From 4c62457e3a38951d566f1d16a551c3dfb57d44e7 Mon Sep 17 00:00:00 2001
From: mizuki-y <mizuki-y@syati.info>
Date: Mon, 12 Oct 2026 19:41:17 +0900
Subject: [PATCH 1/3] refactor: move the core gem into its own
 structured_params/ folder

Mirror structured_params-openapi/ so the repository holds one folder per gem
(as sentry-ruby does). The repository root keeps what is shared: README,
Gemfile, Rakefile, Steepfile, lefthook.yml and the RuboCop configuration.

- lib/, sig/, spec/, docs/, the gemspec, CHANGELOG.md and .rspec move to
  structured_params/; git detects the files as renames
- Rakefile: spec tasks per gem and Bundler::GemHelper for the core gem, so
  rake build/release keep acting on structured_params
- RuboCop: set TargetRubyVersion (it can no longer be inferred from a root
  gemspec) and make the spec excludes match nested spec folders
- release/tagging workflows: new paths for the version file, CHANGELOG and
  the gem build (run from the gem folder)
- README links, AGENTS.md, CONTRIBUTING.md, Procfile.dev, lefthook.yml updated

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
---
 .github/workflows/release.yml                 | 13 +++--
 .github/workflows/tagging.yml                 |  4 +-
 .gitignore                                    |  2 +-
 .rubocop.yml                                  | 10 +++-
 .rubocop_rbs.yml                              |  4 +-
 AGENTS.md                                     | 35 ++++++------
 CONTRIBUTING.md                               | 55 +++++++++++--------
 Gemfile                                       |  2 +-
 Procfile.dev                                  |  3 +-
 README.md                                     | 14 ++---
 README_ja.md                                  | 14 ++---
 Rakefile                                      | 27 +++++----
 Steepfile                                     |  6 +-
 bin/console                                   |  2 +-
 lefthook.yml                                  |  4 +-
 .rspec => structured_params/.rspec            |  0
 .../CHANGELOG.md                              |  0
 structured_params/LICENSE.txt                 | 21 +++++++
 .../docs}/basic-usage.md                      |  0
 .../docs}/error-handling.md                   |  0
 .../docs}/form-objects.md                     |  0
 .../docs}/installation.md                     |  0
 .../docs}/serialization.md                    |  0
 .../docs}/strong-parameters.md                |  0
 .../docs}/validation.md                       |  0
 .../lib}/structured_params.rb                 |  0
 .../structured_params/attribute_methods.rb    |  0
 .../lib}/structured_params/errors.rb          |  0
 .../lib}/structured_params/i18n.rb            |  0
 .../lib}/structured_params/params.rb          |  0
 .../lib}/structured_params/type/array.rb      |  0
 .../lib}/structured_params/type/object.rb     |  0
 .../lib}/structured_params/validations.rb     |  0
 .../lib}/structured_params/version.rb         |  0
 .../sig}/structured_params.rbs                |  0
 .../structured_params/attribute_methods.rbs   |  0
 .../sig}/structured_params/errors.rbs         |  0
 .../sig}/structured_params/i18n.rbs           |  0
 .../sig}/structured_params/params.rbs         |  0
 .../sig}/structured_params/type/array.rbs     |  0
 .../sig}/structured_params/type/object.rbs    |  0
 .../sig}/structured_params/validations.rbs    |  0
 .../sig}/structured_params/version.rbs        |  0
 .../spec}/attribute_methods_spec.rb           |  0
 .../spec}/errors_spec.rb                      |  0
 .../spec}/factories/address_parameters.rb     |  0
 .../spec}/factories/hobby_parameters.rb       |  0
 .../spec}/factories/user_parameters.rb        |  0
 .../spec}/form_object_spec.rb                 |  0
 {spec => structured_params/spec}/i18n_spec.rb |  0
 .../spec}/params_spec.rb                      |  0
 .../spec}/permit_spec.rb                      |  0
 .../spec}/spec_helper.rb                      |  0
 .../spec}/support/locales/ja.yml              |  0
 .../support/shared_contexts/ja_locale.rb      |  0
 .../test_classes/form_object_classes.rb       |  0
 .../support/test_classes/params_classes.rb    |  0
 .../spec}/type/array_spec.rb                  |  0
 .../spec}/type/object_spec.rb                 |  0
 .../spec}/validations_spec.rb                 |  0
 .../structured_params.gemspec                 |  2 +-
 61 files changed, 133 insertions(+), 85 deletions(-)
 rename .rspec => structured_params/.rspec (100%)
 rename CHANGELOG.md => structured_params/CHANGELOG.md (100%)
 create mode 100644 structured_params/LICENSE.txt
 rename {docs => structured_params/docs}/basic-usage.md (100%)
 rename {docs => structured_params/docs}/error-handling.md (100%)
 rename {docs => structured_params/docs}/form-objects.md (100%)
 rename {docs => structured_params/docs}/installation.md (100%)
 rename {docs => structured_params/docs}/serialization.md (100%)
 rename {docs => structured_params/docs}/strong-parameters.md (100%)
 rename {docs => structured_params/docs}/validation.md (100%)
 rename {lib => structured_params/lib}/structured_params.rb (100%)
 rename {lib => structured_params/lib}/structured_params/attribute_methods.rb (100%)
 rename {lib => structured_params/lib}/structured_params/errors.rb (100%)
 rename {lib => structured_params/lib}/structured_params/i18n.rb (100%)
 rename {lib => structured_params/lib}/structured_params/params.rb (100%)
 rename {lib => structured_params/lib}/structured_params/type/array.rb (100%)
 rename {lib => structured_params/lib}/structured_params/type/object.rb (100%)
 rename {lib => structured_params/lib}/structured_params/validations.rb (100%)
 rename {lib => structured_params/lib}/structured_params/version.rb (100%)
 rename {sig => structured_params/sig}/structured_params.rbs (100%)
 rename {sig => structured_params/sig}/structured_params/attribute_methods.rbs (100%)
 rename {sig => structured_params/sig}/structured_params/errors.rbs (100%)
 rename {sig => structured_params/sig}/structured_params/i18n.rbs (100%)
 rename {sig => structured_params/sig}/structured_params/params.rbs (100%)
 rename {sig => structured_params/sig}/structured_params/type/array.rbs (100%)
 rename {sig => structured_params/sig}/structured_params/type/object.rbs (100%)
 rename {sig => structured_params/sig}/structured_params/validations.rbs (100%)
 rename {sig => structured_params/sig}/structured_params/version.rbs (100%)
 rename {spec => structured_params/spec}/attribute_methods_spec.rb (100%)
 rename {spec => structured_params/spec}/errors_spec.rb (100%)
 rename {spec => structured_params/spec}/factories/address_parameters.rb (100%)
 rename {spec => structured_params/spec}/factories/hobby_parameters.rb (100%)
 rename {spec => structured_params/spec}/factories/user_parameters.rb (100%)
 rename {spec => structured_params/spec}/form_object_spec.rb (100%)
 rename {spec => structured_params/spec}/i18n_spec.rb (100%)
 rename {spec => structured_params/spec}/params_spec.rb (100%)
 rename {spec => structured_params/spec}/permit_spec.rb (100%)
 rename {spec => structured_params/spec}/spec_helper.rb (100%)
 rename {spec => structured_params/spec}/support/locales/ja.yml (100%)
 rename {spec => structured_params/spec}/support/shared_contexts/ja_locale.rb (100%)
 rename {spec => structured_params/spec}/support/test_classes/form_object_classes.rb (100%)
 rename {spec => structured_params/spec}/support/test_classes/params_classes.rb (100%)
 rename {spec => structured_params/spec}/type/array_spec.rb (100%)
 rename {spec => structured_params/spec}/type/object_spec.rb (100%)
 rename {spec => structured_params/spec}/validations_spec.rb (100%)
 rename structured_params.gemspec => structured_params/structured_params.gemspec (96%)

diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index dca9870..ab69971 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -56,21 +56,21 @@ jobs:
           echo "" >> temp_changelog.md
           
           # Prepend to existing CHANGELOG (skip the header)
-          if [ -f CHANGELOG.md ]; then
-            tail -n +3 CHANGELOG.md >> temp_changelog.md
+          if [ -f structured_params/CHANGELOG.md ]; then
+            tail -n +3 structured_params/CHANGELOG.md >> temp_changelog.md
           fi
           
           # Add header back
-          echo "# Changelog" > CHANGELOG.md
-          echo "" >> CHANGELOG.md
-          cat temp_changelog.md >> CHANGELOG.md
+          echo "# Changelog" > structured_params/CHANGELOG.md
+          echo "" >> structured_params/CHANGELOG.md
+          cat temp_changelog.md >> structured_params/CHANGELOG.md
           
           # Clean up temporary file
           rm -f temp_changelog.md
 
       - name: Commit CHANGELOG update
         run: |
-          git add CHANGELOG.md
+          git add structured_params/CHANGELOG.md
           if git diff --staged --quiet; then
             echo "No CHANGELOG changes to commit"
           else
@@ -85,6 +85,7 @@ jobs:
           bundler-cache: true
 
       - name: Build gem
+        working-directory: structured_params
         run: |
           gem build structured_params.gemspec
 
diff --git a/.github/workflows/tagging.yml b/.github/workflows/tagging.yml
index 8fc1e11..45f9057 100644
--- a/.github/workflows/tagging.yml
+++ b/.github/workflows/tagging.yml
@@ -32,11 +32,11 @@ jobs:
       - name: Update version file
         run: |
           VERSION="${{ steps.extract_version.outputs.version }}"
-          sed -i "s/VERSION = '[^']*'/VERSION = '$VERSION'/" lib/structured_params/version.rb
+          sed -i "s/VERSION = '[^']*'/VERSION = '$VERSION'/" structured_params/lib/structured_params/version.rb
 
       - name: Commit version update
         run: |
-          git add lib/structured_params/version.rb
+          git add structured_params/lib/structured_params/version.rb
           if git diff --staged --quiet; then
             echo "No version changes to commit"
           else
diff --git a/.gitignore b/.gitignore
index 46688bd..6e5774c 100644
--- a/.gitignore
+++ b/.gitignore
@@ -18,7 +18,7 @@ Gemfile.lock
 /.config
 /coverage/
 /InstalledFiles
-/pkg/
+pkg/
 /spec/reports/
 /spec/examples.txt
 /test/tmp/
diff --git a/.rubocop.yml b/.rubocop.yml
index 03edc96..8d1cae2 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -5,10 +5,18 @@ plugins:
 
 AllCops:
   NewCops: enable
+  # Both gemspecs require Ruby >= 3.2.0; RuboCop cannot infer it from a gemspec in a subdirectory.
+  TargetRubyVersion: 3.2
 
 Style/OneClassPerFile:
   Exclude:
-    - spec/support/test_classes/**/*
+    - '**/spec/support/test_classes/**/*'
+
+# RuboCop's default excludes match spec/ at the repository root only.
+Style/Documentation:
+  Exclude:
+    - '**/spec/**/*'
+    - '**/test/**/*'
 
 Layout/LeadingCommentSpace:
   Enabled: false
diff --git a/.rubocop_rbs.yml b/.rubocop_rbs.yml
index 704a13a..3171f62 100644
--- a/.rubocop_rbs.yml
+++ b/.rubocop_rbs.yml
@@ -11,8 +11,8 @@ Style/RbsInline/MissingTypeAnnotation:
     - '**/spec/**/*'
 Style/RbsInline/UntypedInstanceVariable:
   Exclude:
-    - 'lib/structured_params/params.rb'
-    - 'lib/structured_params.rb'
+    - 'structured_params/lib/structured_params/params.rb'
+    - 'structured_params/lib/structured_params.rb'
     - 'structured_params-openapi/lib/structured_params/openapi/configuration.rb'
     - 'structured_params-openapi/lib/structured_params/openapi/registry.rb'
 
diff --git a/AGENTS.md b/AGENTS.md
index a66deac..72c9328 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -5,22 +5,23 @@
 ## プロジェクト概要
 
 - `structured_params` は Rails 向けの型付きパラメータ/フォームオブジェクト用 gem です。
-- コア実装は `lib/structured_params/` 配下にあります。
+- このリポジトリには 2 つの gem があり、それぞれ独自のフォルダを持ちます。コア gem は `structured_params/`、OpenAPI drift check は `structured_params-openapi/` です。
+- コア実装は `structured_params/lib/structured_params/` 配下にあります。
 - テストは RSpec、Lint は RuboCop、型検査は Steep を使います。
 - RBS シグネチャは `rbs-inline` から生成されます。
 
 ## 主要ディレクトリ
 
-- `structured_params-openapi/`: OpenAPI drift check の別 gem(`structured_params-openapi`)。
-  独自の `lib/`・`sig/`・`spec/`・`docs/` と gemspec を持ちます。コアとは同じリポジトリで管理し、
-  テストは `cd structured_params-openapi && bundle exec rspec` で実行します。
+- `structured_params/`: コア gem。`lib/`・`sig/`・`spec/`・`docs/`・`structured_params.gemspec`・`CHANGELOG.md` を持ちます。
+- `structured_params-openapi/`: OpenAPI drift check の別 gem。同じ構成の独自の `lib/`・`sig/`・`spec/`・`docs/` と gemspec を持ちます。
+- リポジトリ直下: `README.md`、`Gemfile`、`Rakefile`、`Steepfile`、`lefthook.yml`、RuboCop 設定など、両方の gem に共通のもの。
 
-- `lib/structured_params.rb`: エントリーポイント
-- `lib/structured_params/params.rb`: コアの `Params` 実装
-- `lib/structured_params/type/`: `array` / `object` 型ハンドラ
-- `spec/`: RSpec テスト
-- `docs/`: 利用者向けドキュメント
-- `sig/`: `rbs-inline` により生成された RBS
+- `structured_params/lib/structured_params.rb`: エントリーポイント
+- `structured_params/lib/structured_params/params.rb`: コアの `Params` 実装
+- `structured_params/lib/structured_params/type/`: `array` / `object` 型ハンドラ
+- `structured_params/spec/`: RSpec テスト
+- `structured_params/docs/`: 利用者向けドキュメント
+- `structured_params/sig/`: `rbs-inline` により生成された RBS
 
 ## セットアップと実行
 
@@ -43,13 +44,13 @@ Ruby 3.2 系では `steep` や `.rubocop_rbs.yml` 前提のチェックが使え
 個別実行例:
 
 ```bash
-bundle exec rspec spec/params_spec.rb
-bundle exec rubocop lib/structured_params/params.rb
+(cd structured_params && bundle exec rspec spec/params_spec.rb)
+bundle exec rubocop structured_params/lib/structured_params/params.rb
 ```
 
 ## 変更時のルール
 
-- `sig/**/*.rbs` は手編集しないでください。必要なら `bundle exec rbs-inline --output=sig lib/**/*.rb` で再生成します。
+- `sig/**/*.rbs` は手編集しないでください。必要なら各 gem のフォルダ(`structured_params/` など)で `bundle exec rbs-inline --output=sig lib/**/*.rb` を実行して再生成します。
 - Ruby メソッドの型注釈は `rbs-inline` の `method_type_signature` スタイルを使ってください。
 - インスタンス変数の型注釈は `# @rbs` コメントを使ってください。
 - 既存の公開 API を変える場合は、README と `docs/` の整合も確認してください。
@@ -58,16 +59,16 @@ bundle exec rubocop lib/structured_params/params.rb
 ## テスト方針
 
 - 振る舞い変更には RSpec を追加または更新してください。
-- 既存 spec のスタイルに合わせ、必要に応じて `spec/factories/` と `spec/support/` を再利用してください。
+- 既存 spec のスタイルに合わせ、必要に応じて `structured_params/spec/factories/` と `structured_params/spec/support/` を再利用してください。
 - 修正が型やシリアライズ、permit 生成に関わる場合は、関連 spec を広めに実行してください。
 
 ## コミット前チェック
 
 `lefthook.yml` によりコミット前に以下が走ります。
 
-- `bundle exec rbs-inline --output=sig lib/**/*.rb`(`structured_params-openapi/` でも同様)
+- 各 gem のフォルダでの `bundle exec rbs-inline --output=sig lib/**/*.rb`(`structured_params/` と `structured_params-openapi/`)
 - `bundle exec rubocop`
-- `bundle exec rspec`(`structured_params-openapi/` でも実行)
+- 各 gem のフォルダでの `bundle exec rspec`(`structured_params/` と `structured_params-openapi/`)
 - `bundle exec steep check`
 
 フックで失敗しない状態まで揃えてから完了扱いにしてください。
@@ -81,4 +82,4 @@ bundle exec rubocop lib/structured_params/params.rb
 - エラーフォーマットやバリデーション挙動の変更
 - Rails / Ruby サポート範囲の変更
 
-利用者向け概要は `README.md`、詳細仕様は `docs/*.md`、日本語 README が必要なら `README_ja.md` も更新します。
+利用者向け概要は `README.md`、詳細仕様は `structured_params/docs/*.md`、日本語 README が必要なら `README_ja.md` も更新します。
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 2c589d0..e76026f 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -25,7 +25,15 @@ bin/setup
 ### Running Tests
 
 ```bash
-# Run all tests
+# Run the specs of every gem (from the repository root)
+bundle exec rake spec
+
+# The repository holds two gems, each in its own folder:
+#   structured_params/          the core gem
+#   structured_params-openapi/  the OpenAPI drift check gem
+cd structured_params
+
+# Run all tests of the gem
 bundle exec rspec
 
 # Run specific test file
@@ -62,15 +70,15 @@ Automatically regenerate signatures on file changes:
 ./bin/dev
 ```
 
-This command uses `fswatch` to monitor the `lib/` directory and automatically runs `rbs-inline` when files change.
+This command uses `fswatch` to monitor the `lib/` directory of each gem and automatically runs `rbs-inline` when files change.
 
 ### Manual Generation
 
 Generate all signatures manually:
 
 ```bash
-# Generate for all lib files
-bundle exec rbs-inline --output=sig lib/**/*.rb
+# Generate for all lib files (run inside each gem folder, e.g. structured_params/)
+cd structured_params && bundle exec rbs-inline --output=sig lib/**/*.rb
 ```
 
 ### Automatic Generation (Git Hooks)
@@ -88,7 +96,7 @@ The git hook configuration is in `lefthook.yml`:
 prepare-commit-msg:
   commands:
     rbs-inline:
-      run: bundle exec rbs-inline --output=sig lib/**/*.rb
+      run: (cd structured_params && bundle exec rbs-inline --output=sig lib/**/*.rb) && ...
 ```
 
 ## Coding Style
@@ -176,23 +184,26 @@ RAILS_VERSION="~> 8.0.0" bundle update && bundle exec rspec
 ## Project Structure
 
 ```
-structured_params/
-├── lib/
-│   ├── structured_params.rb          # Main entry point
-│   ├── structured_params/
-│   │   ├── params.rb                 # Core Params class
-│   │   ├── errors.rb                 # Enhanced error handling
-│   │   ├── version.rb                # Version constant
-│   │   └── type/
-│   │       ├── array.rb              # Array type handler
-│   │       └── object.rb             # Object type handler
-├── sig/                              # Auto-generated RBS files
-│   └── generated/                    # DO NOT EDIT
-├── spec/                             # RSpec tests
-│   ├── factories/                    # Test parameter classes
-│   ├── support/                      # Test helpers
-│   └── *_spec.rb                     # Test files
-└── docs/                             # Documentation
+.                                     # repository root: README, Gemfile, Rakefile, Steepfile, lefthook.yml, RuboCop config
+├── structured_params/                # core gem
+│   ├── structured_params.gemspec
+│   ├── CHANGELOG.md
+│   ├── lib/
+│   │   ├── structured_params.rb      # Main entry point
+│   │   └── structured_params/
+│   │       ├── params.rb             # Core Params class
+│   │       ├── errors.rb             # Enhanced error handling
+│   │       ├── version.rb            # Version constant
+│   │       └── type/
+│   │           ├── array.rb          # Array type handler
+│   │           └── object.rb         # Object type handler
+│   ├── sig/                          # Auto-generated RBS files (DO NOT EDIT)
+│   ├── spec/                         # RSpec tests
+│   │   ├── factories/                # Test parameter classes
+│   │   ├── support/                  # Test helpers
+│   │   └── *_spec.rb                 # Test files
+│   └── docs/                         # Documentation
+└── structured_params-openapi/        # OpenAPI drift check gem (same layout)
 ```
 
 ## Submitting Changes
diff --git a/Gemfile b/Gemfile
index d70f085..46caa11 100644
--- a/Gemfile
+++ b/Gemfile
@@ -3,7 +3,7 @@
 
 source 'https://rubygems.org'
 
-gemspec
+gemspec path: 'structured_params'
 gemspec path: 'structured_params-openapi'
 
 # Allow testing different Rails versions via environment variable
diff --git a/Procfile.dev b/Procfile.dev
index f1902a5..f0c8dc2 100644
--- a/Procfile.dev
+++ b/Procfile.dev
@@ -1 +1,2 @@
-rbs-inline: fswatch -0 lib | xargs -0 -n1 bundle exec rbs-inline --output=sig
+rbs-inline: sh -c 'cd structured_params && fswatch -0 lib | xargs -0 -n1 bundle exec rbs-inline --output=sig'
+rbs-inline-openapi: sh -c 'cd structured_params-openapi && fswatch -0 lib | xargs -0 -n1 bundle exec rbs-inline --output=sig'
diff --git a/README.md b/README.md
index 51f4aa9..234c04d 100644
--- a/README.md
+++ b/README.md
@@ -123,14 +123,14 @@ bundle exec rake structured_params:openapi:drift_check
 
 ## Documentation
 
-- **[Installation and Setup](docs/installation.md)** - Getting started with StructuredParams
-- **[Basic Usage](docs/basic-usage.md)** - Parameter classes, nested objects, and arrays
-- **[Validation](docs/validation.md)** - Using ActiveModel validations with nested structures
+- **[Installation and Setup](structured_params/docs/installation.md)** - Getting started with StructuredParams
+- **[Basic Usage](structured_params/docs/basic-usage.md)** - Parameter classes, nested objects, and arrays
+- **[Validation](structured_params/docs/validation.md)** - Using ActiveModel validations with nested structures
 - **[OpenAPI Drift Check](structured_params-openapi/docs/drift-check.md)** - Detect differences between request schemas and Params classes (`structured_params-openapi` gem)
-- **[Strong Parameters](docs/strong-parameters.md)** - Automatic permit list generation
-- **[Error Handling](docs/error-handling.md)** - Flat and structured error formats
-- **[Serialization](docs/serialization.md)** - Converting parameters to hashes and JSON
-- **[Form Objects](docs/form-objects.md)** - Form object pattern with Rails views
+- **[Strong Parameters](structured_params/docs/strong-parameters.md)** - Automatic permit list generation
+- **[Error Handling](structured_params/docs/error-handling.md)** - Flat and structured error formats
+- **[Serialization](structured_params/docs/serialization.md)** - Converting parameters to hashes and JSON
+- **[Form Objects](structured_params/docs/form-objects.md)** - Form object pattern with Rails views
 
 ## Contributing
 
diff --git a/README_ja.md b/README_ja.md
index 8e85ef4..09b6508 100644
--- a/README_ja.md
+++ b/README_ja.md
@@ -123,14 +123,14 @@ bundle exec rake structured_params:openapi:drift_check
 
 ## ドキュメント
 
-- **[インストールとセットアップ](docs/installation.md)** - StructuredParams の始め方
-- **[基本的な使い方](docs/basic-usage.md)** - パラメータクラス、ネストオブジェクト、配列
-- **[バリデーション](docs/validation.md)** - ネスト構造での ActiveModel バリデーション
+- **[インストールとセットアップ](structured_params/docs/installation.md)** - StructuredParams の始め方
+- **[基本的な使い方](structured_params/docs/basic-usage.md)** - パラメータクラス、ネストオブジェクト、配列
+- **[バリデーション](structured_params/docs/validation.md)** - ネスト構造での ActiveModel バリデーション
 - **[OpenAPI Drift Check](structured_params-openapi/docs/drift-check_ja.md)** - OpenAPI schema と Params class の乖離検出(`structured_params-openapi` gem)
-- **[Strong Parameters](docs/strong-parameters.md)** - permit リストの自動生成
-- **[エラーハンドリング](docs/error-handling.md)** - フラット形式と構造化形式のエラー
-- **[シリアライゼーション](docs/serialization.md)** - パラメータのハッシュと JSON 変換
-- **[フォームオブジェクト](docs/form-objects.md)** - Rails ビューとのフォームオブジェクトパターン
+- **[Strong Parameters](structured_params/docs/strong-parameters.md)** - permit リストの自動生成
+- **[エラーハンドリング](structured_params/docs/error-handling.md)** - フラット形式と構造化形式のエラー
+- **[シリアライゼーション](structured_params/docs/serialization.md)** - パラメータのハッシュと JSON 変換
+- **[フォームオブジェクト](structured_params/docs/form-objects.md)** - Rails ビューとのフォームオブジェクトパターン
 
 ## コントリビューション
 
diff --git a/Rakefile b/Rakefile
index 0b01eab..ae02914 100644
--- a/Rakefile
+++ b/Rakefile
@@ -1,12 +1,24 @@
 # frozen_string_literal: true
 # rbs_inline: enabled
 
-require 'bundler/gem_tasks'
-require 'rspec/core/rake_task'
+require 'bundler/gem_helper'
+require 'rubocop/rake_task'
 
-RSpec::Core::RakeTask.new(:spec)
+# The repository holds two gems, each in its own directory with its own spec suite.
+# `rake build`/`install`/`release` act on the core gem; build the others from their directory.
+GEM_DIRS = %w[structured_params structured_params-openapi].freeze #: Array[String]
 
-require 'rubocop/rake_task'
+Bundler::GemHelper.install_tasks(dir: 'structured_params', name: 'structured_params')
+
+GEM_DIRS.each do |gem_dir|
+  desc "Run the #{gem_dir} specs"
+  task "spec:#{gem_dir}" do
+    Dir.chdir(gem_dir) { sh 'bundle exec rspec' }
+  end
+end
+
+desc 'Run the specs of every gem'
+task spec: GEM_DIRS.map { |gem_dir| "spec:#{gem_dir}" }
 
 # Use RBS Inline configuration for Ruby 3.3+
 rubocop_config = if RUBY_VERSION >= '3.3.0'
@@ -28,11 +40,4 @@ if RUBY_VERSION >= '3.3.0'
   default_tasks << :steep
 end
 
-# The OpenAPI plugin lives in its own gem directory with its own spec suite.
-desc 'Run the structured_params-openapi specs'
-task :spec_openapi do
-  Dir.chdir('structured_params-openapi') { sh 'bundle exec rspec' }
-end
-default_tasks << :spec_openapi
-
 task default: default_tasks
diff --git a/Steepfile b/Steepfile
index fb68fbe..016d827 100644
--- a/Steepfile
+++ b/Steepfile
@@ -3,9 +3,9 @@
 
 # D = Steep::Diagnostic
 target :lib do
-  signature 'sig'
+  signature 'structured_params/sig'
 
-  check 'lib'
+  check 'structured_params/lib'
 
   # Suppress errors from broken library RBS files in gem_rbs_collection
   configure_code_diagnostics do |hash|
@@ -14,7 +14,7 @@ target :lib do
 end
 
 target :openapi do
-  signature 'sig', 'structured_params-openapi/sig'
+  signature 'structured_params/sig', 'structured_params-openapi/sig'
 
   check 'structured_params-openapi/lib'
 
diff --git a/bin/console b/bin/console
index 4fdf31d..b8263b7 100755
--- a/bin/console
+++ b/bin/console
@@ -9,7 +9,7 @@ require 'structured_params'
 # with your gem easier. You can also use a different console, if you like.
 require 'factory_bot'
 StructuredParams.register_types
-FactoryBot.definition_file_paths = [File.expand_path('../spec/factories', __dir__)]
+FactoryBot.definition_file_paths = [File.expand_path('../structured_params/spec/factories', __dir__)]
 FactoryBot.find_definitions
 
 require 'irb'
diff --git a/lefthook.yml b/lefthook.yml
index 2ddee2e..e79692b 100644
--- a/lefthook.yml
+++ b/lefthook.yml
@@ -1,14 +1,14 @@
 prepare-commit-msg:
   commands:
     rbs-inline:
-      run: bundle exec rbs-inline --output=sig lib/**/*.rb && (cd structured_params-openapi && bundle exec rbs-inline --output=sig lib/**/*.rb) && git add sig/ structured_params-openapi/sig/
+      run: (cd structured_params && bundle exec rbs-inline --output=sig lib/**/*.rb) && (cd structured_params-openapi && bundle exec rbs-inline --output=sig lib/**/*.rb) && git add structured_params/sig/ structured_params-openapi/sig/
 
 pre-commit:
   commands:
     rubocop:
       run: ./bin/rubocop
     rspec:
-      run: bundle exec rspec
+      run: cd structured_params && bundle exec rspec
     rspec-open-api:
       run: cd structured_params-openapi && bundle exec rspec
     steep:
diff --git a/.rspec b/structured_params/.rspec
similarity index 100%
rename from .rspec
rename to structured_params/.rspec
diff --git a/CHANGELOG.md b/structured_params/CHANGELOG.md
similarity index 100%
rename from CHANGELOG.md
rename to structured_params/CHANGELOG.md
diff --git a/structured_params/LICENSE.txt b/structured_params/LICENSE.txt
new file mode 100644
index 0000000..0626645
--- /dev/null
+++ b/structured_params/LICENSE.txt
@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) 2024 Mizuki Yamamoto
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
diff --git a/docs/basic-usage.md b/structured_params/docs/basic-usage.md
similarity index 100%
rename from docs/basic-usage.md
rename to structured_params/docs/basic-usage.md
diff --git a/docs/error-handling.md b/structured_params/docs/error-handling.md
similarity index 100%
rename from docs/error-handling.md
rename to structured_params/docs/error-handling.md
diff --git a/docs/form-objects.md b/structured_params/docs/form-objects.md
similarity index 100%
rename from docs/form-objects.md
rename to structured_params/docs/form-objects.md
diff --git a/docs/installation.md b/structured_params/docs/installation.md
similarity index 100%
rename from docs/installation.md
rename to structured_params/docs/installation.md
diff --git a/docs/serialization.md b/structured_params/docs/serialization.md
similarity index 100%
rename from docs/serialization.md
rename to structured_params/docs/serialization.md
diff --git a/docs/strong-parameters.md b/structured_params/docs/strong-parameters.md
similarity index 100%
rename from docs/strong-parameters.md
rename to structured_params/docs/strong-parameters.md
diff --git a/docs/validation.md b/structured_params/docs/validation.md
similarity index 100%
rename from docs/validation.md
rename to structured_params/docs/validation.md
diff --git a/lib/structured_params.rb b/structured_params/lib/structured_params.rb
similarity index 100%
rename from lib/structured_params.rb
rename to structured_params/lib/structured_params.rb
diff --git a/lib/structured_params/attribute_methods.rb b/structured_params/lib/structured_params/attribute_methods.rb
similarity index 100%
rename from lib/structured_params/attribute_methods.rb
rename to structured_params/lib/structured_params/attribute_methods.rb
diff --git a/lib/structured_params/errors.rb b/structured_params/lib/structured_params/errors.rb
similarity index 100%
rename from lib/structured_params/errors.rb
rename to structured_params/lib/structured_params/errors.rb
diff --git a/lib/structured_params/i18n.rb b/structured_params/lib/structured_params/i18n.rb
similarity index 100%
rename from lib/structured_params/i18n.rb
rename to structured_params/lib/structured_params/i18n.rb
diff --git a/lib/structured_params/params.rb b/structured_params/lib/structured_params/params.rb
similarity index 100%
rename from lib/structured_params/params.rb
rename to structured_params/lib/structured_params/params.rb
diff --git a/lib/structured_params/type/array.rb b/structured_params/lib/structured_params/type/array.rb
similarity index 100%
rename from lib/structured_params/type/array.rb
rename to structured_params/lib/structured_params/type/array.rb
diff --git a/lib/structured_params/type/object.rb b/structured_params/lib/structured_params/type/object.rb
similarity index 100%
rename from lib/structured_params/type/object.rb
rename to structured_params/lib/structured_params/type/object.rb
diff --git a/lib/structured_params/validations.rb b/structured_params/lib/structured_params/validations.rb
similarity index 100%
rename from lib/structured_params/validations.rb
rename to structured_params/lib/structured_params/validations.rb
diff --git a/lib/structured_params/version.rb b/structured_params/lib/structured_params/version.rb
similarity index 100%
rename from lib/structured_params/version.rb
rename to structured_params/lib/structured_params/version.rb
diff --git a/sig/structured_params.rbs b/structured_params/sig/structured_params.rbs
similarity index 100%
rename from sig/structured_params.rbs
rename to structured_params/sig/structured_params.rbs
diff --git a/sig/structured_params/attribute_methods.rbs b/structured_params/sig/structured_params/attribute_methods.rbs
similarity index 100%
rename from sig/structured_params/attribute_methods.rbs
rename to structured_params/sig/structured_params/attribute_methods.rbs
diff --git a/sig/structured_params/errors.rbs b/structured_params/sig/structured_params/errors.rbs
similarity index 100%
rename from sig/structured_params/errors.rbs
rename to structured_params/sig/structured_params/errors.rbs
diff --git a/sig/structured_params/i18n.rbs b/structured_params/sig/structured_params/i18n.rbs
similarity index 100%
rename from sig/structured_params/i18n.rbs
rename to structured_params/sig/structured_params/i18n.rbs
diff --git a/sig/structured_params/params.rbs b/structured_params/sig/structured_params/params.rbs
similarity index 100%
rename from sig/structured_params/params.rbs
rename to structured_params/sig/structured_params/params.rbs
diff --git a/sig/structured_params/type/array.rbs b/structured_params/sig/structured_params/type/array.rbs
similarity index 100%
rename from sig/structured_params/type/array.rbs
rename to structured_params/sig/structured_params/type/array.rbs
diff --git a/sig/structured_params/type/object.rbs b/structured_params/sig/structured_params/type/object.rbs
similarity index 100%
rename from sig/structured_params/type/object.rbs
rename to structured_params/sig/structured_params/type/object.rbs
diff --git a/sig/structured_params/validations.rbs b/structured_params/sig/structured_params/validations.rbs
similarity index 100%
rename from sig/structured_params/validations.rbs
rename to structured_params/sig/structured_params/validations.rbs
diff --git a/sig/structured_params/version.rbs b/structured_params/sig/structured_params/version.rbs
similarity index 100%
rename from sig/structured_params/version.rbs
rename to structured_params/sig/structured_params/version.rbs
diff --git a/spec/attribute_methods_spec.rb b/structured_params/spec/attribute_methods_spec.rb
similarity index 100%
rename from spec/attribute_methods_spec.rb
rename to structured_params/spec/attribute_methods_spec.rb
diff --git a/spec/errors_spec.rb b/structured_params/spec/errors_spec.rb
similarity index 100%
rename from spec/errors_spec.rb
rename to structured_params/spec/errors_spec.rb
diff --git a/spec/factories/address_parameters.rb b/structured_params/spec/factories/address_parameters.rb
similarity index 100%
rename from spec/factories/address_parameters.rb
rename to structured_params/spec/factories/address_parameters.rb
diff --git a/spec/factories/hobby_parameters.rb b/structured_params/spec/factories/hobby_parameters.rb
similarity index 100%
rename from spec/factories/hobby_parameters.rb
rename to structured_params/spec/factories/hobby_parameters.rb
diff --git a/spec/factories/user_parameters.rb b/structured_params/spec/factories/user_parameters.rb
similarity index 100%
rename from spec/factories/user_parameters.rb
rename to structured_params/spec/factories/user_parameters.rb
diff --git a/spec/form_object_spec.rb b/structured_params/spec/form_object_spec.rb
similarity index 100%
rename from spec/form_object_spec.rb
rename to structured_params/spec/form_object_spec.rb
diff --git a/spec/i18n_spec.rb b/structured_params/spec/i18n_spec.rb
similarity index 100%
rename from spec/i18n_spec.rb
rename to structured_params/spec/i18n_spec.rb
diff --git a/spec/params_spec.rb b/structured_params/spec/params_spec.rb
similarity index 100%
rename from spec/params_spec.rb
rename to structured_params/spec/params_spec.rb
diff --git a/spec/permit_spec.rb b/structured_params/spec/permit_spec.rb
similarity index 100%
rename from spec/permit_spec.rb
rename to structured_params/spec/permit_spec.rb
diff --git a/spec/spec_helper.rb b/structured_params/spec/spec_helper.rb
similarity index 100%
rename from spec/spec_helper.rb
rename to structured_params/spec/spec_helper.rb
diff --git a/spec/support/locales/ja.yml b/structured_params/spec/support/locales/ja.yml
similarity index 100%
rename from spec/support/locales/ja.yml
rename to structured_params/spec/support/locales/ja.yml
diff --git a/spec/support/shared_contexts/ja_locale.rb b/structured_params/spec/support/shared_contexts/ja_locale.rb
similarity index 100%
rename from spec/support/shared_contexts/ja_locale.rb
rename to structured_params/spec/support/shared_contexts/ja_locale.rb
diff --git a/spec/support/test_classes/form_object_classes.rb b/structured_params/spec/support/test_classes/form_object_classes.rb
similarity index 100%
rename from spec/support/test_classes/form_object_classes.rb
rename to structured_params/spec/support/test_classes/form_object_classes.rb
diff --git a/spec/support/test_classes/params_classes.rb b/structured_params/spec/support/test_classes/params_classes.rb
similarity index 100%
rename from spec/support/test_classes/params_classes.rb
rename to structured_params/spec/support/test_classes/params_classes.rb
diff --git a/spec/type/array_spec.rb b/structured_params/spec/type/array_spec.rb
similarity index 100%
rename from spec/type/array_spec.rb
rename to structured_params/spec/type/array_spec.rb
diff --git a/spec/type/object_spec.rb b/structured_params/spec/type/object_spec.rb
similarity index 100%
rename from spec/type/object_spec.rb
rename to structured_params/spec/type/object_spec.rb
diff --git a/spec/validations_spec.rb b/structured_params/spec/validations_spec.rb
similarity index 100%
rename from spec/validations_spec.rb
rename to structured_params/spec/validations_spec.rb
diff --git a/structured_params.gemspec b/structured_params/structured_params.gemspec
similarity index 96%
rename from structured_params.gemspec
rename to structured_params/structured_params.gemspec
index 0489492..b1404f2 100644
--- a/structured_params.gemspec
+++ b/structured_params/structured_params.gemspec
@@ -28,7 +28,7 @@ Gem::Specification.new do |spec|
 
   spec.metadata = {
     'homepage_uri' => 'https://github.com/Syati/structured_params#readme',
-    'changelog_uri' => 'https://github.com/Syati/structured_params/blob/main/CHANGELOG.md',
+    'changelog_uri' => 'https://github.com/Syati/structured_params/blob/main/structured_params/CHANGELOG.md',
     'bug_tracker_uri' => 'https://github.com/Syati/structured_params/issues',
     'source_code_uri' => 'https://github.com/Syati/structured_params',
     'rubygems_mfa_required' => 'true'

From 35bd567c1b3ff167a2ad5a6633ae013ccad016b2 Mon Sep 17 00:00:00 2001
From: mizuki-y <mizuki-y@syati.info>
Date: Mon, 12 Oct 2026 20:28:45 +0900
Subject: [PATCH 2/3] fix: release the core gem from its own folder with a
 per-gem Rakefile

rubygems/release-gem waits for pkg/*.gem in its working directory, but the
gem is built under the gem folder's own pkg/. Give structured_params/ a
Rakefile with bundler/gem_tasks and run release-gem with
working-directory: structured_params instead of routing it through the root
Rakefile.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
---
 .github/workflows/release.yml | 2 ++
 Rakefile                      | 7 ++-----
 structured_params/Rakefile    | 6 ++++++
 3 files changed, 10 insertions(+), 5 deletions(-)
 create mode 100644 structured_params/Rakefile

diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index ab69971..5cb613b 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -91,3 +91,5 @@ jobs:
 
       - name: Publish to RubyGems
         uses: rubygems/release-gem@v1
+        with:
+          working-directory: structured_params
diff --git a/Rakefile b/Rakefile
index ae02914..441aa0a 100644
--- a/Rakefile
+++ b/Rakefile
@@ -1,15 +1,12 @@
 # frozen_string_literal: true
 # rbs_inline: enabled
 
-require 'bundler/gem_helper'
 require 'rubocop/rake_task'
 
-# The repository holds two gems, each in its own directory with its own spec suite.
-# `rake build`/`install`/`release` act on the core gem; build the others from their directory.
+# The repository holds two gems, each in its own directory with its own spec suite and its
+# own Rakefile for `build`/`install`/`release` (run those from the gem's directory).
 GEM_DIRS = %w[structured_params structured_params-openapi].freeze #: Array[String]
 
-Bundler::GemHelper.install_tasks(dir: 'structured_params', name: 'structured_params')
-
 GEM_DIRS.each do |gem_dir|
   desc "Run the #{gem_dir} specs"
   task "spec:#{gem_dir}" do
diff --git a/structured_params/Rakefile b/structured_params/Rakefile
new file mode 100644
index 0000000..fa8fbc4
--- /dev/null
+++ b/structured_params/Rakefile
@@ -0,0 +1,6 @@
+# frozen_string_literal: true
+# rbs_inline: enabled
+
+# Release tasks (`rake build`, `rake release`) for this gem; run them from this directory.
+# The repository-wide checks (specs, RuboCop, Steep) live in the root Rakefile.
+require 'bundler/gem_tasks'

From fce2e68bf029f3762c88f362c097815f574bae1d Mon Sep 17 00:00:00 2001
From: mizuki-y <mizuki-y@syati.info>
Date: Tue, 13 Oct 2026 07:44:47 +0900
Subject: [PATCH 3/3] fix: regenerate RBS for every lib file and point docs at
 rake spec

- lefthook ran `rbs-inline lib/**/*.rb` under sh, where ** matches a single
  directory level, so nested files such as lib/structured_params/type/*.rb were
  skipped (6 of 9 files). Pass the lib directory instead, which rbs-inline
  processes recursively. Same change in CONTRIBUTING.md and AGENTS.md.
- Replace the root-level `bundle exec rspec` instructions with
  `bundle exec rake spec`, which runs both gem suites.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
---
 AGENTS.md       |  6 +++---
 CONTRIBUTING.md | 10 +++++-----
 lefthook.yml    |  2 +-
 3 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/AGENTS.md b/AGENTS.md
index 72c9328..1f96a9e 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -34,7 +34,7 @@ bin/setup
 通常の確認:
 
 ```bash
-bundle exec rspec
+bundle exec rake spec        # 両方の gem の spec(各 gem のフォルダで bundle exec rspec でも可)
 bundle exec rubocop
 bundle exec steep check
 ```
@@ -50,7 +50,7 @@ bundle exec rubocop structured_params/lib/structured_params/params.rb
 
 ## 変更時のルール
 
-- `sig/**/*.rbs` は手編集しないでください。必要なら各 gem のフォルダ(`structured_params/` など)で `bundle exec rbs-inline --output=sig lib/**/*.rb` を実行して再生成します。
+- `sig/**/*.rbs` は手編集しないでください。必要なら各 gem のフォルダ(`structured_params/` など)で `bundle exec rbs-inline --output=sig lib` を実行して再生成します。
 - Ruby メソッドの型注釈は `rbs-inline` の `method_type_signature` スタイルを使ってください。
 - インスタンス変数の型注釈は `# @rbs` コメントを使ってください。
 - 既存の公開 API を変える場合は、README と `docs/` の整合も確認してください。
@@ -66,7 +66,7 @@ bundle exec rubocop structured_params/lib/structured_params/params.rb
 
 `lefthook.yml` によりコミット前に以下が走ります。
 
-- 各 gem のフォルダでの `bundle exec rbs-inline --output=sig lib/**/*.rb`(`structured_params/` と `structured_params-openapi/`)
+- 各 gem のフォルダでの `bundle exec rbs-inline --output=sig lib`(`structured_params/` と `structured_params-openapi/`)
 - `bundle exec rubocop`
 - 各 gem のフォルダでの `bundle exec rspec`(`structured_params/` と `structured_params-openapi/`)
 - `bundle exec steep check`
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index e76026f..1850818 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -78,7 +78,7 @@ Generate all signatures manually:
 
 ```bash
 # Generate for all lib files (run inside each gem folder, e.g. structured_params/)
-cd structured_params && bundle exec rbs-inline --output=sig lib/**/*.rb
+cd structured_params && bundle exec rbs-inline --output=sig lib
 ```
 
 ### Automatic Generation (Git Hooks)
@@ -96,7 +96,7 @@ The git hook configuration is in `lefthook.yml`:
 prepare-commit-msg:
   commands:
     rbs-inline:
-      run: (cd structured_params && bundle exec rbs-inline --output=sig lib/**/*.rb) && ...
+      run: (cd structured_params && bundle exec rbs-inline --output=sig lib) && ...
 ```
 
 ## Coding Style
@@ -175,10 +175,10 @@ You can test against different Rails versions using the `RAILS_VERSION` environm
 
 ```bash
 # Test with Rails 7.2
-RAILS_VERSION="~> 7.2.0" bundle update && bundle exec rspec
+RAILS_VERSION="~> 7.2.0" bundle update && bundle exec rake spec
 
 # Test with Rails 8.0
-RAILS_VERSION="~> 8.0.0" bundle update && bundle exec rspec
+RAILS_VERSION="~> 8.0.0" bundle update && bundle exec rake spec
 ```
 
 ## Project Structure
@@ -213,7 +213,7 @@ RAILS_VERSION="~> 8.0.0" bundle update && bundle exec rspec
 1. **Fork the repository** and create your branch from `main`
 2. **Write tests** for your changes
 3. **Update documentation** if needed (README, docs/, inline comments)
-4. **Ensure all tests pass**: `bundle exec rspec`
+4. **Ensure all tests pass**: `bundle exec rake spec`
 5. **Ensure code quality**: `bundle exec rubocop`
 6. **Ensure type safety** (Ruby 3.3+): `bundle exec steep check`
 7. **RBS signatures will be auto-generated** by git hooks
diff --git a/lefthook.yml b/lefthook.yml
index e79692b..8418c52 100644
--- a/lefthook.yml
+++ b/lefthook.yml
@@ -1,7 +1,7 @@
 prepare-commit-msg:
   commands:
     rbs-inline:
-      run: (cd structured_params && bundle exec rbs-inline --output=sig lib/**/*.rb) && (cd structured_params-openapi && bundle exec rbs-inline --output=sig lib/**/*.rb) && git add structured_params/sig/ structured_params-openapi/sig/
+      run: (cd structured_params && bundle exec rbs-inline --output=sig lib) && (cd structured_params-openapi && bundle exec rbs-inline --output=sig lib) && git add structured_params/sig/ structured_params-openapi/sig/
 
 pre-commit:
   commands: