diff --git a/design/03-rust-web/process/3-19-rust-web-browser-runtime-module-extraction-v1.md b/design/03-rust-web/process/3-19-rust-web-browser-runtime-module-extraction-v1.md
index 91ee4429..1f1daba6 100644
--- a/design/03-rust-web/process/3-19-rust-web-browser-runtime-module-extraction-v1.md
+++ b/design/03-rust-web/process/3-19-rust-web-browser-runtime-module-extraction-v1.md
@@ -466,6 +466,36 @@ node scripts/task479-local-folder-markdown-resource-lifecycle-smoke.js
 - `local-upload-runtime.js` route 返回 `200`，`content-type=application/javascript; charset=utf-8`。
 - `task479` 最终 `ok=true`，覆盖主编辑区上传目录、filetree folder drop、broken link 保留、无 active document 附件 tab、文件树滚动、标题来源、单附件删除保留相邻附件。
 
+### 9.5 Batch 4 执行记录（2026-05-24）
+
+Reasonix read-only audit：
+
+- run id: `reasonix-2026-05-24T15-27-18-395Z-12afda31`
+- worker worktree: `/mnt/Data1T/mnote-wt-3-19-local-upload-context-b4`
+- handoff: `/home/lix/.codex/runtime/reasonix-coding-worker/reasonix-2026-05-24T15-27-18-395Z-12afda31/process-handoff.md`
+- 类型：只读审计，主控已读取 Hindsight recall、`process-handoff.md`、`process-handoff.json`。
+
+采纳内容：
+
+- `local-upload-runtime.js` 新增 `resolveEditorUploadContext`、`editorRootFromUploadOptions`、`openEditorUploadFilePicker`。
+- `SIDEBAR_TREE_JS` 中保留同名 wrapper 和 inline fallback；优先委托 `window.__mnoteLocalUploadRuntime`，模块加载失败时保留旧行为。
+- 本批不迁 `uploadFileToMediaAsset`、`uploadFilesWithResolvedTarget`、`insertUploadedAssetIntoEditor`。这些函数仍混合 API POST、file tree refresh、Tiptap chain 插入和 OnlyOffice/resource tab 逻辑，后续需要继续拆边界。
+- `scripts/task472-side-target-secondary-pane-smoke.js` 补齐 `/api/local-folder/assets/upload` 当前必需的 `uploadIntent=editor.markdown.attach`，让 secondary pane smoke 恢复可运行。
+
+已通过验证：
+
+- `node --check rust/crates/mnote-web/browser/local-upload-runtime.js`
+- `cargo fmt --manifest-path rust/Cargo.toml --all --check`
+- `cargo check --manifest-path rust/Cargo.toml -p mnote-web`
+- `cargo test --manifest-path rust/Cargo.toml -p mnote-web local_upload_runtime_contains_editor_upload_context_helpers`
+- `cargo test --manifest-path rust/Cargo.toml -p mnote-web sidebar_upload_runtime_routes_local_markdown_assets_to_local_folder`
+- `node scripts/task479-local-folder-markdown-resource-lifecycle-smoke.js`
+  - 结果：`ok=true`
+  - 证据：命令 stdout JSON，覆盖 `editor-upload-to-page-resource-dir`、`filetree-folder-drop-to-target`、`broken-link-after-real-file-delete`、`direct-attach-open-without-active-md`、`editor-delete-one-attachment-preserves-adjacent` 等检查。
+- `node scripts/task472-side-target-secondary-pane-smoke.js`
+  - 结果：`ok=true`
+  - 证据：命令 stdout JSON，`assetId=local:asset:README/side-target-resource.md`、`officeAssetId=local:asset:README/side-target-office.docx`。
+
 ## 10. 分阶段执行清单
 
 ### P0：定位辅助与基线保护
@@ -498,7 +528,7 @@ node scripts/task479-local-folder-markdown-resource-lifecycle-smoke.js
   - office -> OnlyOffice path builder
 - [ ] 从 `SIDEBAR_TREE_JS` 中迁出本地文件夹上传目标计算和 adapter 调用；资源归属语义仍由 Rust API / kernel 合同决定。
   - 2026-05-24 / `reasonix-2026-05-24T15-17-16-430Z-18054487` 只读审计：`leptos-tiptap` 只应发出上传 intent；本地 Markdown 路径、`rootUri`、`/api/local-folder/files/open` URL、`markdownRelativePath` 与真实上传落盘都归本设计的 shell host runtime。
-  - 下一刀低风险候选：`resolveEditorUploadContext`、`editorRootFromUploadOptions`、`openEditorUploadFilePicker`，优先保持调用 `uploadFilesWithResolvedTarget`，不同时迁上传主流程。
+  - 2026-05-24 / Batch 4 已迁：`resolveEditorUploadContext`、`editorRootFromUploadOptions`、`openEditorUploadFilePicker`，并保持调用 `uploadFilesWithResolvedTarget`，未同时迁上传主流程。
   - 暂不迁：`uploadFileToMediaAsset`、`uploadFilesWithResolvedTarget`、`insertUploadedAssetIntoEditor`。这些函数同时涉及 API POST、file tree refresh、Tiptap chain 插入、OnlyOffice/resource tab，需在后续批次继续拆边界。
 - [ ] 保持现有 smoke：
   - `node scripts/task472-side-target-secondary-pane-smoke.js`
diff --git a/rust/crates/mnote-web/browser/local-upload-runtime.js b/rust/crates/mnote-web/browser/local-upload-runtime.js
index cefda629..0508d7d7 100644
--- a/rust/crates/mnote-web/browser/local-upload-runtime.js
+++ b/rust/crates/mnote-web/browser/local-upload-runtime.js
@@ -20,6 +20,110 @@ function currentRootUri() {
     : '';
 }
 
+function editorUploadRootFromElementWithDeps(target, deps) {
+  if (deps && typeof deps.editorUploadRootFromElement === 'function') {
+    return deps.editorUploadRootFromElement(target);
+  }
+  if (!(target instanceof Element)) return null;
+  var selector = String(deps && deps.rootSelector || '[data-editor-host-kind="leptos_tiptap_island"], [data-editor-host-kind="leptos_tiptap_resource"]');
+  var root = target.closest(selector);
+  return root instanceof HTMLElement ? root : null;
+}
+
+function resolveEditorUploadContext(detail, deps) {
+  var root = null;
+  var selector = detail && detail.editorRootSelector ? String(detail.editorRootSelector) : '';
+  if (selector) {
+    try {
+      var selected = document.querySelector(selector);
+      if (selected instanceof HTMLElement) root = selected;
+    } catch (_) {}
+  }
+  if (!root && window.__mnoteIntendedSlashRoot instanceof HTMLElement && window.__mnoteIntendedSlashRoot.isConnected) {
+    root = window.__mnoteIntendedSlashRoot;
+  }
+  if (!root && window.__mnoteLastEditorUploadRoot instanceof HTMLElement && window.__mnoteLastEditorUploadRoot.isConnected) {
+    root = window.__mnoteLastEditorUploadRoot;
+  }
+  if (!root && document.activeElement instanceof Element) {
+    root = editorUploadRootFromElementWithDeps(document.activeElement, deps);
+  }
+  if (!root) {
+    var rootSelector = String(deps && deps.rootSelector || '[data-editor-host-kind="leptos_tiptap_island"], [data-editor-host-kind="leptos_tiptap_resource"]');
+    var focused = document.querySelector(rootSelector + ' .ProseMirror:focus-within');
+    root = editorUploadRootFromElementWithDeps(focused, deps);
+  }
+  if (!root) {
+    root = document.querySelector('[data-editor-host-kind="leptos_tiptap_island"][data-pane-role="primary"]');
+  }
+  var pane = root instanceof Element ? root.closest('.document-pane[data-pane-role]') : null;
+  var shell = root instanceof Element ? root.closest('.document-shell[data-document-id]') : null;
+  var currentDocumentId = deps && typeof deps.currentDocumentId === 'function' ? deps.currentDocumentId : function() { return ''; };
+  var resolveWorkspaceId = deps && typeof deps.resolveWorkspaceId === 'function' ? deps.resolveWorkspaceId : function() { return ''; };
+  return {
+    root: root instanceof HTMLElement ? root : null,
+    documentId: String(
+      detail && detail.documentId
+      || (root instanceof HTMLElement && root.getAttribute('data-document-id'))
+      || (pane instanceof HTMLElement && pane.getAttribute('data-pane-document-id'))
+      || (shell instanceof HTMLElement && shell.getAttribute('data-document-id'))
+      || currentDocumentId()
+      || ''
+    ).trim(),
+    workspaceId: String(
+      detail && detail.workspaceId
+      || (root instanceof HTMLElement && root.getAttribute('data-workspace-id'))
+      || (pane instanceof HTMLElement && pane.getAttribute('data-pane-workspace-id'))
+      || (shell instanceof HTMLElement && shell.getAttribute('data-workspace-id'))
+      || resolveWorkspaceId(document.body)
+      || ''
+    ).trim()
+  };
+}
+
+function editorRootFromUploadOptions(options, deps) {
+  if (options && options.editorRoot instanceof HTMLElement) return options.editorRoot;
+  if (window.__mnoteIntendedSlashRoot instanceof HTMLElement && window.__mnoteIntendedSlashRoot.isConnected) {
+    return window.__mnoteIntendedSlashRoot;
+  }
+  if (window.__mnoteLastEditorUploadRoot instanceof HTMLElement && window.__mnoteLastEditorUploadRoot.isConnected) {
+    return window.__mnoteLastEditorUploadRoot;
+  }
+  var rootSelector = String(deps && deps.rootSelector || '[data-editor-host-kind="leptos_tiptap_island"], [data-editor-host-kind="leptos_tiptap_resource"]');
+  var focused = document.querySelector(rootSelector + ' .ProseMirror:focus-within');
+  return editorUploadRootFromElementWithDeps(focused, deps);
+}
+
+function openEditorUploadFilePicker(detail, deps) {
+  var uploadContext = resolveEditorUploadContext(detail || {}, deps || {});
+  var input = document.createElement('input');
+  input.type = 'file';
+  input.multiple = detail && detail.multiple !== false;
+  if (detail && detail.accept) input.accept = String(detail.accept);
+  input.style.position = 'fixed';
+  input.style.left = '-9999px';
+  input.style.top = '-9999px';
+  document.body.appendChild(input);
+  input.addEventListener('change', function() {
+    var files = Array.from(input.files || []);
+    input.remove();
+    var resolveWorkspaceId = deps && typeof deps.resolveWorkspaceId === 'function' ? deps.resolveWorkspaceId : function() { return ''; };
+    var currentDocumentId = deps && typeof deps.currentDocumentId === 'function' ? deps.currentDocumentId : function() { return ''; };
+    var uploadFilesWithResolvedTarget = deps && typeof deps.uploadFilesWithResolvedTarget === 'function' ? deps.uploadFilesWithResolvedTarget : null;
+    if (!uploadFilesWithResolvedTarget) return;
+    void uploadFilesWithResolvedTarget(files, {
+      workspaceId: uploadContext.workspaceId || resolveWorkspaceId(document.body),
+      documentId: uploadContext.documentId || currentDocumentId(),
+      targetRowId: null,
+      uploadIntent: 'editor.markdown.attach'
+    }, {
+      insertIntoEditor: detail && detail.insertIntoEditor !== false,
+      editorRoot: uploadContext.root
+    });
+  }, { once: true });
+  input.click();
+}
+
 function localAssetOpenUrl(asset, download, context) {
   if (!isLocalUploadedAsset(asset)) return '';
   var rootUri = String(context && context.rootUri || asset && (asset.rootUri || asset.root_uri) || '').trim() || currentRootUri();
@@ -145,6 +249,9 @@ function uploadedFileSize(asset) {
 window.__mnoteLocalUploadRuntime = {
   uploadedAssetTitle: uploadedAssetTitle,
   uploadedAssetUrl: uploadedAssetUrl,
+  resolveEditorUploadContext: resolveEditorUploadContext,
+  editorRootFromUploadOptions: editorRootFromUploadOptions,
+  openEditorUploadFilePicker: openEditorUploadFilePicker,
   localAssetOpenUrl: localAssetOpenUrl,
   uploadedAssetType: uploadedAssetType,
   fileTreeIconKindForFileName: fileTreeIconKindForFileName,
diff --git a/rust/crates/mnote-web/src/ssr/pages/layout.rs b/rust/crates/mnote-web/src/ssr/pages/layout.rs
index 97452445..751bc7e4 100644
--- a/rust/crates/mnote-web/src/ssr/pages/layout.rs
+++ b/rust/crates/mnote-web/src/ssr/pages/layout.rs
@@ -3775,6 +3775,15 @@ const SIDEBAR_TREE_JS: &str = r##"
   }
 
   function resolveEditorUploadContext(detail) {
+    var runtimeFn = localUploadRuntimeFunction('resolveEditorUploadContext');
+    if (runtimeFn) {
+      return runtimeFn(detail || {}, {
+        rootSelector: EDITOR_UPLOAD_ROOT_SELECTOR,
+        editorUploadRootFromElement: editorUploadRootFromElement,
+        currentDocumentId: currentDocumentId,
+        resolveWorkspaceId: resolveWorkspaceId
+      });
+    }
     var root = null;
     var selector = detail && detail.editorRootSelector ? String(detail.editorRootSelector) : '';
     if (selector) {
@@ -3823,6 +3832,13 @@ const SIDEBAR_TREE_JS: &str = r##"
   }
 
   function editorRootFromUploadOptions(options) {
+    var runtimeFn = localUploadRuntimeFunction('editorRootFromUploadOptions');
+    if (runtimeFn) {
+      return runtimeFn(options || {}, {
+        rootSelector: EDITOR_UPLOAD_ROOT_SELECTOR,
+        editorUploadRootFromElement: editorUploadRootFromElement
+      });
+    }
     if (options && options.editorRoot instanceof HTMLElement) return options.editorRoot;
     if (window.__mnoteIntendedSlashRoot instanceof HTMLElement && window.__mnoteIntendedSlashRoot.isConnected) {
       return window.__mnoteIntendedSlashRoot;
@@ -4029,6 +4045,16 @@ const SIDEBAR_TREE_JS: &str = r##"
   }
 
   function openEditorUploadFilePicker(detail) {
+    var runtimeFn = localUploadRuntimeFunction('openEditorUploadFilePicker');
+    if (runtimeFn) {
+      return runtimeFn(detail || {}, {
+        rootSelector: EDITOR_UPLOAD_ROOT_SELECTOR,
+        editorUploadRootFromElement: editorUploadRootFromElement,
+        currentDocumentId: currentDocumentId,
+        resolveWorkspaceId: resolveWorkspaceId,
+        uploadFilesWithResolvedTarget: uploadFilesWithResolvedTarget
+      });
+    }
     var uploadContext = resolveEditorUploadContext(detail || {});
     var input = document.createElement('input');
     input.type = 'file';
@@ -10795,12 +10821,29 @@ mod tests {
         assert!(SIDEBAR_TREE_JS.contains("refreshLocalFolderSidebarSnapshot"));
         assert!(SIDEBAR_TREE_JS.contains("wolai:local-assets-changed"));
         assert!(SIDEBAR_TREE_JS.contains("function resolveEditorUploadContext"));
+        assert!(
+            SIDEBAR_TREE_JS.contains("localUploadRuntimeFunction('resolveEditorUploadContext')")
+        );
+        assert!(
+            SIDEBAR_TREE_JS.contains("localUploadRuntimeFunction('openEditorUploadFilePicker')")
+        );
         assert!(SIDEBAR_TREE_JS.contains("__mnoteLastEditorUploadRoot"));
         assert!(SIDEBAR_TREE_JS.contains("data-pane-role=\"primary\""));
         assert!(SIDEBAR_TREE_JS.contains("insertUploadedAssetIntoEditor(localPayload.asset, editorRootFromUploadOptions(options))"));
         assert!(SIDEBAR_TREE_JS.contains("editorRoot: uploadContext.root"));
     }
 
+    #[test]
+    fn local_upload_runtime_contains_editor_upload_context_helpers() {
+        const LOCAL_UPLOAD_RUNTIME_JS: &str =
+            include_str!("../../../browser/local-upload-runtime.js");
+        assert!(LOCAL_UPLOAD_RUNTIME_JS.contains("function resolveEditorUploadContext"));
+        assert!(LOCAL_UPLOAD_RUNTIME_JS.contains("function editorRootFromUploadOptions"));
+        assert!(LOCAL_UPLOAD_RUNTIME_JS.contains("function openEditorUploadFilePicker"));
+        assert!(LOCAL_UPLOAD_RUNTIME_JS.contains("uploadFilesWithResolvedTarget"));
+        assert!(LOCAL_UPLOAD_RUNTIME_JS.contains("__mnoteLastEditorUploadRoot"));
+    }
+
     #[test]
     fn sidebar_tree_runtime_focuses_restored_local_folder_row() {
         assert!(SIDEBAR_TREE_JS.contains("applyPendingLocalFolderRestoreFocusOnce"));
diff --git a/scripts/task472-side-target-secondary-pane-smoke.js b/scripts/task472-side-target-secondary-pane-smoke.js
index 921a4ce7..e50d73d5 100644
--- a/scripts/task472-side-target-secondary-pane-smoke.js
+++ b/scripts/task472-side-target-secondary-pane-smoke.js
@@ -64,6 +64,7 @@ async function uploadLocalAsset(page, root, documentId, fileName, mimeType, byte
       const form = new FormData();
       form.append("rootUri", rootUri);
       form.append("documentId", documentId);
+      form.append("uploadIntent", "editor.markdown.attach");
       form.append("kind", kind);
       form.append("file", new File([new Uint8Array(bytes)], fileName, { type: mimeType }));
       const response = await fetch("/api/local-folder/assets/upload", { method: "POST", body: form });