diff --git a/web/src/components/MemoActionMenu/MemoActionMenu.tsx b/web/src/components/MemoActionMenu/MemoActionMenu.tsx
index aaa6d386..999ef7fb 100644
--- a/web/src/components/MemoActionMenu/MemoActionMenu.tsx
+++ b/web/src/components/MemoActionMenu/MemoActionMenu.tsx
@@ -3,10 +3,13 @@ import {
   ArchiveRestoreIcon,
   BookmarkMinusIcon,
   BookmarkPlusIcon,
+  CheckCheckIcon,
   CopyIcon,
   Edit3Icon,
   FileTextIcon,
   LinkIcon,
+  ListChecksIcon,
+  ListRestartIcon,
   MoreVerticalIcon,
   TrashIcon,
 } from "lucide-react";
@@ -24,6 +27,7 @@ import {
 } from "@/components/ui/dropdown-menu";
 import { State } from "@/types/proto/api/v1/common_pb";
 import { useTranslate } from "@/utils/i18n";
+import { countTasks } from "@/utils/markdown-manipulation";
 import { useMemoActionHandlers } from "./hooks";
 import type { MemoActionMenuProps } from "./types";
 
@@ -37,6 +41,10 @@ const MemoActionMenu = (props: MemoActionMenuProps) => {
   // Derived state
   const isComment = Boolean(memo.parent);
   const isArchived = memo.state === State.ARCHIVED;
+  const taskStats = countTasks(memo.content);
+  const canMutateTasks = !readonly && !isArchived && taskStats.total > 0;
+  const hasOpenTasks = taskStats.completed < taskStats.total;
+  const hasCompletedTasks = taskStats.completed > 0;
 
   // Action handlers
   const {
@@ -45,6 +53,8 @@ const MemoActionMenu = (props: MemoActionMenuProps) => {
     handleToggleMemoStatusClick,
     handleCopyLink,
     handleCopyContent,
+    handleCheckAllTaskListItemsClick,
+    handleUncheckAllTaskListItemsClick,
     handleDeleteMemoClick,
     confirmDeleteMemo,
   } = useMemoActionHandlers({
@@ -97,6 +107,26 @@ const MemoActionMenu = (props: MemoActionMenuProps) => {
           </DropdownMenuSub>
         )}
 
+        {/* Task submenu (writable task memos) */}
+        {canMutateTasks && (
+          <DropdownMenuSub>
+            <DropdownMenuSubTrigger>
+              <ListChecksIcon className="w-4 h-auto" />
+              {t("memo.task-actions.title")}
+            </DropdownMenuSubTrigger>
+            <DropdownMenuSubContent>
+              <DropdownMenuItem disabled={!hasOpenTasks} onClick={handleCheckAllTaskListItemsClick}>
+                <CheckCheckIcon className="w-4 h-auto" />
+                {t("memo.task-actions.check-all")}
+              </DropdownMenuItem>
+              <DropdownMenuItem disabled={!hasCompletedTasks} onClick={handleUncheckAllTaskListItemsClick}>
+                <ListRestartIcon className="w-4 h-auto" />
+                {t("memo.task-actions.uncheck-all")}
+              </DropdownMenuItem>
+            </DropdownMenuSubContent>
+          </DropdownMenuSub>
+        )}
+
         {/* Write actions (non-readonly) */}
         {!readonly && (
           <>
diff --git a/web/src/components/MemoActionMenu/hooks.ts b/web/src/components/MemoActionMenu/hooks.ts
index c5cbbf28..d80f6444 100644
--- a/web/src/components/MemoActionMenu/hooks.ts
+++ b/web/src/components/MemoActionMenu/hooks.ts
@@ -12,6 +12,7 @@ import { ROUTES } from "@/router/routes";
 import { State } from "@/types/proto/api/v1/common_pb";
 import type { Memo } from "@/types/proto/api/v1/memo_service_pb";
 import { useTranslate } from "@/utils/i18n";
+import { checkAllTasks, uncheckAllTasks } from "@/utils/markdown-task-actions";
 
 interface UseMemoActionHandlersOptions {
   memo: Memo;
@@ -34,6 +35,31 @@ export const useMemoActionHandlers = ({ memo, onEdit, setDeleteDialogOpen }: Use
     queryClient.invalidateQueries({ queryKey: userKeys.stats() });
   }, [queryClient]);
 
+  const updateMemoContent = useCallback(
+    async (nextContent: string, context: string) => {
+      if (nextContent === memo.content) {
+        return;
+      }
+
+      try {
+        await updateMemo({
+          update: {
+            name: memo.name,
+            content: nextContent,
+          },
+          updateMask: ["content", "update_time"],
+        });
+        toast.success(t("memo.task-actions.updated"));
+      } catch (error: unknown) {
+        handleError(error, toast.error, {
+          context,
+          fallbackMessage: "An error occurred",
+        });
+      }
+    },
+    [memo.content, memo.name, t, updateMemo],
+  );
+
   const handleTogglePinMemoBtnClick = useCallback(async () => {
     try {
       await updateMemo({
@@ -94,6 +120,14 @@ export const useMemoActionHandlers = ({ memo, onEdit, setDeleteDialogOpen }: Use
     toast.success(t("message.succeed-copy-content"));
   }, [memo.content, t]);
 
+  const handleCheckAllTaskListItemsClick = useCallback(async () => {
+    await updateMemoContent(checkAllTasks(memo.content), "Check memo task list items");
+  }, [memo.content, updateMemoContent]);
+
+  const handleUncheckAllTaskListItemsClick = useCallback(async () => {
+    await updateMemoContent(uncheckAllTasks(memo.content), "Uncheck memo task list items");
+  }, [memo.content, updateMemoContent]);
+
   const handleDeleteMemoClick = useCallback(() => {
     setDeleteDialogOpen(true);
   }, [setDeleteDialogOpen]);
@@ -121,6 +155,8 @@ export const useMemoActionHandlers = ({ memo, onEdit, setDeleteDialogOpen }: Use
     handleToggleMemoStatusClick,
     handleCopyLink,
     handleCopyContent,
+    handleCheckAllTaskListItemsClick,
+    handleUncheckAllTaskListItemsClick,
     handleDeleteMemoClick,
     confirmDeleteMemo,
   };
diff --git a/web/src/components/MemoActionMenu/index.ts b/web/src/components/MemoActionMenu/index.ts
index 6a045be6..a837c5db 100644
--- a/web/src/components/MemoActionMenu/index.ts
+++ b/web/src/components/MemoActionMenu/index.ts
@@ -1,3 +1,3 @@
 export { useMemoActionHandlers } from "./hooks";
 export { default, default as MemoActionMenu } from "./MemoActionMenu";
-export type { MemoActionMenuProps, UseMemoActionHandlersReturn } from "./types";
+export type { MemoActionMenuProps } from "./types";
diff --git a/web/src/components/MemoActionMenu/types.ts b/web/src/components/MemoActionMenu/types.ts
index 9133f95e..442c3422 100644
--- a/web/src/components/MemoActionMenu/types.ts
+++ b/web/src/components/MemoActionMenu/types.ts
@@ -6,15 +6,3 @@ export interface MemoActionMenuProps {
   className?: string;
   onEdit?: () => void;
 }
-
-export interface UseMemoActionHandlersReturn {
-  handleTogglePinMemoBtnClick: () => Promise<void>;
-  handleEditMemoClick: () => void;
-  handleToggleMemoStatusClick: () => Promise<void>;
-  handleCopyLink: () => void;
-  handleCopyContent: () => void;
-  handleDeleteMemoClick: () => void;
-  confirmDeleteMemo: () => Promise<void>;
-  handleRemoveCompletedTaskListItemsClick: () => void;
-  confirmRemoveCompletedTaskListItems: () => Promise<void>;
-}
diff --git a/web/src/components/MemoView/components/MemoBody.tsx b/web/src/components/MemoView/components/MemoBody.tsx
index 33839b19..f760e35a 100644
--- a/web/src/components/MemoView/components/MemoBody.tsx
+++ b/web/src/components/MemoView/components/MemoBody.tsx
@@ -1,3 +1,4 @@
+import { useMemo } from "react";
 import { AttachmentListView, LocationDisplayView, RelationListView } from "@/components/MemoMetadata";
 import { cn } from "@/lib/utils";
 import { MemoRelation_Type } from "@/types/proto/api/v1/memo_service_pb";
@@ -22,12 +23,22 @@ const BlurOverlay: React.FC<{ onClick?: () => void }> = ({ onClick }) => {
   );
 };
 
+const getContentRevision = (content: string) => {
+  let hash = 2166136261;
+  for (let i = 0; i < content.length; i++) {
+    hash ^= content.charCodeAt(i);
+    hash = Math.imul(hash, 16777619);
+  }
+  return `${content.length}-${hash >>> 0}`;
+};
+
 const MemoBody: React.FC<MemoBodyProps> = ({ compact }) => {
   const { memo, parentPage, showBlurredContent, blurred, readonly, openEditor, openPreview, toggleBlurVisibility } = useMemoViewContext();
 
   const { handleMemoContentClick, handleMemoContentDoubleClick } = useMemoHandlers({ readonly, openEditor, openPreview });
 
   const referencedMemos = memo.relations.filter((relation) => relation.type === MemoRelation_Type.REFERENCE);
+  const contentRevision = useMemo(() => getContentRevision(memo.content), [memo.content]);
 
   return (
     <>
@@ -38,7 +49,7 @@ const MemoBody: React.FC<MemoBodyProps> = ({ compact }) => {
         )}
       >
         <MemoContent
-          key={`${memo.name}-${memo.updateTime}`}
+          key={`${memo.name}-${contentRevision}`}
           content={memo.content}
           onClick={handleMemoContentClick}
           onDoubleClick={handleMemoContentDoubleClick}
diff --git a/web/src/locales/en.json b/web/src/locales/en.json
index 41799824..fa0112bd 100644
--- a/web/src/locales/en.json
+++ b/web/src/locales/en.json
@@ -292,6 +292,12 @@
     "show-less": "Show less",
     "show-more": "Show more",
     "to-do": "To-do",
+    "task-actions": {
+      "check-all": "Check all tasks",
+      "title": "Tasks",
+      "uncheck-all": "Uncheck all tasks",
+      "updated": "Tasks updated"
+    },
     "view-detail": "View Detail",
     "visibility": {
       "disabled": "Public memos are disabled",
diff --git a/web/src/utils/markdown-task-actions.ts b/web/src/utils/markdown-task-actions.ts
new file mode 100644
index 00000000..61d101ab
--- /dev/null
+++ b/web/src/utils/markdown-task-actions.ts
@@ -0,0 +1,147 @@
+import type { ListItem } from "mdast";
+import { fromMarkdown } from "mdast-util-from-markdown";
+import { gfmFromMarkdown } from "mdast-util-gfm";
+import { gfm } from "micromark-extension-gfm";
+import { visit } from "unist-util-visit";
+
+interface SourceRange {
+  start: number;
+  end: number;
+}
+
+interface MarkdownEdit extends SourceRange {
+  replacement: string;
+}
+
+interface ParsedTaskItem {
+  checked: boolean;
+  checkboxMarker: SourceRange;
+}
+
+interface LineInfo {
+  text: string;
+  startOffset: number;
+  endOffset: number;
+}
+
+const TASK_LINE_REGEXP = /^(\s*)((?:[-*+])|(?:\d+[.)]))(\s+)\[([ xX])\]/;
+
+function getLineStarts(markdown: string): number[] {
+  const starts = [0];
+  for (let index = 0; index < markdown.length; index++) {
+    if (markdown[index] === "\n") {
+      starts.push(index + 1);
+    }
+  }
+  return starts;
+}
+
+function getLineInfo(markdown: string, lineStarts: number[], lineNumber: number): LineInfo | undefined {
+  const startOffset = lineStarts[lineNumber];
+  if (startOffset === undefined) {
+    return undefined;
+  }
+
+  const nextLineStart = lineStarts[lineNumber + 1];
+  const endOffset = nextLineStart === undefined ? markdown.length : nextLineStart - 1;
+  return {
+    text: markdown.slice(startOffset, endOffset),
+    startOffset,
+    endOffset,
+  };
+}
+
+function parseMarkdown(markdown: string) {
+  return fromMarkdown(markdown, {
+    extensions: [gfm()],
+    mdastExtensions: [gfmFromMarkdown()],
+  });
+}
+
+function parseTaskItems(markdown: string): ParsedTaskItem[] {
+  let tree: ReturnType<typeof parseMarkdown>;
+  try {
+    tree = parseMarkdown(markdown);
+  } catch {
+    return [];
+  }
+
+  const lineStarts = getLineStarts(markdown);
+  const tasks: ParsedTaskItem[] = [];
+
+  visit(tree, "listItem", (node: ListItem) => {
+    if (typeof node.checked !== "boolean") {
+      return;
+    }
+
+    const startLine = node.position ? node.position.start.line - 1 : undefined;
+    if (startLine === undefined) {
+      return;
+    }
+
+    const lineInfo = getLineInfo(markdown, lineStarts, startLine);
+    if (!lineInfo) {
+      return;
+    }
+
+    const match = lineInfo.text.match(TASK_LINE_REGEXP);
+    if (!match || match.index !== 0) {
+      return;
+    }
+
+    const markerStart = lineInfo.startOffset + match[1].length + match[2].length + match[3].length + 1;
+
+    tasks.push({
+      checked: node.checked,
+      checkboxMarker: {
+        start: markerStart,
+        end: markerStart + 1,
+      },
+    });
+  });
+
+  return tasks;
+}
+
+function applyMarkdownEdits(markdown: string, edits: MarkdownEdit[]): string {
+  if (edits.length === 0) {
+    return markdown;
+  }
+
+  const sortedEdits = [...edits].sort((a, b) => a.start - b.start);
+  let previousEnd = 0;
+  for (const edit of sortedEdits) {
+    if (edit.start < 0 || edit.end < edit.start || edit.end > markdown.length || edit.start < previousEnd) {
+      return markdown;
+    }
+    previousEnd = edit.end;
+  }
+
+  let nextMarkdown = markdown;
+  for (let index = sortedEdits.length - 1; index >= 0; index--) {
+    const edit = sortedEdits[index];
+    nextMarkdown = `${nextMarkdown.slice(0, edit.start)}${edit.replacement}${nextMarkdown.slice(edit.end)}`;
+  }
+  return nextMarkdown;
+}
+
+function setAllTaskMarkers(markdown: string, checked: boolean): string {
+  const marker = checked ? "x" : " ";
+  const edits = parseTaskItems(markdown)
+    .filter((task) => task.checked !== checked)
+    .map<MarkdownEdit>((task) => ({
+      start: task.checkboxMarker.start,
+      end: task.checkboxMarker.end,
+      replacement: marker,
+    }));
+
+  return applyMarkdownEdits(markdown, edits);
+}
+
+export function uncheckAllTasks(markdown: string): string {
+  return setAllTaskMarkers(markdown, false);
+}
+
+export function checkAllTasks(markdown: string): string {
+  return setAllTaskMarkers(markdown, true);
+}
diff --git a/web/tests/markdown-task-actions.test.ts b/web/tests/markdown-task-actions.test.ts
new file mode 100644
index 00000000..bf5874b0
--- /dev/null
+++ b/web/tests/markdown-task-actions.test.ts
@@ -0,0 +1,38 @@
+import { describe, expect, it } from "vitest";
+import { checkAllTasks, uncheckAllTasks } from "@/utils/markdown-task-actions";
+
+describe("checkAllTasks", () => {
+  it("checks every unchecked task while preserving source formatting", () => {
+    const markdown = ["Intro", "- [ ] first", "* [x] second", "  + [ ] nested", "1. [ ] ordered", "Outro"].join("\n");
+
+    expect(checkAllTasks(markdown)).toBe(["Intro", "- [x] first", "* [x] second", "  + [x] nested", "1. [x] ordered", "Outro"].join("\n"));
+  });
+
+  it("returns the original string when no checkbox markers need changing", () => {
+    const markdown = ["Intro", "- [x] first", "Outro"].join("\n");
+
+    expect(checkAllTasks(markdown)).toBe(markdown);
+  });
+});
+
+describe("uncheckAllTasks", () => {
+  it("unchecks every checked task while preserving source formatting", () => {
+    const markdown = ["Intro", "- [x] first", "* [X] second", "  + [ ] nested", "1. [x] ordered", "Outro"].join("\n");
+
+    expect(uncheckAllTasks(markdown)).toBe(["Intro", "- [ ] first", "* [ ] second", "  + [ ] nested", "1. [ ] ordered", "Outro"].join("\n"));
+  });
+
+  it("returns the original string when no checkbox markers need changing", () => {
+    const markdown = ["Intro", "- [ ] first", "Outro"].join("\n");
+
+    expect(uncheckAllTasks(markdown)).toBe(markdown);
+  });
+
+  it("ignores task-looking text inside fenced and inline code", () => {
+    const markdown = ["```", "- [x] not a task", "```", "", "Inline `- [x] not a task` text", "", "- [x] real task"].join("\n");
+
+    expect(uncheckAllTasks(markdown)).toBe(
+      ["```", "- [x] not a task", "```", "", "Inline `- [x] not a task` text", "", "- [ ] real task"].join("\n"),
+    );
+  });
+});