diff --git a/README.ja.md b/README.ja.md
index 6ed7e01..6ec860e 100644
--- a/README.ja.md
+++ b/README.ja.md
@@ -221,6 +221,7 @@ exstruct input.xlsx --pdf --image --dpi 144
           "text": "開始",
           "l": 148,
           "t": 220,
+          "kind": "shape",
           "type": "AutoShape-FlowchartProcess"
         },
         {
@@ -228,12 +229,13 @@ exstruct input.xlsx --pdf --image --dpi 144
           "text": "入力データ読み込み",
           "l": 132,
           "t": 282,
+          "kind": "shape",
           "type": "AutoShape-FlowchartProcess"
         },
         {
           "l": 193,
           "t": 246,
-          "type": "AutoShape-Mixed",
+          "kind": "arrow",
           "begin_arrow_style": 1,
           "end_arrow_style": 2,
           "begin_id": 1,
diff --git a/README.md b/README.md
index 11a456b..f235e30 100644
--- a/README.md
+++ b/README.md
@@ -222,6 +222,7 @@ Below is a **shortened JSON output example** from parsing this Excel workbook.
           "text": "開始",
           "l": 148,
           "t": 220,
+          "kind": "shape",
           "type": "AutoShape-FlowchartProcess"
         },
         {
@@ -229,12 +230,13 @@ Below is a **shortened JSON output example** from parsing this Excel workbook.
           "text": "入力データ読み込み",
           "l": 132,
           "t": 282,
+          "kind": "shape",
           "type": "AutoShape-FlowchartProcess"
         },
         {
           "l": 193,
           "t": 246,
-          "type": "AutoShape-Mixed",
+          "kind": "arrow",
           "begin_arrow_style": 1,
           "end_arrow_style": 2,
           "begin_id": 1,
diff --git a/docs/README.en.md b/docs/README.en.md
index 5ae275f..e43314b 100644
--- a/docs/README.en.md
+++ b/docs/README.en.md
@@ -222,6 +222,7 @@ Below is a **shortened JSON output example** from parsing this Excel workbook.
           "text": "開始",
           "l": 148,
           "t": 220,
+          "kind": "shape",
           "type": "AutoShape-FlowchartProcess"
         },
         {
@@ -229,12 +230,13 @@ Below is a **shortened JSON output example** from parsing this Excel workbook.
           "text": "入力データ読み込み",
           "l": 132,
           "t": 282,
+          "kind": "shape",
           "type": "AutoShape-FlowchartProcess"
         },
         {
           "l": 193,
           "t": 246,
-          "type": "AutoShape-Mixed",
+          "kind": "arrow",
           "begin_arrow_style": 1,
           "end_arrow_style": 2,
           "begin_id": 1,
diff --git a/docs/README.ja.md b/docs/README.ja.md
index d3e2676..7091001 100644
--- a/docs/README.ja.md
+++ b/docs/README.ja.md
@@ -221,6 +221,7 @@ exstruct input.xlsx --pdf --image --dpi 144
           "text": "開始",
           "l": 148,
           "t": 220,
+          "kind": "shape",
           "type": "AutoShape-FlowchartProcess"
         },
         {
@@ -228,12 +229,13 @@ exstruct input.xlsx --pdf --image --dpi 144
           "text": "入力データ読み込み",
           "l": 132,
           "t": 282,
+          "kind": "shape",
           "type": "AutoShape-FlowchartProcess"
         },
         {
           "l": 193,
           "t": 246,
-          "type": "AutoShape-Mixed",
+          "kind": "arrow",
           "begin_arrow_style": 1,
           "end_arrow_style": 2,
           "begin_id": 1,
diff --git a/docs/release-notes/v0.3.1.md b/docs/release-notes/v0.3.1.md
new file mode 100644
index 0000000..7cd0353
--- /dev/null
+++ b/docs/release-notes/v0.3.1.md
@@ -0,0 +1,16 @@
+# v0.3.1 Release Notes
+
+This release adds SmartArt extraction and updates shape modeling to better
+separate standard shapes, arrows, and SmartArt structures.
+
+## Highlights
+
+- SmartArt extraction via Excel COM, including layout name and nested nodes.
+- Shape modeling split into `Shape`, `Arrow`, and `SmartArt` for clearer semantics.
+- SmartArt node payload optimized for compact output (`layout`, `nodes`, `kids`).
+
+## Compatibility Notes
+
+- `Shape.type` now exists only on `Shape`; it is omitted for `Arrow` and `SmartArt`.
+- SmartArt output uses `layout` and `nodes` with `kids`; previous fields like
+  `layout_name`, `roots`, or `children` are no longer present.
diff --git a/mkdocs.yml b/mkdocs.yml
index fac6be0..528976a 100644
--- a/mkdocs.yml
+++ b/mkdocs.yml
@@ -27,6 +27,7 @@ nav:
   - CLI Guide: cli.md
   - Concept / Why ExStruct?: concept.md
   - Release Notes:
+      - v0.3.1: release-notes/v0.3.1.md
       - v0.3.0: release-notes/v0.3.0.md
       - v0.2.90: release-notes/v0.2.90.md
       - v0.2.80: release-notes/v0.2.80.md
diff --git a/pyproject.toml b/pyproject.toml
index bb38abb..e9fb6ca 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,6 @@
 [project]
 name = "exstruct"
-version = "0.3.0"
+version = "0.3.1"
 description = "Excel to structured JSON (tables, shapes, charts) for LLM/RAG pipelines"
 readme = "README.md"
 license = { file = "LICENSE" }