diff --git a/.trellis/spec/guides/code-reuse-thinking-guide.md b/.trellis/spec/guides/code-reuse-thinking-guide.md
index 90bd946..befbe46 100644
--- a/.trellis/spec/guides/code-reuse-thinking-guide.md
+++ b/.trellis/spec/guides/code-reuse-thinking-guide.md
@@ -42,13 +42,14 @@ Blender 高度与线性颜色。两侧靠 `catalog.check_layers()` 对账集合
 
 ### 区域输出路径
 
-输出路径只在 `scripts/build-area.js:74` 的 `normalizeAreaConfig()` 推导。
-低层脚本读取 `_pipeline/osm2streets-qgis.config.json`，不要重新读取
+输出路径只在 `scripts/lib/area-config.js` 的 `normalizeAreaConfig()` 推导。
+`scripts/build-area.js` 和 `scripts/diagnose-area.js` 都必须通过 `readAreaConfig()` 读取
+区域配置。低层脚本读取 `_pipeline/osm2streets-qgis.config.json`，不要重新读取
 `config/areas/*.json` 或在阶段函数里现场拼路径。
 
-新增产物时，在 `normalizeAreaConfig` 的 `outputs` 里加一项，再按需写入
-`writeDerivedConfig()`（`build-area.js:189`）。这样 `intermediates`、`reimport`、
-`blender`、`cesium`、`preview` 仍然只通过磁盘产物耦合。
+新增产物时，在 `area-config.js` 的 `outputs` 里加一项，再按需写入
+`writeDerivedConfig()`。这样 `intermediates`、`reimport`、`blender`、`cesium`、
+`preview` 和读-only 诊断仍然只通过磁盘产物耦合。
 
 ### 材质声明
 
@@ -65,18 +66,20 @@ Cesium 导出调色也属于同一个材质声明：新场景把 `catalog.MATERI
 
 ## 可接受的重复
 
-### 三份 `parseArgs`
+### 多份 `parseArgs`
 
-`parseArgs` 现在重复在三个独立入口：
+`parseArgs` 现在重复在多个独立入口：
 
-- `scripts/build-area.js:50`
+- `scripts/build-area.js:54`
 - `scripts/build-osm2streets-qgis.js:153`
 - `scripts/reimport-gpkg.js:93`
+- `scripts/compress-glb.js:16`
+- `scripts/diagnose-area.js:17`
 
 语义一致：`--kebab-case value` 变 `kebabCase: "value"`，无值 flag 变字符串 `"true"`。
 
-这份重复目前是可接受技术债，因为三个脚本都能独立运行。改其中一处解析语义时，不要顺手
-只改一份；要么保持三份一致，要么把"抽公共模块"作为独立重构并跑 parity。
+这份重复目前是可接受技术债，因为这些脚本都能独立运行。改其中一处解析语义时，不要顺手
+只改一份；要么保持全部入口一致，要么把"抽公共模块"作为独立重构并跑对应入口检查。
 
 ### JS 与 Python 的图层颜色
 
@@ -132,7 +135,7 @@ Cesium 导出调色也属于同一个材质声明：新场景把 `catalog.MATERI
 
 不要因为代码相似就抽象：
 
-- 三份 `parseArgs` 当前保持独立入口价值
+- 多份 `parseArgs` 当前保持独立入口价值
 - `ROAD_LAYERS` 与 `SCENE_LAYERS` 跨语言且承载不同字段
 - 每个要素模块各自调用 `clip_polygon` 是模块边界，不是可消除重复
 
@@ -156,6 +159,6 @@ Cesium 导出调色也属于同一个材质声明：新场景把 `catalog.MATERI
 | 新增一份图层名列表 | 回到旧的四份同步，漏改静默错栈 |
 | 把两套颜色表统一 | 破坏 QGIS 与 Blender 各自调过的视觉结果 |
 | 低层脚本直接读 `config/areas/*.json` | 两层配置边界失效 |
-| 只改一份 `parseArgs` 的语义 | 三个入口行为分裂 |
+| 只改一份 `parseArgs` 的语义 | 独立入口行为分裂 |
 | 把要素模块裁剪逻辑挪到调用方 | 不同要素的越界处理开始漂移 |
 | 只改 `export_cesium.py` 的旧回退表，不写 `MATERIALS[*]["cesium"]` | 新 `.blend` 不会携带 Cesium 导出契约 |
diff --git a/.trellis/spec/guides/index.md b/.trellis/spec/guides/index.md
index ec2372a..56a457a 100644
--- a/.trellis/spec/guides/index.md
+++ b/.trellis/spec/guides/index.md
@@ -30,8 +30,9 @@
 ### 读代码复用思考指南
 
 - [ ] 准备新增第二份或第三份图层、材质、配置字段枚举
-- [ ] 修改三份重复的 `parseArgs` 之一：
-  `build-area.js:50`、`build-osm2streets-qgis.js:153`、`reimport-gpkg.js:93`
+- [ ] 修改多份重复的 `parseArgs` 之一：
+  `build-area.js:54`、`build-osm2streets-qgis.js:153`、`reimport-gpkg.js:93`、
+  `compress-glb.js:16`、`diagnose-area.js:17`
 - [ ] 多个要素模块都要做同一件几何预处理，比如
   `water.py:9`、`grass.py:9`、`scrub.py:8` 都先 `clip_polygon`
 - [ ] 低层脚本想直接读取 `config/areas/*.json`，绕开派生配置
@@ -66,7 +67,7 @@ grep -rn "要改的值" scripts blender config
 - 先看它有没有读到对应包的 index 和本目录指南
 - 对任何"行为没变"的结论，要求说明是否需要 parity；需要却没跑就是风险
 - 对任何"可以合并重复"的建议，先判断重复是不是刻意边界：
-  三份 `parseArgs` 目前是可接受技术债，JS/Python 图层颜色则是刻意不同步
+  多份 `parseArgs` 目前是可接受技术债，JS/Python 图层颜色则是刻意不同步
 - 对任何"加精度、加默认值、直接覆盖文件"的建议，回到真实代码注释验证；
   `reimport-gpkg.js:152-156` 和 `reimport-gpkg.js:11-13` 都是反直觉约束
 
diff --git a/.trellis/spec/pipeline/cli-and-stages.md b/.trellis/spec/pipeline/cli-and-stages.md
index 00e0ac2..93b1cd3 100644
--- a/.trellis/spec/pipeline/cli-and-stages.md
+++ b/.trellis/spec/pipeline/cli-and-stages.md
@@ -4,13 +4,14 @@
 
 ---
 
-## 三个入口脚本
+## 命令入口脚本
 
 | 脚本 | 角色 | 入口方式 |
 |---|---|---|
 | `scripts/build-area.js` | **主入口**。读区域配置，按阶段调度 | `npm run build` / `build:area` |
 | `scripts/build-osm2streets-qgis.js` | intermediates 阶段的实现 | 由 build-area 调起；`npm run build:qgis` 可单跑 |
 | `scripts/reimport-gpkg.js` | reimport 阶段的实现 | 由 build-area 调起 |
+| `scripts/diagnose-area.js` | 快速区域诊断；只读配置、OSM 和已有产物 | `npm run diagnose:area` |
 
 `scripts/parity.js` 和 `scripts/glb-digest.js` 是校验工具，不属于构建链，见
 [产物一致性指南](../guides/artifact-parity-guide.md)。
@@ -119,10 +120,102 @@ npm run compress:glb -- --input outputs/a/a.glb --output outputs/a/a-compressed-
 
 ---
 
+## 区域诊断命令
+
+### 1. Scope / Trigger
+
+`diagnose:area` 是手工编辑 OSM、排查 building relation、高度语义、植被数量和现有
+产物体量时的快速读-only 检查。它不属于构建阶段，不进入 `--stages`，也不调用 QGIS、
+Blender、Cesium 或 `gltf-transform`。
+
+### 2. Signatures
+
+```bash
+npm run diagnose:area
+npm run diagnose:area -- --config config/areas/<area>.json
+```
+
+底层入口：
+
+```bash
+node scripts/diagnose-area.js [--config config/areas/<area>.json]
+```
+
+### 3. Contracts
+
+- 不传 `--config` 时默认读取 `config/areas/nantaizi-lake-innovation-valley.json`。
+- 区域配置必须通过 `scripts/lib/area-config.js` 的 `readAreaConfig()` 归一化，和
+  `build-area.js` 共用同一套输出路径、压缩文件名、默认阶段和配置字段语义。
+- 命令只读取：
+  - 区域配置
+  - 配置里的 OSM XML
+  - 已存在的 `area.outputs.*` 产物
+  - 已存在的默认 GLB（通过 `scripts/glb-digest.js` 导出的 `digest()`）
+- 输出为 text report，包含 OSM bounds、节点/way/relation 数量、building way、
+  building multipolygon relation、显式 `height` / `building:levels`、植被数量、
+  产物存在性、metadata 摘要、GLB size/counts/extensions 和 warnings。
+- warnings 不改变退出码；配置缺失、输入 OSM 缺失、GLB 文件损坏这类无法继续读取的错误才
+  非零退出。
+
+### 4. Validation & Error Matrix
+
+| 条件 | 结果 |
+|---|---|
+| 配置文件不存在 | `Config file not found: <path>`，非零 |
+| `id` / `input` 缺失 | `Missing config key: <key>`，非零 |
+| OSM XML 不存在 | `Input OSM XML not found: <path>`，非零 |
+| OSM 缺 `<bounds>` | warning，不中断 |
+| building multipolygon 缺 outer / unresolved way / open ring | warning，不中断 |
+| baseline 产物缺失 | warning，不中断 |
+| metadata JSON 损坏 | warning，不中断 |
+| GLB 存在但不是合法 GLB | 抛出 `glb-digest` 错误，非零 |
+| GLB 超过保守预算 | warning，不中断 |
+
+### 5. Good/Base/Bad Cases
+
+- Good: 手工改完 OSM 后先跑 `npm run diagnose:area -- --config ...`，确认 building
+  relation healthy，再跑 `--stages blender,cesium`。
+- Base: 只生成过部分阶段时运行诊断，缺失产物以 warning 暴露，用来判断下一步该补哪个阶段。
+- Bad: 把诊断做成 `build-area` 的新 stage；它是读-only 工具，不应参与构建调度或产物生成。
+
+### 6. Tests Required
+
+- `node --check scripts/diagnose-area.js`
+- `node --check scripts/lib/area-config.js`
+- `node --check scripts/build-area.js`
+- `node --check scripts/glb-digest.js`
+- `npm run diagnose:area -- --config config/areas/nantaizi-lake-innovation-valley.json`
+- 如果抽取了配置归一化，至少跑一个轻量 `build-area` 阶段确认主入口仍能调度：
+  `npm run build:area -- --config config/areas/nantaizi-lake-innovation-valley.json --stages preview`
+
+### 7. Wrong vs Correct
+
+Wrong:
+
+```js
+const config = JSON.parse(fs.readFileSync("config/areas/a.json", "utf8"));
+const glb = path.join(config.outputRoot, config.id, `${config.id}.glb`);
+```
+
+Correct:
+
+```js
+const { readAreaConfig } = require("./lib/area-config");
+const area = readAreaConfig(configPath, { repoRoot });
+const glb = area.outputs.glb;
+```
+
+---
+
 ## CLI 参数解析
 
-三个脚本各有一份**完全相同**的 `parseArgs`
-（`build-area.js:50`、`build-osm2streets-qgis.js:153`、`reimport-gpkg.js:93`）：
+独立入口脚本各有一份同语义的 `parseArgs`：
+
+- `build-area.js:54`
+- `build-osm2streets-qgis.js:153`
+- `reimport-gpkg.js:93`
+- `compress-glb.js:16`
+- `diagnose-area.js:17`
 
 ```js
 --kebab-case value   →   { kebabCase: "value" }
@@ -136,9 +229,9 @@ npm run compress:glb -- --input outputs/a/a.glb --output outputs/a/a-compressed-
 - **不做校验**。未知参数被静默收集，缺失参数由下游的 `requireText` / `Number.isFinite`
   报错
 
-> 这份重复是已知的、**当前被接受的**技术债：三个脚本要能各自独立运行，抽公共模块的
-> 收益还不抵引入一层依赖。改其中一份时**不要**顺手把另外两份重构掉——那是独立的决定，
-> 且会扩大 diff。真要抽取，三处一起改并跑 parity。
+> 这份重复是已知的、**当前被接受的**技术债：这些脚本要能各自独立运行，抽公共模块的
+> 收益还不抵引入一层依赖。改其中一份解析语义时**不要**只改一份；要么保持全部一致，
+> 要么把抽公共解析器作为独立重构并跑对应入口检查。
 
 ---
 
@@ -279,7 +372,7 @@ parity 校验依赖 stage 的 stdout 标记来判断阶段是否跑到（如 `SC
 | 让 `reimport` / `preview` 能从配置文件默认开启 | 恢复动作变成常规行为 |
 | 新阶段忘了 `ensureFile` 前置校验 | 单跑时报底层堆栈而非人话 |
 | 改 stage 的 stdout 标记 | 静默破坏 parity 契约 |
-| 顺手把三份 `parseArgs` 合并 | 扩大 diff，且三个脚本的独立性是刻意的 |
+| 顺手把多份 `parseArgs` 合并 | 扩大 diff，且独立入口的独立性是刻意的 |
 
 ---
 
diff --git a/.trellis/spec/pipeline/index.md b/.trellis/spec/pipeline/index.md
index 1d2b111..3acc039 100644
--- a/.trellis/spec/pipeline/index.md
+++ b/.trellis/spec/pipeline/index.md
@@ -13,6 +13,7 @@
 | 改九个 osm2streets 图层（增/删/改顺序/改色） | [图层表](./layer-registry.md) ← **最容易出静默错误** |
 | 调 QGIS / GDAL / Blender 子进程 | [外部工具调用](./external-tools.md) |
 | 加阶段、加 CLI 参数、改配置字段 | [CLI 与阶段](./cli-and-stages.md) |
+| 改区域诊断命令或共享区域配置归一化 | [CLI 与阶段](./cli-and-stages.md#区域诊断命令) |
 | 改预览页生成 | [../preview/](../preview/index.md) |
 | 声称"纯重构，产物不变" | [产物一致性指南](../guides/artifact-parity-guide.md) |
 
@@ -23,7 +24,9 @@
 ```
 config/areas/<id>.json
       │
-      ▼  build-area.js — normalizeAreaConfig() 推导全部输出路径
+      ▼  lib/area-config.js — normalizeAreaConfig() 推导全部输出路径
+      │
+      ▼  build-area.js — 阶段调度
    _pipeline/osm2streets-qgis.config.json          （派生配置）
       │
       ├─[intermediates]─▶ build-osm2streets-qgis.js
@@ -75,14 +78,16 @@ config/areas/<id>.json
 
 | 文件 | 行数 | 职责 |
 |---|---|---|
-| `build-area.js` | 774 | 主入口：配置归一化、阶段调度、Cesium 预览页与车辆巡航生成 |
+| `build-area.js` | 745 | 主入口：区域配置读取、阶段调度、Cesium 预览页与车辆巡航生成 |
+| `diagnose-area.js` | 438 | 快速诊断：OSM building relation、植被统计、现有产物和 GLB digest |
+| `lib/area-config.js` | 133 | 区域配置归一化与输出路径推导，供 build / diagnose 复用 |
 | `build-osm2streets-qgis.js` | 1468 | intermediates：osm2streets 解析、图层拆分、人行道转角合成、GeoPackage 与 QGIS 工程生成 |
 | `reimport-gpkg.js` | 179 | reimport：GeoPackage → GeoJSON 反向导出 |
 | `lib/scene-layers.js` | 164 | 九个图层的单一事实源 + 四个派生函数 |
 | `lib/cesium-preview.js` / `.css` | 672 / 230 | 预览页运行时，见 [../preview/](../preview/index.md) |
 | `normalize-lane-arrows.py` | 182 | 合并 osm2streets 的三角网箭头（跑在 QGIS Python 里） |
 | `parity.js` | 270 | 产物一致性校验驱动 |
-| `glb-digest.js` | 121 | GLB 结构摘要 |
+| `glb-digest.js` | 132 | GLB 结构摘要，CLI 和诊断脚本共用 |
 
 ---
 
diff --git a/.trellis/tasks/08-04-add-area-diagnostics/check.jsonl b/.trellis/tasks/08-04-add-area-diagnostics/check.jsonl
new file mode 100644
index 0000000..9dd3234
--- /dev/null
+++ b/.trellis/tasks/08-04-add-area-diagnostics/check.jsonl
@@ -0,0 +1 @@
+{"_example": "Fill with {\"file\": \"<path>\", \"reason\": \"<why>\"}. Put spec/research files only — no code paths. Run `python3 .trellis/scripts/get_context.py --mode packages` to list available specs. Delete this line once real entries are added."}
diff --git a/.trellis/tasks/08-04-add-area-diagnostics/implement.jsonl b/.trellis/tasks/08-04-add-area-diagnostics/implement.jsonl
new file mode 100644
index 0000000..9dd3234
--- /dev/null
+++ b/.trellis/tasks/08-04-add-area-diagnostics/implement.jsonl
@@ -0,0 +1 @@
+{"_example": "Fill with {\"file\": \"<path>\", \"reason\": \"<why>\"}. Put spec/research files only — no code paths. Run `python3 .trellis/scripts/get_context.py --mode packages` to list available specs. Delete this line once real entries are added."}
diff --git a/.trellis/tasks/08-04-add-area-diagnostics/prd.md b/.trellis/tasks/08-04-add-area-diagnostics/prd.md
new file mode 100644
index 0000000..fc24b8b
--- /dev/null
+++ b/.trellis/tasks/08-04-add-area-diagnostics/prd.md
@@ -0,0 +1,40 @@
+# Add area diagnostics command
+
+## Goal
+
+Add a fast area diagnostics CLI for OSM structure and existing output artifact health.
+
+## Requirements
+
+- Add a fast diagnostics CLI for an area config.
+- The command must not invoke QGIS, Blender, Cesium, or GLB compression.
+- The report must scan the configured OSM XML for common manual-edit risks:
+  bounds presence, nodes, ways, relations, building ways, building multipolygon
+  relations, explicit heights, building levels, malformed relation members,
+  unresolved member ways, open rings, and basic vegetation counts.
+- The report must inspect existing output artifacts when present:
+  GeoJSON directory, GeoPackage, QGIS project, `.blend`, render PNG, GLB,
+  metadata, Cesium preview, compressed GLB, compressed metadata, and compressed
+  preview.
+- If a GLB exists, the report should reuse the existing GLB digest logic to
+  summarize size, nodes, meshes, materials, images, accessors, and extensions.
+- The command should emit clear warnings for likely trouble, including missing
+  OSM bounds, malformed building multipolygons, missing expected artifacts, GLB
+  over a conservative size budget, high node count, and high texture count.
+- Add an npm script and README usage.
+
+## Acceptance Criteria
+
+- [x] `npm run diagnose:area -- --config config/areas/nantaizi-lake-innovation-valley.json`
+      prints a useful text report without running heavy build stages.
+- [x] The diagnostics report includes OSM structure, building relation health,
+      vegetation counts, output artifact status, and GLB digest summary.
+- [x] Missing optional output artifacts are warnings, not hard failures.
+- [x] Syntax checks pass for the changed Node scripts.
+- [x] README documents the new diagnostic command.
+
+## Notes
+
+- Keep `prd.md` focused on requirements, constraints, and acceptance criteria.
+- Lightweight tasks can remain PRD-only.
+- For complex tasks, add `design.md` for technical design and `implement.md` for execution planning before `task.py start`.
diff --git a/.trellis/tasks/08-04-add-area-diagnostics/task.json b/.trellis/tasks/08-04-add-area-diagnostics/task.json
new file mode 100644
index 0000000..e3247db
--- /dev/null
+++ b/.trellis/tasks/08-04-add-area-diagnostics/task.json
@@ -0,0 +1,26 @@
+{
+  "id": "add-area-diagnostics",
+  "name": "add-area-diagnostics",
+  "title": "Add area diagnostics command",
+  "description": "Add a fast area diagnostics CLI for OSM structure and existing output artifact health.",
+  "status": "in_progress",
+  "dev_type": null,
+  "scope": null,
+  "package": null,
+  "priority": "P2",
+  "creator": "dingkang",
+  "assignee": "dingkang",
+  "createdAt": "2026-08-04",
+  "completedAt": null,
+  "branch": null,
+  "base_branch": "main",
+  "worktree_path": null,
+  "commit": null,
+  "pr_url": null,
+  "subtasks": [],
+  "children": [],
+  "parent": null,
+  "relatedFiles": [],
+  "notes": "",
+  "meta": {}
+}
\ No newline at end of file
diff --git a/README.md b/README.md
index 5def2af..fd0f73e 100644
--- a/README.md
+++ b/README.md
@@ -63,6 +63,19 @@ npm run build:area -- --config config/areas/nantaizi-lake-innovation-valley.json
 npm run build:area -- --config config/areas/nantaizi-lake-innovation-valley.json --stages cesium,compress
 ```
 
+## 区域诊断
+
+手工编辑 OSM 或怀疑产物变大时，先跑快速诊断。它只读取区域配置、OSM XML 和已有输出
+文件，不会启动 QGIS、Blender 或 Cesium 构建：
+
+```bash
+npm run diagnose:area -- --config config/areas/nantaizi-lake-innovation-valley.json
+```
+
+诊断会输出 OSM bounds、building way / multipolygon relation、显式高度、植被数量、
+现有产物状态，以及 GLB 的 size / nodes / meshes / materials / images / extensions。
+缺少已期望的基线产物、异常 building relation、GLB 超过保守预算等会进入 `Warnings`。
+
 ## 区域配置
 
 新区域从模板复制：
diff --git a/docs/changelog.md b/docs/changelog.md
index 4175e0b..6c8990e 100644
--- a/docs/changelog.md
+++ b/docs/changelog.md
@@ -1,5 +1,15 @@
 # Changelog
 
+## 2026-08-04
+
+- 新增区域快速诊断入口：`npm run diagnose:area -- --config config/areas/<area>.json`。
+  诊断只读取区域配置、OSM XML 和已有输出，不启动 QGIS / Blender / Cesium 构建；报告
+  OSM bounds、building way / multipolygon relation、显式 `height` /
+  `building:levels`、植被数量、产物存在性、metadata 和 GLB digest，并对 malformed
+  building relation、缺失基线产物、GLB size / nodes / images 超预算给 warning。
+  同时把区域配置归一化抽到 `scripts/lib/area-config.js`，`build-area.js` 和
+  `diagnose-area.js` 共用同一套输出路径推导，避免诊断脚本复制路径规则。
+
 ## 2026-08-03
 
 - 修复 OSM `type=multipolygon` building relation 不渲染的问题：`parse_osm()` 现在会把
diff --git a/package.json b/package.json
index 5c16077..2e20bf5 100644
--- a/package.json
+++ b/package.json
@@ -7,7 +7,8 @@
     "build": "node scripts/build-area.js",
     "build:area": "node scripts/build-area.js",
     "build:qgis": "node scripts/build-osm2streets-qgis.js",
-    "compress:glb": "node scripts/compress-glb.js"
+    "compress:glb": "node scripts/compress-glb.js",
+    "diagnose:area": "node scripts/diagnose-area.js"
   },
   "dependencies": {
     "osm2streets-js-node": "0.1.4"
diff --git a/scripts/build-area.js b/scripts/build-area.js
index 86fb9f6..e02d968 100755
--- a/scripts/build-area.js
+++ b/scripts/build-area.js
@@ -3,13 +3,14 @@
 const fs = require("fs");
 const path = require("path");
 const { spawnSync } = require("child_process");
+const { readAreaConfig } = require("./lib/area-config");
 
 const repoRoot = path.resolve(__dirname, "..");
 const args = parseArgs(process.argv.slice(2));
 const configPath = path.resolve(
   args.config || path.join(repoRoot, "config", "areas", "nantaizi-lake-innovation-valley.json"),
 );
-const area = normalizeAreaConfig(readJson(configPath));
+const area = readAreaConfig(configPath, { repoRoot });
 const requestedStages = args.stages
   ? splitList(args.stages)
   : null;
@@ -67,129 +68,6 @@ function parseArgs(argv) {
   return out;
 }
 
-function readJson(file) {
-  if (!fs.existsSync(file)) {
-    throw new Error(`Config file not found: ${file}`);
-  }
-  return JSON.parse(fs.readFileSync(file, "utf8"));
-}
-
-function normalizeAreaConfig(raw) {
-  const id = requireText(raw.id, "id");
-  const input = path.resolve(requireText(raw.input, "input"));
-  if (!fs.existsSync(input)) {
-    throw new Error(`Input OSM XML not found: ${input}`);
-  }
-
-  const outputRoot = path.resolve(raw.outputRoot || path.join(repoRoot, "outputs"));
-  const outputOverrides = raw.outputs || {};
-  const areaDir = path.resolve(outputOverrides.areaDir || path.join(outputRoot, id));
-  const fileStem = outputOverrides.fileStem || id;
-  const compress = normalizeCompressConfig(raw.compress);
-  const compressedFileStem = outputOverrides.compressedFileStem ||
-    `${fileStem}-compressed-webp${compress.textureSize}${compress.meshopt ? "-meshopt" : ""}`;
-  const outputs = {
-    areaDir,
-    geojsonDir: path.resolve(outputOverrides.geojsonDir || path.join(areaDir, "osm2streets_web_out")),
-    gpkg: path.resolve(outputOverrides.gpkg || path.join(areaDir, `${fileStem}.gpkg`)),
-    qgisProject: path.resolve(outputOverrides.qgisProject || path.join(areaDir, `${fileStem}.qgz`)),
-    qgisPreview: path.resolve(outputOverrides.qgisPreview || path.join(areaDir, `${fileStem}-preview.png`)),
-    blend: path.resolve(outputOverrides.blend || path.join(areaDir, `${fileStem}.blend`)),
-    render: path.resolve(outputOverrides.render || path.join(areaDir, `${fileStem}.png`)),
-    glb: path.resolve(outputOverrides.glb || path.join(areaDir, `${fileStem}.glb`)),
-    metadata: path.resolve(outputOverrides.metadata || path.join(areaDir, `${fileStem}.json`)),
-    cesiumPreview: path.resolve(
-      outputOverrides.cesiumPreview || path.join(areaDir, `${fileStem}-cesium-preview.html`),
-    ),
-    compressedGlb: path.resolve(
-      outputOverrides.compressedGlb || path.join(areaDir, `${compressedFileStem}.glb`),
-    ),
-    compressedMetadata: path.resolve(
-      outputOverrides.compressedMetadata || path.join(areaDir, `${compressedFileStem}.json`),
-    ),
-    compressedCesiumPreview: path.resolve(
-      outputOverrides.compressedCesiumPreview || path.join(areaDir, `${compressedFileStem}-cesium-preview.html`),
-    ),
-    vehicleRoute: path.resolve(outputOverrides.vehicleRoute || path.join(areaDir, `${fileStem}-vehicle-route.json`)),
-    vehicleModel: path.resolve(outputOverrides.vehicleModel || path.join(areaDir, `${fileStem}-vehicle-car.gltf`)),
-    pipelineDir: path.resolve(outputOverrides.pipelineDir || path.join(areaDir, "_pipeline")),
-  };
-
-  return {
-    id,
-    input,
-    outputRoot,
-    qgisApp: raw.qgisApp || "/Applications/QGIS.app",
-    blenderApp: raw.blenderApp || "/Applications/Blender.app",
-    stages: {
-      intermediates: raw.stages?.intermediates ?? raw.stages?.qgis ?? true,
-      blender: raw.stages?.blender ?? true,
-      cesium: raw.stages?.cesium ?? true,
-      reimport: false,
-      preview: false,
-      compress: false,
-    },
-    qgis: {
-      arrowScale: raw.qgis?.arrowScale ?? raw.arrowScale ?? 0.8,
-      arrowMergeTriangles: raw.qgis?.arrowMergeTriangles ?? raw.arrowMergeTriangles ?? true,
-      arrowOutlineSimplifyMeters: raw.qgis?.arrowOutlineSimplifyMeters ?? raw.arrowOutlineSimplifyMeters ?? 0.05,
-      intersectionCornerSourceMaxDimensionMeters: raw.qgis?.intersectionCornerSourceMaxDimensionMeters ?? raw.intersectionCornerSourceMaxDimensionMeters ?? 2.6,
-      clipPad: raw.qgis?.clipPad ?? raw.clipPad ?? 0.002,
-      canvasPad: raw.qgis?.canvasPad ?? raw.canvasPad ?? 0.001,
-      previewPad: raw.qgis?.previewPad ?? raw.previewPad ?? 0.0007,
-      canvasExtent: raw.qgis?.canvasExtent ?? raw.canvasExtent ?? null,
-      previewExtent: raw.qgis?.previewExtent ?? raw.previewExtent ?? null,
-      layerPrefix: raw.qgis?.layerPrefix ?? raw.layerPrefix ?? "osm2streets",
-    },
-    osm2streets: raw.osm2streets || {
-      debug_each_step: false,
-      dual_carriageway_experiment: false,
-      sidepath_zipping_experiment: false,
-      inferred_sidewalks: true,
-      osm2lanes: true,
-    },
-    blender: {
-      treeStyle: raw.blender?.treeStyle || "natural",
-      officeOverrides: raw.blender?.officeOverrides || raw.blender?.office_overrides || "",
-    },
-    compress,
-    outputs,
-  };
-}
-
-function requireText(value, key) {
-  if (typeof value !== "string" || value.trim() === "") {
-    throw new Error(`Missing config key: ${key}`);
-  }
-  return value;
-}
-
-function normalizeCompressConfig(raw) {
-  const value = raw || {};
-  return {
-    textureSize: numberOption(value.textureSize, 768, "compress.textureSize", 64, 4096),
-    quality: numberOption(value.quality, 82, "compress.quality", 1, 100),
-    effort: numberOption(value.effort, 80, "compress.effort", 0, 100),
-    meshopt: booleanOption(value.meshopt, false, "compress.meshopt"),
-  };
-}
-
-function numberOption(value, fallback, label, min, max) {
-  const number = value === undefined ? fallback : Number(value);
-  if (!Number.isFinite(number) || number < min || number > max) {
-    throw new Error(`${label} must be a finite number in [${min}, ${max}]`);
-  }
-  return number;
-}
-
-function booleanOption(value, fallback, label) {
-  if (value === undefined) return fallback;
-  if (typeof value === "boolean") return value;
-  if (value === "true") return true;
-  if (value === "false") return false;
-  throw new Error(`${label} must be boolean`);
-}
-
 function splitList(value) {
   return String(value)
     .split(",")
diff --git a/scripts/diagnose-area.js b/scripts/diagnose-area.js
new file mode 100644
index 0000000..7a4f4c9
--- /dev/null
+++ b/scripts/diagnose-area.js
@@ -0,0 +1,438 @@
+#!/usr/bin/env node
+"use strict";
+
+const fs = require("fs");
+const path = require("path");
+const { readAreaConfig } = require("./lib/area-config");
+const { digest: glbDigest } = require("./glb-digest");
+
+const repoRoot = path.resolve(__dirname, "..");
+const DEFAULT_CONFIG = path.join(repoRoot, "config", "areas", "nantaizi-lake-innovation-valley.json");
+const BUDGETS = {
+  glbBytes: 25 * 1024 * 1024,
+  glbNodes: 1000,
+  glbImages: 24,
+};
+
+function parseArgs(argv) {
+  const out = {};
+  for (let i = 0; i < argv.length; i += 1) {
+    const arg = argv[i];
+    if (!arg.startsWith("--")) continue;
+    const key = arg.slice(2).replace(/-([a-z])/g, (_, c) => c.toUpperCase());
+    const next = argv[i + 1];
+    if (!next || next.startsWith("--")) {
+      out[key] = "true";
+    } else {
+      out[key] = next;
+      i += 1;
+    }
+  }
+  return out;
+}
+
+function xmlAttrs(text) {
+  const attrs = {};
+  for (const match of text.matchAll(/([:\w-]+)\s*=\s*("([^"]*)"|'([^']*)')/g)) {
+    attrs[match[1]] = match[3] !== undefined ? match[3] : match[4];
+  }
+  return attrs;
+}
+
+function parseTags(body) {
+  const tags = {};
+  for (const match of body.matchAll(/<tag\b([^>]*)\/?>/g)) {
+    const attrs = xmlAttrs(match[1]);
+    if (attrs.k) tags[attrs.k] = attrs.v || "";
+  }
+  return tags;
+}
+
+function parseOsm(xml) {
+  const bounds = parseBounds(xml);
+  const nodeIds = new Set();
+  const nodeStats = { total: 0, naturalTree: 0 };
+  const nodePattern = /<node\b([^>]*?)\/>|<node\b([^>]*?)>([\s\S]*?)<\/node>/g;
+  for (const match of xml.matchAll(nodePattern)) {
+    const attrs = xmlAttrs(match[1] || match[2] || "");
+    if (attrs.id) nodeIds.add(attrs.id);
+    nodeStats.total += 1;
+    const tags = parseTags(match[3] || "");
+    if (tags.natural === "tree") nodeStats.naturalTree += 1;
+  }
+
+  const ways = new Map();
+  const wayStats = {
+    total: 0,
+    buildings: 0,
+    buildingsWithHeight: 0,
+    buildingsWithLevels: 0,
+    buildingsWithBadHeight: 0,
+    missingNodeRefs: 0,
+    grass: 0,
+    scrub: 0,
+    treeRows: 0,
+  };
+  for (const match of xml.matchAll(/<way\b([^>]*)>([\s\S]*?)<\/way>/g)) {
+    const attrs = xmlAttrs(match[1]);
+    const body = match[2];
+    const tags = parseTags(body);
+    const refs = [];
+    for (const ndMatch of body.matchAll(/<nd\b([^>]*)\/?>/g)) {
+      const nd = xmlAttrs(ndMatch[1]);
+      if (nd.ref) refs.push(nd.ref);
+    }
+    const missingNodeRefs = refs.filter((ref) => !nodeIds.has(ref)).length;
+    const way = {
+      id: attrs.id || "",
+      refs,
+      tags,
+      closed: refs.length > 1 && refs[0] === refs[refs.length - 1],
+      missingNodeRefs,
+    };
+    if (way.id) ways.set(way.id, way);
+    wayStats.total += 1;
+    wayStats.missingNodeRefs += missingNodeRefs;
+    if (tags.building) {
+      wayStats.buildings += 1;
+      if (isExplicitHeight(tags)) wayStats.buildingsWithHeight += 1;
+      if (tags["building:levels"]) wayStats.buildingsWithLevels += 1;
+      if (tags.height && !parseHeightMeters(tags.height)) wayStats.buildingsWithBadHeight += 1;
+    }
+    if (tags.landuse === "grass") wayStats.grass += 1;
+    if (tags.natural === "scrub") wayStats.scrub += 1;
+    if (tags.natural === "tree_row") wayStats.treeRows += 1;
+  }
+
+  const relationStats = {
+    total: 0,
+    buildingMultipolygons: 0,
+    buildingsWithHeight: 0,
+    buildingsWithLevels: 0,
+    buildingsWithBadHeight: 0,
+    healthyBuildingMultipolygons: 0,
+    issues: [],
+  };
+  for (const match of xml.matchAll(/<relation\b([^>]*)>([\s\S]*?)<\/relation>/g)) {
+    const attrs = xmlAttrs(match[1]);
+    const body = match[2];
+    const tags = parseTags(body);
+    const members = [];
+    for (const memberMatch of body.matchAll(/<member\b([^>]*)\/?>/g)) {
+      members.push(xmlAttrs(memberMatch[1]));
+    }
+    relationStats.total += 1;
+    if (tags.type !== "multipolygon" || !tags.building) continue;
+    relationStats.buildingMultipolygons += 1;
+    if (isExplicitHeight(tags)) relationStats.buildingsWithHeight += 1;
+    if (tags["building:levels"]) relationStats.buildingsWithLevels += 1;
+    if (tags.height && !parseHeightMeters(tags.height)) relationStats.buildingsWithBadHeight += 1;
+
+    const health = buildingRelationHealth(attrs.id || "", members, ways);
+    if (health.ok) {
+      relationStats.healthyBuildingMultipolygons += 1;
+    } else {
+      relationStats.issues.push(health);
+    }
+  }
+
+  return {
+    bounds,
+    nodes: nodeStats,
+    ways: wayStats,
+    relations: relationStats,
+  };
+}
+
+function parseBounds(xml) {
+  const match = xml.match(/<bounds\b([^>]*)\/?>/);
+  if (!match) return null;
+  const attrs = xmlAttrs(match[1]);
+  const bounds = {
+    minLon: Number(attrs.minlon),
+    minLat: Number(attrs.minlat),
+    maxLon: Number(attrs.maxlon),
+    maxLat: Number(attrs.maxlat),
+  };
+  return Object.values(bounds).every(Number.isFinite) ? bounds : null;
+}
+
+function isExplicitHeight(tags) {
+  return Boolean(tags.height && parseHeightMeters(tags.height));
+}
+
+function parseHeightMeters(value) {
+  const match = String(value).trim().match(/^(-?\d+(?:\.\d+)?)/);
+  if (!match) return null;
+  const height = Number(match[1]);
+  return Number.isFinite(height) && height > 0 ? height : null;
+}
+
+function buildingRelationHealth(id, members, ways) {
+  const issues = [];
+  const outerMembers = members.filter((member) => member.type === "way" && member.role === "outer");
+  const innerMembers = members.filter((member) => member.type === "way" && member.role === "inner");
+  const nonWayMembers = members.filter((member) => member.type && member.type !== "way");
+  if (!outerMembers.length) issues.push("no outer way members");
+  if (nonWayMembers.length) issues.push(`${nonWayMembers.length} non-way member(s)`);
+
+  const outerHealth = ringGroupHealth(outerMembers, ways);
+  const innerHealth = ringGroupHealth(innerMembers, ways);
+  issues.push(...outerHealth.issues.map((issue) => `outer ${issue}`));
+  issues.push(...innerHealth.issues.map((issue) => `inner ${issue}`));
+
+  return {
+    id,
+    ok: issues.length === 0,
+    outerMembers: outerMembers.length,
+    innerMembers: innerMembers.length,
+    unresolvedMembers: outerHealth.unresolved + innerHealth.unresolved,
+    openRings: outerHealth.open + innerHealth.open,
+    issues,
+  };
+}
+
+function ringGroupHealth(members, ways) {
+  if (!members.length) return { issues: [], unresolved: 0, open: 0 };
+  const issues = [];
+  let unresolved = 0;
+  let open = 0;
+  const fragments = [];
+  for (const member of members) {
+    const way = ways.get(member.ref);
+    if (!way) {
+      unresolved += 1;
+      continue;
+    }
+    if (way.refs.length < 4) {
+      issues.push(`member ${member.ref} has fewer than 4 node refs`);
+      continue;
+    }
+    fragments.push(way.refs);
+  }
+  if (unresolved) issues.push(`${unresolved} unresolved member way(s)`);
+  if (!fragments.length) return { issues, unresolved, open };
+
+  if (fragments.length === 1) {
+    if (!isClosedRefs(fragments[0])) {
+      open += 1;
+      issues.push(`member ${members[0].ref} is not closed`);
+    }
+    return { issues, unresolved, open };
+  }
+
+  const endpointDegrees = new Map();
+  for (const refs of fragments) {
+    if (isClosedRefs(refs)) continue;
+    open += 1;
+    addEndpoint(endpointDegrees, refs[0]);
+    addEndpoint(endpointDegrees, refs[refs.length - 1]);
+  }
+  const badEndpoints = [...endpointDegrees.values()].filter((count) => count !== 2).length;
+  if (badEndpoints) {
+    issues.push(`${open} open member fragment(s) do not stitch into closed rings`);
+  }
+  return { issues, unresolved, open: badEndpoints ? open : 0 };
+}
+
+function isClosedRefs(refs) {
+  return refs.length > 1 && refs[0] === refs[refs.length - 1];
+}
+
+function addEndpoint(map, ref) {
+  map.set(ref, (map.get(ref) || 0) + 1);
+}
+
+function artifactStatus(area) {
+  const entries = [
+    ["GeoJSON dir", area.outputs.geojsonDir, true, "dir"],
+    ["GeoPackage", area.outputs.gpkg, true, "file"],
+    ["QGIS project", area.outputs.qgisProject, true, "file"],
+    ["QGIS preview", area.outputs.qgisPreview, true, "file"],
+    ["Blend scene", area.outputs.blend, true, "file"],
+    ["Render PNG", area.outputs.render, true, "file"],
+    ["Cesium GLB", area.outputs.glb, true, "file"],
+    ["Cesium metadata", area.outputs.metadata, true, "file"],
+    ["Cesium preview", area.outputs.cesiumPreview, true, "file"],
+    ["Compressed GLB", area.outputs.compressedGlb, false, "file"],
+    ["Compressed metadata", area.outputs.compressedMetadata, false, "file"],
+    ["Compressed preview", area.outputs.compressedCesiumPreview, false, "file"],
+  ];
+  return entries.map(([label, file, expected, type]) => {
+    const exists = fs.existsSync(file);
+    const stat = exists ? fs.statSync(file) : null;
+    const validType = !exists || (type === "dir" ? stat.isDirectory() : stat.isFile());
+    const geojsonFiles = exists && type === "dir"
+      ? fs.readdirSync(file).filter((entry) => entry.endsWith(".geojson")).length
+      : null;
+    return {
+      label,
+      path: file,
+      expected,
+      type,
+      exists,
+      validType,
+      bytes: stat && stat.isFile() ? stat.size : null,
+      geojsonFiles,
+    };
+  });
+}
+
+function metadataSummary(file, warnings) {
+  if (!fs.existsSync(file)) return null;
+  try {
+    const metadata = JSON.parse(fs.readFileSync(file, "utf8"));
+    return {
+      asset: metadata.asset || null,
+      assets: Array.isArray(metadata.assets) ? metadata.assets.length : 0,
+      origin: metadata.origin || metadata.center || null,
+    };
+  } catch (error) {
+    warnings.push(`Cesium metadata is not valid JSON: ${error.message}`);
+    return null;
+  }
+}
+
+function collectWarnings(area, osm, artifacts, glb, metadata) {
+  const warnings = [];
+  if (!osm.bounds) warnings.push("OSM has no valid <bounds>; scene extent may be wrong.");
+  if (osm.ways.missingNodeRefs) {
+    warnings.push(`OSM ways reference ${osm.ways.missingNodeRefs} missing node(s).`);
+  }
+  if (osm.ways.buildingsWithBadHeight || osm.relations.buildingsWithBadHeight) {
+    warnings.push("Some building height tags could not be parsed as positive meters.");
+  }
+  for (const issue of osm.relations.issues) {
+    warnings.push(`Building relation ${issue.id}: ${issue.issues.join("; ")}.`);
+  }
+  for (const artifact of artifacts) {
+    if (artifact.expected && !artifact.exists) {
+      warnings.push(`Expected artifact missing: ${artifact.label} (${artifact.path}).`);
+    } else if (artifact.exists && !artifact.validType) {
+      warnings.push(`Artifact has wrong type: ${artifact.label} (${artifact.path}).`);
+    }
+  }
+  if (glb) {
+    if (glb.fileBytes > BUDGETS.glbBytes) {
+      warnings.push(`GLB size ${mb(glb.fileBytes)} MB exceeds budget ${mb(BUDGETS.glbBytes)} MB.`);
+    }
+    if (glb.counts.nodes > BUDGETS.glbNodes) {
+      warnings.push(`GLB nodes ${glb.counts.nodes} exceed budget ${BUDGETS.glbNodes}.`);
+    }
+    if (glb.counts.images > BUDGETS.glbImages) {
+      warnings.push(`GLB images ${glb.counts.images} exceed budget ${BUDGETS.glbImages}.`);
+    }
+  }
+  if (metadata && metadata.assets < 1) {
+    warnings.push("Cesium metadata has no assets entries.");
+  }
+  if (!area.blender.treeStyle) {
+    warnings.push("No Blender tree style configured.");
+  }
+  return warnings;
+}
+
+function printReport(area, configPath, osm, artifacts, glb, metadata, warnings) {
+  console.log("Area diagnostics");
+  console.log(`Area: ${area.id}`);
+  console.log(`Config: ${configPath}`);
+  console.log(`Input: ${area.input}`);
+  console.log(`Output: ${area.outputs.areaDir}`);
+  console.log("");
+
+  console.log("OSM");
+  console.log(`  Bounds: ${osm.bounds ? formatBounds(osm.bounds) : "missing"}`);
+  console.log(`  Nodes: ${formatNumber(osm.nodes.total)} (${formatNumber(osm.nodes.naturalTree)} natural=tree)`);
+  console.log(`  Ways: ${formatNumber(osm.ways.total)}`);
+  console.log(`  Relations: ${formatNumber(osm.relations.total)}`);
+  console.log(
+    `  Buildings: ${formatNumber(osm.ways.buildings)} way(s), ` +
+    `${formatNumber(osm.relations.buildingMultipolygons)} multipolygon relation(s)`,
+  );
+  console.log(
+    `  Building heights: ${formatNumber(osm.ways.buildingsWithHeight + osm.relations.buildingsWithHeight)} ` +
+    `height tag(s), ${formatNumber(osm.ways.buildingsWithLevels + osm.relations.buildingsWithLevels)} ` +
+    "building:levels tag(s)",
+  );
+  console.log(
+    `  Building relations healthy: ${formatNumber(osm.relations.healthyBuildingMultipolygons)} / ` +
+    `${formatNumber(osm.relations.buildingMultipolygons)}`,
+  );
+  console.log(
+    `  Vegetation ways: ${formatNumber(osm.ways.grass)} grass, ` +
+    `${formatNumber(osm.ways.scrub)} scrub, ${formatNumber(osm.ways.treeRows)} tree_row`,
+  );
+  if (osm.relations.issues.length) {
+    console.log("  Relation issues:");
+    for (const issue of osm.relations.issues) {
+      console.log(`    - ${issue.id}: ${issue.issues.join("; ")}`);
+    }
+  }
+  console.log("");
+
+  console.log("Artifacts");
+  for (const artifact of artifacts) {
+    const state = artifact.exists && artifact.validType ? "ok" : (artifact.expected ? "missing" : "absent");
+    const suffix = artifact.geojsonFiles !== null
+      ? `, ${artifact.geojsonFiles} GeoJSON file(s)`
+      : artifact.bytes !== null ? `, ${formatBytes(artifact.bytes)}` : "";
+    console.log(`  ${state.padEnd(7)} ${artifact.label}: ${artifact.path}${suffix}`);
+  }
+  if (metadata) {
+    console.log(`  metadata asset: ${metadata.asset || "missing"}, assets: ${metadata.assets}`);
+  }
+  if (glb) {
+    console.log("");
+    console.log("GLB digest");
+    console.log(`  Size: ${mb(glb.fileBytes)} MB`);
+    console.log(
+      `  Counts: ${glb.counts.nodes} nodes, ${glb.counts.meshes} meshes, ` +
+      `${glb.counts.materials} materials, ${glb.counts.images} images, ${glb.counts.accessors} accessors`,
+    );
+    console.log(`  Extensions: ${glb.extensionsUsed.length ? glb.extensionsUsed.join(", ") : "none"}`);
+  }
+  console.log("");
+
+  console.log("Warnings");
+  if (!warnings.length) {
+    console.log("  none");
+  } else {
+    for (const warning of warnings) console.log(`  - ${warning}`);
+  }
+}
+
+function formatBounds(bounds) {
+  return `${bounds.minLon},${bounds.minLat} -> ${bounds.maxLon},${bounds.maxLat}`;
+}
+
+function formatNumber(value) {
+  return new Intl.NumberFormat("en-US").format(value);
+}
+
+function mb(bytes) {
+  return Number((bytes / 1024 / 1024).toFixed(2));
+}
+
+function formatBytes(bytes) {
+  if (bytes >= 1024 * 1024) return `${mb(bytes)} MB`;
+  if (bytes >= 1024) return `${Number((bytes / 1024).toFixed(1))} KB`;
+  return `${bytes} B`;
+}
+
+function main() {
+  const args = parseArgs(process.argv.slice(2));
+  const configPath = path.resolve(args.config || DEFAULT_CONFIG);
+  const area = readAreaConfig(configPath, { repoRoot });
+  const osm = parseOsm(fs.readFileSync(area.input, "utf8"));
+  const artifacts = artifactStatus(area);
+  const metadataWarnings = [];
+  const metadata = metadataSummary(area.outputs.metadata, metadataWarnings);
+  const glb = fs.existsSync(area.outputs.glb) ? glbDigest(area.outputs.glb) : null;
+  const warnings = [
+    ...metadataWarnings,
+    ...collectWarnings(area, osm, artifacts, glb, metadata),
+  ];
+  printReport(area, configPath, osm, artifacts, glb, metadata, warnings);
+}
+
+main();
diff --git a/scripts/glb-digest.js b/scripts/glb-digest.js
index f23b62d..b1451ff 100644
--- a/scripts/glb-digest.js
+++ b/scripts/glb-digest.js
@@ -102,20 +102,31 @@ function digest(file) {
   };
 }
 
-const argv = process.argv.slice(2);
-const file = argv.find((arg) => !arg.startsWith("--"));
-if (!file) {
-  console.error("usage: node scripts/glb-digest.js <file.glb> [--out digest.json]");
-  process.exit(1);
+function main() {
+  const argv = process.argv.slice(2);
+  const file = argv.find((arg) => !arg.startsWith("--"));
+  if (!file) {
+    console.error("usage: node scripts/glb-digest.js <file.glb> [--out digest.json]");
+    process.exit(1);
+  }
+  const outIndex = argv.indexOf("--out");
+  const result = digest(path.resolve(file));
+  const text = `${JSON.stringify(result, null, 2)}\n`;
+  if (outIndex >= 0 && argv[outIndex + 1]) {
+    const out = path.resolve(argv[outIndex + 1]);
+    fs.mkdirSync(path.dirname(out), { recursive: true });
+    fs.writeFileSync(out, text);
+    console.log(`GLB digest: ${out}`);
+  } else {
+    process.stdout.write(text);
+  }
 }
-const outIndex = argv.indexOf("--out");
-const result = digest(path.resolve(file));
-const text = `${JSON.stringify(result, null, 2)}\n`;
-if (outIndex >= 0 && argv[outIndex + 1]) {
-  const out = path.resolve(argv[outIndex + 1]);
-  fs.mkdirSync(path.dirname(out), { recursive: true });
-  fs.writeFileSync(out, text);
-  console.log(`GLB digest: ${out}`);
-} else {
-  process.stdout.write(text);
+
+if (require.main === module) {
+  main();
 }
+
+module.exports = {
+  digest,
+  readGlbJson,
+};
diff --git a/scripts/lib/area-config.js b/scripts/lib/area-config.js
new file mode 100644
index 0000000..1324832
--- /dev/null
+++ b/scripts/lib/area-config.js
@@ -0,0 +1,133 @@
+"use strict";
+
+const fs = require("fs");
+const path = require("path");
+
+function readAreaConfig(file, options = {}) {
+  if (!fs.existsSync(file)) {
+    throw new Error(`Config file not found: ${file}`);
+  }
+  return normalizeAreaConfig(JSON.parse(fs.readFileSync(file, "utf8")), options);
+}
+
+function normalizeAreaConfig(raw, options = {}) {
+  const repoRoot = options.repoRoot || path.resolve(__dirname, "..", "..");
+  const id = requireText(raw.id, "id");
+  const input = path.resolve(requireText(raw.input, "input"));
+  if (!fs.existsSync(input)) {
+    throw new Error(`Input OSM XML not found: ${input}`);
+  }
+
+  const outputRoot = path.resolve(raw.outputRoot || path.join(repoRoot, "outputs"));
+  const outputOverrides = raw.outputs || {};
+  const areaDir = path.resolve(outputOverrides.areaDir || path.join(outputRoot, id));
+  const fileStem = outputOverrides.fileStem || id;
+  const compress = normalizeCompressConfig(raw.compress);
+  const compressedFileStem = outputOverrides.compressedFileStem ||
+    `${fileStem}-compressed-webp${compress.textureSize}${compress.meshopt ? "-meshopt" : ""}`;
+  const outputs = {
+    areaDir,
+    geojsonDir: path.resolve(outputOverrides.geojsonDir || path.join(areaDir, "osm2streets_web_out")),
+    gpkg: path.resolve(outputOverrides.gpkg || path.join(areaDir, `${fileStem}.gpkg`)),
+    qgisProject: path.resolve(outputOverrides.qgisProject || path.join(areaDir, `${fileStem}.qgz`)),
+    qgisPreview: path.resolve(outputOverrides.qgisPreview || path.join(areaDir, `${fileStem}-preview.png`)),
+    blend: path.resolve(outputOverrides.blend || path.join(areaDir, `${fileStem}.blend`)),
+    render: path.resolve(outputOverrides.render || path.join(areaDir, `${fileStem}.png`)),
+    glb: path.resolve(outputOverrides.glb || path.join(areaDir, `${fileStem}.glb`)),
+    metadata: path.resolve(outputOverrides.metadata || path.join(areaDir, `${fileStem}.json`)),
+    cesiumPreview: path.resolve(
+      outputOverrides.cesiumPreview || path.join(areaDir, `${fileStem}-cesium-preview.html`),
+    ),
+    compressedGlb: path.resolve(
+      outputOverrides.compressedGlb || path.join(areaDir, `${compressedFileStem}.glb`),
+    ),
+    compressedMetadata: path.resolve(
+      outputOverrides.compressedMetadata || path.join(areaDir, `${compressedFileStem}.json`),
+    ),
+    compressedCesiumPreview: path.resolve(
+      outputOverrides.compressedCesiumPreview || path.join(areaDir, `${compressedFileStem}-cesium-preview.html`),
+    ),
+    vehicleRoute: path.resolve(outputOverrides.vehicleRoute || path.join(areaDir, `${fileStem}-vehicle-route.json`)),
+    vehicleModel: path.resolve(outputOverrides.vehicleModel || path.join(areaDir, `${fileStem}-vehicle-car.gltf`)),
+    pipelineDir: path.resolve(outputOverrides.pipelineDir || path.join(areaDir, "_pipeline")),
+  };
+
+  return {
+    id,
+    input,
+    outputRoot,
+    qgisApp: raw.qgisApp || "/Applications/QGIS.app",
+    blenderApp: raw.blenderApp || "/Applications/Blender.app",
+    stages: {
+      intermediates: raw.stages?.intermediates ?? raw.stages?.qgis ?? true,
+      blender: raw.stages?.blender ?? true,
+      cesium: raw.stages?.cesium ?? true,
+      reimport: false,
+      preview: false,
+      compress: false,
+    },
+    qgis: {
+      arrowScale: raw.qgis?.arrowScale ?? raw.arrowScale ?? 0.8,
+      arrowMergeTriangles: raw.qgis?.arrowMergeTriangles ?? raw.arrowMergeTriangles ?? true,
+      arrowOutlineSimplifyMeters: raw.qgis?.arrowOutlineSimplifyMeters ?? raw.arrowOutlineSimplifyMeters ?? 0.05,
+      intersectionCornerSourceMaxDimensionMeters: raw.qgis?.intersectionCornerSourceMaxDimensionMeters ?? raw.intersectionCornerSourceMaxDimensionMeters ?? 2.6,
+      clipPad: raw.qgis?.clipPad ?? raw.clipPad ?? 0.002,
+      canvasPad: raw.qgis?.canvasPad ?? raw.canvasPad ?? 0.001,
+      previewPad: raw.qgis?.previewPad ?? raw.previewPad ?? 0.0007,
+      canvasExtent: raw.qgis?.canvasExtent ?? raw.canvasExtent ?? null,
+      previewExtent: raw.qgis?.previewExtent ?? raw.previewExtent ?? null,
+      layerPrefix: raw.qgis?.layerPrefix ?? raw.layerPrefix ?? "osm2streets",
+    },
+    osm2streets: raw.osm2streets || {
+      debug_each_step: false,
+      dual_carriageway_experiment: false,
+      sidepath_zipping_experiment: false,
+      inferred_sidewalks: true,
+      osm2lanes: true,
+    },
+    blender: {
+      treeStyle: raw.blender?.treeStyle || "natural",
+      officeOverrides: raw.blender?.officeOverrides || raw.blender?.office_overrides || "",
+    },
+    compress,
+    outputs,
+  };
+}
+
+function requireText(value, key) {
+  if (typeof value !== "string" || value.trim() === "") {
+    throw new Error(`Missing config key: ${key}`);
+  }
+  return value;
+}
+
+function normalizeCompressConfig(raw) {
+  const value = raw || {};
+  return {
+    textureSize: numberOption(value.textureSize, 768, "compress.textureSize", 64, 4096),
+    quality: numberOption(value.quality, 82, "compress.quality", 1, 100),
+    effort: numberOption(value.effort, 80, "compress.effort", 0, 100),
+    meshopt: booleanOption(value.meshopt, false, "compress.meshopt"),
+  };
+}
+
+function numberOption(value, fallback, label, min, max) {
+  const number = value === undefined ? fallback : Number(value);
+  if (!Number.isFinite(number) || number < min || number > max) {
+    throw new Error(`${label} must be a finite number in [${min}, ${max}]`);
+  }
+  return number;
+}
+
+function booleanOption(value, fallback, label) {
+  if (value === undefined) return fallback;
+  if (typeof value === "boolean") return value;
+  if (value === "true") return true;
+  if (value === "false") return false;
+  throw new Error(`${label} must be boolean`);
+}
+
+module.exports = {
+  normalizeAreaConfig,
+  readAreaConfig,
+};