscriber.on_text_complete(&scope.buffer);
-            }
-        }
-    }
-}
-
-// =============================================================================
-// ToolUseBlock Handler Adapter
-// =============================================================================
-
-/// Subscriber adapter for ToolUseBlockKind
-pub(crate) struct ToolUseBlockSubscriberAdapter<S: WorkerSubscriber> {
-    subscriber: Arc<Mutex<S>>,
-}
-
-impl<S: WorkerSubscriber> ToolUseBlockSubscriberAdapter<S> {
-    pub fn new(subscriber: Arc<Mutex<S>>) -> Self {
-        Self { subscriber }
-    }
-}
-
-impl<S: WorkerSubscriber> Clone for ToolUseBlockSubscriberAdapter<S> {
-    fn clone(&self) -> Self {
-        Self {
-            subscriber: self.subscriber.clone(),
-        }
-    }
-}
-
-/// Wrapper for ToolUseBlock scope
-pub struct ToolUseBlockScopeWrapper<S: WorkerSubscriber> {
-    inner: S::ToolUseBlockScope,
-    id: String,
-    name: String,
-    input_json: String, // JSON accumulation
-}
-
-impl<S: WorkerSubscriber> Default for ToolUseBlockScopeWrapper<S> {
-    fn default() -> Self {
-        Self {
-            inner: S::ToolUseBlockScope::default(),
-            id: String::new(),
-            name: String::new(),
-            input_json: String::new(),
-        }
-    }
-}
-
-impl<S: WorkerSubscriber + 'static> Handler<ToolUseBlockKind> for ToolUseBlockSubscriberAdapter<S> {
-    type Scope = ToolUseBlockScopeWrapper<S>;
-
-    fn on_event(&mut self, scope: &mut Self::Scope, event: &ToolUseBlockEvent) {
-        // Save metadata on Start
-        if let ToolUseBlockEvent::Start(start) = event {
-            scope.id = start.id.clone();
-            scope.name = start.name.clone();
-        }
-
-        // Accumulate InputJsonDelta into buffer
-        if let ToolUseBlockEvent::InputJsonDelta(json) = event {
-            scope.input_json.push_str(json);
-        }
-
-        // Call Subscriber's ToolUseBlock event handler
-        if let Ok(mut subscriber) = self.subscriber.lock() {
-            subscriber.on_tool_use_block(&mut scope.inner, event);
-
-            // Also call on_tool_call_complete on Stop
-            if matches!(event, ToolUseBlockEvent::Stop(_)) {
-                let input: serde_json::Value =
-                    serde_json::from_str(&scope.input_json).unwrap_or_default();
-                let tool_call = ToolCall {
-                    id: scope.id.clone(),
-                    name: scope.name.clone(),
-                    input,
-                };
-                subscriber.on_tool_call_complete(&tool_call);
-            }
-        }
-    }
-}
-
-// =============================================================================
-// Meta Event Handler Adapters
-// =============================================================================
-
-/// Subscriber adapter for UsageKind
-pub(crate) struct UsageSubscriberAdapter<S: WorkerSubscriber> {
-    subscriber: Arc<Mutex<S>>,
-}
-
-impl<S: WorkerSubscriber> UsageSubscriberAdapter<S> {
-    pub fn new(subscriber: Arc<Mutex<S>>) -> Self {
-        Self { subscriber }
-    }
-}
-
-impl<S: WorkerSubscriber> Clone for UsageSubscriberAdapter<S> {
-    fn clone(&self) -> Self {
-        Self {
-            subscriber: self.subscriber.clone(),
-        }
-    }
-}
-
-impl<S: WorkerSubscriber + 'static> Handler<UsageKind> for UsageSubscriberAdapter<S> {
-    type Scope = ();
-
-    fn on_event(&mut self, _scope: &mut Self::Scope, event: &UsageEvent) {
-        if let Ok(mut subscriber) = self.subscriber.lock() {
-            subscriber.on_usage(event);
-        }
-    }
-}
-
-/// Subscriber adapter for StatusKind
-pub(crate) struct StatusSubscriberAdapter<S: WorkerSubscriber> {
-    subscriber: Arc<Mutex<S>>,
-}
-
-impl<S: WorkerSubscriber> StatusSubscriberAdapter<S> {
-    pub fn new(subscriber: Arc<Mutex<S>>) -> Self {
-        Self { subscriber }
-    }
-}
-
-impl<S: WorkerSubscriber> Clone for StatusSubscriberAdapter<S> {
-    fn clone(&self) -> Self {
-        Self {
-            subscriber: self.subscriber.clone(),
-        }
-    }
-}
-
-impl<S: WorkerSubscriber + 'static> Handler<StatusKind> for StatusSubscriberAdapter<S> {
-    type Scope = ();
-
-    fn on_event(&mut self, _scope: &mut Self::Scope, event: &StatusEvent) {
-        if let Ok(mut subscriber) = self.subscriber.lock() {
-            subscriber.on_status(event);
-        }
-    }
-}
-
-/// Subscriber adapter for ErrorKind
-pub(crate) struct ErrorSubscriberAdapter<S: WorkerSubscriber> {
-    subscriber: Arc<Mutex<S>>,
-}
-
-impl<S: WorkerSubscriber> ErrorSubscriberAdapter<S> {
-    pub fn new(subscriber: Arc<Mutex<S>>) -> Self {
-        Self { subscriber }
-    }
-}
-
-impl<S: WorkerSubscriber> Clone for ErrorSubscriberAdapter<S> {
-    fn clone(&self) -> Self {
-        Self {
-            subscriber: self.subscriber.clone(),
-        }
-    }
-}
-
-impl<S: WorkerSubscriber + 'static> Handler<ErrorKind> for ErrorSubscriberAdapter<S> {
-    type Scope = ();
-
-    fn on_event(&mut self, _scope: &mut Self::Scope, event: &ErrorEvent) {
-        if let Ok(mut subscriber) = self.subscriber.lock() {
-            subscriber.on_error(event);
-        }
-    }
-}
diff --git a/crates/llm-worker/src/timeline/mod.rs b/crates/llm-worker/src/timeline/mod.rs
index 1f944a2b..9ee896e8 100644
--- a/crates/llm-worker/src/timeline/mod.rs
+++ b/crates/llm-worker/src/timeline/mod.rs
@@ -17,7 +17,7 @@ mod tool_call_collector;
 // 公開API
 pub use event::*;
 pub use text_block_collector::TextBlockCollector;
-pub use timeline::{ErasedHandler, HandlerWrapper, Timeline};
+pub use timeline::Timeline;
 pub use tool_call_collector::ToolCallCollector;
 
 // 型定義からのre-export
diff --git a/crates/llm-worker/src/worker.rs b/crates/llm-worker/src/worker.rs
index 97ee83f7..c895e918 100644
--- a/crates/llm-worker/src/worker.rs
+++ b/crates/llm-worker/src/worker.rs
@@ -1,6 +1,6 @@
 use std::collections::HashMap;
 use std::marker::PhantomData;
-use std::sync::{Arc, Mutex};
+use std::sync::Arc;
 
 use futures::StreamExt;
 use tokio::sync::mpsc;
@@ -18,11 +18,13 @@ use crate::{
     },
     llm_client::{ClientError, ConfigWarning, LlmClient, Request, RequestConfig, ToolDefinition},
     state::{CacheLocked, Mutable, WorkerState},
-    subscriber::{
-        ErrorSubscriberAdapter, StatusSubscriberAdapter, TextBlockSubscriberAdapter,
-        ToolUseBlockSubscriberAdapter, UsageSubscriberAdapter, WorkerSubscriber,
+    callback::{
+        ClosureMetaHandler, ClosureTextBlockHandler, ClosureToolUseBlockHandler, TextBlockScope,
+        ToolUseBlockScope,
     },
+    handler::{ErrorKind, StatusKind, ToolUseBlockStart, UsageKind},
     timeline::{TextBlockCollector, Timeline, ToolCallCollector},
+    timeline::event::{ErrorEvent, StatusEvent, UsageEvent},
     tool::{ToolDefinition as WorkerToolDefinition, ToolError, ToolOutputProcessor},
     tool_server::{ToolServer, ToolServerError, ToolServerHandle},
 };
@@ -94,34 +96,6 @@ enum ToolExecutionResult {
     Paused,
 }
 
-// =============================================================================
-// Turn Control Callback Storage
-// =============================================================================
-
-/// Callback for notifying turn events (type-erased)
-trait TurnNotifier: Send + Sync {
-    fn on_turn_start(&self, turn: usize);
-    fn on_turn_end(&self, turn: usize);
-}
-
-struct SubscriberTurnNotifier<S: WorkerSubscriber + 'static> {
-    subscriber: Arc<Mutex<S>>,
-}
-
-impl<S: WorkerSubscriber + 'static> TurnNotifier for SubscriberTurnNotifier<S> {
-    fn on_turn_start(&self, turn: usize) {
-        if let Ok(mut s) = self.subscriber.lock() {
-            s.on_turn_start(turn);
-        }
-    }
-
-    fn on_turn_end(&self, turn: usize) {
-        if let Ok(mut s) = self.subscriber.lock() {
-            s.on_turn_end(turn);
-        }
-    }
-}
-
 // =============================================================================
 // Worker
 // =============================================================================
@@ -183,8 +157,10 @@ pub struct Worker<C: LlmClient, S: WorkerState = Mutable> {
     turn_count: usize,
     /// Maximum number of turns (None = unlimited)
     max_turns: Option<u32>,
-    /// Turn notification callbacks
-    turn_notifiers: Vec<Box<dyn TurnNotifier>>,
+    /// Turn-start callbacks
+    turn_start_cbs: Vec<Box<dyn Fn(usize) + Send + Sync>>,
+    /// Turn-end callbacks
+    turn_end_cbs: Vec<Box<dyn Fn(usize) + Send + Sync>>,
     /// Request configuration (max_tokens, temperature, etc.)
     request_config: RequestConfig,
     /// Whether the previous run was interrupted
@@ -256,59 +232,102 @@ impl<C: LlmClient, S: WorkerState> Worker<C, S> {
         }
     }
 
-    /// Register an event subscriber
+    /// Register a text block observer with scoped callbacks.
     ///
-    /// Registered subscribers receive streaming events from the LLM
-    /// in real-time. Useful for streaming display to UI.
-    ///
-    /// # Available Events
-    ///
-    /// - **Block events**: `on_text_block`, `on_tool_use_block`
-    /// - **Meta events**: `on_usage`, `on_status`, `on_error`
-    /// - **Completion events**: `on_text_complete`, `on_tool_call_complete`
-    /// - **Turn control**: `on_turn_start`, `on_turn_end`
+    /// The setup closure is called once per text block. Inside it, register
+    /// `on_delta` and/or `on_stop` callbacks on the provided scope.
     ///
     /// # Examples
     ///
     /// ```ignore
-    /// use llm_worker::{Worker, WorkerSubscriber, TextBlockEvent};
-    ///
-    /// struct MyPrinter;
-    /// impl WorkerSubscriber for MyPrinter {
-    ///     type TextBlockScope = ();
-    ///     type ToolUseBlockScope = ();
-    ///
-    ///     fn on_text_block(&mut self, _: &mut (), event: &TextBlockEvent) {
-    ///         if let TextBlockEvent::Delta(text) = event {
-    ///             print!("{}", text);
-    ///         }
-    ///     }
-    /// }
-    ///
-    /// worker.subscribe(MyPrinter);
+    /// worker.on_text_block(|block| {
+    ///     block.on_delta(|text| print!("{}", text));
+    ///     block.on_stop(|full_text| println!("\n--- {} chars ---", full_text.len()));
+    /// });
     /// ```
-    pub fn subscribe<Sub: WorkerSubscriber + 'static>(&mut self, subscriber: Sub) {
-        let subscriber = Arc::new(Mutex::new(subscriber));
+    pub fn on_text_block(
+        &mut self,
+        setup: impl FnMut(&mut TextBlockScope) + Send + Sync + 'static,
+    ) {
+        self.timeline
+            .on_text_block(ClosureTextBlockHandler {
+                setup: Box::new(setup),
+            });
+    }
 
-        // Register TextBlock handler
+    /// Register a tool use block observer with scoped callbacks.
+    ///
+    /// The setup closure receives `&ToolUseBlockStart` (containing `id` and `name`)
+    /// and a scope for registering `on_delta` and `on_stop` callbacks.
+    ///
+    /// `on_stop` receives a fully assembled `&ToolCall` with parsed JSON input.
+    ///
+    /// # Examples
+    ///
+    /// ```ignore
+    /// worker.on_tool_use_block(|start, block| {
+    ///     println!("Tool: {} ({})", start.name, start.id);
+    ///     block.on_delta(|json| { /* streaming JSON fragment */ });
+    ///     block.on_stop(|call| println!("Done: {}", call.name));
+    /// });
+    /// ```
+    pub fn on_tool_use_block(
+        &mut self,
+        setup: impl FnMut(&ToolUseBlockStart, &mut ToolUseBlockScope) + Send + Sync + 'static,
+    ) {
         self.timeline
-            .on_text_block(TextBlockSubscriberAdapter::new(subscriber.clone()));
+            .on_tool_use_block(ClosureToolUseBlockHandler {
+                setup: Box::new(setup),
+            });
+    }
 
-        // Register ToolUseBlock handler
-        self.timeline
-            .on_tool_use_block(ToolUseBlockSubscriberAdapter::new(subscriber.clone()));
+    /// Register a usage event callback.
+    pub fn on_usage(
+        &mut self,
+        callback: impl FnMut(&UsageEvent) + Send + Sync + 'static,
+    ) {
+        self.timeline.on_usage(ClosureMetaHandler {
+            callback,
+            _kind: PhantomData::<UsageKind>,
+        });
+    }
 
-        // Register meta handlers
-        self.timeline
-            .on_usage(UsageSubscriberAdapter::new(subscriber.clone()));
-        self.timeline
-            .on_status(StatusSubscriberAdapter::new(subscriber.clone()));
-        self.timeline
-            .on_error(ErrorSubscriberAdapter::new(subscriber.clone()));
+    /// Register a status event callback.
+    pub fn on_status(
+        &mut self,
+        callback: impl FnMut(&StatusEvent) + Send + Sync + 'static,
+    ) {
+        self.timeline.on_status(ClosureMetaHandler {
+            callback,
+            _kind: PhantomData::<StatusKind>,
+        });
+    }
 
-        // Register turn control callback
-        self.turn_notifiers
-            .push(Box::new(SubscriberTurnNotifier { subscriber }));
+    /// Register an error event callback.
+    pub fn on_error(
+        &mut self,
+        callback: impl FnMut(&ErrorEvent) + Send + Sync + 'static,
+    ) {
+        self.timeline.on_error(ClosureMetaHandler {
+            callback,
+            _kind: PhantomData::<ErrorKind>,
+        });
+    }
+
+    /// Register a turn-start callback (receives 0-based turn number).
+    pub fn on_turn_start(
+        &mut self,
+        callback: impl Fn(usize) + Send + Sync + 'static,
+    ) {
+        self.turn_start_cbs.push(Box::new(callback));
+    }
+
+    /// Register a turn-end callback (receives 0-based turn number).
+    pub fn on_turn_end(
+        &mut self,
+        callback: impl Fn(usize) + Send + Sync + 'static,
+    ) {
+        self.turn_end_cbs.push(Box::new(callback));
     }
 
     /// Get a shared tool server handle.
@@ -940,8 +959,8 @@ impl<C: LlmClient, S: WorkerState> Worker<C, S> {
             // Notify turn start
             let current_turn = self.turn_count;
             debug!(turn = current_turn, "Turn start");
-            for notifier in &self.turn_notifiers {
-                notifier.on_turn_start(current_turn);
+            for cb in &self.turn_start_cbs {
+                cb(current_turn);
             }
 
             // Hook: pre_llm_request
@@ -952,8 +971,8 @@ impl<C: LlmClient, S: WorkerState> Worker<C, S> {
             match control {
                 PreLlmRequestResult::Cancel(reason) => {
                     info!(reason = %reason, "Aborted by hook");
-                    for notifier in &self.turn_notifiers {
-                        notifier.on_turn_end(current_turn);
+                    for cb in &self.turn_end_cbs {
+                        cb(current_turn);
                     }
                     self.last_run_interrupted = true;
                     return Err(WorkerError::Aborted(reason));
@@ -1047,8 +1066,8 @@ impl<C: LlmClient, S: WorkerState> Worker<C, S> {
             debug!(event_count = event_count, "Stream completed");
 
             // Notify turn end
-            for notifier in &self.turn_notifiers {
-                notifier.on_turn_end(current_turn);
+            for cb in &self.turn_end_cbs {
+                cb(current_turn);
             }
             self.turn_count += 1;
 
@@ -1151,7 +1170,8 @@ impl<C: LlmClient> Worker<C, Mutable> {
             locked_prefix_len: 0,
             turn_count: 0,
             max_turns: None,
-            turn_notifiers: Vec::new(),
+            turn_start_cbs: Vec::new(),
+            turn_end_cbs: Vec::new(),
             request_config: RequestConfig::default(),
             last_run_interrupted: false,
             output_processor: None,
@@ -1386,7 +1406,8 @@ impl<C: LlmClient> Worker<C, Mutable> {
             locked_prefix_len,
             turn_count: self.turn_count,
             max_turns: self.max_turns,
-            turn_notifiers: self.turn_notifiers,
+            turn_start_cbs: self.turn_start_cbs,
+            turn_end_cbs: self.turn_end_cbs,
             request_config: self.request_config,
             last_run_interrupted: self.last_run_interrupted,
             output_processor: self.output_processor,
@@ -1424,7 +1445,8 @@ impl<C: LlmClient> Worker<C, CacheLocked> {
             locked_prefix_len: 0,
             turn_count: self.turn_count,
             max_turns: self.max_turns,
-            turn_notifiers: self.turn_notifiers,
+            turn_start_cbs: self.turn_start_cbs,
+            turn_end_cbs: self.turn_end_cbs,
             request_config: self.request_config,
             last_run_interrupted: self.last_run_interrupted,
             output_processor: self.output_processor,
diff --git a/crates/llm-worker/tests/callback_test.rs b/crates/llm-worker/tests/callback_test.rs
new file mode 100644
index 00000000..c1c4b71a
--- /dev/null
+++ b/crates/llm-worker/tests/callback_test.rs
@@ -0,0 +1,178 @@
+//! Closure callback API tests
+//!
+//! Tests for the closure-based event subscription API on Worker.
+
+mod common;
+
+use std::sync::{Arc, Mutex};
+
+use common::MockLlmClient;
+use llm_worker::Worker;
+use llm_worker::llm_client::event::{Event, ResponseStatus, StatusEvent as ClientStatusEvent};
+
+// =============================================================================
+// Tests
+// =============================================================================
+
+/// Verify that on_text_block correctly receives delta and stop events
+#[tokio::test]
+async fn test_callback_text_block_events() {
+    let events = vec![
+        Event::text_block_start(0),
+        Event::text_delta(0, "Hello, "),
+        Event::text_delta(0, "World!"),
+        Event::text_block_stop(0, None),
+        Event::Status(ClientStatusEvent {
+            status: ResponseStatus::Completed,
+        }),
+    ];
+
+    let client = MockLlmClient::new(events);
+    let mut worker = Worker::new(client);
+
+    let text_deltas = Arc::new(Mutex::new(Vec::new()));
+    let text_completes = Arc::new(Mutex::new(Vec::new()));
+
+    let deltas = text_deltas.clone();
+    let completes = text_completes.clone();
+    worker.on_text_block(move |block| {
+        let d = deltas.clone();
+        block.on_delta(move |text| {
+            d.lock().unwrap().push(text.to_owned());
+        });
+        let c = completes.clone();
+        block.on_stop(move |text| {
+            c.lock().unwrap().push(text.to_owned());
+        });
+    });
+
+    let result = worker.run("Greet me").await;
+    assert!(result.is_ok(), "Worker should complete: {:?}", result);
+
+    let deltas = text_deltas.lock().unwrap();
+    assert_eq!(deltas.len(), 2);
+    assert_eq!(deltas[0], "Hello, ");
+    assert_eq!(deltas[1], "World!");
+
+    let completes = text_completes.lock().unwrap();
+    assert_eq!(completes.len(), 1);
+    assert_eq!(completes[0], "Hello, World!");
+}
+
+/// Verify that on_tool_use_block correctly receives start info and stop with ToolCall
+#[tokio::test]
+async fn test_callback_tool_call_complete() {
+    let events = vec![
+        Event::tool_use_start(0, "call_123", "get_weather"),
+        Event::tool_input_delta(0, r#"{"city":"#),
+        Event::tool_input_delta(0, r#""Tokyo"}"#),
+        Event::tool_use_stop(0),
+        Event::Status(ClientStatusEvent {
+            status: ResponseStatus::Completed,
+        }),
+    ];
+
+    let client = MockLlmClient::new(events);
+    let mut worker = Worker::new(client);
+
+    let tool_starts = Arc::new(Mutex::new(Vec::<(String, String)>::new()));
+    let tool_completes = Arc::new(Mutex::new(Vec::new()));
+
+    let starts = tool_starts.clone();
+    let completes = tool_completes.clone();
+    worker.on_tool_use_block(move |start, block| {
+        starts
+            .lock()
+            .unwrap()
+            .push((start.id.clone(), start.name.clone()));
+        let c = completes.clone();
+        block.on_stop(move |call| {
+            c.lock().unwrap().push(call.clone());
+        });
+    });
+
+    let _ = worker.run("Weather please").await;
+
+    let starts = tool_starts.lock().unwrap();
+    assert_eq!(starts.len(), 1);
+    assert_eq!(starts[0].0, "call_123");
+    assert_eq!(starts[0].1, "get_weather");
+
+    let completes = tool_completes.lock().unwrap();
+    assert_eq!(completes.len(), 1);
+    assert_eq!(completes[0].name, "get_weather");
+    assert_eq!(completes[0].id, "call_123");
+    assert_eq!(completes[0].input["city"], "Tokyo");
+}
+
+/// Verify that on_turn_start and on_turn_end callbacks are called
+#[tokio::test]
+async fn test_callback_turn_events() {
+    let events = vec![
+        Event::text_block_start(0),
+        Event::text_delta(0, "Done!"),
+        Event::text_block_stop(0, None),
+        Event::Status(ClientStatusEvent {
+            status: ResponseStatus::Completed,
+        }),
+    ];
+
+    let client = MockLlmClient::new(events);
+    let mut worker = Worker::new(client);
+
+    let turn_starts = Arc::new(Mutex::new(Vec::new()));
+    let turn_ends = Arc::new(Mutex::new(Vec::new()));
+
+    let starts = turn_starts.clone();
+    worker.on_turn_start(move |turn| {
+        starts.lock().unwrap().push(turn);
+    });
+
+    let ends = turn_ends.clone();
+    worker.on_turn_end(move |turn| {
+        ends.lock().unwrap().push(turn);
+    });
+
+    let result = worker.run("Do something").await;
+    assert!(result.is_ok());
+
+    let starts = turn_starts.lock().unwrap();
+    let ends = turn_ends.lock().unwrap();
+
+    assert_eq!(starts.len(), 1);
+    assert_eq!(starts[0], 0);
+
+    assert_eq!(ends.len(), 1);
+    assert_eq!(ends[0], 0);
+}
+
+/// Verify that on_usage callback receives usage events
+#[tokio::test]
+async fn test_callback_usage_events() {
+    let events = vec![
+        Event::text_block_start(0),
+        Event::text_delta(0, "Hello"),
+        Event::text_block_stop(0, None),
+        Event::usage(100, 50),
+        Event::Status(ClientStatusEvent {
+            status: ResponseStatus::Completed,
+        }),
+    ];
+
+    let client = MockLlmClient::new(events);
+    let mut worker = Worker::new(client);
+
+    let usage_events = Arc::new(Mutex::new(Vec::new()));
+
+    let usages = usage_events.clone();
+    worker.on_usage(move |event| {
+        usages.lock().unwrap().push(event.clone());
+    });
+
+    let _ = worker.run("Hello").await;
+
+    let usages = usage_events.lock().unwrap();
+    assert_eq!(usages.len(), 1);
+    assert_eq!(usages[0].input_tokens, Some(100));
+    assert_eq!(usages[0].output_tokens, Some(50));
+}
diff --git a/crates/llm-worker/tests/subscriber_test.rs b/crates/llm-worker/tests/subscriber_test.rs
deleted file mode 100644
index 552aa043..00000000
--- a/crates/llm-worker/tests/subscriber_test.rs
+++ /dev/null
@@ -1,234 +0,0 @@
-//! WorkerSubscriber tests
-//!
-//! Tests for subscribing to events using WorkerSubscriber
-
-mod common;
-
-use std::sync::{Arc, Mutex};
-
-use common::MockLlmClient;
-use llm_worker::Worker;
-use llm_worker::hook::ToolCall;
-use llm_worker::llm_client::event::{Event, ResponseStatus, StatusEvent as ClientStatusEvent};
-use llm_worker::subscriber::WorkerSubscriber;
-use llm_worker::timeline::event::{ErrorEvent, StatusEvent, UsageEvent};
-use llm_worker::timeline::{TextBlockEvent, ToolUseBlockEvent};
-
-// =============================================================================
-// Test Subscriber
-// =============================================================================
-
-/// Simple Subscriber implementation for testing
-struct TestSubscriber {
-    // Recording buffers
-    text_deltas: Arc<Mutex<Vec<String>>>,
-    text_completes: Arc<Mutex<Vec<String>>>,
-    tool_call_completes: Arc<Mutex<Vec<ToolCall>>>,
-    usage_events: Arc<Mutex<Vec<UsageEvent>>>,
-    status_events: Arc<Mutex<Vec<StatusEvent>>>,
-    turn_starts: Arc<Mutex<Vec<usize>>>,
-    turn_ends: Arc<Mutex<Vec<usize>>>,
-}
-
-impl TestSubscriber {
-    fn new() -> Self {
-        Self {
-            text_deltas: Arc::new(Mutex::new(Vec::new())),
-            text_completes: Arc::new(Mutex::new(Vec::new())),
-            tool_call_completes: Arc::new(Mutex::new(Vec::new())),
-            usage_events: Arc::new(Mutex::new(Vec::new())),
-            status_events: Arc::new(Mutex::new(Vec::new())),
-            turn_starts: Arc::new(Mutex::new(Vec::new())),
-            turn_ends: Arc::new(Mutex::new(Vec::new())),
-        }
-    }
-}
-
-impl WorkerSubscriber for TestSubscriber {
-    type TextBlockScope = String;
-    type ToolUseBlockScope = ();
-
-    fn on_text_block(&mut self, buffer: &mut String, event: &TextBlockEvent) {
-        if let TextBlockEvent::Delta(text) = event {
-            buffer.push_str(text);
-            self.text_deltas.lock().unwrap().push(text.clone());
-        }
-    }
-
-    fn on_text_complete(&mut self, text: &str) {
-        self.text_completes.lock().unwrap().push(text.to_string());
-    }
-
-    fn on_tool_use_block(&mut self, _scope: &mut (), _event: &ToolUseBlockEvent) {
-        // Process as needed
-    }
-
-    fn on_tool_call_complete(&mut self, call: &ToolCall) {
-        self.tool_call_completes.lock().unwrap().push(call.clone());
-    }
-
-    fn on_usage(&mut self, event: &UsageEvent) {
-        self.usage_events.lock().unwrap().push(event.clone());
-    }
-
-    fn on_status(&mut self, event: &StatusEvent) {
-        self.status_events.lock().unwrap().push(event.clone());
-    }
-
-    fn on_error(&mut self, _event: &ErrorEvent) {
-        // Process as needed
-    }
-
-    fn on_turn_start(&mut self, turn: usize) {
-        self.turn_starts.lock().unwrap().push(turn);
-    }
-
-    fn on_turn_end(&mut self, turn: usize) {
-        self.turn_ends.lock().unwrap().push(turn);
-    }
-}
-
-// =============================================================================
-// Tests
-// =============================================================================
-
-/// Verify that WorkerSubscriber correctly receives text block events
-#[tokio::test]
-async fn test_subscriber_text_block_events() {
-    // Event sequence containing text response
-    let events = vec![
-        Event::text_block_start(0),
-        Event::text_delta(0, "Hello, "),
-        Event::text_delta(0, "World!"),
-        Event::text_block_stop(0, None),
-        Event::Status(ClientStatusEvent {
-            status: ResponseStatus::Completed,
-        }),
-    ];
-
-    let client = MockLlmClient::new(events);
-    let mut worker = Worker::new(client);
-
-    // Register Subscriber
-    let subscriber = TestSubscriber::new();
-    let text_deltas = subscriber.text_deltas.clone();
-    let text_completes = subscriber.text_completes.clone();
-    worker.subscribe(subscriber);
-
-    // Execute
-    let result = worker.run("Greet me").await;
-
-    assert!(result.is_ok(), "Worker should complete: {:?}", result);
-
-    // Verify deltas were collected
-    let deltas = text_deltas.lock().unwrap();
-    assert_eq!(deltas.len(), 2);
-    assert_eq!(deltas[0], "Hello, ");
-    assert_eq!(deltas[1], "World!");
-
-    // Verify complete text was collected
-    let completes = text_completes.lock().unwrap();
-    assert_eq!(completes.len(), 1);
-    assert_eq!(completes[0], "Hello, World!");
-}
-
-/// Verify that WorkerSubscriber correctly receives tool call complete events
-#[tokio::test]
-async fn test_subscriber_tool_call_complete() {
-    // Event sequence containing tool call
-    let events = vec![
-        Event::tool_use_start(0, "call_123", "get_weather"),
-        Event::tool_input_delta(0, r#"{"city":"#),
-        Event::tool_input_delta(0, r#""Tokyo"}"#),
-        Event::tool_use_stop(0),
-        Event::Status(ClientStatusEvent {
-            status: ResponseStatus::Completed,
-        }),
-    ];
-
-    let client = MockLlmClient::new(events);
-    let mut worker = Worker::new(client);
-
-    // Register Subscriber
-    let subscriber = TestSubscriber::new();
-    let tool_call_completes = subscriber.tool_call_completes.clone();
-    worker.subscribe(subscriber);
-
-    // Execute
-    let _ = worker.run("Weather please").await;
-
-    // Verify tool call complete was collected
-    let completes = tool_call_completes.lock().unwrap();
-    assert_eq!(completes.len(), 1);
-    assert_eq!(completes[0].name, "get_weather");
-    assert_eq!(completes[0].id, "call_123");
-    assert_eq!(completes[0].input["city"], "Tokyo");
-}
-
-/// Verify that WorkerSubscriber correctly receives turn events
-#[tokio::test]
-async fn test_subscriber_turn_events() {
-    let events = vec![
-        Event::text_block_start(0),
-        Event::text_delta(0, "Done!"),
-        Event::text_block_stop(0, None),
-        Event::Status(ClientStatusEvent {
-            status: ResponseStatus::Completed,
-        }),
-    ];
-
-    let client = MockLlmClient::new(events);
-    let mut worker = Worker::new(client);
-
-    // Register Subscriber
-    let subscriber = TestSubscriber::new();
-    let turn_starts = subscriber.turn_starts.clone();
-    let turn_ends = subscriber.turn_ends.clone();
-    worker.subscribe(subscriber);
-
-    // Execute
-    let result = worker.run("Do something").await;
-
-    assert!(result.is_ok());
-
-    // Verify turn events were collected
-    let starts = turn_starts.lock().unwrap();
-    let ends = turn_ends.lock().unwrap();
-
-    assert_eq!(starts.len(), 1);
-    assert_eq!(starts[0], 0); // First turn
-
-    assert_eq!(ends.len(), 1);
-    assert_eq!(ends[0], 0);
-}
-
-/// Verify that WorkerSubscriber correctly receives Usage events
-#[tokio::test]
-async fn test_subscriber_usage_events() {
-    let events = vec![
-        Event::text_block_start(0),
-        Event::text_delta(0, "Hello"),
-        Event::text_block_stop(0, None),
-        Event::usage(100, 50),
-        Event::Status(ClientStatusEvent {
-            status: ResponseStatus::Completed,
-        }),
-    ];
-
-    let client = MockLlmClient::new(events);
-    let mut worker = Worker::new(client);
-
-    // Register Subscriber
-    let subscriber = TestSubscriber::new();
-    let usage_events = subscriber.usage_events.clone();
-    worker.subscribe(subscriber);
-
-    // Execute
-    let _ = worker.run("Hello").await;
-
-    // Verify Usage events were collected
-    let usages = usage_events.lock().unwrap();
-    assert_eq!(usages.len(), 1);
-    assert_eq!(usages[0].input_tokens, Some(100));
-    assert_eq!(usages[0].output_tokens, Some(50));
-}
diff --git a/crates/pod/src/controller.rs b/crates/pod/src/controller.rs
index 666371b1..bd8478d8 100644
--- a/crates/pod/src/controller.rs
+++ b/crates/pod/src/controller.rs
@@ -1,11 +1,7 @@
 use std::path::Path;
 use std::sync::Arc;
 
-use llm_worker::hook::ToolCall;
 use llm_worker::llm_client::client::LlmClient;
-use llm_worker::subscriber::WorkerSubscriber;
-use llm_worker::timeline::event::{ErrorEvent, UsageEvent};
-use llm_worker::timeline::{TextBlockEvent, ToolUseBlockEvent};
 use llm_worker::WorkerError;
 use llm_worker_persistence::Store;
 use tokio::sync::{broadcast, mpsc};
@@ -87,11 +83,79 @@ impl PodController {
         // Keep the server alive by moving it into the controller task
         // (it will be dropped when the task ends)
 
-        // Register the event bridge subscriber on the worker
-        let bridge = EventBridgeSubscriber {
-            event_tx: event_tx.clone(),
-        };
-        pod.session_mut().worker.subscribe(bridge);
+        // Register event bridge callbacks on the worker
+        {
+            let worker = &mut pod.session_mut().worker;
+
+            let tx = event_tx.clone();
+            worker.on_turn_start(move |turn| {
+                let _ = tx.send(Event::TurnStart { turn });
+            });
+
+            let tx = event_tx.clone();
+            worker.on_turn_end(move |turn| {
+                let _ = tx.send(Event::TurnEnd {
+                    turn,
+                    result: TurnResult::Finished,
+                });
+            });
+
+            let tx = event_tx.clone();
+            worker.on_text_block(move |block| {
+                let tx_d = tx.clone();
+                block.on_delta(move |text| {
+                    let _ = tx_d.send(Event::TextDelta {
+                        text: text.to_owned(),
+                    });
+                });
+                let tx_s = tx.clone();
+                block.on_stop(move |text| {
+                    let _ = tx_s.send(Event::TextDone {
+                        text: text.to_owned(),
+                    });
+                });
+            });
+
+            let tx = event_tx.clone();
+            worker.on_tool_use_block(move |start, block| {
+                let _ = tx.send(Event::ToolCallStart {
+                    id: start.id.clone(),
+                    name: start.name.clone(),
+                });
+                let id_for_delta = start.id.clone();
+                let tx_d = tx.clone();
+                block.on_delta(move |json| {
+                    let _ = tx_d.send(Event::ToolCallArgsDelta {
+                        id: id_for_delta.clone(),
+                        json: json.to_owned(),
+                    });
+                });
+                let tx_s = tx.clone();
+                block.on_stop(move |call| {
+                    let _ = tx_s.send(Event::ToolCallDone {
+                        id: call.id.clone(),
+                        name: call.name.clone(),
+                        arguments: call.input.to_string(),
+                    });
+                });
+            });
+
+            let tx = event_tx.clone();
+            worker.on_usage(move |event| {
+                let _ = tx.send(Event::Usage {
+                    input_tokens: event.input_tokens,
+                    output_tokens: event.output_tokens,
+                });
+            });
+
+            let tx = event_tx.clone();
+            worker.on_error(move |event| {
+                let _ = tx.send(Event::Error {
+                    code: ErrorCode::ProviderError,
+                    message: event.message.clone(),
+                });
+            });
+        }
 
         // Clone cancel sender before moving pod
         let cancel_tx = pod.session_mut().worker.cancel_sender();
@@ -252,83 +316,3 @@ fn worker_error_code(e: &PodError) -> ErrorCode {
     }
 }
 
-// ---------------------------------------------------------------------------
-// EventBridgeSubscriber — bridges Worker events to broadcast channel
-// ---------------------------------------------------------------------------
-
-struct EventBridgeSubscriber {
-    event_tx: broadcast::Sender<Event>,
-}
-
-impl WorkerSubscriber for EventBridgeSubscriber {
-    type TextBlockScope = ();
-    type ToolUseBlockScope = ();
-
-    fn on_turn_start(&mut self, turn: usize) {
-        let _ = self.event_tx.send(Event::TurnStart { turn });
-    }
-
-    fn on_turn_end(&mut self, turn: usize) {
-        let _ = self.event_tx.send(Event::TurnEnd {
-            turn,
-            result: TurnResult::Finished,
-        });
-    }
-
-    fn on_text_block(&mut self, _scope: &mut (), event: &TextBlockEvent) {
-        match event {
-            TextBlockEvent::Delta(text) => {
-                let _ = self.event_tx.send(Event::TextDelta {
-                    text: text.clone(),
-                });
-            }
-            TextBlockEvent::Start(_) | TextBlockEvent::Stop(_) => {}
-        }
-    }
-
-    fn on_text_complete(&mut self, text: &str) {
-        let _ = self.event_tx.send(Event::TextDone {
-            text: text.to_owned(),
-        });
-    }
-
-    fn on_tool_use_block(&mut self, _scope: &mut (), event: &ToolUseBlockEvent) {
-        match event {
-            ToolUseBlockEvent::Start(start) => {
-                let _ = self.event_tx.send(Event::ToolCallStart {
-                    id: start.id.clone(),
-                    name: start.name.clone(),
-                });
-            }
-            ToolUseBlockEvent::InputJsonDelta(json) => {
-                let _ = self.event_tx.send(Event::ToolCallArgsDelta {
-                    id: String::new(),
-                    json: json.clone(),
-                });
-            }
-            ToolUseBlockEvent::Stop(_) => {}
-        }
-    }
-
-    fn on_tool_call_complete(&mut self, call: &ToolCall) {
-        let _ = self.event_tx.send(Event::ToolCallDone {
-            id: call.id.clone(),
-            name: call.name.clone(),
-            arguments: call.input.to_string(),
-        });
-    }
-
-    fn on_usage(&mut self, event: &UsageEvent) {
-        let _ = self.event_tx.send(Event::Usage {
-            input_tokens: event.input_tokens,
-            output_tokens: event.output_tokens,
-        });
-    }
-
-    fn on_error(&mut self, event: &ErrorEvent) {
-        let _ = self.event_tx.send(Event::Error {
-            code: ErrorCode::ProviderError,
-            message: event.message.clone(),
-        });
-    }
-}
diff --git a/tickets/subscriber-closure-api.md b/tickets/subscriber-closure-api.md
deleted file mode 100644
index 69a04f2b..00000000
--- a/tickets/subscriber-closure-api.md
+++ /dev/null
@@ -1,43 +0,0 @@
-# Subscriber API: クロージャベースのスコープ表現
-
-## 背景
-
-Block系イベントは時間的に排他（TextBlock中にToolUseBlockは来ない）で、
-Meta系イベント（Usage等）はいつでも流れ得る。
-現行の `Handler<K>` + `Scope: Default` はこの保証を実現しているが、
-ユーザーから見ると Kind/Scope/型消去のボイラープレートが重く、
-`Timeline` と `WorkerSubscriber` の2層が「どちらを使えばいいか」分かりにくい。
-
-## 方針
-
-クロージャでスコープの寿命を表現し、ブロックの時間的排他性を Rust の借用で自然に保証する。
-
-```rust
-// Block系: クロージャ引数 = スコープの寿命保証
-worker.on_text_block(|block| {
-    block.on_delta(|text| print!("{}", text));
-    block.on_stop(|reason| println!("\n---"));
-});
-
-worker.on_tool_use_block(|block| {
-    block.on_delta(|json| { /* ... */ });
-    block.on_stop(|call| { /* ... */ });
-});
-
-// Meta系: スコープ不要（いつでも来る）
-worker.on_usage(|usage| { /* ... */ });
-```
-
-## 設計ポイント
-
-- ブロックのスコープ = クロージャの借用寿命。ユーザーは `Kind` / `Scope: Default` を知らなくていい
-- Block系の排他性が「ブロックが始まったらクロージャが呼ばれ、終わったら抜ける」という直感に一致する
-- Meta系はフラットなコールバック。スコープ管理不要
-- 内部的には現行の `Handler<K>` + `Timeline` ディスパッチ機構を維持し、クロージャを Handler に変換するアダプタを挟む
-- `WorkerSubscriber` トレイト + 5種の SubscriberAdapter ボイラープレートが不要になる
-
-## 現行からの変更
-
-- `Timeline` は `pub mod` → 内部実装に格下げ（Worker の実装詳細に閉じ込める）
-- `WorkerSubscriber` トレイト → 廃止。クロージャ登録 API に置き換え
-- `Handler<K>` トレイトは内部で維持（クロージャからの変換先として）