add state constraint regression and compile-fail tests

restrict tool registration to mutable state
refactor worker tool execution through tool server
2026-02-19 18:31:49 +09:00 · 2026-02-19 18:29:02 +09:00 · 2026-02-19 18:19:16 +09:00 · 2026-02-19 17:37:29 +09:00 · 2026-01-16 16:58:03 +09:00 · 2026-01-14 16:30:41 +09:00
45 changed files with 3346 additions and 1495 deletions
--- a/AGENTS.md
+++ b/AGENTS.md
@ -1,6 +1,7 @@
-# llm-worker-rs 開発instruction
+# llm-worker-rs Development Instructions

-## パッケージ管理ルール
+## Package Management Rules

- クレートに依存関係を追加・更新する際は必ず
-  `cargo`コマンドを使い、`Cargo.toml`を直接手で書き換えず、必ずコマンド経由で管理すること。
+- When adding or updating crate dependencies, always use the `cargo` command. Do
+  not manually edit `Cargo.toml` directly; always manage dependencies via
+  commands.
--- a/Cargo.lock
+++ b/Cargo.lock
@ -384,6 +384,12 @@ dependencies = [
 "wasip2",
 ]

+[[package]]
+name = "glob"
+version = "0.3.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0cc23270f6e1808e30a928bdc84dea0b9b4136a8bc82338574f23baf47bbd280"
+
 [[package]]
 name = "h2"
 version = "0.4.13"
@ -708,7 +714,7 @@ checksum = "6373607a59f0be73a39b6fe456b8192fcc3585f602af20751600e974dd455e77"

 [[package]]
 name = "llm-worker"
-version = "0.2.0"
+version = "0.2.1"
 dependencies = [
 "async-trait",
 "clap",
@ -726,6 +732,7 @@ dependencies = [
 "tokio-util",
 "tracing",
 "tracing-subscriber",
+ "trybuild",
 ]

 [[package]]
@ -1178,6 +1185,15 @@ dependencies = [
 "zmij",
 ]

+[[package]]
+name = "serde_spanned"
+version = "1.0.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f8bbf91e5a4d6315eee45e704372590b30e260ee83af6639d64557f51b067776"
+dependencies = [
+ "serde_core",
+]
+
 [[package]]
 name = "sharded-slab"
 version = "0.1.7"
@ -1264,6 +1280,12 @@ dependencies = [
 "syn",
 ]

+[[package]]
+name = "target-triple"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "591ef38edfb78ca4771ee32cf494cb8771944bee237a9b91fc9c1424ac4b777b"
+
 [[package]]
 name = "tempfile"
 version = "3.24.0"
@ -1277,6 +1299,15 @@ dependencies = [
 "windows-sys 0.61.2",
 ]

+[[package]]
+name = "termcolor"
+version = "1.4.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "06794f8f6c5c898b3275aebefa6b8a1cb24cd2c6c79397ab15774837a0bc5755"
+dependencies = [
+ "winapi-util",
+]
+
 [[package]]
 name = "thiserror"
 version = "2.0.17"
@ -1375,6 +1406,45 @@ dependencies = [
 "tokio",
 ]

+[[package]]
+name = "toml"
+version = "1.0.3+spec-1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c7614eaf19ad818347db24addfa201729cf2a9b6fdfd9eb0ab870fcacc606c0c"
+dependencies = [
+ "indexmap",
+ "serde_core",
+ "serde_spanned",
+ "toml_datetime",
+ "toml_parser",
+ "toml_writer",
+ "winnow",
+]
+
+[[package]]
+name = "toml_datetime"
+version = "1.0.0+spec-1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "32c2555c699578a4f59f0cc68e5116c8d7cabbd45e1409b989d4be085b53f13e"
+dependencies = [
+ "serde_core",
+]
+
+[[package]]
+name = "toml_parser"
+version = "1.0.9+spec-1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "702d4415e08923e7e1ef96cd5727c0dfed80b4d2fa25db9647fe5eb6f7c5a4c4"
+dependencies = [
+ "winnow",
+]
+
+[[package]]
+name = "toml_writer"
+version = "1.0.6+spec-1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ab16f14aed21ee8bfd8ec22513f7287cd4a91aa92e44edfe2c17ddd004e92607"
+
 [[package]]
 name = "tower"
 version = "0.5.2"
@ -1487,6 +1557,21 @@ version = "0.2.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e421abadd41a4225275504ea4d6566923418b7f05506fbc9c0fe86ba7396114b"

+[[package]]
+name = "trybuild"
+version = "1.0.116"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "47c635f0191bd3a2941013e5062667100969f8c4e9cd787c14f977265d73616e"
+dependencies = [
+ "glob",
+ "serde",
+ "serde_derive",
+ "serde_json",
+ "target-triple",
+ "termcolor",
+ "toml",
+]
+
 [[package]]
 name = "unicode-ident"
 version = "1.0.22"
@ -1640,6 +1725,15 @@ dependencies = [
 "wasm-bindgen",
 ]

+[[package]]
+name = "winapi-util"
+version = "0.1.11"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c2a7b1c03c876122aa43f3020e6c3c3ee5c05081c9a00739faf7503aeba10d22"
+dependencies = [
+ "windows-sys 0.61.2",
+]
+
 [[package]]
 name = "windows-link"
 version = "0.2.1"
@ -1802,6 +1896,12 @@ version = "0.53.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d6bbff5f0aada427a1e5a6da5f1f98158182f26556f345ac9e04d36d0ebed650"

+[[package]]
+name = "winnow"
+version = "0.7.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5a5364e9d77fcdeeaa6062ced926ee3381faa2ee02d3eb83a5c27a8825540829"
+
 [[package]]
 name = "wit-bindgen"
 version = "0.46.0"
--- a/docs/plan/worker_api_plan.md
+++ b/docs/plan/worker_api_plan.md
@ -0,0 +1,83 @@
+# Worker API/DSL 実装計画
+
+## 目的
+
+- [Open Responses](https://www.openresponses.org)(以後"OR")に準拠した正規化を前提に、
+  Item/Part の2段スコープを扱える Worker API を設計する。
+- APIの煩雑化を防ぐため、worker.on_xxx として公開するのを避けつつ、
+  Text/Thinking/Tool など型の違いを静的に扱える DSL を提供する。
+
+## 方針
+
+- 内部は Timeline が Event を正規化し、Item/Part/Meta
+  を単一ストリームとして扱う。
+- API では Item/Part 型ごとに ctx を持てるようにし、DSL
+  で記述の冗長さを削減する。
+- まず macro_rules! 版を作り、必要なら proc-macro に拡張する。
+- Item/Part の型パラメータはクレートが公開する Kind 型を使う。
+
+## 仕様の前提
+
+- Item は OR の item (message, function_call, reasoning など) に対応する。
+- Part は OR の content part (output_text, reasoning_text など) に対応する。
+- Item は必ず start/stop を持つ。Part は Item 内で複数発生し得る。
+- Item/Part の型指定は `Item<Message>` / `Part<ReasoningText>` のように書く。
+
+## 設計ステップ
+
+### 1. 内部イベントモデルの整理
+
+- Event を Item/Part/Meta の3層に整理する。
+- ItemEvent / PartEvent は型パラメータで区別する。
+- 例: ItemEvent<Message>, PartEvent<Message, OutputText>
+
+### 2. スコープの二段化
+
+- Item ctx: Item 型ごとに1つ
+- Part ctx: Part 型ごとに1つ
+- Part のイベントでは常に item ctx と part ctx の両方を渡す。
+
+### 3. Handler trait の再定義
+
+- Item/Part を型で指定できる trait を導入する。
+- 例:
+  - trait ItemHandler<I>
+  - trait PartHandler<I, P>
+- PartHandler には ItemHandler の ItemCtx を必須で渡す。
+- Part の ctx 型は `PartKind::Ctx` 方式 or enum 方式で切り替える。
+
+### 4. Timeline との結合
+
+- Timeline は ItemStart で ItemCtx を生成
+- PartStart で PartCtx を生成
+- Delta/Stop は対応 ctx に流す
+- ItemStop で ItemCtx を破棄
+
+### 5. DSL (macro_rules!) の導入
+
+- まず宣言的 DSL を提供する。
+- 例:
+  - handler! { Item<Message> { type ItemCtx = ...; Part<OutputText> { type
+    PartCtx = ...; } } }
+- DSL は ItemHandler / PartHandler 実装を生成する。
+- Item/Part の Kind 型はクレートが公開する型を参照する。
+
+### 6. 拡張ポイント
+
+- 追加 Part (output_image など) を DSL に追加しやすい形にする。
+- 必要なら proc-macro に移行して構文自由度を上げる。
+
+## 実装順序
+
+1. Event/Item/Part の型定義の整理
+2. Item/Part ctx を持つ Timeline 実装
+3. Handler trait の定義・既存コードの移行
+4. macro_rules! DSL の実装
+5. 既存ユースケースの移植
+
+## TODO
+
+- Item と Part の型対応表を整理する
+- OR と既存 llm_client の差分を再確認する
+- Tool args の delta を OR 拡張として扱うか検討する
+- macro_rules! で表現可能な DSL の最小文法を確定する
--- a/docs/research/openresponses_mapping.md
+++ b/docs/research/openresponses_mapping.md
@ -0,0 +1,80 @@
+# Open Responses mapping (llm_client -> Open Responses)
+
+This document maps the current `llm_client` event model to Open Responses items
+and streaming events. It focuses on output streaming; input items are noted
+where they are the closest semantic match.
+
+## Legend
+
+- **OR item**: Open Responses item types used in `response.output`.
+- **OR event**: Open Responses streaming events (`response.*`).
+- **Note**: Gaps or required adaptation decisions.
+
+## Response lifecycle / meta events
+
+| llm_client               | Open Responses                                                | Note                                                                                           |
+| ------------------------ | ------------------------------------------------------------- | ---------------------------------------------------------------------------------------------- |
+| `StatusEvent::Started`   | `response.created`, `response.queued`, `response.in_progress` | OR has finer-grained lifecycle states; pick a subset or map Started -> `response.in_progress`. |
+| `StatusEvent::Completed` | `response.completed`                                          |                                                                                                |
+| `StatusEvent::Failed`    | `response.failed`                                             |                                                                                                |
+| `StatusEvent::Cancelled` | (no direct event)                                             | Could map to `response.incomplete` or `response.failed` depending on semantics.                |
+| `UsageEvent`             | `response.completed` payload usage                            | OR reports usage on the response object, not as a dedicated streaming event.                   |
+| `ErrorEvent`             | `error` event                                                 | OR has a dedicated error streaming event.                                                      |
+| `PingEvent`              | (no direct event)                                             | OR does not define a heartbeat event.                                                          |
+
+## Output block lifecycle
+
+### Text block
+
+| llm_client                                        | Open Responses                                                                           | Note                                                                                |
+| ------------------------------------------------- | ---------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------- |
+| `BlockStart { block_type: Text, metadata: Text }` | `response.output_item.added` with item type `message` (assistant)                        | OR output items are message/function_call/reasoning. This creates the message item. |
+| `BlockDelta { delta: Text(..) }`                  | `response.output_text.delta`                                                             | Text deltas map 1:1 to output text deltas.                                          |
+| `BlockStop { block_type: Text }`                  | `response.output_text.done` + `response.content_part.done` + `response.output_item.done` | OR emits separate done events for content parts and items.                          |
+
+### Tool use (function call)
+
+| llm_client                                                           | Open Responses                                                        | Note                                                                                                  |
+| -------------------------------------------------------------------- | --------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------- |
+| `BlockStart { block_type: ToolUse, metadata: ToolUse { id, name } }` | `response.output_item.added` with item type `function_call`           | OR uses `call_id` + `name` + `arguments` string. Map `id` -> `call_id`.                               |
+| `BlockDelta { delta: InputJson(..) }`                                | `response.function_call_arguments.delta`                              | OR spec does not explicitly require argument deltas; treat as OpenAI-compatible extension if adopted. |
+| `BlockStop { block_type: ToolUse }`                                  | `response.function_call_arguments.done` + `response.output_item.done` | Item status can be set to `completed` or `incomplete`.                                                |
+
+### Tool result (function call output)
+
+| llm_client                                                                    | Open Responses                        | Note                                                                                     |
+| ----------------------------------------------------------------------------- | ------------------------------------- | ---------------------------------------------------------------------------------------- |
+| `BlockStart { block_type: ToolResult, metadata: ToolResult { tool_use_id } }` | **Input item** `function_call_output` | OR treats tool results as input items, not output items. This is a request-side mapping. |
+| `BlockDelta`                                                                  | (no direct output event)              | OR does not stream tool output deltas as response events.                                |
+| `BlockStop`                                                                   | (no direct output event)              | Tool output lives on the next request as an input item.                                  |
+
+### Thinking / reasoning
+
+| llm_client                                                | Open Responses                                          | Note                                                                                                                                                          |
+| --------------------------------------------------------- | ------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------- |
+| `BlockStart { block_type: Thinking, metadata: Thinking }` | `response.output_item.added` with item type `reasoning` | OR models reasoning as a separate item type.                                                                                                                  |
+| `BlockDelta { delta: Thinking(..) }`                      | `response.reasoning.delta`                              | OR has dedicated reasoning delta events.                                                                                                                      |
+| `BlockStop { block_type: Thinking }`                      | `response.reasoning.done`                               | OR separates reasoning summary events (`response.reasoning_summary_*`) from reasoning deltas. Decide whether Thinking maps to full reasoning or summary only. |
+
+## Stop reasons
+
+| llm_client `StopReason` | Open Responses                                                                 | Note                                           |
+| ----------------------- | ------------------------------------------------------------------------------ | ---------------------------------------------- |
+| `EndTurn`               | `response.completed` + item status `completed`                                 |                                                |
+| `MaxTokens`             | `response.incomplete` + item status `incomplete`                               |                                                |
+| `StopSequence`          | `response.completed`                                                           |                                                |
+| `ToolUse`               | `response.completed` for message item, followed by `function_call` output item | OR models tool call as a separate output item. |
+
+## Gaps / open decisions
+
+- `PingEvent` has no OR equivalent. If needed, keep as internal only.
+- `Cancelled` status needs a policy: map to `response.incomplete` or
+  `response.failed`.
+- OR has `response.refusal.delta` / `response.refusal.done`. `llm_client` has no
+  refusal delta type; consider adding a new block or delta variant if needed.
+- OR splits _item_ and _content part_ lifecycles. `llm_client` currently has a
+  single block lifecycle, so mapping should decide whether to synthesize
+  `content_part.*` events or ignore them.
+- The OR specification does not state how `function_call.arguments` stream
+  deltas; `response.function_call_arguments.*` should be treated as a compatible
+  extension if required.
--- a/docs/spec/worker_design.md
+++ b/docs/spec/worker_design.md
@ -31,41 +31,48 @@ graph TD

 Workerは以下のループ（ターン）を実行します。

-1.  **Start Turn**: `Worker::run(messages)` 呼び出し
-2.  **Hook: OnMessageSend**:
-    *   ユーザーメッセージの改変、バリデーション、キャンセルが可能。
-    *   コンテキストへのシステムプロンプト注入などもここで行う想定。
-3.  **Request & Stream**:
-    *   LLMへリクエスト送信。イベントストリーム開始。
-    *   `Timeline`によるイベント処理。
-4.  **Tool Handling (Parallel)**:
-    *   レスポンス内に含まれる全てのTool Callを収集。
-    *   各Toolに対して **Hook: BeforeToolCall** を実行（実行可否、引数改変）。
-    *   許可されたToolを**並列実行 (`join_all`)**。
-    *   各Tool実行後に **Hook: AfterToolCall** を実行（結果の確認、加工）。
-5.  **Next Request Decision**:
-    *   Tool実行結果がある場合 -> 結果をMessageとしてContextに追加し、**Step 3へ戻る** (自動ループ)。
-    *   Tool実行がない場合 -> Step 6へ。
-6.  **Hook: OnTurnEnd**:
-    *   最終的な応答に対するチェック（Lint/Fmt）。
-    *   エラーがある場合、エラーメッセージをContextに追加して **Step 3へ戻る** ことで自己修正を促せる。
-    *   問題なければターン終了。
+1. **Start Turn**: `Worker::run(messages)` 呼び出し
+2. **Hook: OnMessageSend**:
+   - ユーザーメッセージの改変、バリデーション、キャンセルが可能。
+   - コンテキストへのシステムプロンプト注入などもここで行う想定。
+3. **Request & Stream**:
+   - LLMへリクエスト送信。イベントストリーム開始。
+   - `Timeline`によるイベント処理。
+4. **Tool Handling (Parallel)**:
+   - レスポンス内に含まれる全てのTool Callを収集。
+   - 各Toolに対して **Hook: BeforeToolCall** を実行（実行可否、引数改変）。
+   - 許可されたToolを**並列実行 (`join_all`)**。
+   - 各Tool実行後に **Hook: AfterToolCall** を実行（結果の確認、加工）。
+5. **Next Request Decision**:
+   - Tool実行結果がある場合 -> 結果をMessageとしてContextに追加し、**Step
+     3へ戻る** (自動ループ)。
+   - Tool実行がない場合 -> Step 6へ。
+6. **Hook: OnTurnEnd**:
+   - 最終的な応答に対するチェック（Lint/Fmt）。
+   - エラーがある場合、エラーメッセージをContextに追加して **Step 3へ戻る**
+     ことで自己修正を促せる。
+   - 問題なければターン終了。

 ## Tool 設計

 ### アーキテクチャ概要

-Rustの静的型付けシステムとLLMの動的なツール呼び出し（文字列による指定）を、**Trait Object** と **動的ディスパッチ** を用いて接続します。
+Rustの静的型付けシステムとLLMの動的なツール呼び出し（文字列による指定）を、**Trait
+Object** と **動的ディスパッチ** を用いて接続します。

-1.  **共通インターフェース (`Tool` Trait)**: 全てのツールが実装すべき共通の振る舞い（メタデータ取得と実行）を定義します。
-2.  **ラッパー生成 (`#[tool]` Macro)**: ユーザー定義のメソッドをラップし、`Tool` Traitを実装した構造体を自動生成します。
-3.  **レジストリ (`HashMap`)**: Workerは動的ディスパッチ用に `HashMap<String, Box<dyn Tool>>` でツールを管理します。
+1. **共通インターフェース (`Tool` Trait)**:
+   全てのツールが実装すべき共通の振る舞い（メタデータ取得と実行）を定義します。
+2. **ラッパー生成 (`#[tool]` Macro)**: ユーザー定義のメソッドをラップし、`Tool`
+   Traitを実装した構造体を自動生成します。
+3. **レジストリ (`HashMap`)**: Workerは動的ディスパッチ用に
+   `HashMap<String, Box<dyn Tool>>` でツールを管理します。

 この仕組みにより、「名前からツールを探し、JSON引数を型変換して関数を実行する」フローを安全に実現します。

 ### 1. Tool Trait 定義

-ツールが最低限持つべきインターフェースです。`Send + Sync` を必須とし、マルチスレッド（並列実行）に対応します。
+ツールが最低限持つべきインターフェースです。`Send + Sync`
+を必須とし、マルチスレッド（並列実行）に対応します。

 ```rust
 #[async_trait]
@ -113,7 +120,8 @@ impl MyApp {

 **マクロ展開後のイメージ (擬似コード):**

-マクロは、元のメソッドに対応する**ラッパー構造体**を生成します。このラッパーが `Tool` Trait を実装します。
+マクロは、元のメソッドに対応する**ラッパー構造体**を生成します。このラッパーが
+`Tool` Trait を実装します。

 ```rust
 // 1. 引数をデシリアライズ用の中間構造体に変換
@ -155,15 +163,18 @@ impl Tool for GetUserTool {

 ### 3. Workerによる実行フロー

-Workerは生成されたラッパー構造体を `Box<dyn Tool>` として保持し、以下のフローで実行します。
+Workerは生成されたラッパー構造体を `Box<dyn Tool>`
+として保持し、以下のフローで実行します。

-1.  **登録**: アプリケーション開始時、コンテキスト(`MyApp`)から各ツールのラッパー(`GetUserTool`)を生成し、WorkerのMapに登録。
-2.  **解決**: LLMからのレスポンスに含まれる `ToolUse { name: "get_user", ... }` を受け取る。
-3.  **検索**: `name` をキーに Map から `Box<dyn Tool>` を取得。
-4.  **実行**:
-    *   `tool.execute(json)` を呼び出す。
-    *   内部で `serde_json` による型変換とメソッド実行が行われる。
-    *   結果が返る。
+1. **登録**:
+   アプリケーション開始時、コンテキスト(`MyApp`)から各ツールのラッパー(`GetUserTool`)を生成し、WorkerのMapに登録。
+2. **解決**: LLMからのレスポンスに含まれる `ToolUse { name: "get_user", ... }`
+   を受け取る。
+3. **検索**: `name` をキーに Map から `Box<dyn Tool>` を取得。
+4. **実行**:
+   - `tool.execute(json)` を呼び出す。
+   - 内部で `serde_json` による型変換とメソッド実行が行われる。
+   - 結果が返る。

 これにより、型安全性を保ちつつ、動的なツール実行が可能になります。

@ -171,8 +182,9 @@ Workerは生成されたラッパー構造体を `Box<dyn Tool>` として保持

 ### コンセプト

-*   **制御の介入**: ターンの進行、メッセージの内容、ツールの実行に対して介入します。
-*   **Contextへのアクセス**: メッセージ履歴（Context）を読み書きできます。
+- **制御の介入**:
+  ターンの進行、メッセージの内容、ツールの実行に対して介入します。
+- **Contextへのアクセス**: メッセージ履歴（Context）を読み書きできます。

 ### Hook Trait

@ -219,7 +231,8 @@ pub enum OnTurnEndResult {

 ### Tool Call Context

-`before_tool_call` / `after_tool_call` は、ツール実行の文脈を含む入力を受け取る。
+`before_tool_call` / `after_tool_call`
+は、ツール実行の文脈を含む入力を受け取る。

 ```rust
 pub struct ToolCallContext {
@ -237,17 +250,20 @@ pub struct ToolResultContext {

 ## 実装方針

-1.  **Worker Struct**:
-    *   `Timeline`を所有。
-    *   `Handler`として「ToolCallCollector」をTimelineに登録。
-    *   `stream`終了後に収集したToolCallを処理するロジックを持つ。
+1. **Worker Struct**:
+   - `Timeline`を所有。
+   - `Handler`として「ToolCallCollector」をTimelineに登録。
+   - `stream`終了後に収集したToolCallを処理するロジックを持つ。
+   - **履歴管理**: `set_history`, `with_messages`, `history_mut`
+     等を通じて、会話履歴の注入や編集を可能にする。

-2.  **Tool Executor Handler**:
-    *   Timeline上ではツール実行を行わず、あくまで「ToolCallブロックの収集」に徹する（Toolの実行は非同期かつ並列で、ストリーム終了後あるいはブロック確定後に行うため）。
-    *   ただし、リアルタイム性を重視する場合（ストリーミング中にToolを実行開始等）は将来的な拡張とするが、現状は「結果が揃うのを待って」という要件に従い、収集フェーズと実行フェーズを分ける。
+2. **Tool Executor Handler**:
+   - Timeline上ではツール実行を行わず、あくまで「ToolCallブロックの収集」に徹する（Toolの実行は非同期かつ並列で、ストリーム終了後あるいはブロック確定後に行うため）。
+   - ただし、リアルタイム性を重視する場合（ストリーミング中にToolを実行開始等）は将来的な拡張とするが、現状は「結果が揃うのを待って」という要件に従い、収集フェーズと実行フェーズを分ける。

-3.  **worker-macros**:
-    *   `syn`, `quote` を用いて、関数定義から `Tool` トレイト実装と `InputSchema` (schemars利用) を生成。
+3. **worker-macros**:
+   - `syn`, `quote` を用いて、関数定義から `Tool` トレイト実装と `InputSchema`
+     (schemars利用) を生成。

 ## Worker Event API 設計

@ -256,6 +272,7 @@ pub struct ToolResultContext {
 Workerは内部でイベントを処理し結果を返しますが、UIへのストリーミング表示やリアルタイムフィードバックには、イベントを外部に公開する仕組みが必要です。

 **要件**:
+
 1. テキストデルタをリアルタイムでUIに表示
 2. ツール呼び出しの進行状況を表示
 3. ブロック完了時に累積結果を受け取る
@ -264,10 +281,10 @@ Workerは内部でイベントを処理し結果を返しますが、UIへのス

 Worker APIは **Timeline層のHandler機構の薄いラッパー** として設計します。

-| 層 | 目的 | 提供するもの |
-|---|------|-------------|
-| **Handler (Timeline層)** | 内部実装、役割分離 | スコープ管理 + Deltaイベント |
-| **Worker Event API** | ユーザー向け利便性 | Handler露出 + Completeイベント追加 |
+| 層                       | 目的               | 提供するもの                       |
+| ------------------------ | ------------------ | ---------------------------------- |
+| **Handler (Timeline層)** | 内部実装、役割分離 | スコープ管理 + Deltaイベント       |
+| **Worker Event API**     | ユーザー向け利便性 | Handler露出 + Completeイベント追加 |

 Handlerのスコープ管理パターン（Start→Delta→End）をそのまま活かしつつ、累積済みのCompleteイベントも追加提供します。

@ -448,7 +465,8 @@ impl<C: LlmClient> Worker<C> {
 ### 設計上のポイント

 1. **Handlerの再利用**: 既存のHandler traitをそのまま活用
-2. **スコープ管理の維持**: ブロックイベントはStart→Delta→Endのライフサイクルを保持
+2. **スコープ管理の維持**:
+   ブロックイベントはStart→Delta→Endのライフサイクルを保持
 3. **選択的購読**: on_*で必要なイベントだけ、またはSubscriberで一括
 4. **累積イベントの追加**: Worker層でComplete系イベントを追加提供
 5. **後方互換性**: 従来の`run()`も引き続き使用可能
--- a/flake.lock
+++ b/flake.lock
@ -35,11 +35,11 @@
    },
    "nixpkgs": {
      "locked": {
-        "lastModified": 1767116409,
-        "narHash": "sha256-5vKw92l1GyTnjoLzEagJy5V5mDFck72LiQWZSOnSicw=",
+        "lastModified": 1771369470,
+        "narHash": "sha256-0NBlEBKkN3lufyvFegY4TYv5mCNHbi5OmBDrzihbBMQ=",
        "owner": "nixos",
        "repo": "nixpkgs",
-        "rev": "cad22e7d996aea55ecab064e84834289143e44a0",
+        "rev": "0182a361324364ae3f436a63005877674cf45efb",
        "type": "github"
      },
      "original": {
--- a/llm-worker-macros/src/lib.rs
+++ b/llm-worker-macros/src/lib.rs
@ -1,7 +1,7 @@
-//! llm-worker-macros - Tool生成用手続きマクロ
+//! llm-worker-macros - Procedural macros for Tool generation
 //!
-//! `#[tool_registry]` と `#[tool]` マクロを提供し、
-//! ユーザー定義のメソッドから `Tool` トレイト実装を自動生成する。
+//! Provides `#[tool_registry]` and `#[tool]` macros to
+//! automatically generate `Tool` trait implementations from user-defined methods.

 use proc_macro::TokenStream;
 use quote::{format_ident, quote};
@ -9,22 +9,22 @@ use syn::{
    Attribute, FnArg, ImplItem, ItemImpl, Lit, Meta, Pat, ReturnType, Type, parse_macro_input,
 };

-/// `impl` ブロックに付与し、内部の `#[tool]` 属性がついたメソッドからツールを生成するマクロ。
+/// Macro applied to an `impl` block that generates tools from methods marked with `#[tool]`.
 ///
 /// # Example
 /// ```ignore
 /// #[tool_registry]
 /// impl MyApp {
-///     /// ユーザー情報を取得する
-///     /// 指定されたIDのユーザーをDBから検索します。
+///     /// Get user information
+///     /// Retrieves a user from the database by their ID.
 ///     #[tool]
 ///     async fn get_user(&self, user_id: String) -> Result<User, Error> { ... }
 /// }
 /// ```
 ///
-/// これにより以下が生成されます：
-/// - `GetUserArgs` 構造体（引数用）
-/// - `Tool_get_user` 構造体（Toolラッパー）
+/// This generates:
+/// - `GetUserArgs` struct (for arguments)
+/// - `Tool_get_user` struct (Tool wrapper)
 /// - `impl Tool for Tool_get_user`
 /// - `impl MyApp { fn get_user_tool(&self) -> Tool_get_user }`
 #[proc_macro_attribute]
@ -36,14 +36,14 @@ pub fn tool_registry(_attr: TokenStream, item: TokenStream) -> TokenStream {

    for item in &mut impl_block.items {
        if let ImplItem::Fn(method) = item {
-            // #[tool] 属性を探す
+            // Look for #[tool] attribute
            let mut is_tool = false;

-            // 属性を走査してtoolがあるか確認し、削除する
+            // Iterate through attributes to check for tool and remove it
            method.attrs.retain(|attr| {
                if attr.path().is_ident("tool") {
                    is_tool = true;
-                    false // 属性を削除
+                    false // Remove the attribute
                } else {
                    true
                }
@ -65,7 +65,7 @@ pub fn tool_registry(_attr: TokenStream, item: TokenStream) -> TokenStream {
    TokenStream::from(expanded)
 }

-/// ドキュメントコメントから説明文を抽出
+/// Extract description from doc comments
 fn extract_doc_comment(attrs: &[Attribute]) -> String {
    let mut lines = Vec::new();

@ -75,7 +75,7 @@ fn extract_doc_comment(attrs: &[Attribute]) -> String {
                if let syn::Expr::Lit(expr_lit) = &meta.value {
                    if let Lit::Str(lit_str) = &expr_lit.lit {
                        let line = lit_str.value();
-                        // 先頭の空白を1つだけ除去（/// の後のスペース）
+                        // Remove only the leading space (after ///)
                        let trimmed = line.strip_prefix(' ').unwrap_or(&line);
                        lines.push(trimmed.to_string());
                    }
@ -87,7 +87,7 @@ fn extract_doc_comment(attrs: &[Attribute]) -> String {
    lines.join("\n")
 }

-/// #[description = "..."] 属性から説明を抽出
+/// Extract description from #[description = "..."] attribute
 fn extract_description_attr(attrs: &[syn::Attribute]) -> Option<String> {
    for attr in attrs {
        if attr.path().is_ident("description") {
@ -103,19 +103,19 @@ fn extract_description_attr(attrs: &[syn::Attribute]) -> Option<String> {
    None
 }

-/// メソッドからTool実装を生成
+/// Generate Tool implementation from a method
 fn generate_tool_impl(self_ty: &Type, method: &syn::ImplItemFn) -> proc_macro2::TokenStream {
    let sig = &method.sig;
    let method_name = &sig.ident;
    let tool_name = method_name.to_string();

-    // 構造体名を生成（PascalCase変換）
+    // Generate struct names (convert to PascalCase)
    let pascal_name = to_pascal_case(&method_name.to_string());
    let tool_struct_name = format_ident!("Tool{}", pascal_name);
    let args_struct_name = format_ident!("{}Args", pascal_name);
    let definition_name = format_ident!("{}_definition", method_name);

-    // ドキュメントコメントから説明を取得
+    // Get description from doc comments
    let description = extract_doc_comment(&method.attrs);
    let description = if description.is_empty() {
        format!("Tool: {}", tool_name)
@ -123,7 +123,7 @@ fn generate_tool_impl(self_ty: &Type, method: &syn::ImplItemFn) -> proc_macro2::
        description
    };

-    // 引数を解析（selfを除く）
+    // Parse arguments (excluding self)
    let args: Vec<_> = sig
        .inputs
        .iter()
@ -131,12 +131,12 @@ fn generate_tool_impl(self_ty: &Type, method: &syn::ImplItemFn) -> proc_macro2::
            if let FnArg::Typed(pat_type) = arg {
                Some(pat_type)
            } else {
-                None // selfを除外
+                None // Exclude self
            }
        })
        .collect();

-    // 引数構造体のフィールドを生成
+    // Generate argument struct fields
    let arg_fields: Vec<_> = args
        .iter()
        .map(|pat_type| {
@ -144,14 +144,14 @@ fn generate_tool_impl(self_ty: &Type, method: &syn::ImplItemFn) -> proc_macro2::
            let ty = &pat_type.ty;
            let desc = extract_description_attr(&pat_type.attrs);

-            // パターンから識別子を抽出
+            // Extract identifier from pattern
            let field_name = if let Pat::Ident(pat_ident) = pat.as_ref() {
                &pat_ident.ident
            } else {
                panic!("Only simple identifiers are supported for tool arguments");
            };

-            // #[description] があればschemarsのdocに変換
+            // Convert #[description] to schemars doc if present
            if let Some(desc_str) = desc {
                quote! {
                    #[schemars(description = #desc_str)]
@ -165,7 +165,7 @@ fn generate_tool_impl(self_ty: &Type, method: &syn::ImplItemFn) -> proc_macro2::
        })
        .collect();

-    // execute内で引数を展開するコード
+    // Code to expand arguments in execute
    let arg_names: Vec<_> = args
        .iter()
        .map(|pat_type| {
@ -178,17 +178,17 @@ fn generate_tool_impl(self_ty: &Type, method: &syn::ImplItemFn) -> proc_macro2::
        })
        .collect();

-    // メソッドが非同期かどうか
+    // Check if method is async
    let is_async = sig.asyncness.is_some();

-    // 戻り値の型を解析してResult判定
+    // Parse return type and determine if Result
    let awaiter = if is_async {
        quote! { .await }
    } else {
        quote! {}
    };

-    // 戻り値がResultかどうかを判定
+    // Determine if return type is Result
    let result_handling = if is_result_type(&sig.output) {
        quote! {
            match result {
@ -202,7 +202,7 @@ fn generate_tool_impl(self_ty: &Type, method: &syn::ImplItemFn) -> proc_macro2::
        }
    };

-    // 引数がない場合は空のArgs構造体を作成
+    // Create empty Args struct if no arguments
    let args_struct_def = if arg_fields.is_empty() {
        quote! {
            #[derive(serde::Deserialize, schemars::JsonSchema)]
@ -217,10 +217,10 @@ fn generate_tool_impl(self_ty: &Type, method: &syn::ImplItemFn) -> proc_macro2::
        }
    };

-    // 引数がない場合のexecute処理
+    // Execute body handling for no arguments case
    let execute_body = if args.is_empty() {
        quote! {
-            // 引数なしでも空のJSONオブジェクトを許容
+            // Allow empty JSON object even with no arguments
            let _: #args_struct_name = serde_json::from_str(input_json)
                .unwrap_or(#args_struct_name {});

@ -253,7 +253,7 @@ fn generate_tool_impl(self_ty: &Type, method: &syn::ImplItemFn) -> proc_macro2::
        }

        impl #self_ty {
-            /// ToolDefinition を取得（Worker への登録用）
+            /// Get ToolDefinition (for registering with Worker)
            pub fn #definition_name(&self) -> ::llm_worker::tool::ToolDefinition {
                let ctx = self.clone();
                ::std::sync::Arc::new(move || {
@ -270,12 +270,12 @@ fn generate_tool_impl(self_ty: &Type, method: &syn::ImplItemFn) -> proc_macro2::
    }
 }

-/// 戻り値の型がResultかどうかを判定
+/// Determine if return type is Result
 fn is_result_type(return_type: &ReturnType) -> bool {
    match return_type {
        ReturnType::Default => false,
        ReturnType::Type(_, ty) => {
-            // Type::Pathの場合、最後のセグメントが"Result"かチェック
+            // For Type::Path, check if last segment is "Result"
            if let Type::Path(type_path) = ty.as_ref() {
                if let Some(segment) = type_path.path.segments.last() {
                    return segment.ident == "Result";
@ -286,7 +286,7 @@ fn is_result_type(return_type: &ReturnType) -> bool {
    }
 }

-/// snake_case を PascalCase に変換
+/// Convert snake_case to PascalCase
 fn to_pascal_case(s: &str) -> String {
    s.split('_')
        .map(|part| {
@ -299,20 +299,20 @@ fn to_pascal_case(s: &str) -> String {
        .collect()
 }

-/// マーカー属性。`tool_registry` によって処理されるため、ここでは何もしない。
+/// Marker attribute. Does nothing here as it's processed by `tool_registry`.
 #[proc_macro_attribute]
 pub fn tool(_attr: TokenStream, item: TokenStream) -> TokenStream {
    item
 }

-/// 引数属性用のマーカー。パース時に`tool_registry`で解釈される。
+/// Marker for argument attributes. Interpreted by `tool_registry` during parsing.
 ///
 /// # Example
 /// ```ignore
 /// #[tool]
 /// async fn get_user(
 ///     &self,
-///     #[description = "取得したいユーザーのID"] user_id: String
+///     #[description = "The ID of the user to retrieve"] user_id: String
 /// ) -> Result<User, Error> { ... }
 /// ```
 #[proc_macro_attribute]
--- a/llm-worker/Cargo.toml
+++ b/llm-worker/Cargo.toml
@ -1,7 +1,7 @@
 [package]
 name = "llm-worker"
 description = "A library for building autonomous LLM-powered systems"
-version = "0.2.0"
+version = "0.2.1"
 publish.workspace = true
 edition.workspace = true
 license.workspace = true
@ -26,3 +26,4 @@ schemars = "1.2"
 tempfile = "3.24"
 dotenv = "0.15"
 tracing-subscriber = { version = "0.3", features = ["env-filter"] }
+trybuild = "1.0.116"
--- a/llm-worker/examples/record_test_fixtures/main.rs
+++ b/llm-worker/examples/record_test_fixtures/main.rs
@ -1,18 +1,18 @@
-//! テストフィクスチャ記録ツール
+//! Test fixture recording tool
 //!
-//! 定義されたシナリオのAPIレスポンスを記録する。
+//! Records API responses for defined scenarios.
 //!
-//! ## 使用方法
+//! ## Usage
 //!
 //! ```bash
-//! # 利用可能なシナリオを表示
+//! # Show available scenarios
 //! cargo run --example record_test_fixtures
 //!
-//! # 特定のシナリオを記録
+//! # Record specific scenario
 //! ANTHROPIC_API_KEY=your-key cargo run --example record_test_fixtures -- simple_text
 //! ANTHROPIC_API_KEY=your-key cargo run --example record_test_fixtures -- tool_call
 //!
-//! # 全シナリオを記録
+//! # Record all scenarios
 //! ANTHROPIC_API_KEY=your-key cargo run --example record_test_fixtures -- --all
 //! ```

@ -193,8 +193,8 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
        ClientType::Ollama => "ollama",
    };

-    // シナリオのフィルタリングは main.rs のロジックで実行済み
-    // ここでは単純なループで実行
+    // Scenario filtering is already done in main.rs logic
+    // Here we just execute in a simple loop
    for scenario in scenarios_to_run {
        match args.client {
            ClientType::Anthropic => {
--- a/llm-worker/examples/record_test_fixtures/recorder.rs
+++ b/llm-worker/examples/record_test_fixtures/recorder.rs
@ -1,6 +1,6 @@
-//! テストフィクスチャ記録機構
+//! Test fixture recording mechanism
 //!
-//! イベントをJSONLフォーマットでファイルに保存する
+//! Saves events to files in JSONL format

 use std::fs::{self, File};
 use std::io::{BufWriter, Write};
@ -10,7 +10,7 @@ use std::time::{Instant, SystemTime, UNIX_EPOCH};
 use futures::StreamExt;
 use llm_worker::llm_client::{LlmClient, Request};

-/// 記録されたイベント
+/// Recorded event
 #[derive(Debug, serde::Serialize, serde::Deserialize)]
 pub struct RecordedEvent {
    pub elapsed_ms: u64,
@ -18,7 +18,7 @@ pub struct RecordedEvent {
    pub data: String,
 }

-/// セッションメタデータ
+/// Session metadata
 #[derive(Debug, serde::Serialize, serde::Deserialize)]
 pub struct SessionMetadata {
    pub timestamp: u64,
@ -26,7 +26,7 @@ pub struct SessionMetadata {
    pub description: String,
 }

-/// イベントシーケンスをファイルに保存
+/// Save event sequence to file
 pub fn save_fixture(
    path: impl AsRef<Path>,
    metadata: &SessionMetadata,
@ -43,7 +43,7 @@ pub fn save_fixture(
    Ok(())
 }

-/// リクエストを送信してイベントを記録
+/// Send request and record events
 pub async fn record_request<C: LlmClient>(
    client: &C,
    request: Request,
@ -78,7 +78,7 @@ pub async fn record_request<C: LlmClient>(
        }
    }

-    // 保存
+    // Save
    let fixtures_dir = Path::new("worker/tests/fixtures").join(subdir);
    fs::create_dir_all(&fixtures_dir)?;

--- a/llm-worker/examples/record_test_fixtures/scenarios.rs
+++ b/llm-worker/examples/record_test_fixtures/scenarios.rs
@ -1,20 +1,20 @@
-//! テストフィクスチャ用リクエスト定義
+//! Test fixture request definitions
 //!
-//! 各シナリオのリクエストと出力ファイル名を定義
+//! Defines requests and output file names for each scenario

 use llm_worker::llm_client::{Request, ToolDefinition};

-/// テストシナリオ
+/// Test scenario
 pub struct TestScenario {
-    /// シナリオ名（説明）
+    /// Scenario name (description)
    pub name: &'static str,
-    /// 出力ファイル名（拡張子なし）
+    /// Output file name (without extension)
    pub output_name: &'static str,
-    /// リクエスト
+    /// Request
    pub request: Request,
 }

-/// 全てのテストシナリオを取得
+/// Get all test scenarios
 pub fn scenarios() -> Vec<TestScenario> {
    vec![
        simple_text_scenario(),
@ -23,7 +23,7 @@ pub fn scenarios() -> Vec<TestScenario> {
    ]
 }

-/// シンプルなテキストレスポンス
+/// Simple text response
 fn simple_text_scenario() -> TestScenario {
    TestScenario {
        name: "Simple text response",
@ -35,7 +35,7 @@ fn simple_text_scenario() -> TestScenario {
    }
 }

-/// ツール呼び出しを含むレスポンス
+/// Response with tool call
 fn tool_call_scenario() -> TestScenario {
    let get_weather_tool = ToolDefinition::new("get_weather")
        .description("Get the current weather for a city")
@ -61,7 +61,7 @@ fn tool_call_scenario() -> TestScenario {
    }
 }

-/// 長文生成シナリオ
+/// Long text generation scenario
 fn long_text_scenario() -> TestScenario {
    TestScenario {
        name: "Long text response",
--- a/llm-worker/examples/worker_cancel_demo.rs
+++ b/llm-worker/examples/worker_cancel_demo.rs
@ -1,6 +1,6 @@
-//! Worker のキャンセル機能のデモンストレーション
+//! Worker cancellation demo
 //!
-//! ストリーミング受信中に別スレッドからキャンセルする例
+//! Example of cancelling from another thread during streaming

 use llm_worker::llm_client::providers::anthropic::AnthropicClient;
 use llm_worker::{Worker, WorkerResult};
@ -10,10 +10,10 @@ use tokio::sync::Mutex;

 #[tokio::main]
 async fn main() -> Result<(), Box<dyn std::error::Error>> {
-    // .envファイルを読み込む
+    // Load .env file
    dotenv::dotenv().ok();

-    // ロギング初期化
+    // Initialize logging
    tracing_subscriber::fmt()
        .with_env_filter(
            tracing_subscriber::EnvFilter::try_from_default_env()
@ -30,13 +30,13 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
    println!("🚀 Starting Worker...");
    println!("💡 Will cancel after 2 seconds\n");

-    // キャンセルSenderを先に取得（ロックを保持しない）
+    // Get cancel sender first (without holding lock)
    let cancel_tx = {
        let w = worker.lock().await;
        w.cancel_sender()
    };

-    // タスク1: Workerを実行
+    // Task 1: Run Worker
    let worker_clone = worker.clone();
    let task = tokio::spawn(async move {
        let mut w = worker_clone.lock().await;
@ -55,14 +55,14 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
        }
    });

-    // タスク2: 2秒後にキャンセル
+    // Task 2: Cancel after 2 seconds
    tokio::spawn(async move {
        tokio::time::sleep(Duration::from_secs(2)).await;
        println!("\n🛑 Cancelling worker...");
        let _ = cancel_tx.send(()).await;
    });

-    // タスク完了を待つ
+    // Wait for task completion
    task.await?;

    println!("\n✨ Demo complete!");
--- a/llm-worker/examples/worker_cli.rs
+++ b/llm-worker/examples/worker_cli.rs
@ -1,17 +1,17 @@
-//! Worker を用いた対話型 CLI クライアント
+//! Interactive CLI client using Worker
 //!
-//! 複数のLLMプロバイダ（Anthropic, Gemini, OpenAI, Ollama）と対話するCLIアプリケーション。
-//! ツールの登録と実行、ストリーミングレスポンスの表示をデモする。
+//! A CLI application for interacting with multiple LLM providers (Anthropic, Gemini, OpenAI, Ollama).
+//! Demonstrates tool registration and execution, and streaming response display.
 //!
-//! ## 使用方法
+//! ## Usage
 //!
 //! ```bash
-//! # .envファイルにAPIキーを設定
+//! # Set API keys in .env file
 //! echo "ANTHROPIC_API_KEY=your-api-key" > .env
 //! echo "GEMINI_API_KEY=your-api-key" >> .env
 //! echo "OPENAI_API_KEY=your-api-key" >> .env
 //!
-//! # Anthropic (デフォルト)
+//! # Anthropic (default)
 //! cargo run --example worker_cli
 //!
 //! # Gemini
@ -20,13 +20,13 @@
 //! # OpenAI
 //! cargo run --example worker_cli -- --provider openai --model gpt-4o
 //!
-//! # Ollama (ローカル)
+//! # Ollama (local)
 //! cargo run --example worker_cli -- --provider ollama --model llama3.2
 //!
-//! # オプション指定
+//! # With options
 //! cargo run --example worker_cli -- --provider anthropic --model claude-3-haiku-20240307 --system "You are a helpful assistant."
 //!
-//! # ヘルプ表示
+//! # Show help
 //! cargo run --example worker_cli -- --help
 //! ```

@ -53,15 +53,15 @@ use llm_worker::{
 };
 use llm_worker_macros::tool_registry;

-// 必要なマクロ展開用インポート
+// Required imports for macro expansion
 use schemars;
 use serde;

 // =============================================================================
-// プロバイダ定義
+// Provider Definition
 // =============================================================================

-/// 利用可能なLLMプロバイダ
+/// Available LLM providers
 #[derive(Debug, Clone, Copy, ValueEnum, Default)]
 enum Provider {
    /// Anthropic Claude
@ -71,12 +71,12 @@ enum Provider {
    Gemini,
    /// OpenAI GPT
    Openai,
-    /// Ollama (ローカル)
+    /// Ollama (local)
    Ollama,
 }

 impl Provider {
-    /// プロバイダのデフォルトモデル
+    /// Default model for the provider
    fn default_model(&self) -> &'static str {
        match self {
            Provider::Anthropic => "claude-sonnet-4-20250514",
@ -86,7 +86,7 @@ impl Provider {
        }
    }

-    /// プロバイダの表示名
+    /// Display name for the provider
    fn display_name(&self) -> &'static str {
        match self {
            Provider::Anthropic => "Anthropic Claude",
@ -96,78 +96,78 @@ impl Provider {
        }
    }

-    /// APIキーの環境変数名
+    /// Environment variable name for API key
    fn env_var_name(&self) -> Option<&'static str> {
        match self {
            Provider::Anthropic => Some("ANTHROPIC_API_KEY"),
            Provider::Gemini => Some("GEMINI_API_KEY"),
            Provider::Openai => Some("OPENAI_API_KEY"),
-            Provider::Ollama => None, // Ollamaはローカルなので不要
+            Provider::Ollama => None, // Ollama is local, no key needed
        }
    }
 }

 // =============================================================================
-// CLI引数定義
+// CLI Argument Definition
 // =============================================================================

-/// 複数のLLMプロバイダに対応した対話型CLIクライアント
+/// Interactive CLI client supporting multiple LLM providers
 #[derive(Parser, Debug)]
 #[command(name = "worker-cli")]
 #[command(about = "Interactive CLI client for multiple LLM providers using Worker")]
 #[command(version)]
 struct Args {
-    /// 使用するプロバイダ
+    /// Provider to use
    #[arg(long, value_enum, default_value_t = Provider::Anthropic)]
    provider: Provider,

-    /// 使用するモデル名（未指定時はプロバイダのデフォルト）
+    /// Model name to use (defaults to provider's default if not specified)
    #[arg(short, long)]
    model: Option<String>,

-    /// システムプロンプト
+    /// System prompt
    #[arg(short, long)]
    system: Option<String>,

-    /// ツールを無効化
+    /// Disable tools
    #[arg(long, default_value = "false")]
    no_tools: bool,

-    /// 最初のメッセージ（指定するとそれを送信して終了）
+    /// Initial message (if specified, sends it and exits)
    #[arg(short = 'p', long)]
    prompt: Option<String>,

-    /// APIキー（環境変数より優先）
+    /// API key (takes precedence over environment variable)
    #[arg(long)]
    api_key: Option<String>,
 }

 // =============================================================================
-// ツール定義
+// Tool Definition
 // =============================================================================

-/// アプリケーションコンテキスト
+/// Application context
 #[derive(Clone)]
 struct AppContext;

 #[tool_registry]
 impl AppContext {
-    /// 現在の日時を取得する
+    /// Get the current date and time
    ///
-    /// システムの現在の日付と時刻を返します。
+    /// Returns the system's current date and time.
    #[tool]
    fn get_current_time(&self) -> String {
        let now = std::time::SystemTime::now()
            .duration_since(std::time::UNIX_EPOCH)
            .unwrap()
            .as_secs();
-        // シンプルなUnixタイムスタンプからの変換
+        // Simple conversion from Unix timestamp
        format!("Current Unix timestamp: {}", now)
    }

-    /// 簡単な計算を行う
+    /// Perform a simple calculation
    ///
-    /// 2つの数値の四則演算を実行します。
+    /// Executes arithmetic operations on two numbers.
    #[tool]
    fn calculate(&self, a: f64, b: f64, operation: String) -> Result<String, String> {
        let result = match operation.as_str() {
@ -187,10 +187,10 @@ impl AppContext {
 }

 // =============================================================================
-// ストリーミング表示用ハンドラー
+// Streaming Display Handlers
 // =============================================================================

-/// テキストをリアルタイムで出力するハンドラー
+/// Handler that outputs text in real-time
 struct StreamingPrinter {
    is_first_delta: Arc<Mutex<bool>>,
 }
@ -226,7 +226,7 @@ impl Handler<TextBlockKind> for StreamingPrinter {
    }
 }

-/// ツール呼び出しを表示するハンドラー
+/// Handler that displays tool calls
 struct ToolCallPrinter {
    call_names: Arc<Mutex<HashMap<String, String>>>,
 }
@ -270,7 +270,7 @@ impl Handler<ToolUseBlockKind> for ToolCallPrinter {
    }
 }

-/// ツール実行結果を表示するHook
+/// Hook that displays tool execution results
 struct ToolResultPrinterHook {
    call_names: Arc<Mutex<HashMap<String, String>>>,
 }
@ -302,17 +302,17 @@ impl Hook<PostToolCall> for ToolResultPrinterHook {
 }

 // =============================================================================
-// クライアント作成
+// Client Creation
 // =============================================================================

-/// プロバイダに応じたAPIキーを取得
+/// Get API key based on provider
 fn get_api_key(args: &Args) -> Result<String, String> {
-    // CLI引数のAPIキーが優先
+    // CLI argument API key takes precedence
    if let Some(ref key) = args.api_key {
        return Ok(key.clone());
    }

-    // プロバイダに応じた環境変数を確認
+    // Check environment variable based on provider
    if let Some(env_var) = args.provider.env_var_name() {
        std::env::var(env_var).map_err(|_| {
            format!(
@ -321,12 +321,12 @@ fn get_api_key(args: &Args) -> Result<String, String> {
            )
        })
    } else {
-        // Ollamaなどはキー不要
+        // Ollama etc. don't need a key
        Ok(String::new())
    }
 }

-/// プロバイダに応じたクライアントを作成
+/// Create client based on provider
 fn create_client(args: &Args) -> Result<Box<dyn LlmClient>, String> {
    let model = args
        .model
@ -356,17 +356,17 @@ fn create_client(args: &Args) -> Result<Box<dyn LlmClient>, String> {
 }

 // =============================================================================
-// メイン
+// Main
 // =============================================================================

 #[tokio::main]
 async fn main() -> Result<(), Box<dyn std::error::Error>> {
-    // .envファイルを読み込む
+    // Load .env file
    dotenv::dotenv().ok();

-    // ロギング初期化
-    // RUST_LOG=debug cargo run --example worker_cli ... で詳細ログ表示
-    // デフォルトは warn レベル、RUST_LOG 環境変数で上書き可能
+    // Initialize logging
+    // Use RUST_LOG=debug cargo run --example worker_cli ... for detailed logs
+    // Default is warn level, can be overridden with RUST_LOG environment variable
    let filter = EnvFilter::try_from_default_env().unwrap_or_else(|_| EnvFilter::new("warn"));

    tracing_subscriber::fmt()
@ -374,7 +374,7 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
        .with_target(true)
        .init();

-    // CLI引数をパース
+    // Parse CLI arguments
    let args = Args::parse();

    info!(
@ -383,10 +383,10 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
        "Starting worker CLI"
    );

-    // 対話モードかワンショットモードか
+    // Interactive mode or one-shot mode
    let is_interactive = args.prompt.is_none();

-    // モデル名（表示用）
+    // Model name (for display)
    let model_name = args
        .model
        .clone()
@ -416,7 +416,7 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
        println!("─────────────────────────────────────────────────");
    }

-    // クライアント作成
+    // Create client
    let client = match create_client(&args) {
        Ok(c) => c,
        Err(e) => {
@ -425,17 +425,17 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
        }
    };

-    // Worker作成
+    // Create Worker
    let mut worker = Worker::new(client);

    let tool_call_names = Arc::new(Mutex::new(HashMap::new()));

-    // システムプロンプトを設定
+    // Set system prompt
    if let Some(ref system_prompt) = args.system {
        worker.set_system_prompt(system_prompt);
    }

-    // ツール登録（--no-tools でなければ）
+    // Register tools (unless --no-tools)
    if !args.no_tools {
        let app = AppContext;
        worker
@ -444,7 +444,7 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
        worker.register_tool(app.calculate_definition()).unwrap();
    }

-    // ストリーミング表示用ハンドラーを登録
+    // Register streaming display handlers
    worker
        .timeline_mut()
        .on_text_block(StreamingPrinter::new())
@ -452,7 +452,7 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {

    worker.add_post_tool_call_hook(ToolResultPrinterHook::new(tool_call_names));

-    // ワンショットモード
+    // One-shot mode
    if let Some(prompt) = args.prompt {
        match worker.run(&prompt).await {
            Ok(_) => {}
@ -465,7 +465,7 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
        return Ok(());
    }

-    // 対話ループ
+    // Interactive loop
    loop {
        print!("\n👤 You: ");
        io::stdout().flush()?;
@ -483,7 +483,7 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
            break;
        }

-        // Workerを実行（Workerが履歴を管理）
+        // Run Worker (Worker manages history)
        match worker.run(input).await {
            Ok(_) => {}
            Err(e) => {
--- a/llm-worker/src/event.rs
+++ b/llm-worker/src/event.rs
@ -1,6 +1,6 @@
-//! Worker層の公開イベント型
+//! Public event types for Worker layer
 //!
-//! 外部利用者に公開するためのイベント表現。
+//! Event representation exposed to external users.

 use serde::{Deserialize, Serialize};

@ -8,38 +8,38 @@ use serde::{Deserialize, Serialize};
 // Core Event Types (from llm_client layer)
 // =============================================================================

-/// LLMからのストリーミングイベント
+/// Streaming events from LLM
 ///
-/// 各LLMプロバイダからのレスポンスは、この`Event`のストリームとして
-/// 統一的に処理されます。
+/// Responses from each LLM provider are processed uniformly
+/// as a stream of `Event`.
 ///
-/// # イベントの種類
+/// # Event Types
 ///
-/// - **メタイベント**: `Ping`, `Usage`, `Status`, `Error`
-/// - **ブロックイベント**: `BlockStart`, `BlockDelta`, `BlockStop`, `BlockAbort`
+/// - **Meta events**: `Ping`, `Usage`, `Status`, `Error`
+/// - **Block events**: `BlockStart`, `BlockDelta`, `BlockStop`, `BlockAbort`
 ///
-/// # ブロックのライフサイクル
+/// # Block Lifecycle
 ///
-/// テキストやツール呼び出しは、`BlockStart` → `BlockDelta`(複数) → `BlockStop`
-/// の順序でイベントが発生します。
+/// Text and tool calls have events in the order of
+/// `BlockStart` → `BlockDelta`(multiple) → `BlockStop`.
 #[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
 pub enum Event {
-    /// ハートビート
+    /// Heartbeat
    Ping(PingEvent),
-    /// トークン使用量
+    /// Token usage
    Usage(UsageEvent),
-    /// ストリームのステータス変化
+    /// Stream status change
    Status(StatusEvent),
-    /// エラー発生
+    /// Error occurred
    Error(ErrorEvent),

-    /// ブロック開始（テキスト、ツール使用等）
+    /// Block start (text, tool use, etc.)
    BlockStart(BlockStart),
-    /// ブロックの差分データ
+    /// Block delta data
    BlockDelta(BlockDelta),
-    /// ブロック正常終了
+    /// Block normal end
    BlockStop(BlockStop),
-    /// ブロック中断
+    /// Block abort
    BlockAbort(BlockAbort),
 }

@ -47,47 +47,47 @@ pub enum Event {
 // Meta Events
 // =============================================================================

-/// Pingイベント（ハートビート）
+/// Ping event (heartbeat)
 #[derive(Debug, Clone, PartialEq, Default, Serialize, Deserialize)]
 pub struct PingEvent {
    pub timestamp: Option<u64>,
 }

-/// 使用量イベント
+/// Usage event
 #[derive(Debug, Clone, PartialEq, Default, Serialize, Deserialize)]
 pub struct UsageEvent {
-    /// 入力トークン数
+    /// Input token count
    pub input_tokens: Option<u64>,
-    /// 出力トークン数
+    /// Output token count
    pub output_tokens: Option<u64>,
-    /// 合計トークン数
+    /// Total token count
    pub total_tokens: Option<u64>,
-    /// キャッシュ読み込みトークン数
+    /// Cache read token count
    pub cache_read_input_tokens: Option<u64>,
-    /// キャッシュ作成トークン数
+    /// Cache creation token count
    pub cache_creation_input_tokens: Option<u64>,
 }

-/// ステータスイベント
+/// Status event
 #[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
 pub struct StatusEvent {
    pub status: ResponseStatus,
 }

-/// レスポンスステータス
+/// Response status
 #[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
 pub enum ResponseStatus {
-    /// ストリーム開始
+    /// Stream started
    Started,
-    /// 正常完了
+    /// Completed normally
    Completed,
-    /// キャンセルされた
+    /// Cancelled
    Cancelled,
-    /// エラー発生
+    /// Error occurred
    Failed,
 }

-/// エラーイベント
+/// Error event
 #[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
 pub struct ErrorEvent {
    pub code: Option<String>,
@ -98,27 +98,27 @@ pub struct ErrorEvent {
 // Block Types
 // =============================================================================

-/// ブロックの種別
+/// Block type
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, Serialize, Deserialize)]
 pub enum BlockType {
-    /// テキスト生成
+    /// Text generation
    Text,
-    /// 思考 (Claude Extended Thinking等)
+    /// Thinking (Claude Extended Thinking, etc.)
    Thinking,
-    /// ツール呼び出し
+    /// Tool call
    ToolUse,
-    /// ツール結果
+    /// Tool result
    ToolResult,
 }

-/// ブロック開始イベント
+/// Block start event
 #[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
 pub struct BlockStart {
-    /// ブロックのインデックス
+    /// Block index
    pub index: usize,
-    /// ブロックの種別
+    /// Block type
    pub block_type: BlockType,
-    /// ブロック固有のメタデータ
+    /// Block-specific metadata
    pub metadata: BlockMetadata,
 }

@ -128,7 +128,7 @@ impl BlockStart {
    }
 }

-/// ブロックのメタデータ
+/// Block metadata
 #[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
 pub enum BlockMetadata {
    Text,
@ -137,28 +137,28 @@ pub enum BlockMetadata {
    ToolResult { tool_use_id: String },
 }

-/// ブロックデルタイベント
+/// Block delta event
 #[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
 pub struct BlockDelta {
-    /// ブロックのインデックス
+    /// Block index
    pub index: usize,
-    /// デルタの内容
+    /// Delta content
    pub delta: DeltaContent,
 }

-/// デルタの内容
+/// Delta content
 #[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
 pub enum DeltaContent {
-    /// テキストデルタ
+    /// Text delta
    Text(String),
-    /// 思考デルタ
+    /// Thinking delta
    Thinking(String),
-    /// ツール引数のJSON部分文字列
+    /// JSON substring of tool arguments
    InputJson(String),
 }

 impl DeltaContent {
-    /// デルタのブロック種別を取得
+    /// Get block type of the delta
    pub fn block_type(&self) -> BlockType {
        match self {
            DeltaContent::Text(_) => BlockType::Text,
@ -168,14 +168,14 @@ impl DeltaContent {
    }
 }

-/// ブロック停止イベント
+/// Block stop event
 #[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
 pub struct BlockStop {
-    /// ブロックのインデックス
+    /// Block index
    pub index: usize,
-    /// ブロックの種別
+    /// Block type
    pub block_type: BlockType,
-    /// 停止理由
+    /// Stop reason
    pub stop_reason: Option<StopReason>,
 }

@ -185,14 +185,14 @@ impl BlockStop {
    }
 }

-/// ブロック中断イベント
+/// Block abort event
 #[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
 pub struct BlockAbort {
-    /// ブロックのインデックス
+    /// Block index
    pub index: usize,
-    /// ブロックの種別
+    /// Block type
    pub block_type: BlockType,
-    /// 中断理由
+    /// Abort reason
    pub reason: String,
 }

@ -202,16 +202,16 @@ impl BlockAbort {
    }
 }

-/// 停止理由
+/// Stop reason
 #[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
 pub enum StopReason {
-    /// 自然終了
+    /// Natural end
    EndTurn,
-    /// 最大トークン数到達
+    /// Max tokens reached
    MaxTokens,
-    /// ストップシーケンス到達
+    /// Stop sequence reached
    StopSequence,
-    /// ツール使用
+    /// Tool use
    ToolUse,
 }

@ -220,7 +220,7 @@ pub enum StopReason {
 // =============================================================================

 impl Event {
-    /// テキストブロック開始イベントを作成
+    /// Create text block start event
    pub fn text_block_start(index: usize) -> Self {
        Event::BlockStart(BlockStart {
            index,
@ -229,7 +229,7 @@ impl Event {
        })
    }

-    /// テキストデルタイベントを作成
+    /// Create text delta event
    pub fn text_delta(index: usize, text: impl Into<String>) -> Self {
        Event::BlockDelta(BlockDelta {
            index,
@ -237,7 +237,7 @@ impl Event {
        })
    }

-    /// テキストブロック停止イベントを作成
+    /// Create text block stop event
    pub fn text_block_stop(index: usize, stop_reason: Option<StopReason>) -> Self {
        Event::BlockStop(BlockStop {
            index,
@ -246,7 +246,7 @@ impl Event {
        })
    }

-    /// ツール使用ブロック開始イベントを作成
+    /// Create tool use block start event
    pub fn tool_use_start(index: usize, id: impl Into<String>, name: impl Into<String>) -> Self {
        Event::BlockStart(BlockStart {
            index,
@ -258,7 +258,7 @@ impl Event {
        })
    }

-    /// ツール引数デルタイベントを作成
+    /// Create tool input delta event
    pub fn tool_input_delta(index: usize, json: impl Into<String>) -> Self {
        Event::BlockDelta(BlockDelta {
            index,
@ -266,7 +266,7 @@ impl Event {
        })
    }

-    /// ツール使用ブロック停止イベントを作成
+    /// Create tool use block stop event
    pub fn tool_use_stop(index: usize) -> Self {
        Event::BlockStop(BlockStop {
            index,
@ -275,7 +275,7 @@ impl Event {
        })
    }

-    /// 使用量イベントを作成
+    /// Create usage event
    pub fn usage(input_tokens: u64, output_tokens: u64) -> Self {
        Event::Usage(UsageEvent {
            input_tokens: Some(input_tokens),
@ -286,7 +286,7 @@ impl Event {
        })
    }

-    /// Pingイベントを作成
+    /// Create ping event
    pub fn ping() -> Self {
        Event::Ping(PingEvent { timestamp: None })
    }
--- a/llm-worker/src/handler.rs
+++ b/llm-worker/src/handler.rs
@ -1,8 +1,8 @@
-//! Handler/Kind型
+//! Handler/Kind Types
 //!
-//! Timeline層でイベントを処理するためのトレイト。
-//! カスタムハンドラを実装してTimelineに登録することで、
-//! ストリームイベントを受信できます。
+//! Traits for processing events in the Timeline layer.
+//! By implementing custom handlers and registering them with Timeline,
+//! you can receive stream events.

 use crate::timeline::event::*;

@ -10,13 +10,13 @@ use crate::timeline::event::*;
 // Kind Trait
 // =============================================================================

-/// イベント種別を定義するマーカートレイト
+/// Marker trait defining event types
 ///
-/// 各Kindは対応するイベント型を指定します。
-/// HandlerはこのKindに対して実装され、同じKindに対して
-/// 異なるScope型を持つ複数のHandlerを登録できます。
+/// Each Kind specifies its corresponding event type.
+/// Handlers are implemented for this Kind, and multiple Handlers
+/// with different Scope types can be registered for the same Kind.
 pub trait Kind {
-    /// このKindに対応するイベント型
+    /// Event type corresponding to this Kind
    type Event;
 }

@ -24,10 +24,10 @@ pub trait Kind {
 // Handler Trait
 // =============================================================================

-/// イベントを処理するハンドラトレイト
+/// Handler trait for processing events
 ///
-/// 特定の`Kind`に対するイベント処理を定義します。
-/// `Scope`はブロックのライフサイクル中に保持される状態です。
+/// Defines event processing for a specific `Kind`.
+/// `Scope` is state held during the block's lifecycle.
 ///
 /// # Examples
 ///
@ -39,7 +39,7 @@ pub trait Kind {
 /// }
 ///
 /// impl Handler<TextBlockKind> for TextCollector {
-///     type Scope = String;  // ブロックごとのバッファ
+///     type Scope = String;  // Buffer per block
 ///
 ///     fn on_event(&mut self, buffer: &mut String, event: &TextBlockEvent) {
 ///         match event {
@ -53,13 +53,13 @@ pub trait Kind {
 /// }
 /// ```
 pub trait Handler<K: Kind> {
-    /// Handler固有のスコープ型
+    /// Handler-specific scope type
    ///
-    /// ブロック開始時に`Default::default()`で生成され、
-    /// ブロック終了時に破棄されます。
+    /// Generated with `Default::default()` at block start,
+    /// and destroyed at block end.
    type Scope: Default;

-    /// イベントを処理する
+    /// Process the event
    fn on_event(&mut self, scope: &mut Self::Scope, event: &K::Event);
 }

@ -67,25 +67,25 @@ pub trait Handler<K: Kind> {
 // Meta Kind Definitions
 // =============================================================================

-/// Usage Kind - 使用量イベント用
+/// Usage Kind - for usage events
 pub struct UsageKind;
 impl Kind for UsageKind {
    type Event = UsageEvent;
 }

-/// Ping Kind - Pingイベント用
+/// Ping Kind - for ping events
 pub struct PingKind;
 impl Kind for PingKind {
    type Event = PingEvent;
 }

-/// Status Kind - ステータスイベント用
+/// Status Kind - for status events
 pub struct StatusKind;
 impl Kind for StatusKind {
    type Event = StatusEvent;
 }

-/// Error Kind - エラーイベント用
+/// Error Kind - for error events
 pub struct ErrorKind;
 impl Kind for ErrorKind {
    type Event = ErrorEvent;
@ -95,13 +95,13 @@ impl Kind for ErrorKind {
 // Block Kind Definitions
 // =============================================================================

-/// TextBlock Kind - テキストブロック用
+/// TextBlock Kind - for text blocks
 pub struct TextBlockKind;
 impl Kind for TextBlockKind {
    type Event = TextBlockEvent;
 }

-/// テキストブロックのイベント
+/// Text block events
 #[derive(Debug, Clone, PartialEq)]
 pub enum TextBlockEvent {
    Start(TextBlockStart),
@ -120,13 +120,13 @@ pub struct TextBlockStop {
    pub stop_reason: Option<StopReason>,
 }

-/// ThinkingBlock Kind - 思考ブロック用
+/// ThinkingBlock Kind - for thinking blocks
 pub struct ThinkingBlockKind;
 impl Kind for ThinkingBlockKind {
    type Event = ThinkingBlockEvent;
 }

-/// 思考ブロックのイベント
+/// Thinking block events
 #[derive(Debug, Clone, PartialEq)]
 pub enum ThinkingBlockEvent {
    Start(ThinkingBlockStart),
@ -144,17 +144,17 @@ pub struct ThinkingBlockStop {
    pub index: usize,
 }

-/// ToolUseBlock Kind - ツール使用ブロック用
+/// ToolUseBlock Kind - for tool use blocks
 pub struct ToolUseBlockKind;
 impl Kind for ToolUseBlockKind {
    type Event = ToolUseBlockEvent;
 }

-/// ツール使用ブロックのイベント
+/// Tool use block events
 #[derive(Debug, Clone, PartialEq)]
 pub enum ToolUseBlockEvent {
    Start(ToolUseBlockStart),
-    /// ツール引数のJSON部分文字列
+    /// JSON substring of tool arguments
    InputJsonDelta(String),
    Stop(ToolUseBlockStop),
 }
--- a/llm-worker/src/hook.rs
+++ b/llm-worker/src/hook.rs
@ -1,6 +1,6 @@
-//! Hook関連の型定義
+//! Hook-related type definitions
 //!
-//! Worker層でのターン制御・介入に使用される型
+//! Types used for turn control and intervention in the Worker layer

 use async_trait::async_trait;
 use serde::{Deserialize, Serialize};
@ -52,7 +52,7 @@ pub enum PostToolCallResult {
 #[derive(Debug, Clone)]
 pub enum OnTurnEndResult {
    Finish,
-    ContinueWithMessages(Vec<crate::Message>),
+    ContinueWithMessages(Vec<crate::Item>),
    Paused,
 }

@ -60,35 +60,35 @@ use std::sync::Arc;

 use crate::tool::{Tool, ToolMeta};

-/// PreToolCall の入力コンテキスト
+/// Input context for PreToolCall
 pub struct ToolCallContext {
-    /// ツール呼び出し情報（改変可能）
+    /// Tool call information (modifiable)
    pub call: ToolCall,
-    /// ツールメタ情報（不変）
+    /// Tool meta information (immutable)
    pub meta: ToolMeta,
-    /// ツールインスタンス（状態アクセス用）
+    /// Tool instance (for state access)
    pub tool: Arc<dyn Tool>,
 }

-/// PostToolCall の入力コンテキスト
+/// Input context for PostToolCall
 pub struct PostToolCallContext {
-    /// ツール呼び出し情報
+    /// Tool call information
    pub call: ToolCall,
-    /// ツール実行結果（改変可能）
+    /// Tool execution result (modifiable)
    pub result: ToolResult,
-    /// ツールメタ情報（不変）
+    /// Tool meta information (immutable)
    pub meta: ToolMeta,
-    /// ツールインスタンス（状態アクセス用）
+    /// Tool instance (for state access)
    pub tool: Arc<dyn Tool>,
 }

 impl HookEventKind for OnPromptSubmit {
-    type Input = crate::Message;
+    type Input = crate::Item;
    type Output = OnPromptSubmitResult;
 }

 impl HookEventKind for PreLlmRequest {
-    type Input = Vec<crate::Message>;
+    type Input = Vec<crate::Item>;
    type Output = PreLlmRequestResult;
 }

@ -103,7 +103,7 @@ impl HookEventKind for PostToolCall {
 }

 impl HookEventKind for OnTurnEnd {
-    type Input = Vec<crate::Message>;
+    type Input = Vec<crate::Item>;
    type Output = OnTurnEndResult;
 }

@ -116,35 +116,35 @@ impl HookEventKind for OnAbort {
 // Tool Call / Result Types
 // =============================================================================

-/// ツール呼び出し情報
+/// Tool call information
 ///
-/// LLMからのToolUseブロックを表現し、Hook処理で改変可能
+/// Represents a ToolUse block from LLM, modifiable in Hook processing
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct ToolCall {
-    /// ツール呼び出しID（レスポンスとの紐付けに使用）
+    /// Tool call ID (used for linking with response)
    pub id: String,
-    /// ツール名
+    /// Tool name
    pub name: String,
-    /// 入力引数（JSON）
+    /// Input arguments (JSON)
    pub input: Value,
 }

-/// ツール実行結果
+/// Tool execution result
 ///
-/// ツール実行後の結果を表現し、Hook処理で改変可能
+/// Represents the result after tool execution, modifiable in Hook processing
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct ToolResult {
-    /// 対応するツール呼び出しID
+    /// Corresponding tool call ID
    pub tool_use_id: String,
-    /// 結果コンテンツ
+    /// Result content
    pub content: String,
-    /// エラーかどうか
+    /// Whether this is an error
    #[serde(default)]
    pub is_error: bool,
 }

 impl ToolResult {
-    /// 成功結果を作成
+    /// Create a success result
    pub fn success(tool_use_id: impl Into<String>, content: impl Into<String>) -> Self {
        Self {
            tool_use_id: tool_use_id.into(),
@ -153,7 +153,7 @@ impl ToolResult {
        }
    }

-    /// エラー結果を作成
+    /// Create an error result
    pub fn error(tool_use_id: impl Into<String>, content: impl Into<String>) -> Self {
        Self {
            tool_use_id: tool_use_id.into(),
@ -167,13 +167,13 @@ impl ToolResult {
 // Hook Error
 // =============================================================================

-/// Hookエラー
+/// Hook error
 #[derive(Debug, Error)]
 pub enum HookError {
-    /// 処理が中断された
+    /// Processing was aborted
    #[error("Aborted: {0}")]
    Aborted(String),
-    /// 内部エラー
+    /// Internal error
    #[error("Hook error: {0}")]
    Internal(String),
 }
@ -182,9 +182,9 @@ pub enum HookError {
 // Hook Trait
 // =============================================================================

-/// Hookイベントの処理を行うトレイト
+/// Trait for handling Hook events
 ///
-/// 各イベント種別は戻り値型が異なるため、`HookEventKind`を介して型を制約する。
+/// Each event type has a different return type, constrained via `HookEventKind`.
 #[async_trait]
 pub trait Hook<E: HookEventKind>: Send + Sync {
    async fn call(&self, input: &mut E::Input) -> Result<E::Output, HookError>;
@ -194,9 +194,9 @@ pub trait Hook<E: HookEventKind>: Send + Sync {
 // Hook Registry
 // =============================================================================

-/// 全 Hook を保持するレジストリ
+/// Registry holding all Hooks
 ///
-/// Worker 内部で使用され、各種 Hook を一括管理する。
+/// Used internally by Worker to manage all Hook types.
 pub struct HookRegistry {
    /// on_prompt_submit Hook
    pub(crate) on_prompt_submit: Vec<Box<dyn Hook<OnPromptSubmit>>>,
@ -219,7 +219,7 @@ impl Default for HookRegistry {
 }

 impl HookRegistry {
-    /// 空の HookRegistry を作成
+    /// Create an empty HookRegistry
    pub fn new() -> Self {
        Self {
            on_prompt_submit: Vec::new(),
--- a/llm-worker/src/lib.rs
+++ b/llm-worker/src/lib.rs
@ -1,34 +1,34 @@
-//! llm-worker - LLMワーカーライブラリ
+//! llm-worker - LLM Worker Library
 //!
-//! LLMとの対話を管理するコンポーネントを提供します。
+//! Provides components for managing interactions with LLMs.
 //!
-//! # 主要なコンポーネント
+//! # Main Components
 //!
-//! - [`Worker`] - LLMとの対話を管理する中心コンポーネント
-//! - [`tool::Tool`] - LLMから呼び出し可能なツール
-//! - [`hook::Hook`] - ターン進行への介入
-//! - [`subscriber::WorkerSubscriber`] - ストリーミングイベントの購読
+//! - [`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
 //!
 //! # Quick Start
 //!
 //! ```ignore
-//! use llm_worker::{Worker, Message};
+//! use llm_worker::{Worker, Item};
 //!
-//! // Workerを作成
+//! // Create a Worker
 //! let mut worker = Worker::new(client)
 //!     .system_prompt("You are a helpful assistant.");
 //!
-//! // ツールを登録（オプション）
+//! // Register tools (optional)
 //! // worker.register_tool(my_tool_definition)?;
 //!
-//! // 対話を実行
+//! // Run the interaction
 //! let history = worker.run("Hello!").await?;
 //! ```
 //!
-//! # キャッシュ保護
+//! # Cache Protection
 //!
-//! KVキャッシュのヒット率を最大化するには、[`Worker::lock()`]で
-//! ロック状態に遷移してから実行してください。
+//! To maximize KV cache hit rate, transition to the locked state
+//! with [`Worker::lock()`] before execution.
 //!
 //! ```ignore
 //! let mut locked = worker.lock();
@ -46,6 +46,7 @@ pub mod state;
 pub mod subscriber;
 pub mod timeline;
 pub mod tool;
+pub mod tool_server;

-pub use message::{ContentPart, Message, MessageContent, Role};
+pub use message::{ContentPart, Item, Message, Role};
 pub use worker::{ToolRegistryError, Worker, WorkerConfig, WorkerError, WorkerResult};
--- a/llm-worker/src/llm_client/scheme/anthropic/request.rs
+++ b/llm-worker/src/llm_client/scheme/anthropic/request.rs
@ -1,15 +1,17 @@
-//! Anthropic リクエスト生成
+//! Anthropic Request Builder
+//!
+//! Converts Open Responses native Item model to Anthropic Messages API format.

 use serde::Serialize;

 use crate::llm_client::{
+    types::{ContentPart, Item, Role, ToolDefinition},
    Request,
-    types::{ContentPart, Message, MessageContent, Role, ToolDefinition},
 };

 use super::AnthropicScheme;

-/// Anthropic APIへのリクエストボディ
+/// Anthropic API request body
 #[derive(Debug, Serialize)]
 pub(crate) struct AnthropicRequest {
    pub model: String,
@ -30,14 +32,14 @@ pub(crate) struct AnthropicRequest {
    pub stream: bool,
 }

-/// Anthropic メッセージ
+/// Anthropic message
 #[derive(Debug, Serialize)]
 pub(crate) struct AnthropicMessage {
    pub role: String,
    pub content: AnthropicContent,
 }

-/// Anthropic コンテンツ
+/// Anthropic content
 #[derive(Debug, Serialize)]
 #[serde(untagged)]
 pub(crate) enum AnthropicContent {
@ -45,7 +47,7 @@ pub(crate) enum AnthropicContent {
    Parts(Vec<AnthropicContentPart>),
 }

-/// Anthropic コンテンツパーツ
+/// Anthropic content part
 #[derive(Debug, Serialize)]
 #[serde(tag = "type")]
 pub(crate) enum AnthropicContentPart {
@ -58,13 +60,10 @@ pub(crate) enum AnthropicContentPart {
        input: serde_json::Value,
    },
    #[serde(rename = "tool_result")]
-    ToolResult {
-        tool_use_id: String,
-        content: String,
-    },
+    ToolResult { tool_use_id: String, content: String },
 }

-/// Anthropic ツール定義
+/// Anthropic tool definition
 #[derive(Debug, Serialize)]
 pub(crate) struct AnthropicTool {
    pub name: String,
@ -74,14 +73,9 @@ pub(crate) struct AnthropicTool {
 }

 impl AnthropicScheme {
-    /// RequestからAnthropicのリクエストボディを構築
+    /// Build Anthropic request from Request
    pub(crate) fn build_request(&self, model: &str, request: &Request) -> AnthropicRequest {
-        let messages = request
-            .messages
-            .iter()
-            .map(|m| self.convert_message(m))
-            .collect();
-
+        let messages = self.convert_items_to_messages(&request.items);
        let tools = request.tools.iter().map(|t| self.convert_tool(t)).collect();

        AnthropicRequest {
@ -98,49 +92,160 @@ impl AnthropicScheme {
        }
    }

-    fn convert_message(&self, message: &Message) -> AnthropicMessage {
-        let role = match message.role {
-            Role::User => "user",
-            Role::Assistant => "assistant",
-        };
+    /// Convert Open Responses Items to Anthropic Messages
+    ///
+    /// Anthropic uses a message-based model where:
+    /// - User messages have role "user"
+    /// - Assistant messages have role "assistant"
+    /// - Tool calls are content parts within assistant messages
+    /// - Tool results are content parts within user messages
+    fn convert_items_to_messages(&self, items: &[Item]) -> Vec<AnthropicMessage> {
+        let mut messages = Vec::new();
+        let mut pending_assistant_parts: Vec<AnthropicContentPart> = Vec::new();
+        let mut pending_user_parts: Vec<AnthropicContentPart> = Vec::new();

-        let content = match &message.content {
-            MessageContent::Text(text) => AnthropicContent::Text(text.clone()),
-            MessageContent::ToolResult {
-                tool_use_id,
-                content,
-            } => AnthropicContent::Parts(vec![AnthropicContentPart::ToolResult {
-                tool_use_id: tool_use_id.clone(),
-                content: content.clone(),
-            }]),
-            MessageContent::Parts(parts) => {
-                let converted: Vec<_> = parts
-                    .iter()
-                    .map(|p| match p {
-                        ContentPart::Text { text } => {
-                            AnthropicContentPart::Text { text: text.clone() }
+        for item in items {
+            match item {
+                Item::Message { role, content, .. } => {
+                    // Flush pending parts before a new message
+                    self.flush_pending_parts(
+                        &mut messages,
+                        &mut pending_assistant_parts,
+                        &mut pending_user_parts,
+                    );
+
+                    let anthropic_role = match role {
+                        Role::User => "user",
+                        Role::Assistant => "assistant",
+                        Role::System => continue, // Skip system role items
+                    };
+
+                    let parts: Vec<AnthropicContentPart> = content
+                        .iter()
+                        .map(|p| match p {
+                            ContentPart::InputText { text } => {
+                                AnthropicContentPart::Text { text: text.clone() }
+                            }
+                            ContentPart::OutputText { text } => {
+                                AnthropicContentPart::Text { text: text.clone() }
+                            }
+                            ContentPart::Refusal { refusal } => {
+                                AnthropicContentPart::Text {
+                                    text: refusal.clone(),
+                                }
+                            }
+                        })
+                        .collect();
+
+                    if parts.len() == 1 {
+                        if let AnthropicContentPart::Text { text } = &parts[0] {
+                            messages.push(AnthropicMessage {
+                                role: anthropic_role.to_string(),
+                                content: AnthropicContent::Text(text.clone()),
+                            });
+                        } else {
+                            messages.push(AnthropicMessage {
+                                role: anthropic_role.to_string(),
+                                content: AnthropicContent::Parts(parts),
+                            });
                        }
-                        ContentPart::ToolUse { id, name, input } => AnthropicContentPart::ToolUse {
-                            id: id.clone(),
-                            name: name.clone(),
-                            input: input.clone(),
-                        },
-                        ContentPart::ToolResult {
-                            tool_use_id,
-                            content,
-                        } => AnthropicContentPart::ToolResult {
-                            tool_use_id: tool_use_id.clone(),
-                            content: content.clone(),
-                        },
-                    })
-                    .collect();
-                AnthropicContent::Parts(converted)
-            }
-        };
+                    } else {
+                        messages.push(AnthropicMessage {
+                            role: anthropic_role.to_string(),
+                            content: AnthropicContent::Parts(parts),
+                        });
+                    }
+                }

-        AnthropicMessage {
-            role: role.to_string(),
-            content,
+                Item::FunctionCall {
+                    call_id,
+                    name,
+                    arguments,
+                    ..
+                } => {
+                    // Flush pending user parts first
+                    if !pending_user_parts.is_empty() {
+                        messages.push(AnthropicMessage {
+                            role: "user".to_string(),
+                            content: AnthropicContent::Parts(std::mem::take(
+                                &mut pending_user_parts,
+                            )),
+                        });
+                    }
+
+                    // Parse arguments JSON string to Value
+                    let input = serde_json::from_str(arguments)
+                        .unwrap_or_else(|_| serde_json::Value::Object(serde_json::Map::new()));
+
+                    pending_assistant_parts.push(AnthropicContentPart::ToolUse {
+                        id: call_id.clone(),
+                        name: name.clone(),
+                        input,
+                    });
+                }
+
+                Item::FunctionCallOutput { call_id, output, .. } => {
+                    // Flush pending assistant parts first
+                    if !pending_assistant_parts.is_empty() {
+                        messages.push(AnthropicMessage {
+                            role: "assistant".to_string(),
+                            content: AnthropicContent::Parts(std::mem::take(
+                                &mut pending_assistant_parts,
+                            )),
+                        });
+                    }
+
+                    pending_user_parts.push(AnthropicContentPart::ToolResult {
+                        tool_use_id: call_id.clone(),
+                        content: output.clone(),
+                    });
+                }
+
+                Item::Reasoning { text, .. } => {
+                    // Flush pending user parts first
+                    if !pending_user_parts.is_empty() {
+                        messages.push(AnthropicMessage {
+                            role: "user".to_string(),
+                            content: AnthropicContent::Parts(std::mem::take(
+                                &mut pending_user_parts,
+                            )),
+                        });
+                    }
+
+                    // Reasoning is treated as assistant text in Anthropic
+                    // (actual thinking blocks are handled differently in streaming)
+                    pending_assistant_parts.push(AnthropicContentPart::Text { text: text.clone() });
+                }
+            }
+        }
+
+        // Flush remaining pending parts
+        self.flush_pending_parts(
+            &mut messages,
+            &mut pending_assistant_parts,
+            &mut pending_user_parts,
+        );
+
+        messages
+    }
+
+    fn flush_pending_parts(
+        &self,
+        messages: &mut Vec<AnthropicMessage>,
+        pending_assistant_parts: &mut Vec<AnthropicContentPart>,
+        pending_user_parts: &mut Vec<AnthropicContentPart>,
+    ) {
+        if !pending_assistant_parts.is_empty() {
+            messages.push(AnthropicMessage {
+                role: "assistant".to_string(),
+                content: AnthropicContent::Parts(std::mem::take(pending_assistant_parts)),
+            });
+        }
+        if !pending_user_parts.is_empty() {
+            messages.push(AnthropicMessage {
+                role: "user".to_string(),
+                content: AnthropicContent::Parts(std::mem::take(pending_user_parts)),
+            });
        }
    }

@ -195,4 +300,24 @@ mod tests {
        assert_eq!(anthropic_req.tools.len(), 1);
        assert_eq!(anthropic_req.tools[0].name, "get_weather");
    }
+
+    #[test]
+    fn test_function_call_and_output() {
+        let scheme = AnthropicScheme::new();
+        let request = Request::new()
+            .user("What's the weather?")
+            .item(Item::function_call(
+                "call_123",
+                "get_weather",
+                r#"{"city":"Tokyo"}"#,
+            ))
+            .item(Item::function_call_output("call_123", "Sunny, 25°C"));
+
+        let anthropic_req = scheme.build_request("claude-sonnet-4-20250514", &request);
+
+        assert_eq!(anthropic_req.messages.len(), 3);
+        assert_eq!(anthropic_req.messages[0].role, "user");
+        assert_eq!(anthropic_req.messages[1].role, "assistant");
+        assert_eq!(anthropic_req.messages[2].role, "user");
+    }
 }
--- a/llm-worker/src/llm_client/scheme/gemini/request.rs
+++ b/llm-worker/src/llm_client/scheme/gemini/request.rs
@ -1,130 +1,130 @@
-//! Gemini リクエスト生成
+//! Gemini Request Builder
 //!
-//! Google Gemini APIへのリクエストボディを構築
+//! Converts Open Responses native Item model to Google Gemini API format.

 use serde::Serialize;
 use serde_json::Value;

 use crate::llm_client::{
+    types::{Item, Role, ToolDefinition},
    Request,
-    types::{ContentPart, Message, MessageContent, Role, ToolDefinition},
 };

 use super::GeminiScheme;

-/// Gemini APIへのリクエストボディ
+/// Gemini API request body
 #[derive(Debug, Serialize)]
 #[serde(rename_all = "camelCase")]
 pub(crate) struct GeminiRequest {
-    /// コンテンツ（会話履歴）
+    /// Contents (conversation history)
    pub contents: Vec<GeminiContent>,
-    /// システム指示
+    /// System instruction
    #[serde(skip_serializing_if = "Option::is_none")]
    pub system_instruction: Option<GeminiContent>,
-    /// ツール定義
+    /// Tool definitions
    #[serde(skip_serializing_if = "Vec::is_empty")]
    pub tools: Vec<GeminiTool>,
-    /// ツール設定
+    /// Tool config
    #[serde(skip_serializing_if = "Option::is_none")]
    pub tool_config: Option<GeminiToolConfig>,
-    /// 生成設定
+    /// Generation config
    #[serde(skip_serializing_if = "Option::is_none")]
    pub generation_config: Option<GeminiGenerationConfig>,
 }

-/// Gemini コンテンツ
+/// Gemini content
 #[derive(Debug, Serialize)]
 pub(crate) struct GeminiContent {
-    /// ロール
+    /// Role
    pub role: String,
-    /// パーツ
+    /// Parts
    pub parts: Vec<GeminiPart>,
 }

-/// Gemini パーツ
+/// Gemini part
 #[derive(Debug, Serialize)]
 #[serde(untagged)]
 pub(crate) enum GeminiPart {
-    /// テキストパーツ
+    /// Text part
    Text { text: String },
-    /// 関数呼び出しパーツ
+    /// Function call part
    FunctionCall {
        #[serde(rename = "functionCall")]
        function_call: GeminiFunctionCall,
    },
-    /// 関数レスポンスパーツ
+    /// Function response part
    FunctionResponse {
        #[serde(rename = "functionResponse")]
        function_response: GeminiFunctionResponse,
    },
 }

-/// Gemini 関数呼び出し
+/// Gemini function call
 #[derive(Debug, Serialize)]
 pub(crate) struct GeminiFunctionCall {
    pub name: String,
    pub args: Value,
 }

-/// Gemini 関数レスポンス
+/// Gemini function response
 #[derive(Debug, Serialize)]
 pub(crate) struct GeminiFunctionResponse {
    pub name: String,
    pub response: GeminiFunctionResponseContent,
 }

-/// Gemini 関数レスポンス内容
+/// Gemini function response content
 #[derive(Debug, Serialize)]
 pub(crate) struct GeminiFunctionResponseContent {
    pub name: String,
    pub content: Value,
 }

-/// Gemini ツール定義
+/// Gemini tool definition
 #[derive(Debug, Serialize)]
 #[serde(rename_all = "camelCase")]
 pub(crate) struct GeminiTool {
-    /// 関数宣言
+    /// Function declarations
    pub function_declarations: Vec<GeminiFunctionDeclaration>,
 }

-/// Gemini 関数宣言
+/// Gemini function declaration
 #[derive(Debug, Serialize)]
 pub(crate) struct GeminiFunctionDeclaration {
-    /// 関数名
+    /// Function name
    pub name: String,
-    /// 説明
+    /// Description
    #[serde(skip_serializing_if = "Option::is_none")]
    pub description: Option<String>,
-    /// パラメータスキーマ
+    /// Parameter schema
    pub parameters: Value,
 }

-/// Gemini ツール設定
+/// Gemini tool config
 #[derive(Debug, Serialize)]
 #[serde(rename_all = "camelCase")]
 pub(crate) struct GeminiToolConfig {
-    /// 関数呼び出し設定
+    /// Function calling config
    pub function_calling_config: GeminiFunctionCallingConfig,
 }

-/// Gemini 関数呼び出し設定
+/// Gemini function calling config
 #[derive(Debug, Serialize)]
 #[serde(rename_all = "camelCase")]
 pub(crate) struct GeminiFunctionCallingConfig {
-    /// モード: AUTO, ANY, NONE
+    /// Mode: AUTO, ANY, NONE
    #[serde(skip_serializing_if = "Option::is_none")]
    pub mode: Option<String>,
-    /// ストリーミング関数呼び出し引数を有効にするか
+    /// Enable streaming function call arguments
    #[serde(skip_serializing_if = "Option::is_none")]
    pub stream_function_call_arguments: Option<bool>,
 }

-/// Gemini 生成設定
+/// Gemini generation config
 #[derive(Debug, Serialize)]
 #[serde(rename_all = "camelCase")]
 pub(crate) struct GeminiGenerationConfig {
-    /// 最大出力トークン数
+    /// Max output tokens
    #[serde(skip_serializing_if = "Option::is_none")]
    pub max_output_tokens: Option<u32>,
    /// Temperature
@ -136,27 +136,23 @@ pub(crate) struct GeminiGenerationConfig {
    /// Top K
    #[serde(skip_serializing_if = "Option::is_none")]
    pub top_k: Option<u32>,
-    /// ストップシーケンス
+    /// Stop sequences
    #[serde(skip_serializing_if = "Vec::is_empty")]
    pub stop_sequences: Vec<String>,
 }

 impl GeminiScheme {
-    /// RequestからGeminiのリクエストボディを構築
+    /// Build Gemini request from Request
    pub(crate) fn build_request(&self, request: &Request) -> GeminiRequest {
-        let mut contents = Vec::new();
+        let contents = self.convert_items_to_contents(&request.items);

-        for message in &request.messages {
-            contents.push(self.convert_message(message));
-        }
-
-        // システムプロンプト
+        // System prompt
        let system_instruction = request.system_prompt.as_ref().map(|s| GeminiContent {
-            role: "user".to_string(), // system_instructionではroleは"user"か省略
+            role: "user".to_string(),
            parts: vec![GeminiPart::Text { text: s.clone() }],
        });

-        // ツール
+        // Tools
        let tools = if request.tools.is_empty() {
            vec![]
        } else {
@ -165,7 +161,7 @@ impl GeminiScheme {
            }]
        };

-        // ツール設定
+        // Tool config
        let tool_config = if !request.tools.is_empty() {
            Some(GeminiToolConfig {
                function_calling_config: GeminiFunctionCallingConfig {
@ -181,7 +177,7 @@ impl GeminiScheme {
            None
        };

-        // 生成設定
+        // Generation config
        let generation_config = Some(GeminiGenerationConfig {
            max_output_tokens: request.config.max_tokens,
            temperature: request.config.temperature,
@ -199,58 +195,126 @@ impl GeminiScheme {
        }
    }

-    fn convert_message(&self, message: &Message) -> GeminiContent {
-        let role = match message.role {
-            Role::User => "user",
-            Role::Assistant => "model",
-        };
+    /// Convert Open Responses Items to Gemini Contents
+    ///
+    /// Gemini uses:
+    /// - role "user" for user messages and function responses
+    /// - role "model" for assistant messages and function calls
+    fn convert_items_to_contents(&self, items: &[Item]) -> Vec<GeminiContent> {
+        let mut contents = Vec::new();
+        let mut pending_model_parts: Vec<GeminiPart> = Vec::new();
+        let mut pending_user_parts: Vec<GeminiPart> = Vec::new();

-        let parts = match &message.content {
-            MessageContent::Text(text) => vec![GeminiPart::Text { text: text.clone() }],
-            MessageContent::ToolResult {
-                tool_use_id,
-                content,
-            } => {
-                // Geminiでは関数レスポンスとしてマップ
-                vec![GeminiPart::FunctionResponse {
-                    function_response: GeminiFunctionResponse {
-                        name: tool_use_id.clone(),
-                        response: GeminiFunctionResponseContent {
-                            name: tool_use_id.clone(),
-                            content: serde_json::Value::String(content.clone()),
-                        },
-                    },
-                }]
-            }
-            MessageContent::Parts(parts) => parts
-                .iter()
-                .map(|p| match p {
-                    ContentPart::Text { text } => GeminiPart::Text { text: text.clone() },
-                    ContentPart::ToolUse { id: _, name, input } => GeminiPart::FunctionCall {
+        for item in items {
+            match item {
+                Item::Message { role, content, .. } => {
+                    // Flush pending parts
+                    self.flush_pending_parts(
+                        &mut contents,
+                        &mut pending_model_parts,
+                        &mut pending_user_parts,
+                    );
+
+                    let gemini_role = match role {
+                        Role::User => "user",
+                        Role::Assistant => "model",
+                        Role::System => continue, // Skip system role items
+                    };
+
+                    let parts: Vec<GeminiPart> = content
+                        .iter()
+                        .map(|p| GeminiPart::Text {
+                            text: p.as_text().to_string(),
+                        })
+                        .collect();
+
+                    contents.push(GeminiContent {
+                        role: gemini_role.to_string(),
+                        parts,
+                    });
+                }
+
+                Item::FunctionCall {
+                    name, arguments, ..
+                } => {
+                    // Flush pending user parts first
+                    if !pending_user_parts.is_empty() {
+                        contents.push(GeminiContent {
+                            role: "user".to_string(),
+                            parts: std::mem::take(&mut pending_user_parts),
+                        });
+                    }
+
+                    // Parse arguments
+                    let args = serde_json::from_str(arguments)
+                        .unwrap_or_else(|_| Value::Object(serde_json::Map::new()));
+
+                    pending_model_parts.push(GeminiPart::FunctionCall {
                        function_call: GeminiFunctionCall {
                            name: name.clone(),
-                            args: input.clone(),
+                            args,
                        },
-                    },
-                    ContentPart::ToolResult {
-                        tool_use_id,
-                        content,
-                    } => GeminiPart::FunctionResponse {
+                    });
+                }
+
+                Item::FunctionCallOutput { call_id, output, .. } => {
+                    // Flush pending model parts first
+                    if !pending_model_parts.is_empty() {
+                        contents.push(GeminiContent {
+                            role: "model".to_string(),
+                            parts: std::mem::take(&mut pending_model_parts),
+                        });
+                    }
+
+                    pending_user_parts.push(GeminiPart::FunctionResponse {
                        function_response: GeminiFunctionResponse {
-                            name: tool_use_id.clone(),
+                            name: call_id.clone(),
                            response: GeminiFunctionResponseContent {
-                                name: tool_use_id.clone(),
-                                content: serde_json::Value::String(content.clone()),
+                                name: call_id.clone(),
+                                content: Value::String(output.clone()),
                            },
                        },
-                    },
-                })
-                .collect(),
-        };
+                    });
+                }

-        GeminiContent {
-            role: role.to_string(),
-            parts,
+                Item::Reasoning { text, .. } => {
+                    // Flush pending user parts first
+                    if !pending_user_parts.is_empty() {
+                        contents.push(GeminiContent {
+                            role: "user".to_string(),
+                            parts: std::mem::take(&mut pending_user_parts),
+                        });
+                    }
+
+                    // Reasoning is treated as model text in Gemini
+                    pending_model_parts.push(GeminiPart::Text { text: text.clone() });
+                }
+            }
+        }
+
+        // Flush remaining pending parts
+        self.flush_pending_parts(&mut contents, &mut pending_model_parts, &mut pending_user_parts);
+
+        contents
+    }
+
+    fn flush_pending_parts(
+        &self,
+        contents: &mut Vec<GeminiContent>,
+        pending_model_parts: &mut Vec<GeminiPart>,
+        pending_user_parts: &mut Vec<GeminiPart>,
+    ) {
+        if !pending_model_parts.is_empty() {
+            contents.push(GeminiContent {
+                role: "model".to_string(),
+                parts: std::mem::take(pending_model_parts),
+            });
+        }
+        if !pending_user_parts.is_empty() {
+            contents.push(GeminiContent {
+                role: "user".to_string(),
+                parts: std::mem::take(pending_user_parts),
+            });
        }
    }

@ -318,4 +382,24 @@ mod tests {
        assert_eq!(gemini_req.contents[0].role, "user");
        assert_eq!(gemini_req.contents[1].role, "model");
    }
+
+    #[test]
+    fn test_function_call_and_output() {
+        let scheme = GeminiScheme::new();
+        let request = Request::new()
+            .user("What's the weather?")
+            .item(Item::function_call(
+                "call_123",
+                "get_weather",
+                r#"{"city":"Tokyo"}"#,
+            ))
+            .item(Item::function_call_output("call_123", "Sunny, 25°C"));
+
+        let gemini_req = scheme.build_request(&request);
+
+        assert_eq!(gemini_req.contents.len(), 3);
+        assert_eq!(gemini_req.contents[0].role, "user");
+        assert_eq!(gemini_req.contents[1].role, "model");
+        assert_eq!(gemini_req.contents[2].role, "user");
+    }
 }
--- a/llm-worker/src/llm_client/scheme/openai/request.rs
+++ b/llm-worker/src/llm_client/scheme/openai/request.rs
@ -1,21 +1,23 @@
-//! OpenAI リクエスト生成
+//! OpenAI Request Builder
+//!
+//! Converts Open Responses native Item model to OpenAI Chat Completions API format.

 use serde::Serialize;
 use serde_json::Value;

 use crate::llm_client::{
+    types::{Item, Role, ToolDefinition},
    Request,
-    types::{ContentPart, Message, MessageContent, Role, ToolDefinition},
 };

 use super::OpenAIScheme;

-/// OpenAI APIへのリクエストボディ
+/// OpenAI API request body
 #[derive(Debug, Serialize)]
 pub(crate) struct OpenAIRequest {
    pub model: String,
    #[serde(skip_serializing_if = "Option::is_none")]
-    pub max_completion_tokens: Option<u32>, // max_tokens is deprecated for newer models, generally max_completion_tokens is preferred
+    pub max_completion_tokens: Option<u32>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub max_tokens: Option<u32>, // Legacy field for compatibility (e.g. Ollama)
    #[serde(skip_serializing_if = "Option::is_none")]
@ -31,7 +33,7 @@ pub(crate) struct OpenAIRequest {
    #[serde(skip_serializing_if = "Vec::is_empty")]
    pub tools: Vec<OpenAITool>,
    #[serde(skip_serializing_if = "Option::is_none")]
-    pub tool_choice: Option<String>, // "auto", "none", or specific
+    pub tool_choice: Option<String>,
 }

 #[derive(Debug, Serialize)]
@ -39,20 +41,21 @@ pub(crate) struct StreamOptions {
    pub include_usage: bool,
 }

-/// OpenAI メッセージ
+/// OpenAI message
 #[derive(Debug, Serialize)]
 pub(crate) struct OpenAIMessage {
    pub role: String,
-    pub content: Option<OpenAIContent>, // Optional for assistant tool calls
+    pub content: Option<OpenAIContent>,
    #[serde(skip_serializing_if = "Vec::is_empty")]
    pub tool_calls: Vec<OpenAIToolCall>,
    #[serde(skip_serializing_if = "Option::is_none")]
-    pub tool_call_id: Option<String>, // For tool_result (role: tool)
+    pub tool_call_id: Option<String>,
    #[serde(skip_serializing_if = "Option::is_none")]
-    pub name: Option<String>, // Optional name
+    pub name: Option<String>,
 }

-/// OpenAI コンテンツ
+/// OpenAI content
+#[allow(dead_code)]
 #[derive(Debug, Serialize)]
 #[serde(untagged)]
 pub(crate) enum OpenAIContent {
@ -60,7 +63,7 @@ pub(crate) enum OpenAIContent {
    Parts(Vec<OpenAIContentPart>),
 }

-/// OpenAI コンテンツパーツ
+/// OpenAI content part
 #[allow(dead_code)]
 #[derive(Debug, Serialize)]
 #[serde(tag = "type")]
@ -76,7 +79,7 @@ pub(crate) struct ImageUrl {
    pub url: String,
 }

-/// OpenAI ツール定義
+/// OpenAI tool definition
 #[derive(Debug, Serialize)]
 pub(crate) struct OpenAITool {
    pub r#type: String,
@ -91,7 +94,7 @@ pub(crate) struct OpenAIToolFunction {
    pub parameters: Value,
 }

-/// OpenAI ツール呼び出し（メッセージ内）
+/// OpenAI tool call in message
 #[derive(Debug, Serialize)]
 pub(crate) struct OpenAIToolCall {
    pub id: String,
@ -106,10 +109,11 @@ pub(crate) struct OpenAIToolCallFunction {
 }

 impl OpenAIScheme {
-    /// RequestからOpenAIのリクエストボディを構築
+    /// Build OpenAI request from Request
    pub(crate) fn build_request(&self, model: &str, request: &Request) -> OpenAIRequest {
        let mut messages = Vec::new();

+        // Add system message if present
        if let Some(system) = &request.system_prompt {
            messages.push(OpenAIMessage {
                role: "system".to_string(),
@ -120,7 +124,8 @@ impl OpenAIScheme {
            });
        }

-        messages.extend(request.messages.iter().map(|m| self.convert_message(m)));
+        // Convert items to messages
+        messages.extend(self.convert_items_to_messages(&request.items));

        let tools = request.tools.iter().map(|t| self.convert_tool(t)).collect();

@ -143,107 +148,123 @@ impl OpenAIScheme {
            }),
            messages,
            tools,
-            tool_choice: None, // Default to auto if tools are present? Or let API decide (which is auto)
+            tool_choice: None,
        }
    }

-    fn convert_message(&self, message: &Message) -> OpenAIMessage {
-        match &message.content {
-            MessageContent::ToolResult {
-                tool_use_id,
-                content,
-            } => OpenAIMessage {
-                role: "tool".to_string(),
-                content: Some(OpenAIContent::Text(content.clone())),
-                tool_calls: vec![],
-                tool_call_id: Some(tool_use_id.clone()),
-                name: None,
-            },
-            MessageContent::Text(text) => {
-                let role = match message.role {
-                    Role::User => "user",
-                    Role::Assistant => "assistant",
-                };
-                OpenAIMessage {
-                    role: role.to_string(),
-                    content: Some(OpenAIContent::Text(text.clone())),
-                    tool_calls: vec![],
-                    tool_call_id: None,
-                    name: None,
-                }
-            }
-            MessageContent::Parts(parts) => {
-                let role = match message.role {
-                    Role::User => "user",
-                    Role::Assistant => "assistant",
-                };
+    /// Convert Open Responses Items to OpenAI Messages
+    ///
+    /// OpenAI uses a message-based model where:
+    /// - User messages have role "user"
+    /// - Assistant messages have role "assistant"
+    /// - Tool calls are within assistant messages as tool_calls array
+    /// - Tool results have role "tool" with tool_call_id
+    fn convert_items_to_messages(&self, items: &[Item]) -> Vec<OpenAIMessage> {
+        let mut messages = Vec::new();
+        let mut pending_tool_calls: Vec<OpenAIToolCall> = Vec::new();
+        let mut pending_assistant_text: Option<String> = None;

-                let mut content_parts = Vec::new();
-                let mut tool_calls = Vec::new();
-                let mut is_tool_result = false;
-                let mut tool_result_id = None;
-                let mut tool_result_content = String::new();
+        for item in items {
+            match item {
+                Item::Message { role, content, .. } => {
+                    // Flush pending tool calls
+                    self.flush_pending_assistant(
+                        &mut messages,
+                        &mut pending_tool_calls,
+                        &mut pending_assistant_text,
+                    );

-                for part in parts {
-                    match part {
-                        ContentPart::Text { text } => {
-                            content_parts.push(OpenAIContentPart::Text { text: text.clone() });
-                        }
-                        ContentPart::ToolUse { id, name, input } => {
-                            tool_calls.push(OpenAIToolCall {
-                                id: id.clone(),
-                                r#type: "function".to_string(),
-                                function: OpenAIToolCallFunction {
-                                    name: name.clone(),
-                                    arguments: input.to_string(),
-                                },
-                            });
-                        }
-                        ContentPart::ToolResult {
-                            tool_use_id,
-                            content,
-                        } => {
-                            // OpenAI doesn't support mixed content with ToolResult in the same message easily if not careful
-                            // But strictly speaking, a Message with ToolResult should be its own message with role "tool"
-                            is_tool_result = true;
-                            tool_result_id = Some(tool_use_id.clone());
-                            tool_result_content = content.clone();
-                        }
-                    }
-                }
-
-                if is_tool_result {
-                    OpenAIMessage {
-                        role: "tool".to_string(),
-                        content: Some(OpenAIContent::Text(tool_result_content)),
-                        tool_calls: vec![],
-                        tool_call_id: tool_result_id,
-                        name: None,
-                    }
-                } else {
-                    let content = if content_parts.is_empty() {
-                        None
-                    } else if content_parts.len() == 1 {
-                        // Simplify single text part to just Text content if preferred, or keep as Parts
-                        if let OpenAIContentPart::Text { text } = &content_parts[0] {
-                            Some(OpenAIContent::Text(text.clone()))
-                        } else {
-                            Some(OpenAIContent::Parts(content_parts))
-                        }
-                    } else {
-                        Some(OpenAIContent::Parts(content_parts))
+                    let openai_role = match role {
+                        Role::User => "user",
+                        Role::Assistant => "assistant",
+                        Role::System => "system",
                    };

-                    OpenAIMessage {
-                        role: role.to_string(),
-                        content,
-                        tool_calls,
+                    let text_content: String = content
+                        .iter()
+                        .map(|p| p.as_text())
+                        .collect::<Vec<_>>()
+                        .join("");
+
+                    messages.push(OpenAIMessage {
+                        role: openai_role.to_string(),
+                        content: Some(OpenAIContent::Text(text_content)),
+                        tool_calls: vec![],
                        tool_call_id: None,
                        name: None,
+                    });
+                }
+
+                Item::FunctionCall {
+                    call_id,
+                    name,
+                    arguments,
+                    ..
+                } => {
+                    pending_tool_calls.push(OpenAIToolCall {
+                        id: call_id.clone(),
+                        r#type: "function".to_string(),
+                        function: OpenAIToolCallFunction {
+                            name: name.clone(),
+                            arguments: arguments.clone(),
+                        },
+                    });
+                }
+
+                Item::FunctionCallOutput { call_id, output, .. } => {
+                    // Flush pending tool calls before tool result
+                    self.flush_pending_assistant(
+                        &mut messages,
+                        &mut pending_tool_calls,
+                        &mut pending_assistant_text,
+                    );
+
+                    messages.push(OpenAIMessage {
+                        role: "tool".to_string(),
+                        content: Some(OpenAIContent::Text(output.clone())),
+                        tool_calls: vec![],
+                        tool_call_id: Some(call_id.clone()),
+                        name: None,
+                    });
+                }
+
+                Item::Reasoning { text, .. } => {
+                    // Reasoning is treated as assistant text in OpenAI
+                    // (OpenAI doesn't have native reasoning support like Claude)
+                    if let Some(ref mut existing) = pending_assistant_text {
+                        existing.push_str(text);
+                    } else {
+                        pending_assistant_text = Some(text.clone());
                    }
                }
            }
        }
+
+        // Flush remaining pending items
+        self.flush_pending_assistant(
+            &mut messages,
+            &mut pending_tool_calls,
+            &mut pending_assistant_text,
+        );
+
+        messages
+    }
+
+    fn flush_pending_assistant(
+        &self,
+        messages: &mut Vec<OpenAIMessage>,
+        pending_tool_calls: &mut Vec<OpenAIToolCall>,
+        pending_assistant_text: &mut Option<String>,
+    ) {
+        if !pending_tool_calls.is_empty() || pending_assistant_text.is_some() {
+            messages.push(OpenAIMessage {
+                role: "assistant".to_string(),
+                content: pending_assistant_text.take().map(OpenAIContent::Text),
+                tool_calls: std::mem::take(pending_tool_calls),
+                tool_call_id: None,
+                name: None,
+            });
+        }
    }

    fn convert_tool(&self, tool: &ToolDefinition) -> OpenAITool {
@ -274,7 +295,6 @@ mod tests {
        assert_eq!(body.messages[0].role, "system");
        assert_eq!(body.messages[1].role, "user");

-        // Check system content
        if let Some(OpenAIContent::Text(text)) = &body.messages[0].content {
            assert_eq!(text, "System prompt");
        } else {
@ -301,20 +321,39 @@ mod tests {

        let body = scheme.build_request("llama3", &request);

-        // max_tokens should be set, max_completion_tokens should be None
        assert_eq!(body.max_tokens, Some(100));
        assert!(body.max_completion_tokens.is_none());
    }

    #[test]
    fn test_build_request_modern_max_tokens() {
-        let scheme = OpenAIScheme::new(); // Default matches modern (legacy=false)
+        let scheme = OpenAIScheme::new();
        let request = Request::new().user("Hello").max_tokens(100);

        let body = scheme.build_request("gpt-4o", &request);

-        // max_completion_tokens should be set, max_tokens should be None
        assert_eq!(body.max_completion_tokens, Some(100));
        assert!(body.max_tokens.is_none());
    }
+
+    #[test]
+    fn test_function_call_and_output() {
+        let scheme = OpenAIScheme::new();
+        let request = Request::new()
+            .user("Check weather")
+            .item(Item::function_call(
+                "call_123",
+                "get_weather",
+                r#"{"city":"Tokyo"}"#,
+            ))
+            .item(Item::function_call_output("call_123", "Sunny, 25°C"));
+
+        let body = scheme.build_request("gpt-4o", &request);
+
+        assert_eq!(body.messages.len(), 3);
+        assert_eq!(body.messages[0].role, "user");
+        assert_eq!(body.messages[1].role, "assistant");
+        assert_eq!(body.messages[1].tool_calls.len(), 1);
+        assert_eq!(body.messages[2].role, "tool");
+    }
 }
--- a/llm-worker/src/llm_client/scheme/openresponses/events.rs
+++ b/llm-worker/src/llm_client/scheme/openresponses/events.rs
@ -0,0 +1,494 @@
+//! Open Responses Event Parser
+//!
+//! Parses SSE events from the Open Responses API into internal Event types.
+
+use serde::Deserialize;
+
+use crate::llm_client::{
+    event::{
+        BlockMetadata, BlockStart, BlockStop, DeltaContent, ErrorEvent, Event, ResponseStatus,
+        StatusEvent, StopReason, UsageEvent,
+    },
+    ClientError,
+};
+
+// =============================================================================
+// Open Responses SSE Event Types
+// =============================================================================
+
+/// Response created event
+#[derive(Debug, Deserialize)]
+pub struct ResponseCreatedEvent {
+    pub response: ResponseObject,
+}
+
+/// Response object
+#[derive(Debug, Deserialize)]
+pub struct ResponseObject {
+    pub id: String,
+    pub status: String,
+    #[serde(default)]
+    pub output: Vec<OutputItem>,
+    pub usage: Option<UsageObject>,
+}
+
+/// Output item in response
+#[derive(Debug, Deserialize)]
+#[serde(tag = "type", rename_all = "snake_case")]
+pub enum OutputItem {
+    Message {
+        id: String,
+        role: String,
+        #[serde(default)]
+        content: Vec<ContentPartObject>,
+    },
+    FunctionCall {
+        id: String,
+        call_id: String,
+        name: String,
+        arguments: String,
+    },
+    Reasoning {
+        id: String,
+        #[serde(default)]
+        text: String,
+    },
+}
+
+/// Content part object
+#[derive(Debug, Deserialize)]
+#[serde(tag = "type", rename_all = "snake_case")]
+pub enum ContentPartObject {
+    OutputText { text: String },
+    InputText { text: String },
+    Refusal { refusal: String },
+}
+
+/// Usage object
+#[derive(Debug, Deserialize)]
+pub struct UsageObject {
+    pub input_tokens: Option<u64>,
+    pub output_tokens: Option<u64>,
+    pub total_tokens: Option<u64>,
+}
+
+/// Output item added event
+#[derive(Debug, Deserialize)]
+pub struct OutputItemAddedEvent {
+    pub output_index: usize,
+    pub item: OutputItem,
+}
+
+/// Text delta event
+#[derive(Debug, Deserialize)]
+pub struct TextDeltaEvent {
+    pub output_index: usize,
+    pub content_index: usize,
+    pub delta: String,
+}
+
+/// Text done event
+#[derive(Debug, Deserialize)]
+pub struct TextDoneEvent {
+    pub output_index: usize,
+    pub content_index: usize,
+    pub text: String,
+}
+
+/// Function call arguments delta event
+#[derive(Debug, Deserialize)]
+pub struct FunctionCallArgumentsDeltaEvent {
+    pub output_index: usize,
+    pub call_id: String,
+    pub delta: String,
+}
+
+/// Function call arguments done event
+#[derive(Debug, Deserialize)]
+pub struct FunctionCallArgumentsDoneEvent {
+    pub output_index: usize,
+    pub call_id: String,
+    pub arguments: String,
+}
+
+/// Reasoning delta event
+#[derive(Debug, Deserialize)]
+pub struct ReasoningDeltaEvent {
+    pub output_index: usize,
+    pub delta: String,
+}
+
+/// Reasoning done event
+#[derive(Debug, Deserialize)]
+pub struct ReasoningDoneEvent {
+    pub output_index: usize,
+    pub text: String,
+}
+
+/// Content part done event
+#[derive(Debug, Deserialize)]
+pub struct ContentPartDoneEvent {
+    pub output_index: usize,
+    pub content_index: usize,
+    pub part: ContentPartObject,
+}
+
+/// Output item done event
+#[derive(Debug, Deserialize)]
+pub struct OutputItemDoneEvent {
+    pub output_index: usize,
+    pub item: OutputItem,
+}
+
+/// Response done event
+#[derive(Debug, Deserialize)]
+pub struct ResponseDoneEvent {
+    pub response: ResponseObject,
+}
+
+/// Error event from API
+#[derive(Debug, Deserialize)]
+pub struct ApiErrorEvent {
+    pub error: ApiError,
+}
+
+/// API error details
+#[derive(Debug, Deserialize)]
+pub struct ApiError {
+    pub code: Option<String>,
+    pub message: String,
+}
+
+// =============================================================================
+// Event Parsing
+// =============================================================================
+
+/// Parse SSE event into internal Event(s)
+///
+/// Returns `Ok(None)` for events that should be ignored (e.g., heartbeats)
+/// Returns `Ok(Some(vec))` for events that produce one or more internal Events
+pub fn parse_event(event_type: &str, data: &str) -> Result<Option<Vec<Event>>, ClientError> {
+    // Skip empty data
+    if data.is_empty() || data == "[DONE]" {
+        return Ok(None);
+    }
+
+    let events = match event_type {
+        // Response lifecycle
+        "response.created" => {
+            let _event: ResponseCreatedEvent = parse_json(data)?;
+            Some(vec![Event::Status(StatusEvent {
+                status: ResponseStatus::Started,
+            })])
+        }
+
+        "response.in_progress" => {
+            // Just a status update, no action needed
+            None
+        }
+
+        "response.completed" | "response.done" => {
+            let event: ResponseDoneEvent = parse_json(data)?;
+            let mut events = Vec::new();
+
+            // Emit usage if present
+            if let Some(usage) = event.response.usage {
+                events.push(Event::Usage(UsageEvent {
+                    input_tokens: usage.input_tokens,
+                    output_tokens: usage.output_tokens,
+                    total_tokens: usage.total_tokens,
+                    cache_read_input_tokens: None,
+                    cache_creation_input_tokens: None,
+                }));
+            }
+
+            events.push(Event::Status(StatusEvent {
+                status: ResponseStatus::Completed,
+            }));
+            Some(events)
+        }
+
+        "response.failed" => {
+            // Try to parse error
+            if let Ok(error_event) = parse_json::<ApiErrorEvent>(data) {
+                Some(vec![
+                    Event::Error(ErrorEvent {
+                        code: error_event.error.code,
+                        message: error_event.error.message,
+                    }),
+                    Event::Status(StatusEvent {
+                        status: ResponseStatus::Failed,
+                    }),
+                ])
+            } else {
+                Some(vec![Event::Status(StatusEvent {
+                    status: ResponseStatus::Failed,
+                })])
+            }
+        }
+
+        // Output item events
+        "response.output_item.added" => {
+            let event: OutputItemAddedEvent = parse_json(data)?;
+            Some(vec![convert_item_added(&event)])
+        }
+
+        "response.output_item.done" => {
+            let event: OutputItemDoneEvent = parse_json(data)?;
+            Some(vec![convert_item_done(&event)])
+        }
+
+        // Text content events
+        "response.output_text.delta" => {
+            let event: TextDeltaEvent = parse_json(data)?;
+            Some(vec![Event::text_delta(event.output_index, &event.delta)])
+        }
+
+        "response.output_text.done" => {
+            // Text done - we'll handle stop in output_item.done
+            let _event: TextDoneEvent = parse_json(data)?;
+            None
+        }
+
+        // Content part events
+        "response.content_part.added" => {
+            // Content part added - we handle this via output_item.added
+            None
+        }
+
+        "response.content_part.done" => {
+            // Content part done - we handle stop in output_item.done
+            None
+        }
+
+        // Function call events
+        "response.function_call_arguments.delta" => {
+            let event: FunctionCallArgumentsDeltaEvent = parse_json(data)?;
+            Some(vec![Event::BlockDelta(crate::llm_client::event::BlockDelta {
+                index: event.output_index,
+                delta: DeltaContent::InputJson(event.delta),
+            })])
+        }
+
+        "response.function_call_arguments.done" => {
+            // Arguments done - we handle stop in output_item.done
+            let _event: FunctionCallArgumentsDoneEvent = parse_json(data)?;
+            None
+        }
+
+        // Reasoning events
+        "response.reasoning.delta" | "response.reasoning_summary_text.delta" => {
+            let event: ReasoningDeltaEvent = parse_json(data)?;
+            Some(vec![Event::BlockDelta(crate::llm_client::event::BlockDelta {
+                index: event.output_index,
+                delta: DeltaContent::Thinking(event.delta),
+            })])
+        }
+
+        "response.reasoning.done" | "response.reasoning_summary_text.done" => {
+            // Reasoning done - we handle stop in output_item.done
+            let _event: ReasoningDoneEvent = parse_json(data)?;
+            None
+        }
+
+        // Error event
+        "error" => {
+            let event: ApiErrorEvent = parse_json(data)?;
+            Some(vec![Event::Error(ErrorEvent {
+                code: event.error.code,
+                message: event.error.message,
+            })])
+        }
+
+        // Unknown event type - ignore
+        _ => {
+            tracing::debug!(event_type = event_type, "Unknown Open Responses event type");
+            None
+        }
+    };
+
+    Ok(events)
+}
+
+fn parse_json<T: serde::de::DeserializeOwned>(data: &str) -> Result<T, ClientError> {
+    serde_json::from_str(data).map_err(|e| ClientError::Parse(e.to_string()))
+}
+
+fn convert_item_added(event: &OutputItemAddedEvent) -> Event {
+    match &event.item {
+        OutputItem::Message { id, role: _, content: _ } => Event::BlockStart(BlockStart {
+            index: event.output_index,
+            block_type: crate::llm_client::event::BlockType::Text,
+            metadata: BlockMetadata::Text,
+        }),
+
+        OutputItem::FunctionCall {
+            id,
+            call_id,
+            name,
+            arguments: _,
+        } => Event::BlockStart(BlockStart {
+            index: event.output_index,
+            block_type: crate::llm_client::event::BlockType::ToolUse,
+            metadata: BlockMetadata::ToolUse {
+                id: call_id.clone(),
+                name: name.clone(),
+            },
+        }),
+
+        OutputItem::Reasoning { id, text: _ } => Event::BlockStart(BlockStart {
+            index: event.output_index,
+            block_type: crate::llm_client::event::BlockType::Thinking,
+            metadata: BlockMetadata::Thinking,
+        }),
+    }
+}
+
+fn convert_item_done(event: &OutputItemDoneEvent) -> Event {
+    let stop_reason = match &event.item {
+        OutputItem::FunctionCall { .. } => Some(StopReason::ToolUse),
+        _ => Some(StopReason::EndTurn),
+    };
+
+    Event::BlockStop(BlockStop {
+        index: event.output_index,
+        stop_reason,
+    })
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_parse_response_created() {
+        let data = r#"{"response":{"id":"resp_123","status":"in_progress","output":[]}}"#;
+        let events = parse_event("response.created", data).unwrap().unwrap();
+        assert_eq!(events.len(), 1);
+        assert!(matches!(
+            events[0],
+            Event::Status(StatusEvent {
+                status: ResponseStatus::Started
+            })
+        ));
+    }
+
+    #[test]
+    fn test_parse_text_delta() {
+        let data = r#"{"output_index":0,"content_index":0,"delta":"Hello"}"#;
+        let events = parse_event("response.output_text.delta", data)
+            .unwrap()
+            .unwrap();
+        assert_eq!(events.len(), 1);
+        if let Event::BlockDelta(delta) = &events[0] {
+            assert_eq!(delta.index, 0);
+            assert!(matches!(&delta.delta, DeltaContent::Text(t) if t == "Hello"));
+        } else {
+            panic!("Expected BlockDelta");
+        }
+    }
+
+    #[test]
+    fn test_parse_output_item_added_message() {
+        let data = r#"{"output_index":0,"item":{"type":"message","id":"msg_123","role":"assistant","content":[]}}"#;
+        let events = parse_event("response.output_item.added", data)
+            .unwrap()
+            .unwrap();
+        assert_eq!(events.len(), 1);
+        if let Event::BlockStart(start) = &events[0] {
+            assert_eq!(start.index, 0);
+            assert!(matches!(
+                start.block_type,
+                crate::llm_client::event::BlockType::Text
+            ));
+        } else {
+            panic!("Expected BlockStart");
+        }
+    }
+
+    #[test]
+    fn test_parse_output_item_added_function_call() {
+        let data = r#"{"output_index":1,"item":{"type":"function_call","id":"fc_123","call_id":"call_456","name":"get_weather","arguments":""}}"#;
+        let events = parse_event("response.output_item.added", data)
+            .unwrap()
+            .unwrap();
+        assert_eq!(events.len(), 1);
+        if let Event::BlockStart(start) = &events[0] {
+            assert_eq!(start.index, 1);
+            assert!(matches!(
+                start.block_type,
+                crate::llm_client::event::BlockType::ToolUse
+            ));
+            if let BlockMetadata::ToolUse { id, name } = &start.metadata {
+                assert_eq!(id, "call_456");
+                assert_eq!(name, "get_weather");
+            } else {
+                panic!("Expected ToolUse metadata");
+            }
+        } else {
+            panic!("Expected BlockStart");
+        }
+    }
+
+    #[test]
+    fn test_parse_function_call_arguments_delta() {
+        let data = r#"{"output_index":1,"call_id":"call_456","delta":"{\"city\":"}"#;
+        let events = parse_event("response.function_call_arguments.delta", data)
+            .unwrap()
+            .unwrap();
+        assert_eq!(events.len(), 1);
+        if let Event::BlockDelta(delta) = &events[0] {
+            assert_eq!(delta.index, 1);
+            assert!(matches!(
+                &delta.delta,
+                DeltaContent::InputJson(s) if s == "{\"city\":"
+            ));
+        } else {
+            panic!("Expected BlockDelta");
+        }
+    }
+
+    #[test]
+    fn test_parse_response_completed() {
+        let data = r#"{"response":{"id":"resp_123","status":"completed","output":[],"usage":{"input_tokens":10,"output_tokens":20,"total_tokens":30}}}"#;
+        let events = parse_event("response.completed", data).unwrap().unwrap();
+        assert_eq!(events.len(), 2);
+
+        // First event should be usage
+        if let Event::Usage(usage) = &events[0] {
+            assert_eq!(usage.input_tokens, Some(10));
+            assert_eq!(usage.output_tokens, Some(20));
+            assert_eq!(usage.total_tokens, Some(30));
+        } else {
+            panic!("Expected Usage event");
+        }
+
+        // Second event should be status
+        assert!(matches!(
+            events[1],
+            Event::Status(StatusEvent {
+                status: ResponseStatus::Completed
+            })
+        ));
+    }
+
+    #[test]
+    fn test_parse_error() {
+        let data = r#"{"error":{"code":"rate_limit","message":"Too many requests"}}"#;
+        let events = parse_event("error", data).unwrap().unwrap();
+        assert_eq!(events.len(), 1);
+        if let Event::Error(err) = &events[0] {
+            assert_eq!(err.code, Some("rate_limit".to_string()));
+            assert_eq!(err.message, "Too many requests");
+        } else {
+            panic!("Expected Error event");
+        }
+    }
+
+    #[test]
+    fn test_parse_unknown_event() {
+        let data = r#"{}"#;
+        let events = parse_event("some.unknown.event", data).unwrap();
+        assert!(events.is_none());
+    }
+}
--- a/llm-worker/src/llm_client/scheme/openresponses/mod.rs
+++ b/llm-worker/src/llm_client/scheme/openresponses/mod.rs
@ -0,0 +1,49 @@
+//! Open Responses Scheme
+//!
+//! Handles request/response conversion for the Open Responses API.
+//! Since our internal types are already Open Responses native, this scheme
+//! primarily passes through data with minimal transformation.
+
+mod events;
+mod request;
+
+use crate::llm_client::{ClientError, Request};
+
+pub use events::*;
+pub use request::*;
+
+/// Open Responses Scheme
+///
+/// Handles conversion between internal types and the Open Responses wire format.
+#[derive(Debug, Clone, Default)]
+pub struct OpenResponsesScheme {
+    /// Optional model override
+    pub model: Option<String>,
+}
+
+impl OpenResponsesScheme {
+    /// Create a new OpenResponsesScheme
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    /// Set the model
+    pub fn with_model(mut self, model: impl Into<String>) -> Self {
+        self.model = Some(model.into());
+        self
+    }
+
+    /// Build Open Responses request from internal Request
+    pub fn build_request(&self, model: &str, request: &Request) -> OpenResponsesRequest {
+        build_request(model, request)
+    }
+
+    /// Parse SSE event data into internal Event(s)
+    pub fn parse_event(
+        &self,
+        event_type: &str,
+        data: &str,
+    ) -> Result<Option<Vec<crate::llm_client::Event>>, ClientError> {
+        parse_event(event_type, data)
+    }
+}
--- a/llm-worker/src/llm_client/scheme/openresponses/request.rs
+++ b/llm-worker/src/llm_client/scheme/openresponses/request.rs
@ -0,0 +1,285 @@
+//! Open Responses Request Builder
+//!
+//! Converts internal Request/Item types to Open Responses API format.
+//! Since our internal types are already Open Responses native, this is
+//! mostly a direct serialization with some field renaming.
+
+use serde::Serialize;
+use serde_json::Value;
+
+use crate::llm_client::{types::Item, Request, ToolDefinition};
+
+/// Open Responses API request body
+#[derive(Debug, Serialize)]
+pub struct OpenResponsesRequest {
+    /// Model identifier
+    pub model: String,
+
+    /// Input items (conversation history)
+    pub input: Vec<OpenResponsesItem>,
+
+    /// System instructions
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub instructions: Option<String>,
+
+    /// Tool definitions
+    #[serde(skip_serializing_if = "Vec::is_empty")]
+    pub tools: Vec<OpenResponsesTool>,
+
+    /// Enable streaming
+    pub stream: bool,
+
+    /// Maximum output tokens
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub max_output_tokens: Option<u32>,
+
+    /// Temperature
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub temperature: Option<f32>,
+
+    /// Top P (nucleus sampling)
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub top_p: Option<f32>,
+}
+
+/// Open Responses input item
+#[derive(Debug, Serialize)]
+#[serde(tag = "type", rename_all = "snake_case")]
+pub enum OpenResponsesItem {
+    /// Message item
+    Message {
+        #[serde(skip_serializing_if = "Option::is_none")]
+        id: Option<String>,
+        role: String,
+        content: Vec<OpenResponsesContentPart>,
+    },
+
+    /// Function call item
+    FunctionCall {
+        #[serde(skip_serializing_if = "Option::is_none")]
+        id: Option<String>,
+        call_id: String,
+        name: String,
+        arguments: String,
+    },
+
+    /// Function call output item
+    FunctionCallOutput {
+        #[serde(skip_serializing_if = "Option::is_none")]
+        id: Option<String>,
+        call_id: String,
+        output: String,
+    },
+
+    /// Reasoning item
+    Reasoning {
+        #[serde(skip_serializing_if = "Option::is_none")]
+        id: Option<String>,
+        text: String,
+    },
+}
+
+/// Open Responses content part
+#[derive(Debug, Serialize)]
+#[serde(tag = "type", rename_all = "snake_case")]
+pub enum OpenResponsesContentPart {
+    /// Input text (for user messages)
+    InputText { text: String },
+
+    /// Output text (for assistant messages)
+    OutputText { text: String },
+
+    /// Refusal
+    Refusal { refusal: String },
+}
+
+/// Open Responses tool definition
+#[derive(Debug, Serialize)]
+pub struct OpenResponsesTool {
+    /// Tool type (always "function")
+    pub r#type: String,
+
+    /// Function definition
+    pub name: String,
+
+    /// Description
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub description: Option<String>,
+
+    /// Parameters schema
+    pub parameters: Value,
+}
+
+/// Build Open Responses request from internal Request
+pub fn build_request(model: &str, request: &Request) -> OpenResponsesRequest {
+    let input = request.items.iter().map(convert_item).collect();
+    let tools = request.tools.iter().map(convert_tool).collect();
+
+    OpenResponsesRequest {
+        model: model.to_string(),
+        input,
+        instructions: request.system_prompt.clone(),
+        tools,
+        stream: true,
+        max_output_tokens: request.config.max_tokens,
+        temperature: request.config.temperature,
+        top_p: request.config.top_p,
+    }
+}
+
+fn convert_item(item: &Item) -> OpenResponsesItem {
+    match item {
+        Item::Message {
+            id,
+            role,
+            content,
+            status: _,
+        } => {
+            let role_str = match role {
+                crate::llm_client::types::Role::User => "user",
+                crate::llm_client::types::Role::Assistant => "assistant",
+                crate::llm_client::types::Role::System => "system",
+            };
+
+            let parts = content
+                .iter()
+                .map(|p| match p {
+                    crate::llm_client::types::ContentPart::InputText { text } => {
+                        OpenResponsesContentPart::InputText { text: text.clone() }
+                    }
+                    crate::llm_client::types::ContentPart::OutputText { text } => {
+                        OpenResponsesContentPart::OutputText { text: text.clone() }
+                    }
+                    crate::llm_client::types::ContentPart::Refusal { refusal } => {
+                        OpenResponsesContentPart::Refusal {
+                            refusal: refusal.clone(),
+                        }
+                    }
+                })
+                .collect();
+
+            OpenResponsesItem::Message {
+                id: id.clone(),
+                role: role_str.to_string(),
+                content: parts,
+            }
+        }
+
+        Item::FunctionCall {
+            id,
+            call_id,
+            name,
+            arguments,
+            status: _,
+        } => OpenResponsesItem::FunctionCall {
+            id: id.clone(),
+            call_id: call_id.clone(),
+            name: name.clone(),
+            arguments: arguments.clone(),
+        },
+
+        Item::FunctionCallOutput {
+            id,
+            call_id,
+            output,
+        } => OpenResponsesItem::FunctionCallOutput {
+            id: id.clone(),
+            call_id: call_id.clone(),
+            output: output.clone(),
+        },
+
+        Item::Reasoning {
+            id,
+            text,
+            status: _,
+        } => OpenResponsesItem::Reasoning {
+            id: id.clone(),
+            text: text.clone(),
+        },
+    }
+}
+
+fn convert_tool(tool: &ToolDefinition) -> OpenResponsesTool {
+    OpenResponsesTool {
+        r#type: "function".to_string(),
+        name: tool.name.clone(),
+        description: tool.description.clone(),
+        parameters: tool.input_schema.clone(),
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::llm_client::types::Item;
+
+    #[test]
+    fn test_build_simple_request() {
+        let request = Request::new()
+            .system("You are a helpful assistant.")
+            .user("Hello!");
+
+        let or_req = build_request("gpt-4o", &request);
+
+        assert_eq!(or_req.model, "gpt-4o");
+        assert_eq!(
+            or_req.instructions,
+            Some("You are a helpful assistant.".to_string())
+        );
+        assert_eq!(or_req.input.len(), 1);
+        assert!(or_req.stream);
+    }
+
+    #[test]
+    fn test_build_request_with_tool() {
+        let request = Request::new().user("What's the weather?").tool(
+            ToolDefinition::new("get_weather")
+                .description("Get current weather")
+                .input_schema(serde_json::json!({
+                    "type": "object",
+                    "properties": {
+                        "location": { "type": "string" }
+                    },
+                    "required": ["location"]
+                })),
+        );
+
+        let or_req = build_request("gpt-4o", &request);
+
+        assert_eq!(or_req.tools.len(), 1);
+        assert_eq!(or_req.tools[0].name, "get_weather");
+        assert_eq!(or_req.tools[0].r#type, "function");
+    }
+
+    #[test]
+    fn test_function_call_and_output() {
+        let request = Request::new()
+            .user("What's the weather?")
+            .item(Item::function_call(
+                "call_123",
+                "get_weather",
+                r#"{"city":"Tokyo"}"#,
+            ))
+            .item(Item::function_call_output("call_123", "Sunny, 25°C"));
+
+        let or_req = build_request("gpt-4o", &request);
+
+        assert_eq!(or_req.input.len(), 3);
+
+        // Check function call
+        if let OpenResponsesItem::FunctionCall { call_id, name, .. } = &or_req.input[1] {
+            assert_eq!(call_id, "call_123");
+            assert_eq!(name, "get_weather");
+        } else {
+            panic!("Expected FunctionCall");
+        }
+
+        // Check function call output
+        if let OpenResponsesItem::FunctionCallOutput { call_id, output, .. } = &or_req.input[2] {
+            assert_eq!(call_id, "call_123");
+            assert_eq!(output, "Sunny, 25°C");
+        } else {
+            panic!("Expected FunctionCallOutput");
+        }
+    }
+}
--- a/llm-worker/src/llm_client/types.rs
+++ b/llm-worker/src/llm_client/types.rs
@ -1,189 +1,491 @@
-//! LLMクライアント共通型定義
+//! LLM Client Common Types - Open Responses Native
+//!
+//! This module defines types that are natively aligned with the Open Responses specification.
+//! The core abstraction is `Item` which represents different types of conversation elements:
+//! - Message items (user/assistant messages with content parts)
+//! - FunctionCall items (tool invocations)
+//! - FunctionCallOutput items (tool results)
+//! - Reasoning items (extended thinking)

 use serde::{Deserialize, Serialize};

-/// リクエスト構造体
+// ============================================================================
+// Item - The core unit of conversation
+// ============================================================================
+
+/// Item ID type for tracking items in a conversation
+pub type ItemId = String;
+
+/// Call ID type for linking function calls to their outputs
+pub type CallId = String;
+
+/// Conversation item - the primary unit in Open Responses
+///
+/// Items represent discrete elements in a conversation. Unlike traditional
+/// message-based APIs, Open Responses treats tool calls and reasoning as
+/// first-class items rather than parts of messages.
+///
+/// # Examples
+///
+/// ```ignore
+/// use llm_worker::Item;
+///
+/// // User message
+/// let user_item = Item::user_message("Hello!");
+///
+/// // Assistant message
+/// let assistant_item = Item::assistant_message("Hi there!");
+///
+/// // Function call
+/// let call = Item::function_call("call_123", "get_weather", json!({"city": "Tokyo"}));
+///
+/// // Function call output
+/// let result = Item::function_call_output("call_123", "Sunny, 25°C");
+/// ```
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
+#[serde(tag = "type", rename_all = "snake_case")]
+pub enum Item {
+    /// User or assistant message with content parts
+    Message {
+        /// Optional item ID
+        #[serde(skip_serializing_if = "Option::is_none")]
+        id: Option<ItemId>,
+        /// Message role
+        role: Role,
+        /// Content parts
+        content: Vec<ContentPart>,
+        /// Item status
+        #[serde(skip_serializing_if = "Option::is_none")]
+        status: Option<ItemStatus>,
+    },
+
+    /// Function (tool) call from the assistant
+    FunctionCall {
+        /// Optional item ID
+        #[serde(skip_serializing_if = "Option::is_none")]
+        id: Option<ItemId>,
+        /// Call ID for linking to output
+        call_id: CallId,
+        /// Function name
+        name: String,
+        /// Function arguments as JSON string
+        arguments: String,
+        /// Item status
+        #[serde(skip_serializing_if = "Option::is_none")]
+        status: Option<ItemStatus>,
+    },
+
+    /// Function (tool) call output/result
+    FunctionCallOutput {
+        /// Optional item ID
+        #[serde(skip_serializing_if = "Option::is_none")]
+        id: Option<ItemId>,
+        /// Call ID linking to the function call
+        call_id: CallId,
+        /// Output content
+        output: String,
+    },
+
+    /// Reasoning/thinking item
+    Reasoning {
+        /// Optional item ID
+        #[serde(skip_serializing_if = "Option::is_none")]
+        id: Option<ItemId>,
+        /// Reasoning text
+        text: String,
+        /// Item status
+        #[serde(skip_serializing_if = "Option::is_none")]
+        status: Option<ItemStatus>,
+    },
+}
+
+impl Item {
+    // ========================================================================
+    // Message constructors
+    // ========================================================================
+
+    /// Create a user message item with text content
+    pub fn user_message(text: impl Into<String>) -> Self {
+        Self::Message {
+            id: None,
+            role: Role::User,
+            content: vec![ContentPart::InputText {
+                text: text.into(),
+            }],
+            status: None,
+        }
+    }
+
+    /// Create a user message item with multiple content parts
+    pub fn user_message_parts(parts: Vec<ContentPart>) -> Self {
+        Self::Message {
+            id: None,
+            role: Role::User,
+            content: parts,
+            status: None,
+        }
+    }
+
+    /// Create an assistant message item with text content
+    pub fn assistant_message(text: impl Into<String>) -> Self {
+        Self::Message {
+            id: None,
+            role: Role::Assistant,
+            content: vec![ContentPart::OutputText {
+                text: text.into(),
+            }],
+            status: None,
+        }
+    }
+
+    /// Create an assistant message item with multiple content parts
+    pub fn assistant_message_parts(parts: Vec<ContentPart>) -> Self {
+        Self::Message {
+            id: None,
+            role: Role::Assistant,
+            content: parts,
+            status: None,
+        }
+    }
+
+    // ========================================================================
+    // Function call constructors
+    // ========================================================================
+
+    /// Create a function call item
+    pub fn function_call(
+        call_id: impl Into<String>,
+        name: impl Into<String>,
+        arguments: impl Into<String>,
+    ) -> Self {
+        Self::FunctionCall {
+            id: None,
+            call_id: call_id.into(),
+            name: name.into(),
+            arguments: arguments.into(),
+            status: None,
+        }
+    }
+
+    /// Create a function call item from a JSON value
+    pub fn function_call_json(
+        call_id: impl Into<String>,
+        name: impl Into<String>,
+        arguments: serde_json::Value,
+    ) -> Self {
+        Self::function_call(call_id, name, arguments.to_string())
+    }
+
+    /// Create a function call output item
+    pub fn function_call_output(call_id: impl Into<String>, output: impl Into<String>) -> Self {
+        Self::FunctionCallOutput {
+            id: None,
+            call_id: call_id.into(),
+            output: output.into(),
+        }
+    }
+
+    // ========================================================================
+    // Reasoning constructors
+    // ========================================================================
+
+    /// Create a reasoning item
+    pub fn reasoning(text: impl Into<String>) -> Self {
+        Self::Reasoning {
+            id: None,
+            text: text.into(),
+            status: None,
+        }
+    }
+
+    // ========================================================================
+    // Builder methods
+    // ========================================================================
+
+    /// Set the item ID
+    pub fn with_id(mut self, id: impl Into<String>) -> Self {
+        match &mut self {
+            Self::Message { id: item_id, .. } => *item_id = Some(id.into()),
+            Self::FunctionCall { id: item_id, .. } => *item_id = Some(id.into()),
+            Self::FunctionCallOutput { id: item_id, .. } => *item_id = Some(id.into()),
+            Self::Reasoning { id: item_id, .. } => *item_id = Some(id.into()),
+        }
+        self
+    }
+
+    /// Set the item status
+    pub fn with_status(mut self, new_status: ItemStatus) -> Self {
+        match &mut self {
+            Self::Message { status, .. } => *status = Some(new_status),
+            Self::FunctionCall { status, .. } => *status = Some(new_status),
+            Self::FunctionCallOutput { .. } => {} // Output items don't have status
+            Self::Reasoning { status, .. } => *status = Some(new_status),
+        }
+        self
+    }
+
+    // ========================================================================
+    // Accessors
+    // ========================================================================
+
+    /// Get the item ID if set
+    pub fn id(&self) -> Option<&str> {
+        match self {
+            Self::Message { id, .. } => id.as_deref(),
+            Self::FunctionCall { id, .. } => id.as_deref(),
+            Self::FunctionCallOutput { id, .. } => id.as_deref(),
+            Self::Reasoning { id, .. } => id.as_deref(),
+        }
+    }
+
+    /// Get the item type as a string
+    pub fn item_type(&self) -> &'static str {
+        match self {
+            Self::Message { .. } => "message",
+            Self::FunctionCall { .. } => "function_call",
+            Self::FunctionCallOutput { .. } => "function_call_output",
+            Self::Reasoning { .. } => "reasoning",
+        }
+    }
+
+    /// Check if this is a user message
+    pub fn is_user_message(&self) -> bool {
+        matches!(self, Self::Message { role: Role::User, .. })
+    }
+
+    /// Check if this is an assistant message
+    pub fn is_assistant_message(&self) -> bool {
+        matches!(self, Self::Message { role: Role::Assistant, .. })
+    }
+
+    /// Check if this is a function call
+    pub fn is_function_call(&self) -> bool {
+        matches!(self, Self::FunctionCall { .. })
+    }
+
+    /// Check if this is a function call output
+    pub fn is_function_call_output(&self) -> bool {
+        matches!(self, Self::FunctionCallOutput { .. })
+    }
+
+    /// Check if this is a reasoning item
+    pub fn is_reasoning(&self) -> bool {
+        matches!(self, Self::Reasoning { .. })
+    }
+
+    /// Get text content if this is a simple text message
+    pub fn as_text(&self) -> Option<&str> {
+        match self {
+            Self::Message { content, .. } if content.len() == 1 => match &content[0] {
+                ContentPart::InputText { text } => Some(text),
+                ContentPart::OutputText { text } => Some(text),
+                _ => None,
+            },
+            _ => None,
+        }
+    }
+}
+
+// ============================================================================
+// Content Parts - Components within message items
+// ============================================================================
+
+/// Content part within a message item
+///
+/// Open Responses distinguishes between input and output content types.
+/// Input types are used in user messages, output types in assistant messages.
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
+#[serde(tag = "type", rename_all = "snake_case")]
+pub enum ContentPart {
+    /// Input text (for user messages)
+    InputText {
+        /// The text content
+        text: String,
+    },
+
+    /// Output text (for assistant messages)
+    OutputText {
+        /// The text content
+        text: String,
+    },
+
+    /// Refusal content (for assistant messages)
+    Refusal {
+        /// The refusal message
+        refusal: String,
+    },
+    // Future: InputAudio, OutputAudio, etc.
+}
+
+impl ContentPart {
+    /// Create an input text part
+    pub fn input_text(text: impl Into<String>) -> Self {
+        Self::InputText { text: text.into() }
+    }
+
+    /// Create an output text part
+    pub fn output_text(text: impl Into<String>) -> Self {
+        Self::OutputText { text: text.into() }
+    }
+
+    /// Create a refusal part
+    pub fn refusal(refusal: impl Into<String>) -> Self {
+        Self::Refusal {
+            refusal: refusal.into(),
+        }
+    }
+
+    /// Get the text content regardless of type
+    pub fn as_text(&self) -> &str {
+        match self {
+            Self::InputText { text } => text,
+            Self::OutputText { text } => text,
+            Self::Refusal { refusal } => refusal,
+        }
+    }
+}
+
+// ============================================================================
+// Role and Status
+// ============================================================================
+
+/// Message role
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
+#[serde(rename_all = "lowercase")]
+pub enum Role {
+    /// User
+    User,
+    /// Assistant
+    Assistant,
+    /// System (for system prompts, not typically used in items)
+    System,
+}
+
+/// Item status
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
+#[serde(rename_all = "lowercase")]
+pub enum ItemStatus {
+    /// Item is being generated
+    InProgress,
+    /// Item completed successfully
+    Completed,
+    /// Item was truncated (e.g., max tokens)
+    Incomplete,
+}
+
+// ============================================================================
+// Request Types
+// ============================================================================
+
+/// LLM Request
 #[derive(Debug, Clone, Default)]
 pub struct Request {
-    /// システムプロンプト
+    /// System prompt (instructions)
    pub system_prompt: Option<String>,
-    /// メッセージ履歴
-    pub messages: Vec<Message>,
-    /// ツール定義
+    /// Input items (conversation history)
+    pub items: Vec<Item>,
+    /// Tool definitions
    pub tools: Vec<ToolDefinition>,
-    /// リクエスト設定
+    /// Request configuration
    pub config: RequestConfig,
 }

 impl Request {
-    /// 新しいリクエストを作成
+    /// Create a new empty request
    pub fn new() -> Self {
        Self::default()
    }

-    /// システムプロンプトを設定
+    /// Set the system prompt
    pub fn system(mut self, prompt: impl Into<String>) -> Self {
        self.system_prompt = Some(prompt.into());
        self
    }

-    /// ユーザーメッセージを追加
+    /// Add a user message
    pub fn user(mut self, content: impl Into<String>) -> Self {
-        self.messages.push(Message::user(content));
+        self.items.push(Item::user_message(content));
        self
    }

-    /// アシスタントメッセージを追加
+    /// Add an assistant message
    pub fn assistant(mut self, content: impl Into<String>) -> Self {
-        self.messages.push(Message::assistant(content));
+        self.items.push(Item::assistant_message(content));
        self
    }

-    /// メッセージを追加
-    pub fn message(mut self, message: Message) -> Self {
-        self.messages.push(message);
+    /// Add an item
+    pub fn item(mut self, item: Item) -> Self {
+        self.items.push(item);
        self
    }

-    /// ツールを追加
+    /// Add multiple items
+    pub fn items(mut self, items: impl IntoIterator<Item = Item>) -> Self {
+        self.items.extend(items);
+        self
+    }
+
+    /// Add a tool definition
    pub fn tool(mut self, tool: ToolDefinition) -> Self {
        self.tools.push(tool);
        self
    }

-    /// 設定を適用
+    /// Set the request config
    pub fn config(mut self, config: RequestConfig) -> Self {
        self.config = config;
        self
    }

-    /// max_tokensを設定
+    /// Set max tokens
    pub fn max_tokens(mut self, max_tokens: u32) -> Self {
        self.config.max_tokens = Some(max_tokens);
        self
    }

-    /// temperatureを設定
+    /// Set temperature
    pub fn temperature(mut self, temperature: f32) -> Self {
        self.config.temperature = Some(temperature);
        self
    }

-    /// top_pを設定
+    /// Set top_p
    pub fn top_p(mut self, top_p: f32) -> Self {
        self.config.top_p = Some(top_p);
        self
    }

-    /// top_kを設定
+    /// Set top_k
    pub fn top_k(mut self, top_k: u32) -> Self {
        self.config.top_k = Some(top_k);
        self
    }

-    /// ストップシーケンスを追加
+    /// Add a stop sequence
    pub fn stop_sequence(mut self, sequence: impl Into<String>) -> Self {
        self.config.stop_sequences.push(sequence.into());
        self
    }
 }

-/// メッセージ
-#[derive(Debug, Clone, Serialize, Deserialize)]
-pub struct Message {
-    /// ロール
-    pub role: Role,
-    /// コンテンツ
-    pub content: MessageContent,
-}
+// ============================================================================
+// Tool Definition
+// ============================================================================

-impl Message {
-    /// ユーザーメッセージを作成
-    pub fn user(content: impl Into<String>) -> Self {
-        Self {
-            role: Role::User,
-            content: MessageContent::Text(content.into()),
-        }
-    }
-
-    /// アシスタントメッセージを作成
-    pub fn assistant(content: impl Into<String>) -> Self {
-        Self {
-            role: Role::Assistant,
-            content: MessageContent::Text(content.into()),
-        }
-    }
-
-    /// ツール結果メッセージを作成
-    pub fn tool_result(tool_use_id: impl Into<String>, content: impl Into<String>) -> Self {
-        Self {
-            role: Role::User,
-            content: MessageContent::ToolResult {
-                tool_use_id: tool_use_id.into(),
-                content: content.into(),
-            },
-        }
-    }
-}
-
-/// ロール
-#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
-#[serde(rename_all = "lowercase")]
-pub enum Role {
-    User,
-    Assistant,
-}
-
-/// メッセージコンテンツ
-#[derive(Debug, Clone, Serialize, Deserialize)]
-#[serde(untagged)]
-pub enum MessageContent {
-    /// テキストコンテンツ
-    Text(String),
-    /// ツール結果
-    ToolResult {
-        tool_use_id: String,
-        content: String,
-    },
-    /// 複合コンテンツ (テキスト + ツール使用等)
-    Parts(Vec<ContentPart>),
-}
-
-/// コンテンツパーツ
-#[derive(Debug, Clone, Serialize, Deserialize)]
-#[serde(tag = "type")]
-pub enum ContentPart {
-    /// テキスト
-    #[serde(rename = "text")]
-    Text { text: String },
-    /// ツール使用
-    #[serde(rename = "tool_use")]
-    ToolUse {
-        id: String,
-        name: String,
-        input: serde_json::Value,
-    },
-    /// ツール結果
-    #[serde(rename = "tool_result")]
-    ToolResult {
-        tool_use_id: String,
-        content: String,
-    },
-}
-
-/// ツール定義
+/// Tool (function) definition
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct ToolDefinition {
-    /// ツール名
+    /// Tool name
    pub name: String,
-    /// 説明
+    /// Tool description
    pub description: Option<String>,
-    /// 入力スキーマ (JSON Schema)
+    /// Input schema (JSON Schema)
    pub input_schema: serde_json::Value,
 }

 impl ToolDefinition {
-    /// 新しいツール定義を作成
+    /// Create a new tool definition
    pub fn new(name: impl Into<String>) -> Self {
        Self {
            name: name.into(),
@ -195,65 +497,69 @@ impl ToolDefinition {
        }
    }

-    /// 説明を設定
+    /// Set the description
    pub fn description(mut self, desc: impl Into<String>) -> Self {
        self.description = Some(desc.into());
        self
    }

-    /// 入力スキーマを設定
+    /// Set the input schema
    pub fn input_schema(mut self, schema: serde_json::Value) -> Self {
        self.input_schema = schema;
        self
    }
 }

-/// リクエスト設定
+// ============================================================================
+// Request Config
+// ============================================================================
+
+/// Request configuration
 #[derive(Debug, Clone, Default)]
 pub struct RequestConfig {
-    /// 最大トークン数
+    /// Maximum tokens to generate
    pub max_tokens: Option<u32>,
-    /// Temperature
+    /// Temperature (randomness)
    pub temperature: Option<f32>,
    /// Top P (nucleus sampling)
    pub top_p: Option<f32>,
    /// Top K
    pub top_k: Option<u32>,
-    /// ストップシーケンス
+    /// Stop sequences
    pub stop_sequences: Vec<String>,
 }

 impl RequestConfig {
-    /// 新しいデフォルト設定を作成
+    /// Create a new default config
    pub fn new() -> Self {
        Self::default()
    }

-    /// 最大トークン数を設定
+    /// Set max tokens
    pub fn with_max_tokens(mut self, max_tokens: u32) -> Self {
        self.max_tokens = Some(max_tokens);
        self
    }

-    /// temperatureを設定
+    /// Set temperature
    pub fn with_temperature(mut self, temperature: f32) -> Self {
        self.temperature = Some(temperature);
        self
    }

-    /// top_pを設定
+    /// Set top_p
    pub fn with_top_p(mut self, top_p: f32) -> Self {
        self.top_p = Some(top_p);
        self
    }

-    /// top_kを設定
+    /// Set top_k
    pub fn with_top_k(mut self, top_k: u32) -> Self {
        self.top_k = Some(top_k);
        self
    }

-    /// ストップシーケンスを追加
+    /// Add a stop sequence
    pub fn with_stop_sequence(mut self, sequence: impl Into<String>) -> Self {
        self.stop_sequences.push(sequence.into());
        self
--- a/llm-worker/src/message.rs
+++ b/llm-worker/src/message.rs
@ -1,116 +1,16 @@
-//! メッセージ型
+//! Message and Item Types
 //!
-//! LLMとの会話で使用されるメッセージ構造。
-//! [`Message::user`]や[`Message::assistant`]で簡単に作成できます。
+//! This module provides the core types for representing conversation items
+//! in the Open Responses format.
+//!
+//! The primary type is [`Item`], which represents different kinds of conversation
+//! elements: messages, function calls, function call outputs, and reasoning.

-use serde::{Deserialize, Serialize};
+// Re-export all types from llm_client::types
+pub use crate::llm_client::types::{ContentPart, Item, Role};

-/// メッセージのロール
-#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
-#[serde(rename_all = "lowercase")]
-pub enum Role {
-    /// ユーザー
-    User,
-    /// アシスタント
-    Assistant,
-}
-
-/// 会話のメッセージ
+/// Convenience alias for backward compatibility
 ///
-/// # Examples
-///
-/// ```ignore
-/// use llm_worker::Message;
-///
-/// // ユーザーメッセージ
-/// let user_msg = Message::user("Hello!");
-///
-/// // アシスタントメッセージ
-/// let assistant_msg = Message::assistant("Hi there!");
-/// ```
-#[derive(Debug, Clone, Serialize, Deserialize)]
-pub struct Message {
-    /// ロール
-    pub role: Role,
-    /// コンテンツ
-    pub content: MessageContent,
-}
-
-/// メッセージコンテンツ
-#[derive(Debug, Clone, Serialize, Deserialize)]
-#[serde(untagged)]
-pub enum MessageContent {
-    /// テキストコンテンツ
-    Text(String),
-    /// ツール結果
-    ToolResult {
-        tool_use_id: String,
-        content: String,
-    },
-    /// 複合コンテンツ (テキスト + ツール使用等)
-    Parts(Vec<ContentPart>),
-}
-
-/// コンテンツパーツ
-#[derive(Debug, Clone, Serialize, Deserialize)]
-#[serde(tag = "type")]
-pub enum ContentPart {
-    /// テキスト
-    #[serde(rename = "text")]
-    Text { text: String },
-    /// ツール使用
-    #[serde(rename = "tool_use")]
-    ToolUse {
-        id: String,
-        name: String,
-        input: serde_json::Value,
-    },
-    /// ツール結果
-    #[serde(rename = "tool_result")]
-    ToolResult {
-        tool_use_id: String,
-        content: String,
-    },
-}
-
-impl Message {
-    /// ユーザーメッセージを作成
-    ///
-    /// # Examples
-    ///
-    /// ```ignore
-    /// use llm_worker::Message;
-    /// let msg = Message::user("こんにちは");
-    /// ```
-    pub fn user(content: impl Into<String>) -> Self {
-        Self {
-            role: Role::User,
-            content: MessageContent::Text(content.into()),
-        }
-    }
-
-    /// アシスタントメッセージを作成
-    ///
-    /// 通常はWorker内部で自動生成されますが、
-    /// 履歴の初期化などで手動作成も可能です。
-    pub fn assistant(content: impl Into<String>) -> Self {
-        Self {
-            role: Role::Assistant,
-            content: MessageContent::Text(content.into()),
-        }
-    }
-
-    /// ツール結果メッセージを作成
-    ///
-    /// Worker内部でツール実行後に自動生成されます。
-    /// 通常は直接作成する必要はありません。
-    pub fn tool_result(tool_use_id: impl Into<String>, content: impl Into<String>) -> Self {
-        Self {
-            role: Role::User,
-            content: MessageContent::ToolResult {
-                tool_use_id: tool_use_id.into(),
-                content: content.into(),
-            },
-        }
-    }
-}
+/// In the Open Responses model, messages are just one type of Item.
+/// This alias allows code that expects a "Message" type to continue working.
+pub type Message = Item;
--- a/llm-worker/src/state.rs
+++ b/llm-worker/src/state.rs
@ -1,25 +1,25 @@
-//! Worker状態
+//! Worker State
 //!
-//! Type-stateパターンによるキャッシュ保護のための状態マーカー型。
-//! Workerは`Mutable` → `CacheLocked`の状態遷移を持ちます。
+//! State marker types for cache protection using the Type-state pattern.
+//! Worker has state transitions from `Mutable` → `CacheLocked`.

-/// Worker状態を表すマーカートレイト
+/// Marker trait representing Worker state
 ///
-/// このトレイトはシールされており、外部から実装することはできません。
+/// This trait is sealed and cannot be implemented externally.
 pub trait WorkerState: private::Sealed + Send + Sync + 'static {}

 mod private {
    pub trait Sealed {}
 }

-/// 編集可能状態
+/// Mutable state (editable)
 ///
-/// この状態では以下の操作が可能です：
-/// - システムプロンプトの設定・変更
-/// - メッセージ履歴の編集（追加、削除、クリア）
-/// - ツール・Hookの登録
+/// In this state, the following operations are available:
+/// - Setting/changing system prompt
+/// - Editing message history (add, delete, clear)
+/// - Registering tools and hooks
 ///
-/// `Worker::lock()`により[`CacheLocked`]状態へ遷移できます。
+/// Can transition to [`CacheLocked`] state via `Worker::lock()`.
 ///
 /// # Examples
 ///
@ -29,11 +29,11 @@ mod private {
 /// let mut worker = Worker::new(client)
 ///     .system_prompt("You are helpful.");
 ///
-/// // 履歴を編集可能
+/// // History can be edited
 /// worker.push_message(Message::user("Hello"));
 /// worker.clear_history();
 ///
-/// // ロックして保護状態へ
+/// // Lock to protected state
 /// let locked = worker.lock();
 /// ```
 #[derive(Debug, Clone, Copy, Default)]
@ -42,17 +42,17 @@ pub struct Mutable;
 impl private::Sealed for Mutable {}
 impl WorkerState for Mutable {}

-/// キャッシュロック状態（キャッシュ保護）
+/// Cache locked state (cache protected)
 ///
-/// この状態では以下の制限があります：
-/// - システムプロンプトの変更不可
-/// - 既存メッセージ履歴の変更不可（末尾への追記のみ）
+/// In this state, the following restrictions apply:
+/// - System prompt cannot be changed
+/// - Existing message history cannot be modified (only appending to the end)
 ///
-/// LLM APIのKVキャッシュヒットを保証するため、
-/// 実行時にはこの状態の使用が推奨されます。
+/// To ensure LLM API KV cache hits,
+/// using this state during execution is recommended.
 ///
-/// `Worker::unlock()`により[`Mutable`]状態へ戻せますが、
-/// キャッシュ保護が解除されることに注意してください。
+/// Can return to [`Mutable`] state via `Worker::unlock()`,
+/// but note that cache protection will be released.
 #[derive(Debug, Clone, Copy, Default)]
 pub struct CacheLocked;

--- a/llm-worker/src/subscriber.rs
+++ b/llm-worker/src/subscriber.rs
@ -1,7 +1,7 @@
-//! イベント購読
+//! Event Subscription
 //!
-//! LLMからのストリーミングイベントをリアルタイムで受信するためのトレイト。
-//! UIへのストリーム表示やプログレス表示に使用します。
+//! Trait for receiving streaming events from LLM in real-time.
+//! Used for stream display to UI and progress display.

 use std::sync::{Arc, Mutex};

@ -18,17 +18,17 @@ use crate::{
 // WorkerSubscriber Trait
 // =============================================================================

-/// LLMからのストリーミングイベントを購読するトレイト
+/// Trait for subscribing to streaming events from LLM
 ///
-/// Workerに登録すると、テキスト生成やツール呼び出しのイベントを
-/// リアルタイムで受信できます。UIへのストリーム表示に最適です。
+/// When registered with Worker, you can receive events from text generation
+/// and tool calls in real-time. Ideal for stream display to UI.
 ///
-/// # 受信できるイベント
+/// # Available Events
 ///
-/// - **ブロックイベント**: テキスト、ツール使用（スコープ付き）
-/// - **メタイベント**: 使用量、ステータス、エラー
-/// - **完了イベント**: テキスト完了、ツール呼び出し完了
-/// - **ターン制御**: ターン開始、ターン終了
+/// - **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
 ///
@ -44,7 +44,7 @@ use crate::{
 ///
 ///     fn on_text_block(&mut self, _: &mut (), event: &TextBlockEvent) {
 ///         if let TextBlockEvent::Delta(text) = event {
-///             print!("{}", text);  // リアルタイム出力
+///             print!("{}", text);  // Real-time output
 ///         }
 ///     }
 ///
@ -53,37 +53,37 @@ use crate::{
 ///     }
 /// }
 ///
-/// // Workerに登録
+/// // Register with Worker
 /// worker.subscribe(StreamPrinter);
 /// ```
 pub trait WorkerSubscriber: Send {
    // =========================================================================
-    // スコープ型（ブロックイベント用）
+    // Scope Types (for block events)
    // =========================================================================

-    /// テキストブロック処理用のスコープ型
+    /// Scope type for text block processing
    ///
-    /// ブロック開始時にDefault::default()で生成され、
-    /// ブロック終了時に破棄される。
+    /// Generated with Default::default() at block start,
+    /// destroyed at block end.
    type TextBlockScope: Default + Send + Sync;

-    /// ツール使用ブロック処理用のスコープ型
+    /// Scope type for tool use block processing
    type ToolUseBlockScope: Default + Send + Sync;

    // =========================================================================
-    // ブロックイベント（スコープ管理あり）
+    // Block Events (with scope management)
    // =========================================================================

-    /// テキストブロックイベント
+    /// Text block event
    ///
-    /// Start/Delta/Stopのライフサイクルを持つ。
-    /// scopeはブロック開始時に生成され、終了時に破棄される。
+    /// 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) {}

-    /// ツール使用ブロックイベント
+    /// Tool use block event
    ///
-    /// Start/InputJsonDelta/Stopのライフサイクルを持つ。
+    /// Has Start/InputJsonDelta/Stop lifecycle.
    #[allow(unused_variables)]
    fn on_tool_use_block(
        &mut self,
@ -93,62 +93,62 @@ pub trait WorkerSubscriber: Send {
    }

    // =========================================================================
-    // 単発イベント（スコープ不要）
+    // Single Events (no scope needed)
    // =========================================================================

-    /// 使用量イベント
+    /// Usage event
    #[allow(unused_variables)]
    fn on_usage(&mut self, event: &UsageEvent) {}

-    /// ステータスイベント
+    /// Status event
    #[allow(unused_variables)]
    fn on_status(&mut self, event: &StatusEvent) {}

-    /// エラーイベント
+    /// Error event
    #[allow(unused_variables)]
    fn on_error(&mut self, event: &ErrorEvent) {}

    // =========================================================================
-    // 累積イベント（Worker層で追加）
+    // Accumulated Events (added in Worker layer)
    // =========================================================================

-    /// テキスト完了イベント
+    /// Text complete event
    ///
-    /// テキストブロックが完了した時点で、累積されたテキスト全体が渡される。
-    /// ブロック処理後の最終結果を受け取るのに便利。
+    /// 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) {}

-    /// ツール呼び出し完了イベント
+    /// Tool call complete event
    ///
-    /// ツール使用ブロックが完了した時点で、完全なToolCallが渡される。
+    /// When a tool use block completes, the complete ToolCall is passed.
    #[allow(unused_variables)]
    fn on_tool_call_complete(&mut self, call: &ToolCall) {}

    // =========================================================================
-    // ターン制御
+    // Turn Control
    // =========================================================================

-    /// ターン開始時
+    /// On turn start
    ///
-    /// `turn`は0から始まるターン番号。
+    /// `turn` is a 0-based turn number.
    #[allow(unused_variables)]
    fn on_turn_start(&mut self, turn: usize) {}

-    /// ターン終了時
+    /// On turn end
    #[allow(unused_variables)]
    fn on_turn_end(&mut self, turn: usize) {}
 }

 // =============================================================================
-// SubscriberAdapter - WorkerSubscriberをTimelineハンドラにブリッジ
+// SubscriberAdapter - Bridge WorkerSubscriber to Timeline handlers
 // =============================================================================

 // =============================================================================
 // TextBlock Handler Adapter
 // =============================================================================

-/// TextBlockKind用のSubscriberアダプター
+/// Subscriber adapter for TextBlockKind
 pub(crate) struct TextBlockSubscriberAdapter<S: WorkerSubscriber> {
    subscriber: Arc<Mutex<S>>,
 }
@ -167,10 +167,10 @@ impl<S: WorkerSubscriber> Clone for TextBlockSubscriberAdapter<S> {
    }
 }

-/// TextBlockのスコープをラップ
+/// Wrapper for TextBlock scope
 pub struct TextBlockScopeWrapper<S: WorkerSubscriber> {
    inner: S::TextBlockScope,
-    buffer: String, // on_text_complete用のバッファ
+    buffer: String, // Buffer for on_text_complete
 }

 impl<S: WorkerSubscriber> Default for TextBlockScopeWrapper<S> {
@ -186,16 +186,16 @@ impl<S: WorkerSubscriber + 'static> Handler<TextBlockKind> for TextBlockSubscrib
    type Scope = TextBlockScopeWrapper<S>;

    fn on_event(&mut self, scope: &mut Self::Scope, event: &TextBlockEvent) {
-        // Deltaの場合はバッファに蓄積
+        // Accumulate deltas into buffer
        if let TextBlockEvent::Delta(text) = event {
            scope.buffer.push_str(text);
        }

-        // SubscriberのTextBlockイベントハンドラを呼び出し
+        // Call Subscriber's TextBlock event handler
        if let Ok(mut subscriber) = self.subscriber.lock() {
            subscriber.on_text_block(&mut scope.inner, event);

-            // Stopの場合はon_text_completeも呼び出し
+            // Also call on_text_complete on Stop
            if matches!(event, TextBlockEvent::Stop(_)) {
                subscriber.on_text_complete(&scope.buffer);
            }
@ -207,7 +207,7 @@ impl<S: WorkerSubscriber + 'static> Handler<TextBlockKind> for TextBlockSubscrib
 // ToolUseBlock Handler Adapter
 // =============================================================================

-/// ToolUseBlockKind用のSubscriberアダプター
+/// Subscriber adapter for ToolUseBlockKind
 pub(crate) struct ToolUseBlockSubscriberAdapter<S: WorkerSubscriber> {
    subscriber: Arc<Mutex<S>>,
 }
@ -226,12 +226,12 @@ impl<S: WorkerSubscriber> Clone for ToolUseBlockSubscriberAdapter<S> {
    }
 }

-/// ToolUseBlockのスコープをラップ
+/// Wrapper for ToolUseBlock scope
 pub struct ToolUseBlockScopeWrapper<S: WorkerSubscriber> {
    inner: S::ToolUseBlockScope,
    id: String,
    name: String,
-    input_json: String, // JSON蓄積用
+    input_json: String, // JSON accumulation
 }

 impl<S: WorkerSubscriber> Default for ToolUseBlockScopeWrapper<S> {
@ -249,22 +249,22 @@ impl<S: WorkerSubscriber + 'static> Handler<ToolUseBlockKind> for ToolUseBlockSu
    type Scope = ToolUseBlockScopeWrapper<S>;

    fn on_event(&mut self, scope: &mut Self::Scope, event: &ToolUseBlockEvent) {
-        // Start時にメタデータを保存
+        // Save metadata on Start
        if let ToolUseBlockEvent::Start(start) = event {
            scope.id = start.id.clone();
            scope.name = start.name.clone();
        }

-        // InputJsonDeltaの場合はバッファに蓄積
+        // Accumulate InputJsonDelta into buffer
        if let ToolUseBlockEvent::InputJsonDelta(json) = event {
            scope.input_json.push_str(json);
        }

-        // SubscriberのToolUseBlockイベントハンドラを呼び出し
+        // Call Subscriber's ToolUseBlock event handler
        if let Ok(mut subscriber) = self.subscriber.lock() {
            subscriber.on_tool_use_block(&mut scope.inner, event);

-            // Stopの場合はon_tool_call_completeも呼び出し
+            // 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();
@ -283,7 +283,7 @@ impl<S: WorkerSubscriber + 'static> Handler<ToolUseBlockKind> for ToolUseBlockSu
 // Meta Event Handler Adapters
 // =============================================================================

-/// UsageKind用のSubscriberアダプター
+/// Subscriber adapter for UsageKind
 pub(crate) struct UsageSubscriberAdapter<S: WorkerSubscriber> {
    subscriber: Arc<Mutex<S>>,
 }
@ -312,7 +312,7 @@ impl<S: WorkerSubscriber + 'static> Handler<UsageKind> for UsageSubscriberAdapte
    }
 }

-/// StatusKind用のSubscriberアダプター
+/// Subscriber adapter for StatusKind
 pub(crate) struct StatusSubscriberAdapter<S: WorkerSubscriber> {
    subscriber: Arc<Mutex<S>>,
 }
@ -341,7 +341,7 @@ impl<S: WorkerSubscriber + 'static> Handler<StatusKind> for StatusSubscriberAdap
    }
 }

-/// ErrorKind用のSubscriberアダプター
+/// Subscriber adapter for ErrorKind
 pub(crate) struct ErrorSubscriberAdapter<S: WorkerSubscriber> {
    subscriber: Arc<Mutex<S>>,
 }
--- a/llm-worker/src/tool.rs
+++ b/llm-worker/src/tool.rs
@ -1,7 +1,7 @@
-//! ツール定義
+//! Tool Definition
 //!
-//! LLMから呼び出し可能なツールを定義するためのトレイト。
-//! 通常は`#[tool]`マクロを使用して自動実装します。
+//! Traits for defining tools callable by LLM.
+//! Usually auto-implemented using the `#[tool]` macro.

 use std::sync::Arc;

@ -9,40 +9,40 @@ use async_trait::async_trait;
 use serde_json::Value;
 use thiserror::Error;

-/// ツール実行時のエラー
+/// Error during tool execution
 #[derive(Debug, Error)]
 pub enum ToolError {
-    /// 引数が不正
+    /// Invalid argument
    #[error("Invalid argument: {0}")]
    InvalidArgument(String),
-    /// 実行に失敗
+    /// Execution failed
    #[error("Execution failed: {0}")]
    ExecutionFailed(String),
-    /// 内部エラー
+    /// Internal error
    #[error("Internal error: {0}")]
    Internal(String),
 }

 // =============================================================================
-// ToolMeta - 不変のメタ情報
+// ToolMeta - Immutable Meta Information
 // =============================================================================

-/// ツールのメタ情報（登録時に固定、不変）
+/// Tool meta information (fixed at registration, immutable)
 ///
-/// `ToolDefinition` ファクトリから生成され、Worker に登録後は変更されません。
-/// LLM へのツール定義送信に使用されます。
+/// Generated from `ToolDefinition` factory and does not change after registration with Worker.
+/// Used for sending tool definitions to LLM.
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct ToolMeta {
-    /// ツール名（LLMが識別に使用）
+    /// Tool name (used by LLM for identification)
    pub name: String,
-    /// ツールの説明（LLMへのプロンプトに含まれる）
+    /// Tool description (included in prompt to LLM)
    pub description: String,
-    /// 引数のJSON Schema
+    /// JSON Schema for arguments
    pub input_schema: Value,
 }

 impl ToolMeta {
-    /// 新しい ToolMeta を作成
+    /// Create a new ToolMeta
    pub fn new(name: impl Into<String>) -> Self {
        Self {
            name: name.into(),
@ -51,13 +51,13 @@ impl ToolMeta {
        }
    }

-    /// 説明を設定
+    /// Set the description
    pub fn description(mut self, desc: impl Into<String>) -> Self {
        self.description = desc.into();
        self
    }

-    /// 引数スキーマを設定
+    /// Set the argument schema
    pub fn input_schema(mut self, schema: Value) -> Self {
        self.input_schema = schema;
        self
@ -65,14 +65,14 @@ impl ToolMeta {
 }

 // =============================================================================
-// ToolDefinition - ファクトリ型
+// ToolDefinition - Factory Type
 // =============================================================================

-/// ツール定義ファクトリ
+/// Tool definition factory
 ///
-/// 呼び出すと `(ToolMeta, Arc<dyn Tool>)` を返します。
-/// Worker への登録時に一度だけ呼び出され、メタ情報とインスタンスが
-/// セッションスコープでキャッシュされます。
+/// When called, returns `(ToolMeta, Arc<dyn Tool>)`.
+/// Called once during Worker registration, and the meta information and instance
+/// are cached at session scope.
 ///
 /// # Examples
 ///
@ -93,15 +93,15 @@ pub type ToolDefinition = Arc<dyn Fn() -> (ToolMeta, Arc<dyn Tool>) + Send + Syn
 // Tool trait
 // =============================================================================

-/// LLMから呼び出し可能なツールを定義するトレイト
+/// Trait for defining tools callable by LLM
 ///
-/// ツールはLLMが外部リソースにアクセスしたり、
-/// 計算を実行したりするために使用します。
-/// セッション中の状態を保持できます。
+/// Tools are used by LLM to access external resources
+/// or execute computations.
+/// Can maintain state during the session.
 ///
-/// # 実装方法
+/// # How to Implement
 ///
-/// 通常は`#[tool_registry]`マクロを使用して自動実装します:
+/// Usually auto-implemented using the `#[tool_registry]` macro:
 ///
 /// ```ignore
 /// #[tool_registry]
@ -112,11 +112,11 @@ pub type ToolDefinition = Arc<dyn Fn() -> (ToolMeta, Arc<dyn Tool>) + Send + Syn
 ///     }
 /// }
 ///
-/// // 登録
+/// // Register
 /// worker.register_tool(app.search_definition())?;
 /// ```
 ///
-/// # 手動実装
+/// # Manual Implementation
 ///
 /// ```ignore
 /// use llm_worker::tool::{Tool, ToolError, ToolMeta, ToolDefinition};
@ -143,12 +143,12 @@ pub type ToolDefinition = Arc<dyn Fn() -> (ToolMeta, Arc<dyn Tool>) + Send + Syn
 /// ```
 #[async_trait]
 pub trait Tool: Send + Sync {
-    /// ツールを実行する
+    /// Execute the tool
    ///
    /// # Arguments
-    /// * `input_json` - LLMが生成したJSON形式の引数
+    /// * `input_json` - JSON-formatted arguments generated by LLM
    ///
    /// # Returns
-    /// 実行結果の文字列。この内容がLLMに返されます。
+    /// Result string from execution. This content is returned to LLM.
    async fn execute(&self, input_json: &str) -> Result<String, ToolError>;
 }
--- a/llm-worker/src/tool_server.rs
+++ b/llm-worker/src/tool_server.rs
@ -0,0 +1,182 @@
+use std::collections::HashMap;
+use std::sync::{Arc, Mutex};
+
+use thiserror::Error;
+
+use crate::llm_client::ToolDefinition as LlmToolDefinition;
+use crate::tool::{Tool, ToolDefinition as WorkerToolDefinition, ToolMeta};
+
+type ToolMap = HashMap<String, (ToolMeta, Arc<dyn Tool>)>;
+
+/// Errors produced by ToolServer operations.
+#[derive(Debug, Error, PartialEq, Eq)]
+pub enum ToolServerError {
+    /// A tool with the same name already exists.
+    #[error("Tool with name '{0}' already registered")]
+    DuplicateName(String),
+    /// Requested tool was not found.
+    #[error("Tool '{0}' not found")]
+    ToolNotFound(String),
+    /// Tool execution failed.
+    #[error("Tool execution failed: {0}")]
+    ToolExecution(String),
+}
+
+/// In-memory tool server.
+#[derive(Clone, Default)]
+pub struct ToolServer {
+    tools: Arc<Mutex<ToolMap>>,
+}
+
+impl ToolServer {
+    /// Create a new empty tool server.
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    /// Create a handle for shared access.
+    pub fn handle(&self) -> ToolServerHandle {
+        ToolServerHandle {
+            tools: Arc::clone(&self.tools),
+        }
+    }
+}
+
+/// Shareable handle to a tool server.
+#[derive(Clone, Default)]
+pub struct ToolServerHandle {
+    tools: Arc<Mutex<ToolMap>>,
+}
+
+impl ToolServerHandle {
+    /// Register one tool.
+    pub(crate) fn register_tool(
+        &self,
+        factory: WorkerToolDefinition,
+    ) -> Result<(), ToolServerError> {
+        let (meta, instance) = factory();
+        let mut guard = self.tools.lock().unwrap_or_else(|e| e.into_inner());
+        if guard.contains_key(&meta.name) {
+            return Err(ToolServerError::DuplicateName(meta.name));
+        }
+        guard.insert(meta.name.clone(), (meta, instance));
+        Ok(())
+    }
+
+    /// Register many tools.
+    pub(crate) fn register_tools(
+        &self,
+        factories: impl IntoIterator<Item = WorkerToolDefinition>,
+    ) -> Result<(), ToolServerError> {
+        for factory in factories {
+            self.register_tool(factory)?;
+        }
+        Ok(())
+    }
+
+    /// Get a tool by name for hook contexts.
+    pub fn get_tool(&self, name: &str) -> Option<(ToolMeta, Arc<dyn Tool>)> {
+        let guard = self.tools.lock().unwrap_or_else(|e| e.into_inner());
+        guard.get(name).map(|(meta, tool)| (meta.clone(), Arc::clone(tool)))
+    }
+
+    /// Execute a tool by name.
+    pub async fn call_tool(&self, name: &str, input_json: &str) -> Result<String, ToolServerError> {
+        let tool = {
+            let guard = self.tools.lock().unwrap_or_else(|e| e.into_inner());
+            let (_, tool) = guard
+                .get(name)
+                .ok_or_else(|| ToolServerError::ToolNotFound(name.to_string()))?;
+            Arc::clone(tool)
+        };
+        tool.execute(input_json)
+            .await
+            .map_err(|e| ToolServerError::ToolExecution(e.to_string()))
+    }
+
+    /// Build deterministic tool definitions sorted by tool name.
+    pub fn tool_definitions_sorted(&self) -> Vec<LlmToolDefinition> {
+        let guard = self.tools.lock().unwrap_or_else(|e| e.into_inner());
+        let mut defs: Vec<_> = guard
+            .values()
+            .map(|(meta, _)| {
+                LlmToolDefinition::new(&meta.name)
+                    .description(&meta.description)
+                    .input_schema(meta.input_schema.clone())
+            })
+            .collect();
+        defs.sort_by(|a, b| a.name.cmp(&b.name));
+        defs
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use std::sync::Arc;
+
+    use async_trait::async_trait;
+    use serde_json::json;
+
+    use super::*;
+    use crate::tool::{Tool, ToolDefinition, ToolError, ToolMeta};
+
+    struct EchoTool;
+
+    #[async_trait]
+    impl Tool for EchoTool {
+        async fn execute(&self, input_json: &str) -> Result<String, ToolError> {
+            Ok(input_json.to_string())
+        }
+    }
+
+    fn def(name: &'static str) -> ToolDefinition {
+        Arc::new(move || {
+            (
+                ToolMeta::new(name)
+                    .description(format!("desc-{name}"))
+                    .input_schema(json!({"type":"object"})),
+                Arc::new(EchoTool) as Arc<dyn Tool>,
+            )
+        })
+    }
+
+    #[test]
+    fn register_duplicate_name_fails() {
+        let handle = ToolServer::new().handle();
+        handle.register_tool(def("alpha")).expect("first register");
+        let err = handle
+            .register_tool(def("alpha"))
+            .expect_err("duplicate should fail");
+        assert_eq!(err, ToolServerError::DuplicateName("alpha".to_string()));
+    }
+
+    #[tokio::test]
+    async fn call_tool_success_and_not_found() {
+        let handle = ToolServer::new().handle();
+        handle.register_tool(def("echo")).expect("register");
+
+        let out = handle.call_tool("echo", r#"{"x":1}"#).await.expect("call");
+        assert_eq!(out, r#"{"x":1}"#);
+
+        let err = handle
+            .call_tool("missing", "{}")
+            .await
+            .expect_err("missing tool");
+        assert_eq!(err, ToolServerError::ToolNotFound("missing".to_string()));
+    }
+
+    #[test]
+    fn tool_definitions_are_sorted() {
+        let handle = ToolServer::new().handle();
+        handle.register_tool(def("zeta")).expect("register zeta");
+        handle.register_tool(def("alpha")).expect("register alpha");
+        handle.register_tool(def("beta")).expect("register beta");
+
+        let names: Vec<_> = handle
+            .tool_definitions_sorted()
+            .into_iter()
+            .map(|d| d.name)
+            .collect();
+        assert_eq!(names, vec!["alpha", "beta", "zeta"]);
+    }
+}
--- a/llm-worker/src/worker.rs
+++ b/llm-worker/src/worker.rs
--- a/llm-worker/tests/anthropic_fixtures.rs
+++ b/llm-worker/tests/anthropic_fixtures.rs
@ -1,4 +1,4 @@
-//! Anthropic フィクスチャベースの統合テスト
+//! Anthropic fixture-based integration tests

 mod common;

--- a/llm-worker/tests/compile_fail.rs
+++ b/llm-worker/tests/compile_fail.rs
@ -0,0 +1,6 @@
+#[test]
+fn compile_fail_state_constraints() {
+    let t = trybuild::TestCases::new();
+    t.compile_fail("tests/ui/cache_locked_register_tool.rs");
+    t.compile_fail("tests/ui/tool_server_handle_register_tool.rs");
+}
--- a/llm-worker/tests/gemini_fixtures.rs
+++ b/llm-worker/tests/gemini_fixtures.rs
@ -1,4 +1,4 @@
-//! Gemini フィクスチャベースの統合テスト
+//! Gemini fixture-based integration tests

 mod common;

--- a/llm-worker/tests/ollama_fixtures.rs
+++ b/llm-worker/tests/ollama_fixtures.rs
@ -1,4 +1,4 @@
-//! Ollama フィクスチャベースの統合テスト
+//! Ollama fixture-based integration tests

 mod common;

--- a/llm-worker/tests/openai_fixtures.rs
+++ b/llm-worker/tests/openai_fixtures.rs
@ -1,4 +1,4 @@
-//! OpenAI フィクスチャベースの統合テスト
+//! OpenAI fixture-based integration tests

 mod common;

--- a/llm-worker/tests/parallel_execution_test.rs
+++ b/llm-worker/tests/parallel_execution_test.rs
@ -1,6 +1,6 @@
-//! 並列ツール実行のテスト
+//! Parallel tool execution tests
 //!
-//! Workerが複数のツールを並列に実行することを確認する。
+//! Verify that Worker executes multiple tools in parallel.

 use std::sync::Arc;
 use std::sync::atomic::{AtomicUsize, Ordering};
@ -22,7 +22,7 @@ use common::MockLlmClient;
 // Parallel Execution Test Tools
 // =============================================================================

-/// 一定時間待機してから応答するツール
+/// Tool that waits for a specified time before responding
 #[derive(Clone)]
 struct SlowTool {
    name: String,
@ -43,7 +43,7 @@ impl SlowTool {
        self.call_count.load(Ordering::SeqCst)
    }

-    /// ToolDefinition を作成
+    /// Create ToolDefinition
    fn definition(&self) -> ToolDefinition {
        let tool = self.clone();
        Arc::new(move || {
@ -71,13 +71,13 @@ impl Tool for SlowTool {
 // Tests
 // =============================================================================

-/// 複数のツールが並列に実行されることを確認
+/// Verify that multiple tools are executed in parallel
 ///
-/// 各ツールが100msかかる場合、逐次実行なら300ms以上かかるが、
-/// 並列実行なら100ms程度で完了するはず。
+/// If each tool takes 100ms, sequential execution would take 300ms+,
+/// but parallel execution should complete in about 100ms.
 #[tokio::test]
 async fn test_parallel_tool_execution() {
-    // 3つのツール呼び出しを含むイベントシーケンス
+    // Event sequence containing 3 tool calls
    let events = vec![
        Event::tool_use_start(0, "call_1", "slow_tool_1"),
        Event::tool_input_delta(0, r#"{}"#),
@ -96,7 +96,7 @@ async fn test_parallel_tool_execution() {
    let client = MockLlmClient::new(events);
    let mut worker = Worker::new(client);

-    // 各ツールは100ms待機
+    // Each tool waits 100ms
    let tool1 = SlowTool::new("slow_tool_1", 100);
    let tool2 = SlowTool::new("slow_tool_2", 100);
    let tool3 = SlowTool::new("slow_tool_3", 100);
@ -113,13 +113,13 @@ async fn test_parallel_tool_execution() {
    let _result = worker.run("Run all tools").await;
    let elapsed = start.elapsed();

-    // 全ツールが呼び出されたことを確認
+    // Verify all tools were called
    assert_eq!(tool1_clone.call_count(), 1, "Tool 1 should be called once");
    assert_eq!(tool2_clone.call_count(), 1, "Tool 2 should be called once");
    assert_eq!(tool3_clone.call_count(), 1, "Tool 3 should be called once");

-    // 並列実行なら200ms以下で完了するはず（逐次なら300ms以上）
-    // マージン込みで250msをしきい値とする
+    // Parallel execution should complete in under 200ms (sequential would be 300ms+)
+    // Using 250ms as threshold with margin
    assert!(
        elapsed < Duration::from_millis(250),
        "Parallel execution should complete in ~100ms, but took {:?}",
@ -129,7 +129,7 @@ async fn test_parallel_tool_execution() {
    println!("Parallel execution completed in {:?}", elapsed);
 }

-/// Hook: pre_tool_call でスキップされたツールは実行されないことを確認
+/// Hook: pre_tool_call - verify that skipped tools are not executed
 #[tokio::test]
 async fn test_before_tool_call_skip() {
    let events = vec![
@ -156,7 +156,7 @@ async fn test_before_tool_call_skip() {
    worker.register_tool(allowed_tool.definition()).unwrap();
    worker.register_tool(blocked_tool.definition()).unwrap();

-    // "blocked_tool" をスキップするHook
+    // Hook to skip "blocked_tool"
    struct BlockingHook;

    #[async_trait]
@ -174,7 +174,7 @@ async fn test_before_tool_call_skip() {

    let _result = worker.run("Test hook").await;

-    // allowed_tool は呼び出されるが、blocked_tool は呼び出されない
+    // allowed_tool is called, but blocked_tool is not
    assert_eq!(
        allowed_clone.call_count(),
        1,
@ -187,12 +187,12 @@ async fn test_before_tool_call_skip() {
    );
 }

-/// Hook: post_tool_call で結果が改変されることを確認
+/// Hook: post_tool_call - verify that results can be modified
 #[tokio::test]
 async fn test_post_tool_call_modification() {
-    // 複数リクエストに対応するレスポンスを準備
+    // Prepare responses for multiple requests
    let client = MockLlmClient::with_responses(vec![
-        // 1回目のリクエスト: ツール呼び出し
+        // First request: tool call
        vec![
            Event::tool_use_start(0, "call_1", "test_tool"),
            Event::tool_input_delta(0, r#"{}"#),
@ -201,7 +201,7 @@ async fn test_post_tool_call_modification() {
                status: ResponseStatus::Completed,
            }),
        ],
-        // 2回目のリクエスト: ツール結果を受けてテキストレスポンス
+        // Second request: text response after receiving tool result
        vec![
            Event::text_block_start(0),
            Event::text_delta(0, "Done!"),
@ -235,7 +235,7 @@ async fn test_post_tool_call_modification() {

    worker.register_tool(simple_tool_definition()).unwrap();

-    // 結果を改変するHook
+    // Hook to modify results
    struct ModifyingHook {
        modified_content: Arc<std::sync::Mutex<Option<String>>>,
    }
@ -261,7 +261,7 @@ async fn test_post_tool_call_modification() {

    assert!(result.is_ok(), "Worker should complete: {:?}", result);

-    // Hookが呼ばれて内容が改変されたことを確認
+    // Verify hook was called and content was modified
    let content = modified_content.lock().unwrap().clone();
    assert!(content.is_some(), "Hook should have been called");
    assert!(
--- a/llm-worker/tests/subscriber_test.rs
+++ b/llm-worker/tests/subscriber_test.rs
@ -1,6 +1,6 @@
-//! WorkerSubscriberのテスト
+//! WorkerSubscriber tests
 //!
-//! WorkerSubscriberを使ってイベントを購読するテスト
+//! Tests for subscribing to events using WorkerSubscriber

 mod common;

@ -18,9 +18,9 @@ use llm_worker::timeline::{TextBlockEvent, ToolUseBlockEvent};
 // Test Subscriber
 // =============================================================================

-/// テスト用のシンプルなSubscriber実装
+/// Simple Subscriber implementation for testing
 struct TestSubscriber {
-    // 記録用のバッファ
+    // Recording buffers
    text_deltas: Arc<Mutex<Vec<String>>>,
    text_completes: Arc<Mutex<Vec<String>>>,
    tool_call_completes: Arc<Mutex<Vec<ToolCall>>>,
@ -60,7 +60,7 @@ impl WorkerSubscriber for TestSubscriber {
    }

    fn on_tool_use_block(&mut self, _scope: &mut (), _event: &ToolUseBlockEvent) {
-        // 必要に応じて処理
+        // Process as needed
    }

    fn on_tool_call_complete(&mut self, call: &ToolCall) {
@ -76,7 +76,7 @@ impl WorkerSubscriber for TestSubscriber {
    }

    fn on_error(&mut self, _event: &ErrorEvent) {
-        // 必要に応じて処理
+        // Process as needed
    }

    fn on_turn_start(&mut self, turn: usize) {
@ -92,10 +92,10 @@ impl WorkerSubscriber for TestSubscriber {
 // Tests
 // =============================================================================

-/// WorkerSubscriberがテキストブロックイベントを正しく受け取ることを確認
+/// Verify that WorkerSubscriber correctly receives text block events
 #[tokio::test]
 async fn test_subscriber_text_block_events() {
-    // テキストレスポンスを含むイベントシーケンス
+    // Event sequence containing text response
    let events = vec![
        Event::text_block_start(0),
        Event::text_delta(0, "Hello, "),
@ -109,33 +109,33 @@ async fn test_subscriber_text_block_events() {
    let client = MockLlmClient::new(events);
    let mut worker = Worker::new(client);

-    // Subscriberを登録
+    // Register Subscriber
    let subscriber = TestSubscriber::new();
    let text_deltas = subscriber.text_deltas.clone();
    let text_completes = subscriber.text_completes.clone();
    worker.subscribe(subscriber);

-    // 実行
+    // Execute
    let result = worker.run("Greet me").await;

    assert!(result.is_ok(), "Worker should complete: {:?}", result);

-    // デルタが収集されていることを確認
+    // 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!");

-    // 完了テキストが収集されていることを確認
+    // Verify complete text was collected
    let completes = text_completes.lock().unwrap();
    assert_eq!(completes.len(), 1);
    assert_eq!(completes[0], "Hello, World!");
 }

-/// WorkerSubscriberがツール呼び出し完了イベントを正しく受け取ることを確認
+/// Verify that WorkerSubscriber correctly receives tool call complete events
 #[tokio::test]
 async fn test_subscriber_tool_call_complete() {
-    // ツール呼び出しを含むイベントシーケンス
+    // Event sequence containing tool call
    let events = vec![
        Event::tool_use_start(0, "call_123", "get_weather"),
        Event::tool_input_delta(0, r#"{"city":"#),
@ -149,15 +149,15 @@ async fn test_subscriber_tool_call_complete() {
    let client = MockLlmClient::new(events);
    let mut worker = Worker::new(client);

-    // Subscriberを登録
+    // Register Subscriber
    let subscriber = TestSubscriber::new();
    let tool_call_completes = subscriber.tool_call_completes.clone();
    worker.subscribe(subscriber);

-    // 実行
+    // Execute
    let _ = worker.run("Weather please").await;

-    // ツール呼び出し完了が収集されていることを確認
+    // 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");
@ -165,7 +165,7 @@ async fn test_subscriber_tool_call_complete() {
    assert_eq!(completes[0].input["city"], "Tokyo");
 }

-/// WorkerSubscriberがターンイベントを正しく受け取ることを確認
+/// Verify that WorkerSubscriber correctly receives turn events
 #[tokio::test]
 async fn test_subscriber_turn_events() {
    let events = vec![
@ -180,29 +180,29 @@ async fn test_subscriber_turn_events() {
    let client = MockLlmClient::new(events);
    let mut worker = Worker::new(client);

-    // Subscriberを登録
+    // Register Subscriber
    let subscriber = TestSubscriber::new();
    let turn_starts = subscriber.turn_starts.clone();
    let turn_ends = subscriber.turn_ends.clone();
    worker.subscribe(subscriber);

-    // 実行
+    // Execute
    let result = worker.run("Do something").await;

    assert!(result.is_ok());

-    // ターンイベントが収集されていることを確認
+    // 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); // 最初のターン
+    assert_eq!(starts[0], 0); // First turn

    assert_eq!(ends.len(), 1);
    assert_eq!(ends[0], 0);
 }

-/// WorkerSubscriberがUsageイベントを正しく受け取ることを確認
+/// Verify that WorkerSubscriber correctly receives Usage events
 #[tokio::test]
 async fn test_subscriber_usage_events() {
    let events = vec![
@ -218,15 +218,15 @@ async fn test_subscriber_usage_events() {
    let client = MockLlmClient::new(events);
    let mut worker = Worker::new(client);

-    // Subscriberを登録
+    // Register Subscriber
    let subscriber = TestSubscriber::new();
    let usage_events = subscriber.usage_events.clone();
    worker.subscribe(subscriber);

-    // 実行
+    // Execute
    let _ = worker.run("Hello").await;

-    // Usageイベントが収集されていることを確認
+    // Verify Usage events were collected
    let usages = usage_events.lock().unwrap();
    assert_eq!(usages.len(), 1);
    assert_eq!(usages[0].input_tokens, Some(100));
--- a/llm-worker/tests/tool_macro_test.rs
+++ b/llm-worker/tests/tool_macro_test.rs
@ -1,11 +1,11 @@
-//! ツールマクロのテスト
+//! Tool macro tests
 //!
-//! `#[tool_registry]` と `#[tool]` マクロの動作を確認する。
+//! Verify the behavior of `#[tool_registry]` and `#[tool]` macros.

 use std::sync::Arc;
 use std::sync::atomic::{AtomicUsize, Ordering};

-// マクロ展開に必要なインポート
+// Imports needed for macro expansion
 use schemars;
 use serde;

@ -15,7 +15,7 @@ use llm_worker_macros::tool_registry;
 // Test: Basic Tool Generation
 // =============================================================================

-/// シンプルなコンテキスト構造体
+/// Simple context struct
 #[derive(Clone)]
 struct SimpleContext {
    prefix: String,
@ -23,21 +23,21 @@ struct SimpleContext {

 #[tool_registry]
 impl SimpleContext {
-    /// メッセージに挨拶を追加する
+    /// Add greeting to message
    ///
-    /// 指定されたメッセージにプレフィックスを付けて返します。
+    /// Returns the message with a prefix added.
    #[tool]
    async fn greet(&self, message: String) -> String {
        format!("{}: {}", self.prefix, message)
    }

-    /// 二つの数を足す
+    /// Add two numbers
    #[tool]
    async fn add(&self, a: i32, b: i32) -> i32 {
        a + b
    }

-    /// 引数なしのツール
+    /// Tool with no arguments
    #[tool]
    async fn get_prefix(&self) -> String {
        self.prefix.clone()
@ -50,16 +50,16 @@ async fn test_basic_tool_generation() {
        prefix: "Hello".to_string(),
    };

-    // ファクトリメソッドでToolDefinitionを取得
+    // Get ToolDefinition from factory method
    let greet_definition = ctx.greet_definition();

-    // ファクトリを呼び出してMetaとToolを取得
+    // Call factory to get Meta and Tool
    let (meta, tool) = greet_definition();

-    // メタ情報の確認
+    // Verify meta information
    assert_eq!(meta.name, "greet");
    assert!(
-        meta.description.contains("メッセージに挨拶を追加する"),
+        meta.description.contains("Add greeting to message"),
        "Description should contain doc comment: {}",
        meta.description
    );
@ -73,7 +73,7 @@ async fn test_basic_tool_generation() {
        serde_json::to_string_pretty(&meta.input_schema).unwrap()
    );

-    // 実行テスト
+    // Execution test
    let result = tool.execute(r#"{"message": "World"}"#).await;
    assert!(result.is_ok(), "Should execute successfully");
    let output = result.unwrap();
@ -107,7 +107,7 @@ async fn test_no_arguments() {

    assert_eq!(meta.name, "get_prefix");

-    // 空のJSONオブジェクトで呼び出し
+    // Call with empty JSON object
    let result = tool.execute(r#"{}"#).await;
    assert!(result.is_ok());
    let output = result.unwrap();
@ -126,7 +126,7 @@ async fn test_invalid_arguments() {

    let (_, tool) = ctx.greet_definition()();

-    // 不正なJSON
+    // Invalid JSON
    let result = tool.execute(r#"{"wrong_field": "value"}"#).await;
    assert!(result.is_err(), "Should fail with invalid arguments");
 }
@ -149,7 +149,7 @@ impl std::fmt::Display for MyError {

 #[tool_registry]
 impl FallibleContext {
-    /// 与えられた値を検証する
+    /// Validate the given value
    #[tool]
    async fn validate(&self, value: i32) -> Result<String, MyError> {
        if value > 0 {
@ -198,7 +198,7 @@ struct SyncContext {

 #[tool_registry]
 impl SyncContext {
-    /// カウンターをインクリメントして返す (非async)
+    /// Increment counter and return (non-async)
    #[tool]
    fn increment(&self) -> usize {
        self.counter.fetch_add(1, Ordering::SeqCst) + 1
@ -213,7 +213,7 @@ async fn test_sync_method() {

    let (_, tool) = ctx.increment_definition()();

-    // 3回実行
+    // Execute 3 times
    let result1 = tool.execute(r#"{}"#).await;
    let result2 = tool.execute(r#"{}"#).await;
    let result3 = tool.execute(r#"{}"#).await;
@ -222,7 +222,7 @@ async fn test_sync_method() {
    assert!(result2.is_ok());
    assert!(result3.is_ok());

-    // カウンターは3になっているはず
+    // Counter should be 3
    assert_eq!(ctx.counter.load(Ordering::SeqCst), 3);
 }

@ -236,7 +236,7 @@ async fn test_tool_meta_immutability() {
        prefix: "Test".to_string(),
    };

-    // 2回取得しても同じメタ情報が得られることを確認
+    // Verify same meta info is returned on multiple calls
    let (meta1, _) = ctx.greet_definition()();
    let (meta2, _) = ctx.greet_definition()();

--- a/llm-worker/tests/ui/cache_locked_register_tool.rs
+++ b/llm-worker/tests/ui/cache_locked_register_tool.rs
@ -0,0 +1,11 @@
+use llm_worker::Worker;
+use llm_worker::llm_client::providers::ollama::OllamaClient;
+use std::sync::Arc;
+
+fn main() {
+    let client = OllamaClient::new("dummy-model");
+    let worker = Worker::new(client);
+    let mut locked = worker.lock();
+    let def: llm_worker::tool::ToolDefinition = Arc::new(|| panic!("unused"));
+    let _ = locked.register_tool(def);
+}
--- a/llm-worker/tests/ui/cache_locked_register_tool.stderr
+++ b/llm-worker/tests/ui/cache_locked_register_tool.stderr
@ -0,0 +1,8 @@
+error[E0599]: no method named `register_tool` found for struct `Worker<OllamaClient, CacheLocked>` in the current scope
+  --> tests/ui/cache_locked_register_tool.rs:10:20
+   |
+10 |     let _ = locked.register_tool(def);
+   |                    ^^^^^^^^^^^^^ method not found in `Worker<OllamaClient, CacheLocked>`
+   |
+   = note: the method was found for
+           - `Worker<C>`
--- a/llm-worker/tests/ui/tool_server_handle_register_tool.rs
+++ b/llm-worker/tests/ui/tool_server_handle_register_tool.rs
@ -0,0 +1,11 @@
+use llm_worker::Worker;
+use llm_worker::llm_client::providers::ollama::OllamaClient;
+use std::sync::Arc;
+
+fn main() {
+    let client = OllamaClient::new("dummy-model");
+    let worker = Worker::new(client);
+    let handle = worker.tool_server_handle();
+    let def: llm_worker::tool::ToolDefinition = Arc::new(|| panic!("unused"));
+    let _ = handle.register_tool(def);
+}
--- a/llm-worker/tests/ui/tool_server_handle_register_tool.stderr
+++ b/llm-worker/tests/ui/tool_server_handle_register_tool.stderr
@ -0,0 +1,13 @@
+error[E0624]: method `register_tool` is private
+  --> tests/ui/tool_server_handle_register_tool.rs:10:20
+   |
+10 |       let _ = handle.register_tool(def);
+   |                      ^^^^^^^^^^^^^ private method
+   |
+  ::: src/tool_server.rs
+   |
+   | /     pub(crate) fn register_tool(
+   | |         &self,
+   | |         factory: WorkerToolDefinition,
+   | |     ) -> Result<(), ToolServerError> {
+   | |____________________________________- private method defined here
--- a/llm-worker/tests/validation_test.rs
+++ b/llm-worker/tests/validation_test.rs
@ -3,16 +3,16 @@ use llm_worker::{Worker, WorkerError};

 #[test]
 fn test_openai_top_k_warning() {
-    // ダミーキーでクライアント作成（validate_configは通信しないため安全）
+    // Create client with dummy key (validate_config doesn't make network calls, so safe)
    let client = OpenAIClient::new("dummy-key", "gpt-4o");

-    // top_kを設定したWorkerを作成
-    let worker = Worker::new(client).top_k(50); // OpenAIはtop_k非対応
+    // Create Worker with top_k set (OpenAI doesn't support top_k)
+    let worker = Worker::new(client).top_k(50);

-    // validate()を実行
+    // Run validate()
    let result = worker.validate();

-    // エラーが返り、ConfigWarningsが含まれていることを確認
+    // Verify error is returned and ConfigWarnings is included
    match result {
        Err(WorkerError::ConfigWarnings(warnings)) => {
            assert_eq!(warnings.len(), 1);
@ -28,12 +28,12 @@ fn test_openai_top_k_warning() {
 fn test_openai_valid_config() {
    let client = OpenAIClient::new("dummy-key", "gpt-4o");

-    // validな設定（temperatureのみ）
+    // Valid configuration (temperature only)
    let worker = Worker::new(client).temperature(0.7);

-    // validate()を実行
+    // Run validate()
    let result = worker.validate();

-    // 成功を確認
+    // Verify success
    assert!(result.is_ok());
 }
--- a/llm-worker/tests/worker_fixtures.rs
+++ b/llm-worker/tests/worker_fixtures.rs
@ -1,7 +1,7 @@
-//! Workerフィクスチャベースの統合テスト
+//! Worker fixture-based integration tests
 //!
-//! 記録されたAPIレスポンスを使ってWorkerの動作をテストする。
-//! APIキー不要でローカルで実行可能。
+//! Tests Worker behavior using recorded API responses.
+//! Can run locally without API keys.

 mod common;

@ -14,12 +14,12 @@ use common::MockLlmClient;
 use llm_worker::Worker;
 use llm_worker::tool::{Tool, ToolDefinition, ToolError, ToolMeta};

-/// フィクスチャディレクトリのパス
+/// Fixture directory path
 fn fixtures_dir() -> std::path::PathBuf {
    Path::new(env!("CARGO_MANIFEST_DIR")).join("tests/fixtures/anthropic")
 }

-/// シンプルなテスト用ツール
+/// Simple test tool
 #[derive(Clone)]
 struct MockWeatherTool {
    call_count: Arc<AtomicUsize>,
@ -61,13 +61,13 @@ impl Tool for MockWeatherTool {
    async fn execute(&self, input_json: &str) -> Result<String, ToolError> {
        self.call_count.fetch_add(1, Ordering::SeqCst);

-        // 入力をパース
+        // Parse input
        let input: serde_json::Value = serde_json::from_str(input_json)
            .map_err(|e| ToolError::InvalidArgument(e.to_string()))?;

        let city = input["city"].as_str().unwrap_or("Unknown");

-        // モックのレスポンスを返す
+        // Return mock response
        Ok(format!("Weather in {}: Sunny, 22°C", city))
    }
 }
@ -76,12 +76,12 @@ impl Tool for MockWeatherTool {
 // Basic Fixture Tests
 // =============================================================================

-/// MockLlmClientがJSONLフィクスチャファイルから正しくイベントをロードできることを確認
+/// Verify that MockLlmClient can correctly load events from JSONL fixture files
 ///
-/// 既存のanthropic_*.jsonlファイルを使用し、イベントがパース・ロードされることを検証する。
+/// Uses existing anthropic_*.jsonl files to verify events are parsed and loaded.
 #[test]
 fn test_mock_client_from_fixture() {
-    // 既存のフィクスチャをロード
+    // Load existing fixture
    let fixture_path = fixtures_dir().join("anthropic_1767624445.jsonl");
    if !fixture_path.exists() {
        println!("Fixture not found, skipping test");
@ -93,14 +93,14 @@ fn test_mock_client_from_fixture() {
    println!("Loaded {} events from fixture", client.event_count());
 }

-/// MockLlmClientが直接指定されたイベントリストで正しく動作することを確認
+/// Verify that MockLlmClient works correctly with directly specified event lists
 ///
-/// fixtureファイルを使わず、プログラムでイベントを構築してクライアントを作成する。
+/// Creates a client with programmatically constructed events instead of using fixture files.
 #[test]
 fn test_mock_client_from_events() {
    use llm_worker::llm_client::event::Event;

-    // 直接イベントを指定
+    // Specify events directly
    let events = vec![
        Event::text_block_start(0),
        Event::text_delta(0, "Hello!"),
@ -115,10 +115,10 @@ fn test_mock_client_from_events() {
 // Worker Tests with Fixtures
 // =============================================================================

-/// Workerがシンプルなテキストレスポンスを正しく処理できることを確認
+/// Verify that Worker can correctly process simple text responses
 ///
-/// simple_text.jsonlフィクスチャを使用し、ツール呼び出しなしのシナリオをテストする。
-/// フィクスチャがない場合はスキップされる。
+/// Uses simple_text.jsonl fixture to test scenarios without tool calls.
+/// Skipped if fixture is not present.
 #[tokio::test]
 async fn test_worker_simple_text_response() {
    let fixture_path = fixtures_dir().join("simple_text.jsonl");
@ -131,16 +131,16 @@ async fn test_worker_simple_text_response() {
    let client = MockLlmClient::from_fixture(&fixture_path).unwrap();
    let mut worker = Worker::new(client);

-    // シンプルなメッセージを送信
+    // Send a simple message
    let result = worker.run("Hello").await;

    assert!(result.is_ok(), "Worker should complete successfully");
 }

-/// Workerがツール呼び出しを含むレスポンスを正しく処理できることを確認
+/// Verify that Worker can correctly process responses containing tool calls
 ///
-/// tool_call.jsonlフィクスチャを使用し、MockWeatherToolが呼び出されることをテストする。
-/// max_turns=1に設定し、ツール実行後のループを防止。
+/// Uses tool_call.jsonl fixture to test that MockWeatherTool is called.
+/// Sets max_turns=1 to prevent loop after tool execution.
 #[tokio::test]
 async fn test_worker_tool_call() {
    let fixture_path = fixtures_dir().join("tool_call.jsonl");
@ -153,32 +153,32 @@ async fn test_worker_tool_call() {
    let client = MockLlmClient::from_fixture(&fixture_path).unwrap();
    let mut worker = Worker::new(client);

-    // ツールを登録
+    // Register tool
    let weather_tool = MockWeatherTool::new();
    let tool_for_check = weather_tool.clone();
    worker.register_tool(weather_tool.definition()).unwrap();

-    // メッセージを送信
+    // Send message
    let _result = worker.run("What's the weather in Tokyo?").await;

-    // ツールが呼び出されたことを確認
-    // Note: max_turns=1なのでツール結果後のリクエストは送信されない
+    // Verify tool was called
+    // Note: max_turns=1 so no request is sent after tool result
    let call_count = tool_for_check.get_call_count();
    println!("Tool was called {} times", call_count);

-    // フィクスチャにToolUseが含まれていればツールが呼び出されるはず
-    // ただしmax_turns=1なので1回で終了
+    // Tool should be called if fixture contains ToolUse
+    // But ends after 1 turn due to max_turns=1
 }

-/// fixtureファイルなしでWorkerが動作することを確認
+/// Verify that Worker works without fixture files
 ///
-/// プログラムでイベントシーケンスを構築し、MockLlmClientに渡してテストする。
-/// テストの独立性を高め、外部ファイルへの依存を排除したい場合に有用。
+/// Constructs event sequence programmatically and passes to MockLlmClient.
+/// Useful when test independence is needed and external file dependency should be eliminated.
 #[tokio::test]
 async fn test_worker_with_programmatic_events() {
    use llm_worker::llm_client::event::{Event, ResponseStatus, StatusEvent};

-    // プログラムでイベントシーケンスを構築
+    // Construct event sequence programmatically
    let events = vec![
        Event::text_block_start(0),
        Event::text_delta(0, "Hello, "),
@ -197,16 +197,16 @@ async fn test_worker_with_programmatic_events() {
    assert!(result.is_ok(), "Worker should complete successfully");
 }

-/// ToolCallCollectorがToolUseブロックイベントから正しくToolCallを収集することを確認
+/// Verify that ToolCallCollector correctly collects ToolCall from ToolUse block events
 ///
-/// Timelineにイベントをディスパッチし、ToolCallCollectorが
-/// id, name, input（JSON）を正しく抽出できることを検証する。
+/// Dispatches events to Timeline and verifies ToolCallCollector
+/// correctly extracts id, name, and input (JSON).
 #[tokio::test]
 async fn test_tool_call_collector_integration() {
    use llm_worker::llm_client::event::Event;
    use llm_worker::timeline::{Timeline, ToolCallCollector};

-    // ToolUseブロックを含むイベントシーケンス
+    // Event sequence containing ToolUse block
    let events = vec![
        Event::tool_use_start(0, "call_123", "get_weather"),
        Event::tool_input_delta(0, r#"{"city":"#),
@ -218,13 +218,13 @@ async fn test_tool_call_collector_integration() {
    let mut timeline = Timeline::new();
    timeline.on_tool_use_block(collector.clone());

-    // イベントをディスパッチ
+    // Dispatch events
    for event in &events {
        let timeline_event: llm_worker::timeline::event::Event = event.clone().into();
        timeline.dispatch(&timeline_event);
    }

-    // 収集されたToolCallを確認
+    // Verify collected ToolCall
    let calls = collector.take_collected();
    assert_eq!(calls.len(), 1, "Should collect one tool call");
    assert_eq!(calls[0].name, "get_weather");
--- a/llm-worker/tests/worker_state_test.rs
+++ b/llm-worker/tests/worker_state_test.rs
@ -1,20 +1,25 @@
-//! Worker状態管理のテスト
+//! Worker state management tests
 //!
-//! Type-stateパターン（Mutable/CacheLocked）による状態遷移と
-//! ターン間の状態保持をテストする。
+//! Tests for state transitions using the Type-state pattern (Mutable/CacheLocked)
+//! and state preservation between turns.

 mod common;

+use std::sync::Arc;
+use std::sync::atomic::{AtomicUsize, Ordering};
+
+use async_trait::async_trait;
 use common::MockLlmClient;
 use llm_worker::Worker;
 use llm_worker::llm_client::event::{Event, ResponseStatus, StatusEvent};
-use llm_worker::{Message, MessageContent};
+use llm_worker::tool::{Tool, ToolDefinition, ToolError, ToolMeta};
+use llm_worker::Item;

 // =============================================================================
-// Mutable状態のテスト
+// Mutable State Tests
 // =============================================================================

-/// Mutable状態でシステムプロンプトを設定できることを確認
+/// Verify that system prompt can be set in Mutable state
 #[test]
 fn test_mutable_set_system_prompt() {
    let client = MockLlmClient::new(vec![]);
@ -29,114 +34,164 @@ fn test_mutable_set_system_prompt() {
    );
 }

-/// Mutable状態で履歴を自由に編集できることを確認
+/// Verify that history can be freely edited in Mutable state
 #[test]
 fn test_mutable_history_manipulation() {
    let client = MockLlmClient::new(vec![]);
    let mut worker = Worker::new(client);

-    // 初期状態は空
+    // Initial state is empty
    assert!(worker.history().is_empty());

-    // 履歴を追加
-    worker.push_message(Message::user("Hello"));
-    worker.push_message(Message::assistant("Hi there!"));
+    // Add to history
+    worker.push_item(Item::user_message("Hello"));
+    worker.push_item(Item::assistant_message("Hi there!"));
    assert_eq!(worker.history().len(), 2);

-    // 履歴への可変アクセス
-    worker.history_mut().push(Message::user("How are you?"));
+    // Mutable access to history
+    worker.history_mut().push(Item::user_message("How are you?"));
    assert_eq!(worker.history().len(), 3);

-    // 履歴をクリア
+    // Clear history
    worker.clear_history();
    assert!(worker.history().is_empty());

-    // 履歴を設定
-    let messages = vec![Message::user("Test"), Message::assistant("Response")];
-    worker.set_history(messages);
+    // Set history
+    let items = vec![Item::user_message("Test"), Item::assistant_message("Response")];
+    worker.set_history(items);
    assert_eq!(worker.history().len(), 2);
 }

-/// ビルダーパターンでWorkerを構築できることを確認
+/// Verify that Worker can be constructed using builder pattern
 #[test]
 fn test_mutable_builder_pattern() {
    let client = MockLlmClient::new(vec![]);
    let worker = Worker::new(client)
        .system_prompt("System prompt")
-        .with_message(Message::user("Hello"))
-        .with_message(Message::assistant("Hi!"))
-        .with_messages(vec![
-            Message::user("How are you?"),
-            Message::assistant("I'm fine!"),
+        .with_item(Item::user_message("Hello"))
+        .with_item(Item::assistant_message("Hi!"))
+        .with_items(vec![
+            Item::user_message("How are you?"),
+            Item::assistant_message("I'm fine!"),
        ]);

    assert_eq!(worker.get_system_prompt(), Some("System prompt"));
    assert_eq!(worker.history().len(), 4);
 }

-/// extend_historyで複数メッセージを追加できることを確認
+/// Verify that multiple items can be added with extend_history
 #[test]
 fn test_mutable_extend_history() {
    let client = MockLlmClient::new(vec![]);
    let mut worker = Worker::new(client);

-    worker.push_message(Message::user("First"));
+    worker.push_item(Item::user_message("First"));

    worker.extend_history(vec![
-        Message::assistant("Response 1"),
-        Message::user("Second"),
-        Message::assistant("Response 2"),
+        Item::assistant_message("Response 1"),
+        Item::user_message("Second"),
+        Item::assistant_message("Response 2"),
    ]);

    assert_eq!(worker.history().len(), 4);
 }

+#[derive(Clone)]
+struct CountingTool {
+    name: String,
+    calls: Arc<AtomicUsize>,
+}
+
+impl CountingTool {
+    fn new(name: impl Into<String>) -> Self {
+        Self {
+            name: name.into(),
+            calls: Arc::new(AtomicUsize::new(0)),
+        }
+    }
+
+    fn definition(&self) -> ToolDefinition {
+        let tool = self.clone();
+        Arc::new(move || {
+            (
+                ToolMeta::new(&tool.name)
+                    .description("Counting tool")
+                    .input_schema(serde_json::json!({"type":"object","properties":{}})),
+                Arc::new(tool.clone()) as Arc<dyn Tool>,
+            )
+        })
+    }
+
+    fn call_count(&self) -> usize {
+        self.calls.load(Ordering::SeqCst)
+    }
+}
+
+#[async_trait]
+impl Tool for CountingTool {
+    async fn execute(&self, _input_json: &str) -> Result<String, ToolError> {
+        self.calls.fetch_add(1, Ordering::SeqCst);
+        Ok(format!("{}-ok", self.name))
+    }
+}
+
+/// Verify that tools can be registered in Mutable state.
+#[test]
+fn test_mutable_can_register_tool() {
+    let client = MockLlmClient::new(vec![]);
+    let mut worker = Worker::new(client);
+    let tool = CountingTool::new("count_tool");
+
+    let result = worker.register_tool(tool.definition());
+    assert!(result.is_ok(), "Mutable should allow tool registration");
+}
+
 // =============================================================================
-// 状態遷移テスト
+// State Transition Tests
 // =============================================================================

-/// lock()でMutable -> CacheLocked状態に遷移することを確認
+/// Verify that lock() transitions from Mutable -> CacheLocked state
 #[test]
 fn test_lock_transition() {
    let client = MockLlmClient::new(vec![]);
    let mut worker = Worker::new(client);

    worker.set_system_prompt("System");
-    worker.push_message(Message::user("Hello"));
-    worker.push_message(Message::assistant("Hi"));
+    worker.push_item(Item::user_message("Hello"));
+    worker.push_item(Item::assistant_message("Hi"));

-    // ロック
+    // Lock
    let locked_worker = worker.lock();

-    // CacheLocked状態でも履歴とシステムプロンプトにアクセス可能
+    // History and system prompt are still accessible in CacheLocked state
    assert_eq!(locked_worker.get_system_prompt(), Some("System"));
    assert_eq!(locked_worker.history().len(), 2);
    assert_eq!(locked_worker.locked_prefix_len(), 2);
 }

-/// unlock()でCacheLocked -> Mutable状態に遷移することを確認
+/// Verify that unlock() transitions from CacheLocked -> Mutable state
 #[test]
 fn test_unlock_transition() {
    let client = MockLlmClient::new(vec![]);
    let mut worker = Worker::new(client);

-    worker.push_message(Message::user("Hello"));
+    worker.push_item(Item::user_message("Hello"));
    let locked_worker = worker.lock();

-    // アンロック
+    // Unlock
    let mut worker = locked_worker.unlock();

-    // Mutable状態に戻ったので履歴操作が可能
-    worker.push_message(Message::assistant("Hi"));
+    // History operations are available again in Mutable state
+    worker.push_item(Item::assistant_message("Hi"));
    worker.clear_history();
    assert!(worker.history().is_empty());
 }

 // =============================================================================
-// ターン実行と状態保持のテスト
+// Turn Execution and State Preservation Tests
 // =============================================================================

-/// Mutable状態でターンを実行し、履歴が正しく更新されることを確認
+/// Verify that history is correctly updated after running a turn in Mutable state
 #[tokio::test]
 async fn test_mutable_run_updates_history() {
    let events = vec![
@ -151,33 +206,27 @@ async fn test_mutable_run_updates_history() {
    let client = MockLlmClient::new(events);
    let mut worker = Worker::new(client);

-    // 実行
+    // Execute
    let result = worker.run("Hi there").await;
    assert!(result.is_ok());

-    // 履歴が更新されている
+    // History is updated
    let history = worker.history();
    assert_eq!(history.len(), 2); // user + assistant

-    // ユーザーメッセージ
-    assert!(matches!(
-        &history[0].content,
-        MessageContent::Text(t) if t == "Hi there"
-    ));
+    // User message
+    assert_eq!(history[0].as_text(), Some("Hi there"));

-    // アシスタントメッセージ
-    assert!(matches!(
-        &history[1].content,
-        MessageContent::Text(t) if t == "Hello, I'm an assistant!"
-    ));
+    // Assistant message
+    assert_eq!(history[1].as_text(), Some("Hello, I'm an assistant!"));
 }

-/// CacheLocked状態で複数ターンを実行し、履歴が正しく累積することを確認
+/// Verify that history accumulates correctly over multiple turns in CacheLocked state
 #[tokio::test]
 async fn test_locked_multi_turn_history_accumulation() {
-    // 2回のリクエストに対応するレスポンスを準備
+    // Prepare responses for 2 requests
    let client = MockLlmClient::with_responses(vec![
-        // 1回目のレスポンス
+        // First response
        vec![
            Event::text_block_start(0),
            Event::text_delta(0, "Nice to meet you!"),
@ -186,7 +235,7 @@ async fn test_locked_multi_turn_history_accumulation() {
                status: ResponseStatus::Completed,
            }),
        ],
-        // 2回目のレスポンス
+        // Second response
        vec![
            Event::text_block_start(0),
            Event::text_delta(0, "I can help with that."),
@ -199,37 +248,37 @@ async fn test_locked_multi_turn_history_accumulation() {

    let worker = Worker::new(client).system_prompt("You are helpful.");

-    // ロック（システムプロンプト設定後）
+    // Lock (after setting system prompt)
    let mut locked_worker = worker.lock();
-    assert_eq!(locked_worker.locked_prefix_len(), 0); // メッセージはまだない
+    assert_eq!(locked_worker.locked_prefix_len(), 0); // No items yet

-    // 1ターン目
+    // Turn 1
    let result1 = locked_worker.run("Hello!").await;
    assert!(result1.is_ok());
    assert_eq!(locked_worker.history().len(), 2); // user + assistant

-    // 2ターン目
+    // Turn 2
    let result2 = locked_worker.run("Can you help me?").await;
    assert!(result2.is_ok());
    assert_eq!(locked_worker.history().len(), 4); // 2 * (user + assistant)

-    // 履歴の内容を確認
+    // Verify history contents
    let history = locked_worker.history();

-    // 1ターン目のユーザーメッセージ
-    assert!(matches!(&history[0].content, MessageContent::Text(t) if t == "Hello!"));
+    // Turn 1 user message
+    assert_eq!(history[0].as_text(), Some("Hello!"));

-    // 1ターン目のアシスタントメッセージ
-    assert!(matches!(&history[1].content, MessageContent::Text(t) if t == "Nice to meet you!"));
+    // Turn 1 assistant message
+    assert_eq!(history[1].as_text(), Some("Nice to meet you!"));

-    // 2ターン目のユーザーメッセージ
-    assert!(matches!(&history[2].content, MessageContent::Text(t) if t == "Can you help me?"));
+    // Turn 2 user message
+    assert_eq!(history[2].as_text(), Some("Can you help me?"));

-    // 2ターン目のアシスタントメッセージ
-    assert!(matches!(&history[3].content, MessageContent::Text(t) if t == "I can help with that."));
+    // Turn 2 assistant message
+    assert_eq!(history[3].as_text(), Some("I can help with that."));
 }

-/// locked_prefix_lenがロック時点の履歴長を正しく記録することを確認
+/// Verify that locked_prefix_len correctly records history length at lock time
 #[tokio::test]
 async fn test_locked_prefix_len_tracking() {
    let client = MockLlmClient::with_responses(vec![
@ -253,25 +302,25 @@ async fn test_locked_prefix_len_tracking() {

    let mut worker = Worker::new(client);

-    // 事前にメッセージを追加
-    worker.push_message(Message::user("Pre-existing message 1"));
-    worker.push_message(Message::assistant("Pre-existing response 1"));
+    // Add items beforehand
+    worker.push_item(Item::user_message("Pre-existing message 1"));
+    worker.push_item(Item::assistant_message("Pre-existing response 1"));

    assert_eq!(worker.history().len(), 2);

-    // ロック
+    // Lock
    let mut locked_worker = worker.lock();
-    assert_eq!(locked_worker.locked_prefix_len(), 2); // ロック時点で2メッセージ
+    assert_eq!(locked_worker.locked_prefix_len(), 2); // 2 items at lock time

-    // ターン実行
+    // Execute turn
    locked_worker.run("New message").await.unwrap();

-    // 履歴は増えるが、locked_prefix_lenは変わらない
+    // History grows but locked_prefix_len remains unchanged
    assert_eq!(locked_worker.history().len(), 4); // 2 + 2
-    assert_eq!(locked_worker.locked_prefix_len(), 2); // 変わらない
+    assert_eq!(locked_worker.locked_prefix_len(), 2); // Unchanged
 }

-/// ターンカウントが正しくインクリメントされることを確認
+/// Verify that turn count is correctly incremented
 #[tokio::test]
 async fn test_turn_count_increment() {
    let client = MockLlmClient::with_responses(vec![
@ -304,7 +353,7 @@ async fn test_turn_count_increment() {
    assert_eq!(worker.turn_count(), 2);
 }

-/// unlock後に履歴を編集し、再度lockできることを確認
+/// Verify that history can be edited after unlock and re-locked
 #[tokio::test]
 async fn test_unlock_edit_relock() {
    let client = MockLlmClient::with_responses(vec![vec![
@ -317,30 +366,91 @@ async fn test_unlock_edit_relock() {
    ]]);

    let worker = Worker::new(client)
-        .with_message(Message::user("Hello"))
-        .with_message(Message::assistant("Hi"));
+        .with_item(Item::user_message("Hello"))
+        .with_item(Item::assistant_message("Hi"));

-    // ロック -> アンロック
+    // Lock -> Unlock
    let locked = worker.lock();
    assert_eq!(locked.locked_prefix_len(), 2);

    let mut unlocked = locked.unlock();

-    // 履歴を編集
+    // Edit history
    unlocked.clear_history();
-    unlocked.push_message(Message::user("Fresh start"));
+    unlocked.push_item(Item::user_message("Fresh start"));

-    // 再ロック
+    // Re-lock
    let relocked = unlocked.lock();
    assert_eq!(relocked.history().len(), 1);
    assert_eq!(relocked.locked_prefix_len(), 1);
 }

+/// Verify that tools registered before lock and after unlock remain effective.
+#[tokio::test]
+async fn test_lock_unlock_relock_tools_remain_effective() {
+    let client = MockLlmClient::with_responses(vec![
+        vec![
+            Event::tool_use_start(0, "call_1", "tool_a"),
+            Event::tool_input_delta(0, r#"{}"#),
+            Event::tool_use_stop(0),
+            Event::Status(StatusEvent {
+                status: ResponseStatus::Completed,
+            }),
+        ],
+        vec![
+            Event::text_block_start(0),
+            Event::text_delta(0, "done-a"),
+            Event::text_block_stop(0, None),
+            Event::Status(StatusEvent {
+                status: ResponseStatus::Completed,
+            }),
+        ],
+        vec![
+            Event::tool_use_start(0, "call_2", "tool_b"),
+            Event::tool_input_delta(0, r#"{}"#),
+            Event::tool_use_stop(0),
+            Event::Status(StatusEvent {
+                status: ResponseStatus::Completed,
+            }),
+        ],
+        vec![
+            Event::text_block_start(0),
+            Event::text_delta(0, "done-b"),
+            Event::text_block_stop(0, None),
+            Event::Status(StatusEvent {
+                status: ResponseStatus::Completed,
+            }),
+        ],
+    ]);
+
+    let mut worker = Worker::new(client);
+    let tool_a = CountingTool::new("tool_a");
+    worker
+        .register_tool(tool_a.definition())
+        .expect("register tool_a should succeed");
+
+    let mut locked = worker.lock();
+    locked.run("first").await.expect("first run");
+    assert_eq!(tool_a.call_count(), 1, "tool_a should be called once");
+
+    let mut unlocked = locked.unlock();
+    let tool_b = CountingTool::new("tool_b");
+    unlocked
+        .register_tool(tool_b.definition())
+        .expect("register tool_b after unlock should succeed");
+
+    let mut relocked = unlocked.lock();
+    relocked.run("second").await.expect("second run");
+
+    assert_eq!(tool_a.call_count(), 1, "tool_a should not be called again");
+    assert_eq!(tool_b.call_count(), 1, "tool_b should be called once");
+}
+
 // =============================================================================
-// システムプロンプト保持のテスト
+// System Prompt Preservation Tests
 // =============================================================================

-/// CacheLocked状態でもシステムプロンプトが保持されることを確認
+/// Verify that system prompt is preserved in CacheLocked state
 #[test]
 fn test_system_prompt_preserved_in_locked_state() {
    let client = MockLlmClient::new(vec![]);
@ -356,7 +466,7 @@ fn test_system_prompt_preserved_in_locked_state() {
    );
 }

-/// unlock -> 再lock でシステムプロンプトを変更できることを確認
+/// Verify that system prompt can be changed after unlock -> re-lock
 #[test]
 fn test_system_prompt_change_after_unlock() {
    let client = MockLlmClient::new(vec![]);
Author	SHA1	Message	Date
Hare	cba96e4f46	add state constraint regression and compile-fail tests	2026-02-19 18:31:49 +09:00
Hare	d63b4ea470	restrict tool registration to mutable state	2026-02-19 18:29:02 +09:00
Hare	b12785ed93	refactor worker tool execution through tool server	2026-02-19 18:19:16 +09:00
Hare	3c62970967	feat: OpenResponses	2026-02-19 17:37:29 +09:00
Hare	6c43ac9969	docs: Translate ja -> en	2026-01-16 16:58:03 +09:00
Hare	6d87da90d1	Bump llm-worker to 0.2.1	2026-01-14 16:30:41 +09:00