diff --git a/.changeset/calm-tooltips-float.md b/.changeset/calm-tooltips-float.md
new file mode 100644
index 00000000..156e078d
--- /dev/null
+++ b/.changeset/calm-tooltips-float.md
@@ -0,0 +1,6 @@
+---
+'@doc-kit/generator-react': patch
+---
+
+Render sidebar stability tooltips in a portal so that the table of contents
+scroll container does not clip them.
diff --git a/e2e/stability-tooltip.spec.js b/e2e/stability-tooltip.spec.js
new file mode 100644
index 00000000..fc99a5a2
--- /dev/null
+++ b/e2e/stability-tooltip.spec.js
@@ -0,0 +1,33 @@
+import { expect, test } from '@playwright/test';
+
+test('renders stability tooltips outside the MetaBar scroll container', async ({
+  page,
+}) => {
+  await page.goto('/assert.html');
+
+  const badge = page.getByLabel('Stability: Legacy').first();
+  await badge.scrollIntoViewIfNeeded();
+  await expect(badge.locator('xpath=ancestor::is-land[1]')).toHaveAttribute(
+    'ready',
+    ''
+  );
+  await badge.hover();
+
+  const tooltip = page.getByRole('tooltip').filter({ hasText: 'Legacy' });
+  await expect(tooltip).toBeVisible();
+
+  expect(await tooltip.evaluate(element => element.closest('aside dl'))).toBe(
+    null
+  );
+
+  const box = await tooltip.boundingBox();
+  const viewport = page.viewportSize();
+
+  expect(box.x).toBeGreaterThanOrEqual(0);
+  expect(box.x + box.width).toBeLessThanOrEqual(viewport.width);
+
+  await page.mouse.move(0, 0);
+  await expect(tooltip).not.toBeVisible();
+  await badge.focus();
+  await expect(tooltip).toBeVisible();
+});
diff --git a/packages/react/src/html/ui/components/MetaBar/StabilityBadge.jsx b/packages/react/src/html/ui/components/MetaBar/StabilityBadge.jsx
new file mode 100644
index 00000000..08dd4161
--- /dev/null
+++ b/packages/react/src/html/ui/components/MetaBar/StabilityBadge.jsx
@@ -0,0 +1,106 @@
+import Badge from '@node-core/ui-components/Common/Badge';
+import { createPortal } from 'preact/compat';
+import { useCallback, useLayoutEffect, useRef, useState } from 'preact/hooks';
+
+import styles from './index.module.css';
+import withIsland from '../../islands/withIsland.jsx';
+
+const VIEWPORT_MARGIN = 8;
+
+/**
+ * Renders a stability badge with a tooltip that is portalled outside the
+ * MetaBar's scroll container.
+ * @param {{ label: string, tooltip: string, ariaLabel: string, kind: string }} props
+ */
+const StabilityBadge = ({ label, tooltip, ariaLabel, kind }) => {
+  const triggerRef = useRef(null);
+  const tooltipRef = useRef(null);
+  const [open, setOpen] = useState(false);
+  const [position, setPosition] = useState(null);
+
+  const updatePosition = useCallback(() => {
+    const trigger = triggerRef.current;
+    const content = tooltipRef.current;
+
+    if (!trigger || !content) {
+      return;
+    }
+
+    const triggerBox = trigger.getBoundingClientRect();
+    const contentBox = content.getBoundingClientRect();
+    const centeredLeft =
+      triggerBox.left + triggerBox.width / 2 - contentBox.width / 2;
+    const left = Math.min(
+      Math.max(centeredLeft, VIEWPORT_MARGIN),
+      window.innerWidth - contentBox.width - VIEWPORT_MARGIN
+    );
+    const below = triggerBox.bottom + VIEWPORT_MARGIN;
+    const fitsBelow =
+      below + contentBox.height <= window.innerHeight - VIEWPORT_MARGIN;
+
+    setPosition({
+      left,
+      top: fitsBelow
+        ? below
+        : triggerBox.top - contentBox.height - VIEWPORT_MARGIN,
+    });
+  }, []);
+
+  useLayoutEffect(() => {
+    if (!open) {
+      return undefined;
+    }
+
+    const frame = window.requestAnimationFrame(updatePosition);
+    window.addEventListener('resize', updatePosition);
+    window.addEventListener('scroll', updatePosition, true);
+
+    return () => {
+      window.cancelAnimationFrame(frame);
+      window.removeEventListener('resize', updatePosition);
+      window.removeEventListener('scroll', updatePosition, true);
+    };
+  }, [open, updatePosition]);
+
+  const closeTooltip = () => {
+    setOpen(false);
+    setPosition(null);
+  };
+
+  return (
+    <>
+      <span
+        ref={triggerRef}
+        className={styles.tooltipTrigger}
+        aria-label={ariaLabel}
+        tabIndex={0}
+        onMouseEnter={() => setOpen(true)}
+        onMouseLeave={closeTooltip}
+        onFocus={() => setOpen(true)}
+        onBlur={closeTooltip}
+      >
+        <Badge size="small" kind={kind}>
+          {label}
+        </Badge>
+      </span>
+
+      {open &&
+        createPortal(
+          <span
+            ref={tooltipRef}
+            role="tooltip"
+            className={styles.tooltipContent}
+            style={position ?? { visibility: 'hidden' }}
+          >
+            {tooltip}
+          </span>,
+          document.body
+        )}
+    </>
+  );
+};
+
+export default withIsland(StabilityBadge, {
+  name: 'StabilityBadge',
+  on: { idle: true },
+});
diff --git a/packages/react/src/html/ui/components/MetaBar/index.jsx b/packages/react/src/html/ui/components/MetaBar/index.jsx
index 5f705efd..cbfe8b4c 100644
--- a/packages/react/src/html/ui/components/MetaBar/index.jsx
+++ b/packages/react/src/html/ui/components/MetaBar/index.jsx
@@ -1,9 +1,9 @@
 import { CodeBracketIcon, DocumentIcon } from '@heroicons/react/24/outline';
-import Badge from '@node-core/ui-components/Common/Badge';
 import MetaBar from '@node-core/ui-components/Containers/MetaBar';
 import GitHubIcon from '@node-core/ui-components/Icons/Social/GitHub';
 
 import styles from './index.module.css';
+import StabilityBadge from './StabilityBadge.jsx';
 
 import { editURL } from '#theme/config';
 
@@ -25,24 +25,19 @@ const HeadingValue = ({ value, stability }) => {
     return value;
   }
 
-  const ariaLabel = STABILITY_TOOLTIPS[stability]
-    ? `Stability: ${STABILITY_TOOLTIPS[stability]}`
-    : undefined;
+  const tooltip = STABILITY_TOOLTIPS[stability];
+  const ariaLabel = tooltip ? `Stability: ${tooltip}` : undefined;
 
   return (
     <>
       {value}
 
-      <Badge
-        size="small"
-        className={styles.badge}
+      <StabilityBadge
         kind={STABILITY_KINDS[stability]}
-        data-tooltip={STABILITY_TOOLTIPS[stability]}
-        aria-label={ariaLabel}
-        tabIndex={0}
-      >
-        {STABILITY_LABELS[stability]}
-      </Badge>
+        label={STABILITY_LABELS[stability]}
+        tooltip={tooltip}
+        ariaLabel={ariaLabel}
+      />
     </>
   );
 };
diff --git a/packages/react/src/html/ui/components/MetaBar/index.module.css b/packages/react/src/html/ui/components/MetaBar/index.module.css
index 0f3163ee..c35f1b1d 100644
--- a/packages/react/src/html/ui/components/MetaBar/index.module.css
+++ b/packages/react/src/html/ui/components/MetaBar/index.module.css
@@ -5,7 +5,32 @@
   margin-right: 0.25rem;
 }
 
-.badge {
+.tooltipTrigger {
   display: inline-block;
   margin-left: 0.25rem;
 }
+
+.tooltipContent {
+  position: fixed;
+  z-index: 50;
+  width: max-content;
+  max-width: 16rem;
+  padding: 0.375rem 0.625rem;
+  color: var(--color-neutral-900);
+  font-size: 0.875rem;
+  font-weight: 500;
+  line-height: 1.25rem;
+  pointer-events: none;
+  background-color: var(--color-white);
+  border: 1px solid var(--color-neutral-200);
+  border-radius: 0.375rem;
+  box-shadow:
+    0 4px 6px -2px rgb(16 24 40 / 3%),
+    0 12px 16px -4px rgb(16 24 40 / 8%);
+}
+
+:global([data-theme='dark']) .tooltipContent {
+  color: var(--color-white);
+  background-color: var(--color-neutral-950);
+  border-color: var(--color-neutral-900);
+}
diff --git a/packages/react/src/html/ui/islands/loaders.mjs b/packages/react/src/html/ui/islands/loaders.mjs
index b5661a4a..82ce1b89 100644
--- a/packages/react/src/html/ui/islands/loaders.mjs
+++ b/packages/react/src/html/ui/islands/loaders.mjs
@@ -8,4 +8,5 @@ export default {
   ThemeToggle: () => import('../components/ThemeToggle.jsx'),
   SearchBox: () => import('../components/SearchBox'),
   SideBar: () => import('#theme/Sidebar'),
+  StabilityBadge: () => import('../components/MetaBar/StabilityBadge.jsx'),
 };