b-re-w · Oct 3, 2026 · Oct 3, 2026
diff --git a/AGENTS.md b/AGENTS.md
@@ -188,8 +188,9 @@ worktree so a test can see it. Read it in place.
   `.tmp/` (rule 2), not in the home directory.
 - Tests that exercise the binder's adaptation layer read it, read-only, from a `PythonMultiplatform`
   checkout: the sibling directory `../PythonMultiplatform`, or `PYTHONMULTIPLATFORM_HOME`. Without
-  one they **skip**; with a checkout older than python-multiplatform `ba4c6f49`, 5 of them skip for
-  want of its member resolver (see `docs/SPEC.md` §0). Report both numbers and say which environment you ran in. A skip is not
+  one they **skip**; against an older python-multiplatform some still skip, each saying which binder
+  feature it needs (the member resolver, `ba4c6f49`; `describe(module, name)`, #36; see
+  `docs/SPEC.md` §0). Report both numbers and say which environment you ran in. A skip is not
   a pass.
 - The suite runs on GitHub Actions (`.github/workflows/tests.yml`) in both environments, without and
   with a python-multiplatform checkout, for every pull request into `develop`. Local runs are for

diff --git a/PROJECT.md b/PROJECT.md
@@ -27,22 +27,24 @@ Compose(`androidx.compose.*`)를 파이썬에서 쓰기 위한 pip 패키지 **`
 
 | 상태 | 항목 |
 |---|---|
-| 구현 | 매핑 매니페스트 `pythonx-map.toml`, `@Composable` 항등 데코레이터, 실제 디스크 패키지 `pythonx` 와 모듈 수준 규칙 기반 재노출(snake_case 이름·키워드·시그니처, 오버로드 디스패치, 값 클래스 허용 목록), 실제 Compose 1.11.1 에서 생성한 `.pyi` 스텁과 `py.typed`(wheel 포함, mypy 로 검사) |
-| 부분 | 배포 설정, proxy 메서드의 키워드 인자는 아직 Kotlin 이름(`m.padding(paddingValues=...)`), Material 3 위젯(렌더 증거는 python-multiplatform 에만), `Icon`·색 스킴(import 만 됨), `Alignment`/`Arrangement` 상수(`pythonx` 에서 읽힘; 묶음 표기는 python-multiplatform #36 대기) |
+| 구현 | 매핑 매니페스트 `pythonx-map.toml`, `@Composable` 항등 데코레이터, 실제 디스크 패키지 `pythonx` 와 모듈 수준 규칙 기반 재노출(snake_case 이름·키워드·시그니처, 오버로드 디스패치, 값 클래스 허용 목록), 실제 Compose 1.11.1 에서 생성한 `.pyi` 스텁과 `py.typed`(wheel 포함, mypy 로 검사), `Alignment`/`Arrangement` 상수(평면 `Alignment.End` 와 묶음 `Alignment.Horizontal.End` 모두, #9) |
+| 부분 | 배포 설정, proxy 메서드의 키워드 인자는 아직 Kotlin 이름(`m.padding(paddingValues=...)`), Material 3 위젯(렌더 증거는 python-multiplatform 에만), `Icon`·색 스킴(import 만 됨) |
 | 계획 | 선언형 앱 루트(#11), `remember_saveable`·`DefaultIcons`·코루틴 스코프 |
 
 ### 테스트 기준선
 
 ```
 python3 -m pytest tests -q
-  PythonMultiplatform 체크아웃 없음       84 passed, 60 skipped
-  python-multiplatform develop ba4c6f49+    143 passed, 1 skipped
-  그보다 오래된 체크아웃                    같은 수, 그중 5 개 건너뜀  (member resolver 없음)
+  PythonMultiplatform 체크아웃 없음       91 passed, 73 skipped
+  python-multiplatform develop d6d39787+    163 passed, 1 skipped
+  describe(module, name) 없는 체크아웃      같은 수, 그중 13 개 건너뜀  (python-multiplatform #36 이전)
+  그보다 오래된 체크아웃                    거기에 5 개 더 건너뜀  (member resolver 없음)
 ```
 
+`describe(module, name)`(python-multiplatform #36)이 없는 바인더에서는 묶음 상수를 확인하는 13 개가,
 member resolver(python-multiplatform `ba4c6f49`)가 없는 바인더에서는 proxy 의 snake_case 메서드를 부르는
-5 개가 건너뛴다. 두 환경 모두의 건너뜀 1 개는 worktree 에 없는 `UI.ipynb` 의 테스트다. 건너뜀은 통과가 아니다.
-체크아웃 없이 통과하는 84 개 중 30 개는 타입 스텁과 wheel 을 검사하고(SPEC S1.2), 나머지 다수는 *부재*(옛 토큰·삭제된
+5 개가 더 건너뛴다. 두 환경 모두의 건너뜀 1 개는 worktree 에 없는 `UI.ipynb` 의 테스트다. 건너뜀은 통과가 아니다.
+체크아웃 없이 통과하는 91 개 중 37 개는 타입 스텁과 wheel 을 검사하고(SPEC S1.2), 나머지 다수는 *부재*(옛 토큰·삭제된
 파일이 없음)를 확인하는 것이라 기능 진척으로 세지 않는다.
 
 ### 마일스톤

diff --git a/README.md b/README.md
@@ -48,7 +48,9 @@ proofs are still pending. See [Status](#-status).</sub>
   exactly as it does in Kotlin. Keyword arguments to such a method are still Kotlin's own
   (`m.padding(paddingValues=...)`); the module function takes `padding(m, padding_values=...)`.
 - **Kotlin objects are namespaces.** `Alignment.Center` and `Arrangement.End` are read without
-  parentheses; functions inside them are `snake_case`: `Arrangement.spaced_by(8)`.
+  parentheses; functions inside them are `snake_case`: `Arrangement.spaced_by(8)`. Constants can
+  also be reached grouped by their declared type, as the notebook writes them:
+  `Alignment.Horizontal.End` is `Alignment.End`.
 - **`@Composable` stays.** Screens are decorated Python functions.
 - **A real package.** `pythonx/` is ordinary Python source that imports `androidx.compose.*` and
   reshapes it. The binder never renames anything — renaming is this package's job.
@@ -150,7 +152,7 @@ standalone desktop toolkit.
 | `Column`, `Row`, `Spacer` from `material3` as well as `layout` | ✅ implemented and tested |
 | Method keyword arguments in `snake_case` | 🟡 partial — module functions yes; methods still take Kotlin's keywords |
 | The empty `Modifier` | 🟡 partial — `Modifier.padding(16)` from the class needs an app-supplied factory against real Compose |
-| `Alignment` / `Arrangement` | 🟡 partial — `Alignment.Center`, `Arrangement.spaced_by(8)` work; grouped `Alignment.Horizontal.End` pending |
+| `Alignment` / `Arrangement` | ✅ implemented and tested — `Alignment.Center`, `Arrangement.spaced_by(8)`, and grouped `Alignment.Horizontal.End` beside `Alignment.End` |
 | Material 3 widgets (`Text`, `Button`, `Card`, `TextField`, …) | 🟡 partial — re-exported by rule; render proofs per widget pending (#9) |
 | Type stubs (`.pyi`) from real Compose 1.11.1, `py.typed` | ✅ implemented and checked with mypy; many types are still `Any`, and method keywords are Kotlin's (#12) |
 | Distribution (`pythonx-compose`) | 🟡 partial — the wheel carries the manifest, the re-export rule, the stubs and `py.typed` |

diff --git a/docs/SPEC.md b/docs/SPEC.md
@@ -14,24 +14,26 @@ Each item carries a status:
 
 A behaviour change starts here, then becomes a failing test, then code (`AGENTS.md` §5).
 
-## 0. Test baseline (2026-10-03, after issue #12)
+## 0. Test baseline (2026-10-03, after issue #9's grouped constants)
 
 Run from a worktree with `python -m pytest tests -q -rs` (pytest 8, mypy 2.4, CPython 3.13), where
 `UI.ipynb` is absent and its one test skips:
 
 | Environment | Result |
 |---|---|
-| No `PythonMultiplatform` checkout found | **84 passed, 60 skipped**, 115 subtests passed |
-| python-multiplatform `develop` at `ba4c6f49` or later (has `add_member_resolver`) | **143 passed, 1 skipped**, 139 subtests passed |
-| an older checkout, without `add_member_resolver` | the same, with 5 more skipped |
-
-Without a checkout, the 59 tests that install the binder's layers through `tests/adapter.py` skip.
-Against a binder older than `ba4c6f49`, the 5 that call a snake_case method on a proxy the binder
-returned skip, because that needs its member resolver (python-multiplatform #17). The 1 skip in both
+| No `PythonMultiplatform` checkout found | **91 passed, 73 skipped**, 122 subtests passed |
+| python-multiplatform `develop` at `d6d39787` or later (has `add_member_resolver` and `describe(module, name)`) | **163 passed, 1 skipped**, 149 subtests passed |
+| an older checkout, without `describe(module, name)` (python-multiplatform #36) | the same, with 13 more skipped |
+| an older one still, without `add_member_resolver` | with 5 more skipped again |
+
+Without a checkout, the 72 tests that install the binder's layers through `tests/adapter.py` skip.
+Against a binder without `describe(module, name)`, the 13 that check grouped constants (§7, S7.1)
+skip. Against a binder older than `ba4c6f49`, the 5 that call a snake_case method on a proxy the
+binder returned skip as well, because that needs its member resolver (python-multiplatform #17). The 1 skip in both
 rows is `UI.ipynb`'s (§2). `tests/test_typing.py` skips where mypy is not installed. A skip is not a
 pass.
 
-Of the 84 that pass without a checkout, 30 check the type stubs and the wheel (S1.2); most of the
+Of the 91 that pass without a checkout, 37 check the type stubs and the wheel (S1.2); most of the
 rest assert **absence** (a retired token, a deleted file, a docstring that exists). Those are listed
 in §9 and are not counted as features.
 
@@ -261,7 +263,7 @@ a name is adapted once and then lives in the module dict; `dir()` reports the Py
 without the binding layer a name read says the host never installed it; dropping a proxy releases
 its Kotlin handle. Evidence: `tests/test_chain.py::Laziness` (5 tests), `::Handles` (1 test).
 
-## 7. Layout constants — `Alignment` and `Arrangement` — `partial`
+## 7. Layout constants — `Alignment` and `Arrangement` — `implemented`
 
 The bound constant names are documented in `pythonx/compose/ui/alignment.py` (15 `Alignment`
 names) and `pythonx/compose/layout/arrangement.py` (8 `Arrangement` names), checked by
@@ -277,11 +279,55 @@ the Kotlin module does not list is tried as a Kotlin object sub-package and serv
 `KotlinObject` namespace by the §3 rule. Constants keep their Kotlin spelling and are read again on
 every access; a function inside the object is snake_case (`Arrangement.spaced_by`). Evidence:
 `tests/test_chain.py::ObjectNamespaces` (6 tests); without the sub-package step 6 fail. The binder
-will list these objects itself (python-multiplatform #35).
-
-Decided (INTENT §5.3) and not built: the notebook's grouping by type, `Alignment.Horizontal.End`.
-It needs a constant's declared type without reading it, `python_multiplatform.describe(module,
-name)` (python-multiplatform #36; issue #9).
+now lists these objects itself (python-multiplatform #35), and either way reaches them.
+
+### S7.1 Grouped constants — `Alignment.Horizontal.End` — `implemented`
+
+INTENT §5.3: the notebook groups constants by type, `Alignment.Horizontal.End`, and Kotlin writes
+them flat, `Alignment.End` (which *is* an `Alignment.Horizontal`). Both spellings are served, by one
+rule that names no declaration:
+
+- Inside the `KotlinObject` for a Kotlin object `P`, an upper-case name `G` that is **not** a member
+  of `P` but is the simple name of a type nested in `P` -- some constant of `P` is declared as
+  exactly `P.G` -- is a **group**: a namespace whose members are exactly the constants of `P` whose
+  declared type is `P.G`. `Alignment.Horizontal` holds `CenterHorizontally`, `End`, `Start`;
+  `Alignment.Vertical` holds `Bottom`, `CenterVertically`, `Top`; `Arrangement.HorizontalOrVertical`
+  holds `Center`, `SpaceAround`, `SpaceBetween`, `SpaceEvenly`.
+- A constant's declared type is read with `python_multiplatform.describe(module, name)`
+  (python-multiplatform #36), which answers from the binder's table and never runs the getter. A
+  constant's value is never read to classify it. The classification is metadata and is computed
+  once per object; values are not cached.
+- Reading a group member reads that constant then and there, exactly as the flat spelling does:
+  `Alignment.Horizontal.End` and `Alignment.End` are the same read of the same Kotlin getter.
+- **A group holds a constant only under its exact declared type.** A constant declared as a
+  supertype is in no narrower group: `Alignment.Center` (declared `Alignment`) is in none, and
+  `Arrangement.SpaceBetween` (declared `Arrangement.HorizontalOrVertical`) is in
+  `Arrangement.HorizontalOrVertical` only, not in `Arrangement.Horizontal`, although Kotlin accepts
+  it wherever an `Arrangement.Horizontal` is expected. The notebook groups by declared type, and the
+  declared type is what the binder describes; subtyping is not modelled.
+- **Kotlin members win.** If `P` has a member named `G` (a constant, a function, a nested object
+  the binder lists), that member is what `P.G` reads, and there is no group of that name.
+- `dir()` of an object lists its group names next to its members; `dir()` of a group lists its
+  constants. A name a group does not hold raises `AttributeError` naming the group's Kotlin type
+  (`androidx.compose.ui.Alignment.Horizontal`), so `Alignment.Horizontal.Top` fails: `Top` is an
+  `Alignment.Vertical`.
+- On a binder without `describe(module, name)` there are no groups; the flat spelling is unchanged.
+- **Stubs.** `tools/gen_stubs.py` emits each group as a class nested in the object's stub class,
+  holding the same `ClassVar` constants, grouped by the declared type the upstream stub's docstring
+  carries (`"""Kotlin: androidx.compose.ui.Alignment.End(): androidx.compose.ui.Alignment.Horizontal"""`),
+  so a type checker accepts `Alignment.Horizontal.End` and rejects `Alignment.Horizontal.Top`. A
+  reference to the Kotlin type `Alignment.Horizontal` in a signature stays `typing.Any`: the group
+  class is a namespace, not the type of the constants.
+
+Evidence: `tests/test_chain.py::GroupedObjectConstants` (12 tests, runtime, against the fake host;
+with the group lookup disabled 11 fail, and the one that stays green checks the binder without
+`describe(module, name)`), `tests/test_stubs.py::TheConstantGroups` (5 tests, generator),
+`::TheCommittedStubs::test_the_committed_alignment_and_arrangement_carry_their_groups`,
+`::TheStubMatchesTheRuntime::test_a_group_in_the_stub_holds_what_the_runtime_group_holds`, and
+`tests/test_typing.py::TheStubsTypeCheck::test_a_grouped_constant_type_checks` (mypy). In the real
+`kotlin-stubs` artefact only `Alignment` and `Arrangement` have such groups. Nothing in the walked
+Compose surface is an extension receiver named `Alignment.Horizontal` or `Arrangement.Horizontal`, so
+the binder lists no member that would win over these groups.
 
 ## 8. The notebook surface not yet covered — `planned`
 
@@ -330,7 +376,7 @@ Found in the repository; not covered by `docs/INTENT.md`, or in conflict with it
    `pythonx.compose.foundation.layout` (plus `pythonx.compose.foundation` and `pythonx.compose`)
    "while the spelling settles".
 5. *(Resolved, #31.)* `material3/icon.py` and `color_scheme.py`, dead reflection code, are deleted.
-6. *(Decided, INTENT §5.3.)* Grouped alignment constants: both spellings are to be served; the grouped one is not built yet (§7).
+6. *(Resolved, INTENT §5.3, issue #9.)* Grouped alignment constants: both spellings are served (§7, S7.1).
 7. The submodule `pythonx/compose/native` → `thisisthepy/swing-graalvm-demo`, which INTENT does not
    mention. (The 29 empty `material3/*.py` files are deleted, #31.)
 8. **The `test/` directory** — a 2023–2024 Kotlin Multiplatform sample (`pycomposeui`, chaquopy

diff --git a/docs/guide/concepts.html b/docs/guide/concepts.html
@@ -80,8 +80,9 @@ <h2><span data-lang="en">Kotlin objects</span><span data-lang="ko">Kotlin 객체
 
 Alignment.Center
 Arrangement.End
-Arrangement.spaced_by(8)</code></pre>
-<p data-lang="en">The notebook's grouping by type, <code>Alignment.Horizontal.End</code>, is decided but not built yet; write <code>Alignment.End</code>.</p><p data-lang="ko">노트북의 타입별 묶음 표기 <code>Alignment.Horizontal.End</code> 는 결정되었지만 아직 만들어지지 않았습니다. <code>Alignment.End</code> 로 쓰세요.</p>
+Arrangement.spaced_by(8)
+Alignment.Horizontal.End      # the same constant as Alignment.End</code></pre>
+<p data-lang="en">A constant can also be read grouped by its declared type, as the notebook writes it: <code>Alignment.Horizontal.End</code> is <code>Alignment.End</code>, read the same way. A group holds only the constants declared as exactly that type, so <code>Alignment.Center</code> (declared <code>Alignment</code>) is in no group, and <code>Arrangement.SpaceBetween</code> is under <code>Arrangement.HorizontalOrVertical</code>, not <code>Arrangement.Horizontal</code>.</p><p data-lang="ko">노트북처럼 상수를 선언된 타입별로 묶어서 읽을 수도 있습니다. <code>Alignment.Horizontal.End</code> 는 <code>Alignment.End</code> 이며 같은 방식으로 읽힙니다. 묶음에는 정확히 그 타입으로 선언된 상수만 들어가므로 <code>Alignment.Center</code>(선언 타입 <code>Alignment</code>)는 어느 묶음에도 없고, <code>Arrangement.SpaceBetween</code> 은 <code>Arrangement.Horizontal</code> 이 아니라 <code>Arrangement.HorizontalOrVertical</code> 아래에 있습니다.</p>
 </section>
 
 <section>

diff --git a/docs/guide/getting-started.html b/docs/guide/getting-started.html
@@ -43,7 +43,7 @@ <h2><span data-lang="en">1. Get the source</span><span data-lang="ko">1. 소스
 <section>
 <h2><span data-lang="en">2. Run the tests</span><span data-lang="ko">2. 테스트 실행</span></h2>
 <pre><code class="language-bash">python3 -m pytest tests -q</code></pre>
-<p data-lang="en">Expect <strong>84 passed, 60 skipped</strong>. One skipped test reads the maintainer's <code>UI.ipynb</code>, which a clone does not have; mypy type-checks the stubs. The other skipped tests drive the binder's adaptation layer and need a <a href="https://github.com/thisisthepy/python-multiplatform">python-multiplatform</a> checkout beside this one, or:</p><p data-lang="ko"><strong>84 passed, 60 skipped</strong> 가 정상입니다. 건너뛴 테스트 하나는 클론에는 없는 메인테이너의 <code>UI.ipynb</code> 를 읽으며, mypy 는 스텁을 타입 검사합니다. 나머지 건너뛴 테스트는 바인더의 적응 계층을 구동하며, 옆에 <a href="https://github.com/thisisthepy/python-multiplatform">python-multiplatform</a> 체크아웃이 있거나 다음이 필요합니다:</p>
+<p data-lang="en">Expect <strong>91 passed, 73 skipped</strong>. One skipped test reads the maintainer's <code>UI.ipynb</code>, which a clone does not have; mypy type-checks the stubs. The other skipped tests drive the binder's adaptation layer and need a <a href="https://github.com/thisisthepy/python-multiplatform">python-multiplatform</a> checkout beside this one, or:</p><p data-lang="ko"><strong>91 passed, 73 skipped</strong> 가 정상입니다. 건너뛴 테스트 하나는 클론에는 없는 메인테이너의 <code>UI.ipynb</code> 를 읽으며, mypy 는 스텁을 타입 검사합니다. 나머지 건너뛴 테스트는 바인더의 적응 계층을 구동하며, 옆에 <a href="https://github.com/thisisthepy/python-multiplatform">python-multiplatform</a> 체크아웃이 있거나 다음이 필요합니다:</p>
 <pre><code class="language-bash">PYTHONMULTIPLATFORM_HOME=/path/to/python-multiplatform python3 -m pytest tests -q</code></pre>
 <p data-lang="en">With a current one (<code>ba4c6f49</code> or later) <strong>143 pass</strong> and only the <code>UI.ipynb</code> test skips; an older one skips 5 that call a snake_case method on a proxy the binder returned. That is expected and recorded.</p><p data-lang="ko">최신 체크아웃(<code>ba4c6f49</code> 이후)이면 <strong>143 개가 통과</strong>하고 <code>UI.ipynb</code> 테스트만 건너뛰며, 오래된 체크아웃은 바인더가 돌려준 proxy 의 snake_case 메서드를 부르는 5 개를 <strong>건너뜁니다</strong>. 예상된 상태이며 기록되어 있습니다.</p>
 </section>