diff --git a/.github/workflows/architecture.yml b/.github/workflows/architecture.yml
new file mode 100644
index 0000000..acaf4bc
--- /dev/null
+++ b/.github/workflows/architecture.yml
@@ -0,0 +1,72 @@
+name: Architecture contracts
+
+on:
+  pull_request:
+  push:
+    branches: [main]
+  merge_group:
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+concurrency:
+  group: architecture-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  architecture-contracts:
+    name: architecture-contracts
+    runs-on: ubuntu-24.04
+    timeout-minutes: 15
+    env:
+      PYTHONUTF8: "1"
+      PYTHONDONTWRITEBYTECODE: "1"
+      CARGO_TARGET_DIR: ${{ runner.temp }}/pebrel-i18n-contract
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+          persist-credentials: false
+      - uses: actions/setup-python@v5
+        with:
+          python-version: "3.13"
+      - name: Test the guardrails themselves
+        run: >-
+          python3 -m unittest
+          scripts.tests.test_architecture_budgets
+          scripts.tests.test_architecture_dependencies
+          scripts.tests.test_architecture_governance
+      - name: Check source size and dependency direction
+        env:
+          ARCHITECTURE_BASE: ${{ github.event.pull_request.base.sha || github.event.merge_group.base_sha || github.event.before }}
+        run: |
+          arguments=()
+          if [[ -n "$ARCHITECTURE_BASE" && ! "$ARCHITECTURE_BASE" =~ ^0+$ ]]; then
+            arguments+=(--base "$ARCHITECTURE_BASE")
+          fi
+          python3 scripts/check_architecture.py "${arguments[@]}"
+      - uses: dtolnay/rust-toolchain@stable
+        with:
+          toolchain: "1.97.1"
+      - name: Test shared settings without the UI dependency graph
+        run: |
+          mkdir -p "$RUNNER_TEMP/pebrel-contracts"
+          rustc --test --edition 2024 --crate-name nebula_settings \
+            nebula_settings/src/lib.rs -o "$RUNNER_TEMP/pebrel-contracts/settings"
+          "$RUNNER_TEMP/pebrel-contracts/settings"
+      - name: Test the Rust line-budget adapter
+        env:
+          CARGO_MANIFEST_DIR: ${{ github.workspace }}/nebula_app
+        run: |
+          rustc --test --edition 2024 nebula_app/tests/file_line_budget.rs \
+            -o "$RUNNER_TEMP/pebrel-contracts/line-budget"
+          "$RUNNER_TEMP/pebrel-contracts/line-budget"
+      - name: Test renderer-independent translation and allocation contracts
+        run: cargo test --manifest-path tools/i18n-contract/Cargo.toml --locked
+      - name: Test branding and image compatibility
+        run: >-
+          python3 -m unittest
+          scripts.tests.test_pebrel_branding
+          scripts.tests.test_windows_resources
+          scripts.tests.test_app_icons
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4d92cda..5b24f4e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -45,6 +45,7 @@ Every release entry is provided in English and Simplified Chinese.
 - SSH editing now offers common usernames alongside recent entries, keeps manual usernames available, and makes host icons and pin controls clearer. Connection screens show completed stages and failures more accurately.
 - Terminal completion lists now scroll to reveal keyboard selections, support wheel scrolling and hover feedback, and clear stale list positions when the query changes.
 - Completion, bell, and Agent attention notifications now follow their source pane, including after a tab moves to another window. Clicking a notification focuses that pane, and activity in one pane no longer suppresses another pane's notification.
+- Contributors can run the shared source-size, dependency-direction, translation, and branding checks locally and in the architecture workflow. Cross-platform metadata checks are documented separately from native build and UI validation.
 
 ### 简体中文
 
@@ -85,6 +86,7 @@ Every release entry is provided in English and Simplified Chinese.
 - SSH 编辑器在最近使用项之外提供常用用户名，保留手动输入，并改进主机图标与置顶控件；连接界面更准确地显示已完成阶段和失败状态。
 - 终端补全列表现在会滚动到键盘选中项，支持滚轮浏览与悬停反馈，并在查询变化后清除过期列表位置。
 - 命令完成、响铃和 Agent 待处理通知现在跟随来源 pane，即使标签已移动到另一个窗口；点击通知会聚焦来源 pane，一个 pane 的活动不再抑制另一个 pane 的通知。
+- 贡献者可在本地及架构工作流中运行统一的源码规模、依赖方向、翻译和品牌检查；跨平台元数据检查与原生构建、界面验证的边界分别说明。
 
 ### Contributors
 - [@Sakyvo](https://github.com/Sakyvo): terminal network proxy, conditional `Ctrl+C` copy, and word deletion with `Ctrl+Backspace` / 终端网络代理、`Ctrl+C` 按选区复制及 `Ctrl+Backspace` 按词删除。
diff --git a/architecture/dependencies.toml b/architecture/dependencies.toml
new file mode 100644
index 0000000..4615804
--- /dev/null
+++ b/architecture/dependencies.toml
@@ -0,0 +1,37 @@
+version = 1
+renderer_packages = ["gpui", "gpui_platform", "gpui-component", "gpui-component-assets", "winit", "glutin", "crossfont"]
+
+[crates.nebula_app]
+layer = "application"
+dependencies = ["nebula_terminal", "nebula_config", "nebula_config_derive", "nebula_settings", "nebula_split", "nebula-completions"]
+build-dependencies = ["nebula_settings"]
+dev-dependencies = []
+
+[crates.nebula_terminal]
+layer = "core"
+
+[crates.nebula_config]
+layer = "core"
+dev-dependencies = ["nebula_config_derive"]
+
+[crates.nebula_config_derive]
+layer = "core"
+dev-dependencies = ["nebula_config"]
+
+[crates.nebula-completions]
+layer = "core"
+
+[crates.nebula_settings]
+layer = "core"
+zero_production_dependencies = true
+
+[crates.nebula_split]
+layer = "core"
+zero_production_dependencies = true
+
+[crates.nebula_hook]
+layer = "hook"
+zero_production_dependencies = true
+
+[crates.nebula_gpui]
+layer = "lab"
diff --git a/architecture/file-budgets.txt b/architecture/file-budgets.txt
new file mode 100644
index 0000000..9df7572
--- /dev/null
+++ b/architecture/file-budgets.txt
@@ -0,0 +1,23 @@
+limit 2000
+root nebula_app
+root nebula_terminal
+root nebula_config
+root nebula_config_derive
+root nebula-completions
+root nebula_hook
+root nebula_gpui
+root nebula_settings
+root nebula_split
+root scripts
+root tools
+nebula_app/src/display/chrome.rs 2442
+nebula_app/src/display/command_palette.rs 3935
+nebula_app/src/display/markdown_view.rs 2067
+nebula_app/src/display/mod.rs 11150
+nebula_app/src/display/settings.rs 8434
+nebula_app/src/display/terminal_math.rs 2783
+nebula_app/src/event.rs 3594
+nebula_app/src/gpui_shell/terminal/view.rs 2416
+nebula_app/src/gpui_shell/workspace.rs 4798
+nebula_app/src/window_context.rs 3735
+nebula_terminal/src/term/mod.rs 2716
diff --git a/docs/release-notes/unreleased.md b/docs/release-notes/unreleased.md
index 41c7362..2762293 100644
--- a/docs/release-notes/unreleased.md
+++ b/docs/release-notes/unreleased.md
@@ -41,6 +41,7 @@ This file contains changes that are not part of a numbered release yet.
 - SSH editing now offers common usernames alongside recent entries, keeps manual usernames available, and makes host icons and pin controls clearer. Connection screens show completed stages and failures more accurately.
 - Terminal completion lists now scroll to reveal keyboard selections, support wheel scrolling and hover feedback, and clear stale list positions when the query changes.
 - Completion, bell, and Agent attention notifications now follow their source pane, including after a tab moves to another window. Clicking a notification focuses that pane, and activity in one pane no longer suppresses another pane's notification.
+- Contributors can run the shared source-size, dependency-direction, translation, and branding checks locally and in the architecture workflow. Cross-platform metadata checks are documented separately from native build and UI validation.
 
 ## 中文
 
@@ -81,6 +82,7 @@ This file contains changes that are not part of a numbered release yet.
 - SSH 编辑器在最近使用项之外提供常用用户名，保留手动输入，并改进主机图标与置顶控件；连接界面更准确地显示已完成阶段和失败状态。
 - 终端补全列表现在会滚动到键盘选中项，支持滚轮浏览与悬停反馈，并在查询变化后清除过期列表位置。
 - 命令完成、响铃和 Agent 待处理通知现在跟随来源 pane，即使标签已移动到另一个窗口；点击通知会聚焦来源 pane，一个 pane 的活动不再抑制另一个 pane 的通知。
+- 贡献者可在本地及架构工作流中运行统一的源码规模、依赖方向、翻译和品牌检查；跨平台元数据检查与原生构建、界面验证的边界分别说明。
 
 ## Contributors
 - [@Sakyvo](https://github.com/Sakyvo): terminal network proxy, conditional `Ctrl+C` copy, and word deletion with `Ctrl+Backspace` / 终端网络代理、`Ctrl+C` 按选区复制及 `Ctrl+Backspace` 按词删除。
diff --git a/nebula_app/src/display/side_panel/tests.rs b/nebula_app/src/display/side_panel/tests.rs
index 012517a..7f34b3b 100644
--- a/nebula_app/src/display/side_panel/tests.rs
+++ b/nebula_app/src/display/side_panel/tests.rs
@@ -6,6 +6,24 @@ use super::*;
 mod tests {
     use super::*;
 
+    fn remove_test_directory(path: &Path) {
+        let deadline = Instant::now() + Duration::from_secs(5);
+        loop {
+            match std::fs::remove_dir_all(path) {
+                Ok(()) => return,
+                Err(error) if error.kind() == std::io::ErrorKind::NotFound => return,
+                Err(error)
+                    if cfg!(windows)
+                        && matches!(error.raw_os_error(), Some(32 | 33))
+                        && Instant::now() < deadline =>
+                {
+                    std::thread::sleep(Duration::from_millis(20));
+                },
+                Err(error) => panic!("could not remove test directory {}: {error}", path.display()),
+            }
+        }
+    }
+
     #[test]
     fn toggle_switches_views_without_closing() {
         let mut p = SidePanel::new();
@@ -104,7 +122,7 @@ mod tests {
 
         panel.wait_snapshot();
         panel.file_index.release_for_test();
-        std::fs::remove_dir_all(&base).unwrap();
+        remove_test_directory(&base);
     }
 
     #[test]
@@ -129,7 +147,7 @@ mod tests {
 
         panel.wait_snapshot();
         panel.file_index.release_for_test();
-        std::fs::remove_dir_all(&base).unwrap();
+        remove_test_directory(&base);
     }
 
     #[test]
@@ -398,7 +416,7 @@ mod tests {
         assert_eq!(rows[2].depth, 1);
 
         p.file_index.release_for_test();
-        std::fs::remove_dir_all(&base).unwrap();
+        remove_test_directory(&base);
     }
 
     #[test]
@@ -455,7 +473,7 @@ mod tests {
         assert!(panel.custom_root_active(), "upward navigation is window-local");
 
         panel.file_index.release_for_test();
-        std::fs::remove_dir_all(&base).unwrap();
+        remove_test_directory(&base);
     }
 
     #[test]
@@ -485,7 +503,7 @@ mod tests {
         assert!(!panel.click_drag_source(&stale), "a changed source row must be ignored");
 
         panel.file_index.release_for_test();
-        std::fs::remove_dir_all(&base).unwrap();
+        remove_test_directory(&base);
     }
 
     #[test]
diff --git a/nebula_app/tests/file_line_budget.rs b/nebula_app/tests/file_line_budget.rs
index b63fac6..ad65848 100644
--- a/nebula_app/tests/file_line_budget.rs
+++ b/nebula_app/tests/file_line_budget.rs
@@ -1,115 +1,103 @@
-//! 文件行数预算守护（docs/project-constraints.md 第 1 条）。
-//!
-//! 单个 `.rs` 文件硬上限 2000 行；存量超标文件在 [`GRANDFATHERED`] 登记，
-//! 登记值只允许下调。测试失败的正确动作是拆文件，不是上调预算。
-
+use std::collections::{HashMap, HashSet};
 use std::fs;
 use std::path::{Path, PathBuf};
 
-/// 新代码红线：超过它就必须拆（docs/project-constraints.md）。
-const MAX_LINES: usize = 2000;
+const POLICY: &str = include_str!("../../architecture/file-budgets.txt");
 
-/// 存量豁免清单（相对仓库根，正斜杠路径 → 行数上限）。
-///
-/// 登记值 = 收录当天的行数加不足百行的呼吸空间：小修小补不触线，成规模
-/// 新增必须伴随拆分。拆小后同步下调或删除对应条目。
-const GRANDFATHERED: &[(&str, usize)] = &[
-    ("nebula_app/src/display/mod.rs", 12000),
-    ("nebula_app/src/display/settings.rs", 8650),
-    // 2026-08-31 下调（5150 → 4980）：VCS 抽屉页搬到 workspace/vcs_panel.rs。
-    ("nebula_app/src/gpui_shell/workspace.rs", 4880),
-    ("nebula_app/src/display/command_palette.rs", 3980),
-    ("nebula_app/src/window_context.rs", 3750),
-    ("nebula_app/src/event.rs", 3620),
-    ("nebula_terminal/src/term/mod.rs", 2760),
-    // 2026-08-17 上调（2900 → 2970）：draw_overlays 几何抽成两壳共享的 plan。
-    ("nebula_app/src/display/terminal_math.rs", 2800),
-    // 2026-08-31 条目删除：side_panel.rs（4031 行）拆成 side_panel/{mod,vcs,
-    // enumerate,render,tests}.rs，最大的 render.rs 也只有 869 行，全部在红线内。
-    ("nebula_app/src/gpui_shell/terminal/view.rs", 2460),
-    ("nebula_app/src/display/chrome.rs", 2550),
-    ("nebula_app/src/display/markdown_view.rs", 2150),
-];
-
-/// 这些目录不受预算约束：构建产物、vendored 第三方代码、版本库内部。
-fn excluded(component: &str) -> bool {
-    component == ".git"
-        || component == "third_party"
-        || component == "target"
-        || component.starts_with(".target")
+fn line_count(content: &[u8]) -> usize {
+    content.iter().filter(|byte| **byte == b'\n').count()
+        + usize::from(!content.is_empty() && content.last() != Some(&b'\n'))
 }
 
-fn collect_rust_files(root: &Path, out: &mut Vec<PathBuf>) {
-    let Ok(entries) = fs::read_dir(root) else {
-        return;
-    };
-    for entry in entries.flatten() {
-        let path = entry.path();
+fn collect_sources(root: &Path, files: &mut Vec<PathBuf>) {
+    assert!(!root.is_symlink(), "source directory must not be a symlink: {}", root.display());
+    let cargo_root = root.join("Cargo.toml").is_file();
+    for entry in fs::read_dir(root).expect("source directories must be readable") {
+        let entry = entry.expect("source directory entries must be readable");
         let name = entry.file_name();
         let name = name.to_string_lossy();
-        // 隐藏项（.git、.tmp_* 草稿等）不是源码，不受预算约束。
-        if name.starts_with('.') {
+        if name == "node_modules" || name == "__pycache__" || (cargo_root && name == "target") {
             continue;
         }
+        let path = entry.path();
+        assert!(!path.is_symlink(), "source must not be a symlink: {}", path.display());
         if path.is_dir() {
-            if !excluded(&name) {
-                collect_rust_files(&path, out);
-            }
-        } else if path.extension().is_some_and(|extension| extension == "rs") {
-            out.push(path);
+            collect_sources(&path, files);
+        } else if path
+            .extension()
+            .and_then(|value| value.to_str())
+            .is_some_and(|value| matches!(value, "rs" | "py" | "ps1" | "mjs" | "js" | "sh" | "lua"))
+        {
+            files.push(path);
         }
     }
 }
 
 #[test]
 fn every_source_file_respects_its_line_budget() {
-    let repo_root = Path::new(env!("CARGO_MANIFEST_DIR"))
-        .parent()
-        .expect("nebula_app sits directly under the repo root")
-        .to_path_buf();
-
-    let mut files = Vec::new();
-    collect_rust_files(&repo_root, &mut files);
-    assert!(
-        files.len() > 100,
-        "行数守护扫到的文件数异常（{}），排除规则可能吞掉了源码目录",
-        files.len()
-    );
-
-    let mut violations = Vec::new();
-    let mut stale_grants = Vec::new();
-    for path in files {
-        let relative = path
-            .strip_prefix(&repo_root)
-            .expect("collected files live under the repo root")
-            .to_string_lossy()
-            .replace('\\', "/");
-        let Ok(content) = fs::read(&path) else {
-            panic!("无法读取 {relative}");
-        };
-        // 按换行字节计数：与编码无关，空文件为 0 行。
-        let lines = content.iter().filter(|byte| **byte == b'\n').count()
-            + usize::from(!content.is_empty() && content.last() != Some(&b'\n'));
-        let grant =
-            GRANDFATHERED.iter().find(|(name, _)| *name == relative).map(|(_, budget)| *budget);
-        let budget = grant.unwrap_or(MAX_LINES);
-        if lines > budget {
-            violations.push(format!("{relative}: {lines} 行 > 预算 {budget}"));
-        }
-        // 豁免文件瘦身到红线以内后，条目必须删除，防止预算复胖。
-        if let Some(budget) = grant
-            && lines <= MAX_LINES
-        {
-            stale_grants.push(format!(
-                "{relative}: 已降到 {lines} 行（≤{MAX_LINES}），豁免条目（{budget}）应删除"
-            ));
+    let repo_root = Path::new(env!("CARGO_MANIFEST_DIR")).parent().unwrap();
+    let mut limit = None;
+    let mut roots = HashSet::new();
+    let mut exceptions = HashMap::new();
+    for record in POLICY.lines().filter(|record| !record.trim().is_empty()) {
+        let fields = record.split_whitespace().collect::<Vec<_>>();
+        assert_eq!(fields.len(), 2, "invalid budget record: {record}");
+        match fields[0] {
+            "limit" => {
+                assert!(limit.is_none(), "duplicate default limit");
+                limit = Some(fields[1].parse::<usize>().unwrap());
+            },
+            "root" => assert!(roots.insert(fields[1]), "duplicate source root"),
+            name => {
+                let count = fields[1].parse::<usize>().unwrap();
+                assert!(exceptions.insert(name, count).is_none(), "duplicate exception: {name}");
+            },
         }
     }
-
-    assert!(
-        violations.is_empty(),
-        "以下文件超出行数预算（docs/project-constraints.md 第 1 条，正确动作是拆文件）：\n{}",
-        violations.join("\n")
-    );
-    assert!(stale_grants.is_empty(), "以下豁免条目已过期：\n{}", stale_grants.join("\n"));
+    let limit = limit.expect("missing default limit");
+    assert!(limit > 0 && !roots.is_empty());
+    let mut files = Vec::new();
+    for root in roots {
+        assert!(!Path::new(root).is_absolute() && !root.contains("..") && !root.contains(':'));
+        let mut directory = repo_root.to_path_buf();
+        for component in Path::new(root).components() {
+            directory.push(component);
+            assert!(!directory.is_symlink(), "source ancestor must not be a symlink");
+        }
+        collect_sources(&repo_root.join(root), &mut files);
+    }
+    assert!(files.len() > 100, "unexpectedly empty source scan: {}", files.len());
+    files.sort();
+    let mut errors = Vec::new();
+    for path in files {
+        let name = path.strip_prefix(repo_root).unwrap().to_string_lossy().replace('\\', "/");
+        let content = fs::read(&path).expect("source files must be readable");
+        let count = line_count(&content);
+        let exception = exceptions.remove(name.as_str());
+        let budget = exception.unwrap_or(limit);
+        if count > budget {
+            errors.push(format!("{name}: {count} lines > {budget}; split by responsibility"));
+        }
+        if exception.is_some() && count <= limit {
+            errors.push(format!("{name}: remove the obsolete exception ({count} lines)"));
+        }
+    }
+    for name in exceptions.keys() {
+        errors.push(format!("{name}: remove the missing-source exception"));
+    }
+    assert!(errors.is_empty(), "docs/project-constraints.md:\n{}", errors.join("\n"));
+}
+
+#[test]
+fn physical_lines_ignore_encoding_and_newline_convention() {
+    for (content, expected) in [
+        ("", 0),
+        ("\n", 1),
+        ("a\nb", 2),
+        ("a\r\nb\r\n", 2),
+        ("中文\n", 1),
+        ("vertical\u{000b}tab", 1),
+    ] {
+        assert_eq!(line_count(content.as_bytes()), expected);
+    }
 }
diff --git a/scripts/architecture/__init__.py b/scripts/architecture/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/scripts/architecture/budgets.py b/scripts/architecture/budgets.py
new file mode 100644
index 0000000..a9ef1d2
--- /dev/null
+++ b/scripts/architecture/budgets.py
@@ -0,0 +1,139 @@
+from dataclasses import dataclass
+import os
+from pathlib import Path, PurePosixPath
+
+
+BUDGET_PATH = "architecture/file-budgets.txt"
+SOURCE_SUFFIXES = {".rs", ".py", ".ps1", ".mjs", ".js", ".sh", ".lua"}
+EXCLUDED = {"node_modules", "__pycache__"}
+
+
+def line_count(content: bytes) -> int:
+    return content.count(b"\n") + int(bool(content) and not content.endswith(b"\n"))
+
+
+def relative_path(value: str) -> str:
+    path = PurePosixPath(value)
+    if (not value or path.is_absolute() or ".." in path.parts
+            or "\\" in value or ":" in value or path.as_posix() != value
+            or any(part.startswith(".") for part in path.parts)):
+        raise ValueError(f"invalid first-party path: {value!r}")
+    return value
+
+
+def checked_path(root: Path, relative: str) -> Path:
+    path = PurePosixPath(relative)
+    if path.is_absolute() or "\\" in relative or ":" in relative:
+        raise ValueError(f"invalid repository path: {relative}")
+    boundary = root.resolve()
+    current = boundary
+    for component in path.parts:
+        current = current.parent if component == ".." else current / component
+        if not current.is_relative_to(boundary) or current.is_symlink():
+            raise ValueError(f"out-of-repository or symlinked source path: {relative}")
+    return current
+
+
+@dataclass
+class Budget:
+    limit: int
+    roots: tuple[str, ...]
+    exceptions: dict[str, int]
+
+    @classmethod
+    def parse(cls, text: str) -> "Budget":
+        limit = None
+        roots = []
+        exceptions = {}
+        for number, record in enumerate(text.splitlines(), 1):
+            if not record.strip():
+                continue
+            fields = record.split()
+            if len(fields) != 2:
+                raise ValueError(f"{BUDGET_PATH}:{number}: expected two fields")
+            name, value = fields
+            if name == "limit":
+                if limit is not None or not value.isascii() or not value.isdecimal() or int(value) < 1:
+                    raise ValueError("invalid or duplicate line limit")
+                limit = int(value)
+            elif name == "root":
+                relative_path(value)
+                if value in roots:
+                    raise ValueError(f"duplicate source root: {value}")
+                roots.append(value)
+            else:
+                relative_path(name)
+                if name in exceptions or not value.isascii() or not value.isdecimal():
+                    raise ValueError(f"invalid or duplicate exception: {name}")
+                exceptions[name] = int(value)
+        if limit is None or not roots:
+            raise ValueError("line budget needs a limit and source roots")
+        for name, count in exceptions.items():
+            if count <= limit or PurePosixPath(name).suffix not in SOURCE_SUFFIXES:
+                raise ValueError(f"invalid exception: {name} ({count})")
+            if not any(name.startswith(root + "/") for root in roots):
+                raise ValueError(f"exception outside source roots: {name}")
+        for root in roots:
+            if any(root.startswith(other + "/") for other in roots if other != root):
+                raise ValueError(f"overlapping source root: {root}")
+        return cls(limit, tuple(roots), exceptions)
+
+
+def source_files(root: Path, roots: tuple[str, ...]):
+    def fail(error):
+        raise error
+
+    for relative in roots:
+        directory = checked_path(root, relative)
+        if directory.is_symlink() or not directory.is_dir():
+            raise ValueError(f"missing or symlinked source root: {relative}")
+        for parent, directories, files in os.walk(directory, onerror=fail):
+            excluded = EXCLUDED | ({"target"} if "Cargo.toml" in files else set())
+            directories[:] = sorted(
+                name for name in directories
+                if name not in excluded
+            )
+            for name in directories + files:
+                if (Path(parent) / name).is_symlink():
+                    raise ValueError(f"symlink in first-party sources: {parent}/{name}")
+            for name in sorted(files):
+                path = Path(parent) / name
+                if path.suffix in SOURCE_SUFFIXES:
+                    yield path
+
+
+def check(root: Path, budget: Budget, previous=None, read_previous=None):
+    errors = []
+    notices = []
+    counts = {
+        path.relative_to(root.resolve()).as_posix(): line_count(path.read_bytes())
+        for path in source_files(root, budget.roots)
+    }
+    if not counts:
+        errors.append("no first-party sources found")
+    if previous is not None:
+        if budget.limit > previous.limit:
+            errors.append("line limit may not increase against the base revision")
+        if not set(previous.roots).issubset(budget.roots):
+            errors.append("source roots may not be removed from the budget")
+        for name, limit in budget.exceptions.items():
+            if name not in previous.exceptions or limit > previous.exceptions[name]:
+                errors.append(f"{name}: new or increased exception against base revision")
+    for name, count in counts.items():
+        limit = budget.exceptions.get(name, budget.limit)
+        if previous is not None and name in previous.exceptions and read_previous:
+            content = read_previous(name)
+            if content is None:
+                errors.append(f"{name}: exception has no source in base revision")
+            else:
+                limit = min(limit, max(budget.limit, line_count(content)))
+        if count > limit:
+            errors.append(f"{name}: {count} lines > {limit}; split by responsibility")
+        elif name in budget.exceptions:
+            if count <= budget.limit:
+                errors.append(f"{name}: remove the exception; now {count} lines")
+            elif count < budget.exceptions[name]:
+                notices.append(f"{name}: tighten exception to {count}")
+    for name in sorted(budget.exceptions.keys() - counts.keys()):
+        errors.append(f"{name}: remove missing-source exception")
+    return errors, notices, counts
diff --git a/scripts/architecture/dependencies.py b/scripts/architecture/dependencies.py
new file mode 100644
index 0000000..38e9466
--- /dev/null
+++ b/scripts/architecture/dependencies.py
@@ -0,0 +1,134 @@
+from pathlib import Path
+import tomllib
+
+from scripts.architecture.budgets import checked_path, relative_path
+
+
+POLICY_PATH = "architecture/dependencies.toml"
+KINDS = ("dependencies", "build-dependencies", "dev-dependencies")
+
+
+def load(path: Path) -> dict:
+    return tomllib.loads(path.read_text(encoding="utf-8-sig"))
+
+
+def dependency_entries(manifest: dict, workspace: dict):
+    for section in [manifest, *manifest.get("target", {}).values()]:
+        for kind in KINDS:
+            for alias, original in section.get(kind, {}).items():
+                specification = {"version": original} if isinstance(original, str) else original
+                inherited = specification.get("workspace", False)
+                if inherited:
+                    if alias not in workspace.get("dependencies", {}):
+                        raise ValueError(f"unresolved workspace dependency: {alias}")
+                    base = workspace["dependencies"][alias]
+                    base = {"version": base} if isinstance(base, str) else base
+                    specification = dict(base, **specification)
+                yield kind, alias, specification, inherited
+
+
+def cycles(graph: dict[str, set[str]]) -> list[str]:
+    visited = set()
+    active = []
+    errors = []
+
+    def visit(node):
+        if node in active:
+            start = active.index(node)
+            errors.append("production dependency cycle: " + " -> ".join(active[start:] + [node]))
+            return
+        if node in visited:
+            return
+        active.append(node)
+        for target in sorted(graph[node]):
+            visit(target)
+        active.pop()
+        visited.add(node)
+
+    for node in sorted(graph):
+        visit(node)
+    return errors
+
+
+def check(root: Path, policy: dict, source_roots=None, scanned_paths=None):
+    workspace = load(root / "Cargo.toml")["workspace"]
+    members = workspace["members"]
+    if not isinstance(members, list) or not members or len(set(members)) != len(members):
+        raise ValueError("workspace architecture needs nonempty, unique members")
+    if any(any(character in member for character in "*?[") for member in members):
+        raise ValueError("workspace members must be explicit for architecture classification")
+    for member in members:
+        relative_path(member)
+        checked_path(root, member)
+    if workspace.get("exclude"):
+        raise ValueError("workspace exclusions require explicit architecture support")
+    rules = policy.get("crates", {})
+    errors = []
+    if policy.get("version") != 1:
+        raise ValueError("unsupported dependency policy version")
+    if policy.keys() - {"version", "crates", "renderer_packages"}:
+        raise ValueError("unknown dependency policy field")
+    for member in sorted(set(members) ^ rules.keys()):
+        errors.append(f"{member}: workspace membership and architecture classification differ")
+    manifests = {member: load(root / member / "Cargo.toml") for member in members}
+    names = {manifest["package"]["name"]: member for member, manifest in manifests.items()}
+    paths = {(root / member).resolve(): member for member in members}
+    if len(names) != len(members):
+        raise ValueError("duplicate workspace package names")
+    graph = {member: set() for member in members}
+    source_roots = source_roots if source_roots is not None else members
+    forbidden = set(policy.get("renderer_packages", []))
+    for member, manifest in manifests.items():
+        rule = rules.get(member)
+        if rule is None:
+            continue
+        if rule.keys() - {*KINDS, "layer", "zero_production_dependencies"}:
+            errors.append(f"{member}: unknown dependency rule field")
+        if rule.get("layer") not in {"core", "application", "lab", "hook"}:
+            errors.append(f"{member}: invalid architecture layer")
+            continue
+        targets = [manifest.get("lib", {})]
+        targets.extend(target for kind in ("bin", "test", "bench", "example") for target in manifest.get(kind, []))
+        build = manifest["package"].get("build")
+        if isinstance(build, str):
+            targets.append({"path": build})
+        for target_spec in targets:
+            if "path" in target_spec:
+                target_path = checked_path(root, member + "/" + target_spec["path"])
+                covered = any(target_path.is_relative_to(checked_path(root, source)) for source in source_roots)
+                if scanned_paths is not None:
+                    covered = target_path.relative_to(root.resolve()).as_posix() in scanned_paths
+                if not target_path.is_file() or not covered or target_path.suffix != ".rs":
+                    errors.append(f"{member}: invalid custom source path {target_spec['path']}")
+        for kind in KINDS:
+            for target in rule.get(kind, []):
+                if target not in manifests or target == member:
+                    errors.append(f"{member}: invalid {kind} allowance: {target}")
+        for kind, alias, specification, inherited in dependency_entries(manifest, workspace):
+            name = specification.get("package", alias)
+            target = None
+            if "path" in specification:
+                directory = root if inherited else root / member
+                resolved = (directory / specification["path"]).resolve()
+                local_target = paths.get(resolved)
+                if local_target is None:
+                    errors.append(f"{member}: unclassified path dependency {alias}")
+                    continue
+                if names.get(name) != local_target:
+                    errors.append(f"{member}: dependency package/path mismatch for {alias}")
+                    continue
+                target = local_target
+            if rule.get("zero_production_dependencies", False) and kind != "dev-dependencies":
+                errors.append(f"{member}: zero-dependency contract forbids {kind} {alias}")
+            if rule["layer"] in {"core", "hook"} and kind != "dev-dependencies" and name in forbidden:
+                errors.append(f"{member}: renderer dependency {name} is not allowed in core")
+            if target is not None:
+                if target not in rule.get(kind, []):
+                    errors.append(f"{member}: forbidden {kind} edge to {target}")
+                if kind != "dev-dependencies":
+                    target_layer = rules.get(target, {}).get("layer")
+                    if ((rule["layer"] == "core" and target_layer != "core")
+                            or (rule["layer"] == "application" and target_layer == "lab")):
+                        errors.append(f"{member}: forbidden production layer direction to {target}")
+                    graph[member].add(target)
+    return errors + cycles(graph), members
diff --git a/scripts/check_architecture.py b/scripts/check_architecture.py
new file mode 100644
index 0000000..0375e35
--- /dev/null
+++ b/scripts/check_architecture.py
@@ -0,0 +1,78 @@
+import argparse
+from pathlib import Path
+import subprocess
+import sys
+
+if __package__ in (None, ""):
+    sys.path.insert(0, str(Path(__file__).resolve().parent.parent))
+
+from scripts.architecture import budgets, dependencies
+
+
+ROOT = Path(__file__).resolve().parents[1]
+
+
+class Revision:
+    def __init__(self, root: Path, reference: str):
+        self.root = root
+        result = subprocess.run(
+            ["git", "rev-parse", "--verify", "--end-of-options", reference + "^{commit}"],
+            cwd=root, capture_output=True, text=True, encoding="utf-8", check=True,
+        )
+        self.commit = result.stdout.strip()
+
+    def read(self, path: str):
+        result = subprocess.run(
+            ["git", "--literal-pathspecs", "ls-tree", "--name-only", "-z", self.commit, "--", path],
+            cwd=self.root, capture_output=True, check=True,
+        )
+        if not result.stdout:
+            return None
+        return subprocess.run(
+            ["git", "show", f"{self.commit}:{path}"],
+            cwd=self.root, capture_output=True, check=True,
+        ).stdout
+
+
+def run(root: Path, base: str | None = None, report: bool = False) -> int:
+    budget = budgets.Budget.parse((root / budgets.BUDGET_PATH).read_text(encoding="utf-8"))
+    revision = Revision(root, base) if base else None
+    previous_source = revision.read(budgets.BUDGET_PATH) if revision else None
+    previous = budgets.Budget.parse(previous_source.decode("utf-8")) if previous_source is not None else None
+    errors, notices, counts = budgets.check(root, budget, previous, revision.read if revision else None)
+    dependency_errors, members = dependencies.check(
+        root, dependencies.load(root / dependencies.POLICY_PATH), budget.roots, set(counts)
+    )
+    errors.extend(dependency_errors)
+    for member in members:
+        if member not in budget.roots:
+            errors.append(f"{member}: workspace member missing from line-budget roots")
+    print(f"Architecture: {len(counts)} source files, {len(members)} crates, {len(budget.exceptions)} legacy exceptions")
+    advisory = sorted(((name, count) for name, count in counts.items() if count > 800), key=lambda item: -item[1])
+    print(f"Review guidance only: {len(advisory)} files exceed the 800-line soft target")
+    if revision and previous is None:
+        print("Initial policy adoption: no budget in base; review the initial debt inventory")
+    for notice in notices:
+        print(f"NOTICE: {notice}")
+    if report:
+        for name, count in advisory:
+            print(f"REVIEW: {name}: {count} lines")
+    for error in errors:
+        print(f"ERROR: {error}", file=sys.stderr)
+    return int(bool(errors))
+
+
+def main() -> int:
+    parser = argparse.ArgumentParser(description="Offline first-party size and dependency contracts (Python 3.11+)")
+    parser.add_argument("--base", help="PR base commit; rejects new/increased debt and regrowth")
+    parser.add_argument("--report", action="store_true", help="also list advisory-size files")
+    options = parser.parse_args()
+    try:
+        return run(ROOT, options.base, options.report)
+    except (OSError, ValueError, KeyError, subprocess.CalledProcessError) as error:
+        print(f"Architecture check could not complete: {error}", file=sys.stderr)
+        return 1
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())
diff --git a/scripts/tests/test_architecture_budgets.py b/scripts/tests/test_architecture_budgets.py
new file mode 100644
index 0000000..bbfa0f6
--- /dev/null
+++ b/scripts/tests/test_architecture_budgets.py
@@ -0,0 +1,165 @@
+from pathlib import Path
+import io
+import subprocess
+import tempfile
+import unittest
+from unittest.mock import patch
+
+from scripts.architecture.budgets import Budget, check, line_count, source_files
+from scripts import check_architecture
+
+
+class LineBudgetTests(unittest.TestCase):
+    def setUp(self):
+        self.temporary = tempfile.TemporaryDirectory()
+        self.addCleanup(self.temporary.cleanup)
+        self.root = Path(self.temporary.name)
+        (self.root / "app/src").mkdir(parents=True)
+
+    def write(self, name, count):
+        path = self.root / name
+        path.parent.mkdir(parents=True, exist_ok=True)
+        path.write_bytes(b"source\n" * count)
+
+    def policy(self, exceptions="", limit=2000):
+        return Budget.parse(f"limit {limit}\nroot app\n{exceptions}")
+
+    def test_physical_lines(self):
+        for content, expected in [(b"", 0), (b"\n", 1), (b"a\nb", 2),
+                                  (b"a\r\nb\r\n", 2), ("中文\n".encode(), 1),
+                                  (b"vertical\vtab", 1)]:
+            with self.subTest(content=content):
+                self.assertEqual(line_count(content), expected)
+
+    def test_soft_target_is_not_a_failure(self):
+        for count in (0, 1, 800, 801, 2000):
+            with self.subTest(count=count):
+                self.write("app/src/view.rs", count)
+                self.assertEqual(check(self.root, self.policy())[0], [])
+
+    def test_hard_limit_includes_scripts_and_untracked_files(self):
+        for suffix in ("rs", "py", "ps1", "mjs", "js", "sh", "lua"):
+            with self.subTest(suffix=suffix):
+                self.write(f"app/src/new.{suffix}", 2001)
+                self.assertTrue(check(self.root, self.policy())[0])
+
+    def test_exact_exception_and_tightening_notice(self):
+        self.write("app/src/legacy.rs", 2100)
+        errors, notices, _ = check(self.root, self.policy("app/src/legacy.rs 2101"))
+        self.assertEqual(errors, [])
+        self.assertIn("tighten exception to 2100", notices[0])
+        self.assertEqual(check(self.root, self.policy("app/src/legacy.rs 2100"))[0], [])
+
+    def test_deleted_and_shrunk_exceptions_fail(self):
+        budget = self.policy("app/src/legacy.rs 2100")
+        self.write("app/src/other.rs", 1)
+        self.assertIn("missing-source", check(self.root, budget)[0][0])
+        self.write("app/src/legacy.rs", 2000)
+        self.assertIn("remove the exception", check(self.root, budget)[0][0])
+
+    def test_duplicate_and_invalid_records_fail(self):
+        for text in (
+            "limit 2000\nlimit 2000\nroot app", "root app", "limit 0\nroot app",
+            "limit 2000\nroot app\nroot app", "limit 2000\nroot ../app", "limit ٢٠٠٠\nroot app",
+            "limit 2000\nroot /app", "limit 2000\nroot D:/app",
+            "limit 2000\nroot app\nroot app/src", "limit 2000\nroot app\nbogus 2001",
+            "limit 2000\nroot app\napp/src/file.rs 2000",
+            "limit 2000\nroot app\nother/file.rs 2100",
+            "limit 2000\nroot app\napp/src/file.rs 2100\napp/src/file.rs 2100",
+        ):
+            with self.subTest(text=text):
+                with self.assertRaises(ValueError):
+                    Budget.parse(text)
+
+    def test_scanner_includes_hidden_source_but_not_build_outputs(self):
+        (self.root / "app/Cargo.toml").write_text("[package]\n", encoding="utf-8")
+        for name in ("app/src/normal.rs", "app/src/target/real.rs", "app/.internal/source.rs",
+                     "app/target/generated.rs", "tmp/probe.rs", "third_party/copied.rs"):
+            self.write(name, 1)
+        names = {path.relative_to(self.root).as_posix() for path in source_files(self.root, ("app",))}
+        self.assertEqual(names, {"app/src/normal.rs", "app/src/target/real.rs", "app/.internal/source.rs"})
+
+    def test_missing_empty_and_unreadable_roots_fail(self):
+        with self.assertRaises(ValueError):
+            list(source_files(self.root, ("missing",)))
+        self.assertIn("no first-party sources", check(self.root, self.policy())[0][0])
+        with patch("scripts.architecture.budgets.os.walk", side_effect=PermissionError("unreadable")):
+            with self.assertRaises(PermissionError):
+                list(source_files(self.root, ("app",)))
+
+    def test_symlinks_are_not_followed(self):
+        self.write("outside.rs", 1)
+        try:
+            (self.root / "app/src/link.rs").symlink_to(self.root / "outside.rs")
+        except OSError as error:
+            self.skipTest(f"symlink unavailable: {error}")
+        with self.assertRaises(ValueError):
+            list(source_files(self.root, ("app",)))
+
+    def test_symlinked_root_ancestor_is_rejected(self):
+        try:
+            (self.root / "redirect").symlink_to(self.root / "app", target_is_directory=True)
+        except OSError as error:
+            self.skipTest(f"symlink unavailable: {error}")
+        with self.assertRaises(ValueError):
+            list(source_files(self.root, ("redirect/src",)))
+
+    def test_empty_existing_base_budget_is_not_bootstrap(self):
+        with patch("scripts.check_architecture.Revision") as revision:
+            revision.return_value.read.return_value = b""
+            with self.assertRaises(ValueError):
+                check_architecture.run(check_architecture.ROOT, base="HEAD")
+
+    def test_base_rejects_limit_increase_and_scope_removal(self):
+        self.write("app/src/view.rs", 1)
+        self.assertIn("may not increase", check(self.root, self.policy(limit=2100), self.policy())[0][0])
+        previous = Budget.parse("limit 2000\nroot app\nroot other")
+        self.assertIn("may not be removed", check(self.root, self.policy(), previous)[0][0])
+
+    def test_base_rejects_new_or_increased_exceptions(self):
+        self.write("app/src/legacy.rs", 2100)
+        current = self.policy("app/src/legacy.rs 2100")
+        self.assertIn("new or increased", check(self.root, current, self.policy())[0][0])
+        previous = self.policy("app/src/legacy.rs 2099")
+        self.assertIn("new or increased", check(self.root, current, previous)[0][0])
+
+    def test_base_actual_size_prevents_regrowth_under_stale_budget(self):
+        self.write("app/src/legacy.rs", 2101)
+        budget = self.policy("app/src/legacy.rs 2200")
+        errors = check(self.root, budget, budget, lambda name: b"line\n" * 2100)[0]
+        self.assertIn("2101 lines > 2100", errors[0])
+
+    def test_base_that_already_shrank_below_limit_cannot_regrow(self):
+        self.write("app/src/legacy.rs", 2100)
+        budget = self.policy("app/src/legacy.rs 2200")
+        errors = check(self.root, budget, budget, lambda name: b"line\n" * 1800)[0]
+        self.assertIn("2100 lines > 2000", errors[0])
+
+    def test_missing_base_source_is_an_error(self):
+        self.write("app/src/legacy.rs", 2100)
+        budget = self.policy("app/src/legacy.rs 2100")
+        self.assertIn("no source in base", check(self.root, budget, budget, lambda name: None)[0][0])
+
+    def test_invalid_base_is_not_treated_as_bootstrap(self):
+        with patch("scripts.check_architecture.subprocess.run", side_effect=subprocess.CalledProcessError(128, "git")):
+            with self.assertRaises(subprocess.CalledProcessError):
+                check_architecture.Revision(self.root, "missing")
+
+    def test_unreadable_base_tree_is_not_treated_as_missing_budget(self):
+        revision = object.__new__(check_architecture.Revision)
+        revision.root = self.root
+        revision.commit = "a" * 40
+        with patch("scripts.check_architecture.subprocess.run", side_effect=subprocess.CalledProcessError(128, "git")):
+            with self.assertRaises(subprocess.CalledProcessError):
+                revision.read("architecture/file-budgets.txt")
+
+    def test_cli_fails_closed_when_configuration_cannot_be_read(self):
+        with (patch.object(check_architecture, "ROOT", self.root),
+              patch("sys.argv", ["check_architecture"]),
+              patch("sys.stderr", new_callable=io.StringIO) as output):
+            self.assertEqual(check_architecture.main(), 1)
+            self.assertIn("could not complete", output.getvalue())
+
+
+if __name__ == "__main__":
+    unittest.main()
diff --git a/scripts/tests/test_architecture_dependencies.py b/scripts/tests/test_architecture_dependencies.py
new file mode 100644
index 0000000..722ab60
--- /dev/null
+++ b/scripts/tests/test_architecture_dependencies.py
@@ -0,0 +1,166 @@
+from pathlib import Path
+import tempfile
+import unittest
+
+from scripts.architecture.dependencies import check
+
+
+class DependencyTests(unittest.TestCase):
+    def setUp(self):
+        self.temporary = tempfile.TemporaryDirectory()
+        self.addCleanup(self.temporary.cleanup)
+        self.root = Path(self.temporary.name)
+        self.workspace()
+        self.manifest("app", "application")
+        self.manifest("core", "core-model")
+        self.manifest("derive", "derive-helper")
+        self.policy = {
+            "version": 1,
+            "renderer_packages": ["gpui", "winit"],
+            "crates": {
+                "app": {"layer": "application", "dependencies": ["core"]},
+                "core": {"layer": "core", "dev-dependencies": ["derive"]},
+                "derive": {"layer": "core", "dev-dependencies": ["core"]},
+            },
+        }
+
+    def workspace(self, extra="", members='"app", "core", "derive"'):
+        (self.root / "Cargo.toml").write_text(f"[workspace]\nmembers = [{members}]\n{extra}", encoding="utf-8")
+
+    def manifest(self, member, package, extra=""):
+        directory = self.root / member
+        directory.mkdir(exist_ok=True)
+        (directory / "Cargo.toml").write_text(
+            f'[package]\nname = "{package}"\nversion = "0.0.0"\n{extra}', encoding="utf-8"
+        )
+
+    def errors(self):
+        return check(self.root, self.policy)[0]
+
+    def test_legal_inward_dependency_and_package_rename(self):
+        self.manifest("app", "application", '[dependencies]\nmodel = { package = "core-model", path = "../core" }')
+        self.assertEqual(self.errors(), [])
+
+    def test_reverse_dependency_is_rejected(self):
+        self.manifest("core", "core-model", '[dependencies]\napplication = { path = "../app" }')
+        self.assertIn("forbidden dependencies edge to app", self.errors()[0])
+
+    def test_core_cannot_whitelist_a_reverse_production_layer(self):
+        self.policy["crates"]["core"]["dependencies"] = ["app"]
+        self.manifest("core", "core-model", '[dependencies]\napplication = { path = "../app" }')
+        self.assertIn("forbidden production layer direction", self.errors()[0])
+
+    def test_optional_target_and_renamed_renderer_are_checked(self):
+        self.manifest("core", "core-model", '''[target.'cfg(windows)'.dependencies]
+display_adapter = { package = "gpui", version = "0.2", optional = true }''')
+        self.assertIn("renderer dependency gpui", self.errors()[0])
+
+    def test_workspace_inheritance_resolves_paths_from_workspace_root(self):
+        self.workspace('[workspace.dependencies]\nmodel = { package = "core-model", path = "core" }')
+        self.manifest("app", "application", '[dependencies]\nmodel.workspace = true')
+        self.assertEqual(self.errors(), [])
+
+    def test_workspace_inherited_renderer_is_checked(self):
+        self.workspace('[workspace.dependencies]\nwindow = { package = "winit", version = "0.30" }')
+        self.manifest("core", "core-model", '[dependencies]\nwindow.workspace = true')
+        self.assertIn("renderer dependency winit", self.errors()[0])
+
+    def test_unresolved_workspace_dependency_fails(self):
+        self.manifest("core", "core-model", '[dependencies]\nmissing.workspace = true')
+        with self.assertRaises(ValueError):
+            self.errors()
+
+    def test_build_dependencies_are_checked(self):
+        self.manifest("core", "core-model", '[build-dependencies]\napplication = { path = "../app" }')
+        self.assertIn("forbidden build-dependencies", self.errors()[0])
+
+    def test_production_cycle_is_rejected_even_when_edges_are_allowed(self):
+        self.policy["crates"]["core"]["build-dependencies"] = ["app"]
+        self.manifest("core", "core-model", '[build-dependencies]\napplication = { path = "../app" }')
+        self.manifest("app", "application", '[dependencies]\ncore-model = { path = "../core" }')
+        self.assertTrue(any("production dependency cycle" in error for error in self.errors()))
+
+    def test_cargo_legal_dev_cycle_is_not_a_production_cycle(self):
+        self.manifest("core", "core-model", '[dev-dependencies]\nderive-helper = { path = "../derive" }')
+        self.manifest("derive", "derive-helper", '[dev-dependencies]\ncore-model = { path = "../core" }')
+        self.assertEqual(self.errors(), [])
+
+    def test_zero_production_dependencies_allow_test_tools(self):
+        self.policy["crates"]["core"]["zero_production_dependencies"] = True
+        self.manifest("core", "core-model", '[dev-dependencies]\nproptest = "1"')
+        self.assertEqual(self.errors(), [])
+        self.manifest("core", "core-model", '[dependencies]\nserde = "1"')
+        self.assertIn("zero-dependency contract", self.errors()[0])
+
+    def test_unclassified_workspace_member_is_rejected(self):
+        self.manifest("lab", "lab")
+        self.workspace(members='"app", "core", "derive", "lab"')
+        self.assertIn("classification differ", self.errors()[0])
+
+    def test_unclassified_path_dependency_cannot_hide_an_edge(self):
+        self.manifest("app", "application", '[dependencies]\nmodel = { path = "../unknown" }')
+        self.assertIn("unclassified path dependency", self.errors()[0])
+
+    def test_mismatched_package_and_path_is_rejected(self):
+        self.manifest("app", "application", '[dependencies]\nderive-helper = { path = "../core" }')
+        self.assertIn("package/path mismatch", self.errors()[0])
+
+    def test_comment_or_module_alias_is_not_a_dependency(self):
+        self.manifest("core", "core-model", '# crate::gpui and #[path = "../display.rs"] are not dependencies')
+        (self.root / "core/source.rs").write_text('const TEXT: &str = "gpui::Window";', encoding="utf-8")
+        self.assertEqual(self.errors(), [])
+
+    def test_invalid_toml_and_unknown_policy_fields_fail(self):
+        self.policy["crates"]["core"]["zero_dependenices"] = True
+        self.assertIn("unknown dependency rule field", self.errors()[0])
+        (self.root / "core/Cargo.toml").write_text("[broken", encoding="utf-8")
+        with self.assertRaises(ValueError):
+            self.errors()
+
+    def test_unhandled_workspace_layout_fails_instead_of_skipping(self):
+        for extra, members in [('exclude = ["other"]', '"app", "core", "derive"'),
+                               ("", '"crates/*"'), ("", '"../outside"')]:
+            with self.subTest(extra=extra, members=members):
+                self.workspace(extra, members)
+                with self.assertRaises(ValueError):
+                    self.errors()
+
+    def test_empty_or_duplicate_workspace_cannot_pass(self):
+        for members in ("", '"app", "app"'):
+            with self.subTest(members=members):
+                self.workspace(members=members)
+                with self.assertRaises(ValueError):
+                    self.errors()
+
+    def test_custom_source_paths_cannot_escape_coverage(self):
+        self.manifest("core", "core-model", '[lib]\npath = "../outside.rs"')
+        self.assertIn("invalid custom source path", self.errors()[0])
+
+    def test_same_package_from_registry_is_not_a_workspace_edge(self):
+        self.manifest("app", "application", '[dev-dependencies]\nprevious = { package = "core-model", version = "=0.9.0" }')
+        self.assertEqual(self.errors(), [])
+
+    def test_shared_custom_source_is_allowed_inside_scanned_roots(self):
+        (self.root / "derive/shared.rs").write_text("", encoding="utf-8")
+        self.manifest("core", "core-model", '[lib]\npath = "../derive/shared.rs"')
+        self.assertEqual(self.errors(), [])
+
+    def test_custom_target_inside_excluded_output_is_rejected(self):
+        (self.root / "core/target").mkdir()
+        (self.root / "core/target/real.rs").write_text("", encoding="utf-8")
+        self.manifest("core", "core-model", '[lib]\npath = "target/real.rs"')
+        errors = check(self.root, self.policy, scanned_paths=set())[0]
+        self.assertIn("invalid custom source path", errors[0])
+
+    def test_symlinked_workspace_ancestor_is_rejected(self):
+        try:
+            (self.root / "redirect").symlink_to(self.root, target_is_directory=True)
+        except OSError as error:
+            self.skipTest(f"symlink unavailable: {error}")
+        self.workspace(members='"redirect/core"')
+        with self.assertRaises(ValueError):
+            self.errors()
+
+
+if __name__ == "__main__":
+    unittest.main()
diff --git a/scripts/tests/test_architecture_governance.py b/scripts/tests/test_architecture_governance.py
new file mode 100644
index 0000000..f6f3069
--- /dev/null
+++ b/scripts/tests/test_architecture_governance.py
@@ -0,0 +1,119 @@
+from pathlib import Path
+import re
+import subprocess
+import unittest
+
+
+ROOT = Path(__file__).resolve().parents[2]
+DOCUMENTS = (
+    "CONTRIBUTING.md", "docs/project-constraints.md", "docs/architecture.md",
+    "docs/architecture-decisions.md", "docs/engineering-evidence.md",
+    "docs/internationalization.md",
+)
+
+
+class GovernanceTests(unittest.TestCase):
+    def ignored_paths(self, paths):
+        result = subprocess.run(
+            ["git", "check-ignore", "--no-index", "--stdin"], cwd=ROOT,
+            input="\n".join(paths) + "\n", text=True, encoding="utf-8",
+            capture_output=True,
+        )
+        self.assertIn(result.returncode, (0, 1), result.stderr)
+        return set(result.stdout.splitlines())
+
+    def test_contributor_documents_exist_and_are_not_ignored(self):
+        for name in DOCUMENTS:
+            with self.subTest(name=name):
+                self.assertTrue((ROOT / name).is_file())
+        self.assertEqual(self.ignored_paths(DOCUMENTS), set(), "public contributor docs must not be ignored")
+
+    def test_private_investigations_remain_ignored(self):
+        paths = (
+            "docs/private-product-comparison.md", "docs/new-investigation/README.md",
+            "docs/screenshots/vendor-gap-analysis.md", "docs/release-notes/vendor-study.md",
+            "docs/screenshots/vendor-research.md", "docs/screenshots/vendor-competitor-notes.md",
+            "docs/screenshots/research/raw-capture.json",
+            "docs/release-notes/reference-projects/vendor/src/main.rs",
+            "docs/screenshots/external-probes/inspect.ps1",
+            "research/vendor/README.md", "reference-projects/vendor/src/main.rs",
+            "external-probes/inspect-vendor.py", "impeccable/research.md",
+        )
+        self.assertEqual(self.ignored_paths(paths), set(paths))
+
+    def test_html_prototypes_do_not_escape_through_public_doc_directories(self):
+        paths = (
+            "settings.html", "settings.htm", "docs/design/settings/index.html",
+            "docs/screenshots/settings.html", "docs/release-notes/demo.htm",
+            "scripts/design/settings-prototype.html", "tools/design/settings_mockup.html",
+            "scripts/design/settings-prototype.htm", "tools/design/settings_mockup.htm",
+            "prototypes/sidebar/assets/preview.png", "scripts/render_shell_icon.html",
+        )
+        self.assertEqual(self.ignored_paths(paths), set(paths))
+
+    def test_scratch_scripts_and_caches_remain_ignored(self):
+        paths = (
+            "tmp/test-expanded-icons-20260905.ps1", "tmp/check-tool.py",
+            "tmp/vendor-probe/main.rs", "tmp-check.ps1", "tmp_check.py",
+            "scratch/inspect-window.ps1", ".tmp-check.py", ".probe-round/probe.ps1",
+            "scripts/ghost_repro/probe.ps1", "scripts/drawer_repro.ps1",
+            "scripts/__pycache__/helper.cpython-313.pyc", "tools/diagnostic.pyc",
+            "scripts/diagnostic.pyo", ".pytest_cache/v/cache/nodeids",
+            ".mypy_cache/check.json", ".ruff_cache/cache.bin",
+        )
+        self.assertEqual(self.ignored_paths(paths), set(paths))
+
+    def test_maintained_tests_dependencies_and_public_assets_stay_visible(self):
+        paths = (
+            *DOCUMENTS, ".github/CODEOWNERS", ".github/PULL_REQUEST_TEMPLATE.md",
+            ".github/workflows/architecture.yml", "architecture/dependencies.toml",
+            "architecture/file-budgets.txt", "scripts/check_architecture.py",
+            "scripts/tests/test_architecture_governance.py", "scripts/tests/new_regression.py",
+            "scripts/conformance/tests/test_harness.py", "scripts/launch_probe_instance.ps1",
+            "scripts/probe_ssh_connect.ps1", "tools/probe_ime.rs",
+            "tools/i18n-contract/Cargo.toml", "tools/i18n-contract/Cargo.lock",
+            "nebula_app/tests/i18n_contract.rs", "nebula_app/tests/fixtures/page.html",
+            "nebula_app/i18n/fr-FR.json", "third_party/winit-0.30.13/Cargo.toml",
+            "third_party/winit-0.30.13/src/lib.rs", "docs/screenshots/SHOTLIST.md",
+            "docs/screenshots/hero.png", "docs/release-notes/v1.5.0.md",
+            "docs/skills/nebula-runtime/SKILL.md",
+        )
+        self.assertEqual(self.ignored_paths(paths), set())
+
+    def test_relative_document_links_resolve(self):
+        for name in DOCUMENTS:
+            document = ROOT / name
+            text = document.read_text(encoding="utf-8")
+            for link in re.findall(r"\]\(([^)]+)\)", text):
+                if "://" in link or link.startswith("#"):
+                    continue
+                target = link.split("#", 1)[0]
+                with self.subTest(document=name, target=target):
+                    self.assertTrue((document.parent / target).exists())
+
+    def test_required_job_is_unfiltered_and_unprivileged(self):
+        workflow = (ROOT / ".github/workflows/architecture.yml").read_text(encoding="utf-8")
+        for required in ("  pull_request:", "  merge_group:", "contents: read",
+                         "name: architecture-contracts", "persist-credentials: false",
+                         "fetch-depth: 0", "--base", "tools/i18n-contract/Cargo.toml --locked",
+                         "scripts.tests.test_architecture_governance"):
+            with self.subTest(required=required):
+                self.assertIn(required, workflow)
+        for unsafe in ("pull_request_target:", "continue-on-error:", "paths:", "paths-ignore:"):
+            with self.subTest(unsafe=unsafe):
+                self.assertNotIn(unsafe, workflow)
+
+    def test_review_and_activation_contracts_are_documented(self):
+        owners = (ROOT / ".github/CODEOWNERS").read_text(encoding="utf-8")
+        self.assertRegex(owners, r"(?m)^\*\s+@[A-Za-z0-9]")
+        template = (ROOT / ".github/PULL_REQUEST_TEMPLATE.md").read_text(encoding="utf-8")
+        self.assertIn("CONTRIBUTING.md", template)
+        self.assertIn("counterexample", template)
+        constraints = (ROOT / "docs/project-constraints.md").read_text(encoding="utf-8")
+        self.assertIn("do **not** activate GitHub merge protection", constraints)
+        self.assertIn("Empty/invalid budgets", constraints)
+        self.assertIn("an author cannot approve their own PR", constraints)
+
+
+if __name__ == "__main__":
+    unittest.main()
diff --git a/scripts/xplat/check.sh b/scripts/xplat/check.sh
new file mode 100644
index 0000000..f662d8b
--- /dev/null
+++ b/scripts/xplat/check.sh
@@ -0,0 +1,44 @@
+#!/usr/bin/env bash
+# 在 Windows 本机对 macOS / Linux 目标做 `cargo check`，不需要对应的 SDK。
+#
+# 用法：scripts/xplat/check.sh [macos|linux|all]
+#
+# 这是跨目标元数据检查，可发现部分 cfg 与依赖声明不一致的问题
+# （比如 Cargo.toml 里按平台排除了某个 crate 而代码无条件使用）。
+# 使用占位 C 编译器与绑定，不能替代原生 runner 的真实 build/test。
+set -eu
+here="$(cd "$(dirname "$0")" && pwd)"
+repo="$(cd "$here/../.." && pwd)"
+targets=()
+case "${1:-all}" in
+  macos) targets=(aarch64-apple-darwin) ;;
+  linux) targets=(x86_64-unknown-linux-gnu) ;;
+  all) targets=(aarch64-apple-darwin x86_64-unknown-linux-gnu) ;;
+  *) echo "usage: $0 [macos|linux|all]" >&2; exit 2 ;;
+esac
+export CARGO_TARGET_DIR="${CARGO_TARGET_DIR:-$repo/.target-xplat}"
+case "$(uname -s)" in MINGW*|MSYS*|CYGWIN*) fake="$(cygpath -w "$here/fake-cc.cmd")" ;; *) fake="$here/fake-cc.sh" ;; esac
+status=0
+seed_media_stub() {
+  # zed `media` 的 build.rs 按宿主 cfg 决定是否生成 bindings.rs，Windows 宿主
+  # 交叉到 macOS 时什么都不生成。把桩放进它的 OUT_DIR（首轮 check 后才存在）。
+  local root="$CARGO_TARGET_DIR/$1/debug/build" dir
+  for dir in "$root"/media-*/out; do
+    [ -d "$dir" ] && [ ! -f "$dir/bindings.rs" ] && cp "$here/media-bindings-stub.rs" "$dir/bindings.rs"
+  done
+  # gpui_macos 用 `include_bytes!` 嵌 Metal 着色器库，同样只有 Mac 宿主能编；
+  # check 不执行它，空文件即可。
+  for dir in "$root"/gpui_macos-*/out; do
+    [ -d "$dir" ] && [ ! -f "$dir/shaders.metallib" ] && : > "$dir/shaders.metallib"
+  done
+  return 0
+}
+for target in "${targets[@]}"; do
+  echo "== cargo check --target $target"
+  env_target="$(echo "$target" | tr '-' '_')"
+  case "$target" in *apple-darwin) seed_media_stub "$target" ;; esac
+  env "CC_${env_target}=$fake" "CXX_${env_target}=$fake" "AR_${env_target}=$fake" \
+    "PKG_CONFIG_ALLOW_CROSS=1" "RUST_FONTCONFIG_DLOPEN=1" \
+    cargo check --offline --workspace --target "$target" "${@:2}" || status=$?
+done
+exit $status
diff --git a/scripts/xplat/fake-cc.cmd b/scripts/xplat/fake-cc.cmd
new file mode 100644
index 0000000..772ff84
--- /dev/null
+++ b/scripts/xplat/fake-cc.cmd
@@ -0,0 +1,17 @@
+@echo off
+rem 假 C 编译器（Windows 版，见 fake-cc.sh 的说明）：只给交叉 cargo check 用。
+rem 对每个 "-o <path>" 产出空文件；--version / -E 打印占位并成功返回。
+setlocal EnableDelayedExpansion
+set "prev="
+set "out="
+for %%A in (%*) do (
+    set "arg=%%~A"
+    if "!arg!"=="--version" ( echo fake-cc 0.0 ^(nebula cross-check stub^) & exit /b 0 )
+    if "!arg!"=="-dumpversion" ( echo 0.0 & exit /b 0 )
+    if "!arg!"=="-dumpmachine" ( echo fake & exit /b 0 )
+    if "!arg!"=="-E" ( echo #define __FAKE_CC__ 1 & exit /b 0 )
+    if "!prev!"=="-o" set "out=!arg!"
+    set "prev=!arg!"
+)
+if defined out type nul > "!out!"
+exit /b 0
diff --git a/scripts/xplat/fake-cc.sh b/scripts/xplat/fake-cc.sh
new file mode 100644
index 0000000..999ea48
--- /dev/null
+++ b/scripts/xplat/fake-cc.sh
@@ -0,0 +1,20 @@
+#!/usr/bin/env bash
+# 假 C 编译器：只给 `cargo check --target <非本机>` 用。
+#
+# 交叉 check 时 cargo 仍会跑 tree-sitter / ring / libsqlite3-sys / mlua-sys 等
+# crate 的 build script，它们用 cc-rs 编 C。本机没有 macOS SDK，真编不了；
+# 但 check 不链接，只要 build script 成功、产出「一个文件」即可。这里对每个
+# `-o <path>` 产出一个空文件，其余参数忽略。绝不能用于 build/test。
+set -eu
+out=""
+prev=""
+for arg in "$@"; do
+  if [ "$prev" = "-o" ]; then out="$arg"; fi
+  case "$arg" in
+    --version|-v|-dumpversion|-dumpmachine) echo "fake-cc 0.0 (nebula cross-check stub)"; exit 0 ;;
+    -E) echo "#define __FAKE_CC__ 1"; exit 0 ;;
+  esac
+  prev="$arg"
+done
+if [ -n "$out" ]; then : > "$out"; fi
+exit 0
diff --git a/scripts/xplat/media-bindings-stub.rs b/scripts/xplat/media-bindings-stub.rs
new file mode 100644
index 0000000..93dcae7
--- /dev/null
+++ b/scripts/xplat/media-bindings-stub.rs
@@ -0,0 +1,50 @@
+// 交叉 `cargo check --target aarch64-apple-darwin` 用的 CoreMedia 绑定桩。
+//
+// zed 的 `media` crate 在 build.rs 里用 bindgen + `xcrun` 从 macOS SDK 生成
+// `bindings.rs`，而且 build.rs 的 `#[cfg(target_os = "macos")]` 看的是**宿主**，
+// 所以在 Windows 上交叉 check 时它什么都不生成。这里手写它实际用到的那几个
+// 符号（类型布局与 CoreMedia 一致），只为让 Rust 层通过类型检查。
+// 绝不能进入真实 macOS 构建——那里由 bindgen 产出真货。
+
+
+pub type CFStringRef = *const core::ffi::c_void;
+pub type CVReturn = i32;
+pub type CMItemIndex = i64;
+pub type CMTimeValue = i64;
+pub type CMTimeScale = i32;
+pub type CMTimeFlags = u32;
+pub type CMTimeEpoch = i64;
+pub type CMVideoCodecType = u32;
+pub type VTEncodeInfoFlags = u32;
+
+#[repr(C)]
+#[derive(Debug, Copy, Clone)]
+pub struct CMTime {
+    pub value: CMTimeValue,
+    pub timescale: CMTimeScale,
+    pub flags: CMTimeFlags,
+    pub epoch: CMTimeEpoch,
+}
+
+#[repr(C)]
+#[derive(Debug, Copy, Clone)]
+pub struct CMSampleTimingInfo {
+    pub duration: CMTime,
+    pub presentationTimeStamp: CMTime,
+    pub decodeTimeStamp: CMTime,
+}
+
+pub const VTEncodeInfoFlags_kVTEncodeInfo_Asynchronous: VTEncodeInfoFlags = 1;
+pub const VTEncodeInfoFlags_kVTEncodeInfo_FrameDropped: VTEncodeInfoFlags = 2;
+pub const kCVReturnSuccess: CVReturn = 0;
+pub const kCVPixelFormatType_32BGRA: u32 = 0x4247_5241; // 'BGRA'
+pub const kCVPixelFormatType_420YpCbCr8Planar: u32 = 0x7934_3230; // 'y420'
+pub const kCVPixelFormatType_420YpCbCr8BiPlanarVideoRange: u32 = 0x3432_3076; // '420v'
+pub const kCVPixelFormatType_420YpCbCr8BiPlanarFullRange: u32 = 0x3432_3066; // '420f'
+pub const kCMVideoCodecType_H264: CMVideoCodecType = 0x6176_6331; // 'avc1'
+
+unsafe extern "C" {
+    pub static kCMTimeInvalid: CMTime;
+    pub static kCMSampleAttachmentKey_NotSync: CFStringRef;
+    pub fn CMTimeMake(value: i64, timescale: i32) -> CMTime;
+}