diff --git a/apps/desktop/src/renderer/styles/task-ledger.css b/apps/desktop/src/renderer/styles/task-ledger.css
index b459c32cc2..d34f89d3b0 100644
--- a/apps/desktop/src/renderer/styles/task-ledger.css
+++ b/apps/desktop/src/renderer/styles/task-ledger.css
@@ -22,14 +22,24 @@
   min-height: 0;
   overflow-y: auto;
   padding: var(--space-2);
+  /* The compact row layout keys off THIS panel's width, not the viewport: the
+     right workbar resizes down to SESSION_WORKBAR_MIN_WIDTH (320px) inside an
+     otherwise wide window, where a viewport media query would never fire. */
+  container: maka-task-ledger / inline-size;
 }
 
 .maka-task-ledger-tree {
   display: grid;
   gap: var(--border-width-hairline);
+  min-width: 0;
 }
 
 .maka-task-ledger-row {
+  display: grid;
+  min-width: 0;
+}
+
+.maka-task-ledger-row-content {
   font: var(--maka-text-supporting);
   display: grid;
   grid-template-columns: 14px minmax(34px, auto) minmax(100px, 1fr) auto;
@@ -45,18 +55,19 @@
   display: grid;
   grid-column: 1 / -1;
   gap: var(--border-width-hairline);
+  min-width: 0;
 }
 
-.maka-task-ledger-row:hover { background: var(--state-hover-bg); }
+.maka-task-ledger-row:hover > .maka-task-ledger-row-content { background: var(--state-hover-bg); }
 
-.maka-task-ledger-row:focus-visible {
+.maka-task-ledger-row:focus-visible > .maka-task-ledger-row-content {
   outline: none;
   box-shadow: inset 0 0 0 var(--focus-ring-width) var(--focus-ring);
 }
-.maka-task-ledger-row[data-status="in_progress"] > svg { color: var(--status-running); }
-.maka-task-ledger-row[data-status="blocked"] > svg { color: var(--warning); }
-.maka-task-ledger-row[data-status="completed"] > svg { color: var(--success); }
-.maka-task-ledger-row[data-status="failed"] > svg { color: var(--destructive); }
+.maka-task-ledger-row[data-status="in_progress"] > .maka-task-ledger-row-content > svg { color: var(--status-running); }
+.maka-task-ledger-row[data-status="blocked"] > .maka-task-ledger-row-content > svg { color: var(--warning); }
+.maka-task-ledger-row[data-status="completed"] > .maka-task-ledger-row-content > svg { color: var(--success); }
+.maka-task-ledger-row[data-status="failed"] > .maka-task-ledger-row-content > svg { color: var(--destructive); }
 
 .maka-task-ledger-key {
   font: var(--maka-text-supporting);
@@ -128,8 +139,12 @@
   outline-offset: 1px;
 }
 
-@media (max-width: 620px) {
-  .maka-task-ledger-row { grid-template-columns: 14px minmax(32px, auto) minmax(0, 1fr); }
+/* Below ~420px of panel width the four-column grid can no longer hold the
+   deepest clamped indent (128px at depth 6) plus key + subject + status/meta,
+   so status/detail drop under the subject and the subject column may shrink to
+   zero. 420px keeps the 480px default wide while covering the 320px floor. */
+@container maka-task-ledger (max-width: 420px) {
+  .maka-task-ledger-row-content { grid-template-columns: 14px minmax(32px, auto) minmax(0, 1fr); }
   .maka-task-ledger-meta { grid-column: 3; justify-content: flex-start; }
   .maka-task-ledger-detail { grid-column: 3; white-space: normal; overflow-wrap: anywhere; }
 }
diff --git a/apps/desktop/stories/session-workbar.stories.tsx b/apps/desktop/stories/session-workbar.stories.tsx
index 8df2bef6ba..9beeccf539 100644
--- a/apps/desktop/stories/session-workbar.stories.tsx
+++ b/apps/desktop/stories/session-workbar.stories.tsx
@@ -200,6 +200,20 @@ const tasks: Task[] = [
   }),
 ];
 
+// An eight-level parent→child chain, all still active, to exercise the task
+// panel's depth clamp (`Math.min(depth, 6)`): a level-8 row indents no further
+// than level 7.
+const deepTaskChain: Task[] = Array.from({ length: 8 }, (_, index) => {
+  const level = index + 1;
+  return task({
+    id: `td-${level}`,
+    key: `T${Array.from({ length: level }, () => '1').join('.')}`,
+    subject: `第 ${level} 层子任务，验证深层缩进仍可完整显示`,
+    parentId: level === 1 ? undefined : `td-${level - 1}`,
+    status: level === 8 ? 'in_progress' : 'pending',
+  });
+});
+
 const artifacts: ArtifactRecord[] = [
   {
     id: 'artifact-patch',
@@ -1228,6 +1242,107 @@ export const TasksLoadFailed: Story = {
   render: () => <Workbar tab="tasks" />,
 };
 
+// Real path: 任务工作栏 → 任务 after a run finished with mixed outcomes. The
+// 最近结束 section (collapsed by default) holds the terminal tasks — a failed
+// one with its reason and a cancelled one — and caps at three, so a fourth
+// finished task is dropped rather than growing the list.
+export const TasksRecentlyFinished: Story = {
+  decorators: [
+    bridge({
+      tasks: [
+        task({
+          id: 'trf-active',
+          key: 'T1',
+          subject: '巡检发布前检查项',
+          status: 'in_progress',
+          owner: { actor: 'main_agent', runId: 'run-trf' },
+        }),
+        task({
+          id: 'trf-old',
+          key: 'T2',
+          subject: '归档上一轮实验数据',
+          status: 'completed',
+          completionEvidence: '已归档到对象存储。',
+          endedAt: NOW - 300_000,
+          updatedAt: NOW - 300_000,
+        }),
+        task({
+          id: 'trf-notes',
+          key: 'T3',
+          subject: '生成变更说明',
+          status: 'completed',
+          endedAt: NOW - 120_000,
+          updatedAt: NOW - 120_000,
+        }),
+        task({
+          id: 'trf-smoke',
+          key: 'T4',
+          subject: '回归冒烟用例',
+          status: 'failed',
+          failureReason: '两个用例在 CI 上超时，任务标记为失败。',
+          endedAt: NOW - 90_000,
+          updatedAt: NOW - 90_000,
+        }),
+        task({
+          id: 'trf-dupe',
+          key: 'T5',
+          subject: '取消重复的部署任务',
+          status: 'cancelled',
+          endedAt: NOW - 30_000,
+          updatedAt: NOW - 30_000,
+        }),
+      ],
+    }),
+  ],
+  render: () => <Workbar tab="tasks" />,
+  play: async ({ canvasElement }) => {
+    // Four terminal tasks, but the recent section freezes its count at three.
+    const trigger = await waitFor(() => {
+      const el = canvasElement.querySelector<HTMLElement>('.maka-task-ledger-terminal-trigger');
+      if (!el) throw new Error('recent-finished trigger not rendered yet');
+      return el;
+    });
+    await expect(trigger.textContent).toContain('3');
+    await userEvent.click(trigger);
+    await waitFor(() => {
+      // Failed and cancelled outcomes both render, with the failed reason…
+      const failed = canvasElement.querySelector('.maka-task-ledger-row[data-status="failed"]');
+      expect(failed?.textContent).toContain('两个用例在 CI 上超时');
+      expect(
+        canvasElement.querySelector('.maka-task-ledger-row[data-status="cancelled"]'),
+      ).not.toBeNull();
+      // …and the oldest finished task is the one the cap dropped.
+      expect(canvasElement.textContent).not.toContain('归档上一轮实验数据');
+    });
+  },
+};
+
+// Real path: 任务工作栏 → 任务 on a deeply decomposed task. The row indent is
+// clamped at depth 6, so an eighth-level subtask stays legible instead of
+// marching off the panel. Pinned at the 320px workbar floor
+// (SESSION_WORKBAR_MIN_WIDTH), the width where the depth-6 indent would
+// overflow a four-column row — the panel container query must collapse to the
+// compact layout so the deepest row still fits.
+export const TasksDeepNesting: Story = {
+  decorators: [bridge({ tasks: deepTaskChain })],
+  render: () => <Workbar tab="tasks" width={320} />,
+  play: async ({ canvasElement }) => {
+    await waitFor(() => {
+      const panel = canvasElement.querySelector<HTMLElement>('.maka-task-ledger-panel');
+      const deepestRowContent = canvasElement.querySelector<HTMLElement>(
+        '.maka-task-ledger-row[aria-level="8"] > .maka-task-ledger-row-content',
+      );
+      if (!panel || !deepestRowContent) throw new Error('deep task row not rendered yet');
+
+      const panelRect = panel.getBoundingClientRect();
+      const rowRect = deepestRowContent.getBoundingClientRect();
+      expect(panel.scrollWidth).toBeLessThanOrEqual(panel.clientWidth);
+      expect(rowRect.left).toBeGreaterThanOrEqual(panelRect.left);
+      expect(rowRect.right).toBeLessThanOrEqual(panelRect.right);
+    });
+  },
+};
+
 // Storybook cannot host the native WebContentsView, so these pin what the panel
 // itself draws — chrome and empty state — inside the real workbar shell.
 export const BrowserEmpty: Story = {
diff --git a/packages/ui/src/task-ledger-panel.tsx b/packages/ui/src/task-ledger-panel.tsx
index 068bcdb091..60154f8dd4 100644
--- a/packages/ui/src/task-ledger-panel.tsx
+++ b/packages/ui/src/task-ledger-panel.tsx
@@ -188,14 +188,16 @@ function TaskLedgerRow({ task, copy, level, position, setSize, children }: {
       data-status={task.status}
       style={{ '--task-depth': Math.min(depth, 6) } as CSSProperties}
     >
-      <StatusIcon size={ICON_SIZE.control} aria-hidden="true" />
-      <code className="maka-task-ledger-key">{task.key}</code>
-      <span className="maka-task-ledger-subject" title={task.subject}>{task.subject}</span>
-      <span className="maka-task-ledger-meta">
-        <span>{copy.status[task.status]}</span>
-        {owner && <span title={owner}>{owner}</span>}
-      </span>
-      {detail && <span className="maka-task-ledger-detail" title={detail}>{detail}</span>}
+      <div className="maka-task-ledger-row-content">
+        <StatusIcon size={ICON_SIZE.control} aria-hidden="true" />
+        <code className="maka-task-ledger-key">{task.key}</code>
+        <span className="maka-task-ledger-subject" title={task.subject}>{task.subject}</span>
+        <span className="maka-task-ledger-meta">
+          <span>{copy.status[task.status]}</span>
+          {owner && <span title={owner}>{owner}</span>}
+        </span>
+        {detail && <span className="maka-task-ledger-detail" title={detail}>{detail}</span>}
+      </div>
       {children}
     </div>
   );