diff --git a/design/03-rust-web/process/3-20-browser-runtime-followup-checklist-v1.md b/design/03-rust-web/process/3-20-browser-runtime-followup-checklist-v1.md
index e994ece9..fc38ed29 100644
--- a/design/03-rust-web/process/3-20-browser-runtime-followup-checklist-v1.md
+++ b/design/03-rust-web/process/3-20-browser-runtime-followup-checklist-v1.md
@@ -83,3 +83,7 @@ UI / 浏览器可见项必须有真实浏览器截图或结构化 smoke 证据
   - `reasonix-2026-05-24T17-07-59-638Z-29274a46` 产生 handoff，但内容串到 Worker B 的 block menu 任务，worktree 无 diff，拒绝采纳。
   - `reasonix-2026-05-24T17-12-41-044Z-25b9d5d7` 仅产生 `prompt.md` / `memory-recall.json` / `reasonix-transcript.jsonl`，无 `final.md`、`result.json`、`process-handoff.md/json`，worktree 无 diff，拒绝采纳。
   - 该项保持未完成；下一刀应进一步缩窄为只迁 editor 插入 DOM 拼接中的一个纯 helper，或由 Codex 本地实现后再交 Reasonix 做浏览器 smoke。
+- 2026-05-25：Codex 主控完成 `insertUploadedAssetIntoEditor` 外置切片：`local-upload-runtime.js` 新增并导出 `insertUploadedAssetIntoEditor(asset, targetRoot, deps)`，`layout.rs` 优先委托 runtime，保留完整 inline fallback。
+  - 修改：`rust/crates/mnote-web/browser/local-upload-runtime.js`、`rust/crates/mnote-web/src/ssr/pages/layout.rs`。
+  - 已验证：`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 -- --test-threads=1`、`cargo test --manifest-path rust/Cargo.toml -p mnote-web sidebar_upload_runtime_routes_local_markdown_assets_to_local_folder -- --test-threads=1`、`node scripts/task479-local-folder-markdown-resource-lifecycle-smoke.js`。
+  - 未完成：`uploadFileToMediaAsset` 编排壳、`uploadFilesWithResolvedTarget`、conflict merge / accept / keep 业务逻辑、secondary pane conflict smoke 仍未迁出。
diff --git a/rust/crates/mnote-web/browser/local-upload-runtime.js b/rust/crates/mnote-web/browser/local-upload-runtime.js
index 49b6e7f3..543c4fc2 100644
--- a/rust/crates/mnote-web/browser/local-upload-runtime.js
+++ b/rust/crates/mnote-web/browser/local-upload-runtime.js
@@ -183,6 +183,101 @@ async function uploadLocalFolderAsset(file, plan, context) {
   };
 }
 
+async function insertUploadedAssetIntoEditor(asset, targetRoot, deps) {
+  deps = deps || {};
+  var editorRoot = targetRoot instanceof HTMLElement
+    ? targetRoot.querySelector('.editor-surface .ProseMirror')
+    : document.querySelector('.editor-surface .ProseMirror');
+  if (targetRoot instanceof HTMLElement) window.__mnoteLastEditorUploadRoot = targetRoot;
+  var editor = editorRoot && editorRoot.editor;
+  if (!editor || !editor.chain) {
+    document.documentElement.setAttribute('data-mnote-last-upload-inserted', 'false');
+    document.documentElement.setAttribute('data-mnote-last-upload-insert-error', 'editor_unavailable');
+    return false;
+  }
+  var title = typeof deps.uploadedAssetTitle === 'function' ? deps.uploadedAssetTitle(asset) : uploadedAssetTitle(asset);
+  var localOpenUrl = typeof deps.localAssetOpenUrl === 'function' ? deps.localAssetOpenUrl(asset, false) : localAssetOpenUrl(asset, false);
+  var fallbackUrl = typeof deps.uploadedAssetUrl === 'function' ? deps.uploadedAssetUrl(asset) : uploadedAssetUrl(asset);
+  var url = localOpenUrl || fallbackUrl;
+  var type = typeof deps.uploadedAssetType === 'function' ? deps.uploadedAssetType(asset) : uploadedAssetType(asset);
+  var assetId = String(asset && asset.id || '').trim();
+  var sizeLabel = typeof deps.uploadedFileSize === 'function' ? deps.uploadedFileSize(asset) : uploadedFileSize(asset);
+  try {
+    if (type === 'image' && url) {
+      return editor.chain().focus().setImage({ src: url, alt: title, title: title }).run() === true;
+    }
+    var isLocalAsset = typeof deps.isLocalUploadedAsset === 'function' ? deps.isLocalUploadedAsset(asset) : isLocalUploadedAsset(asset);
+    var userId = '';
+    var buildOnlyOfficeAssetOpenUrl = typeof deps.buildOnlyOfficeAssetOpenUrl === 'function' ? deps.buildOnlyOfficeAssetOpenUrl : function() { return ''; };
+    var onlyOfficeUrl = buildOnlyOfficeAssetOpenUrl(asset, userId);
+    if (onlyOfficeUrl && assetId) {
+      userId = typeof deps.fetchCurrentOnlyOfficeUserId === 'function' ? await deps.fetchCurrentOnlyOfficeUserId() : '';
+      onlyOfficeUrl = buildOnlyOfficeAssetOpenUrl(asset, userId);
+    }
+    var href = onlyOfficeUrl || url;
+    if (href) {
+      var storedHref = onlyOfficeUrl
+        ? (isLocalAsset ? onlyOfficeUrl : deps.buildOnlyOfficeOpenPath({
+            fileUrl: '',
+            fileName: title,
+            fileType: deps.inferOnlyOfficeFileType(title, asset && asset.mime_type) || 'docx',
+            assetId: assetId,
+            documentId: String(asset && (asset.document_id || asset.documentId) || deps.currentDocumentId() || '').trim(),
+            userId: userId || '',
+            mode: 'view'
+          }))
+        : href;
+      var inserted = editor.chain().focus().insertContent([
+        {
+          type: 'paragraph',
+          content: [{
+            type: 'text',
+            text: title,
+            marks: [{
+              type: 'link',
+              attrs: {
+                href: storedHref,
+                target: '_blank',
+                rel: 'noopener noreferrer nofollow',
+                class: typeof deps.uploadedAttachmentClass === 'function' ? deps.uploadedAttachmentClass(asset) : uploadedAttachmentClass(asset)
+              }
+            }]
+          }]
+        },
+        { type: 'paragraph' }
+      ]).focus('end').run() === true;
+      if (inserted) {
+        document.documentElement.setAttribute('data-mnote-last-upload-inserted', 'true');
+        document.documentElement.setAttribute('data-mnote-last-upload-asset-id', assetId || '');
+        document.documentElement.removeAttribute('data-mnote-last-upload-insert-error');
+      } else {
+        document.documentElement.setAttribute('data-mnote-last-upload-inserted', 'false');
+        document.documentElement.setAttribute('data-mnote-last-upload-insert-error', 'insert_content_failed');
+      }
+      window.setTimeout(function() {
+        if (targetRoot instanceof HTMLElement) window.__mnoteLastEditorUploadRoot = targetRoot;
+        if (typeof deps.enhanceEditorAttachmentLinks === 'function') deps.enhanceEditorAttachmentLinks();
+        var cssEscape = typeof deps.cssEscape === 'function' ? deps.cssEscape : function(value) { return String(value || '').replace(/"/g, '\\"'); };
+        var selector = assetId
+          ? '.editor-surface .ProseMirror a[href*="' + cssEscape(assetId) + '"]'
+          : '.editor-surface .ProseMirror a';
+        var link = targetRoot instanceof HTMLElement
+          ? targetRoot.querySelector(selector)
+          : document.querySelector(selector);
+        if (link instanceof HTMLElement) {
+          link.setAttribute('data-mnote-attachment-link', 'true');
+          if (assetId) link.setAttribute('data-asset-id', assetId);
+          if (sizeLabel) link.setAttribute('data-file-size', sizeLabel);
+        }
+      }, 0);
+      return inserted;
+    }
+  } catch (error) {
+    console.warn('[mnote upload] insert uploaded asset failed', error);
+  }
+  return false;
+}
+
 function localAssetOpenUrl(asset, download, context) {
   if (!isLocalUploadedAsset(asset)) return '';
   var rootUri = String(context && context.rootUri || asset && (asset.rootUri || asset.root_uri) || '').trim() || currentRootUri();
@@ -313,6 +408,7 @@ window.__mnoteLocalUploadRuntime = {
   openEditorUploadFilePicker: openEditorUploadFilePicker,
   fetchWithTimeout: fetchWithTimeout,
   uploadLocalFolderAsset: uploadLocalFolderAsset,
+  insertUploadedAssetIntoEditor: insertUploadedAssetIntoEditor,
   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 eedc6ff4..8b8f5e1f 100644
--- a/rust/crates/mnote-web/src/ssr/pages/layout.rs
+++ b/rust/crates/mnote-web/src/ssr/pages/layout.rs
@@ -3905,6 +3905,25 @@ const SIDEBAR_TREE_JS: &str = r##"
   }
 
   async function insertUploadedAssetIntoEditor(asset, targetRoot) {
+    var runtimeFn = localUploadRuntimeFunction('insertUploadedAssetIntoEditor');
+    if (runtimeFn) {
+      return await runtimeFn(asset, targetRoot, {
+        uploadedAssetTitle: uploadedAssetTitle,
+        localAssetOpenUrl: localAssetOpenUrl,
+        uploadedAssetUrl: uploadedAssetUrl,
+        uploadedAssetType: uploadedAssetType,
+        isLocalUploadedAsset: isLocalUploadedAsset,
+        buildOnlyOfficeAssetOpenUrl: buildOnlyOfficeAssetOpenUrl,
+        fetchCurrentOnlyOfficeUserId: fetchCurrentOnlyOfficeUserId,
+        buildOnlyOfficeOpenPath: buildOnlyOfficeOpenPath,
+        inferOnlyOfficeFileType: inferOnlyOfficeFileType,
+        currentDocumentId: currentDocumentId,
+        uploadedAttachmentClass: uploadedAttachmentClass,
+        uploadedFileSize: uploadedFileSize,
+        cssEscape: cssEscape,
+        enhanceEditorAttachmentLinks: enhanceEditorAttachmentLinks
+      });
+    }
     var editorRoot = targetRoot instanceof HTMLElement
       ? targetRoot.querySelector('.editor-surface .ProseMirror')
       : document.querySelector('.editor-surface .ProseMirror');
@@ -10932,6 +10951,9 @@ mod tests {
         assert!(
             SIDEBAR_TREE_JS.contains("localUploadRuntimeFunction('openEditorUploadFilePicker')")
         );
+        assert!(
+            SIDEBAR_TREE_JS.contains("localUploadRuntimeFunction('insertUploadedAssetIntoEditor')")
+        );
         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))"));
@@ -10947,6 +10969,8 @@ mod tests {
         assert!(LOCAL_UPLOAD_RUNTIME_JS.contains("function openEditorUploadFilePicker"));
         assert!(LOCAL_UPLOAD_RUNTIME_JS.contains("function fetchWithTimeout"));
         assert!(LOCAL_UPLOAD_RUNTIME_JS.contains("function uploadLocalFolderAsset"));
+        assert!(LOCAL_UPLOAD_RUNTIME_JS.contains("function insertUploadedAssetIntoEditor"));
+        assert!(LOCAL_UPLOAD_RUNTIME_JS.contains("data-mnote-last-upload-inserted"));
         assert!(LOCAL_UPLOAD_RUNTIME_JS.contains("uploadFilesWithResolvedTarget"));
         assert!(LOCAL_UPLOAD_RUNTIME_JS.contains("__mnoteLastEditorUploadRoot"));
     }