Tooltips Accessibility Skill

Canonical source: examples/TOOLTIP_ACCESSIBILITY_BEST_PRACTICES.md in mgifford/ACCESSIBILITY.md This skill is derived from that file. When in doubt, the example is authoritative.

Apply these rules when implementing or reviewing tooltip components. Only load this skill if the project contains tooltips.

Core Mandate

Tooltips must convey supplementary information to all users regardless of input method. A tooltip unreachable by keyboard is an accessibility barrier.

Tooltips are non-interactive supplementary labels only. If the content is essential, or contains links/buttons, use persistent text or a popover instead.

Severity Scale (this skill)

Critical: Essential Information Must Not Live Only in a Tooltip

A tooltip is supplementary by definition. If the information it contains is required to complete a task, it must also appear as persistent visible text. Hiding essential content behind hover/focus only is Critical.

Serious: Tooltips Must Appear on Both Hover and Focus

A tooltip that only appears on hover is Serious — keyboard users cannot trigger it.

function showTooltip() { tooltip.removeAttribute('hidden'); }
function hideTooltip() { tooltip.setAttribute('hidden', ''); }

trigger.addEventListener('mouseenter', showTooltip);
trigger.addEventListener('mouseleave', hideTooltip);
trigger.addEventListener('focusin',    showTooltip);
trigger.addEventListener('focusout',   hideTooltip);

// Escape dismisses without moving focus
trigger.addEventListener('keydown', (e) => {
  if (e.key === 'Escape') hideTooltip();
});

Serious: ARIA Pattern Must Be Correct

Incorrect ARIA on tooltips is Serious — AT users receive wrong or no supplementary information.

<button type="button" aria-describedby="save-tooltip">Save</button>
<div id="save-tooltip" role="tooltip" hidden>
  Save changes to your draft
</div>

Rules:

• Tooltip element must have role="tooltip"
• Trigger must reference tooltip via aria-describedby (not aria-labelledby)
• Use hidden to conceal; never aria-hidden="true" on an active tooltip
• Each tooltip must have a unique id
• Do not put role="tooltip" on the trigger itself
• Tooltips must not be focusable — no tabindex on the tooltip container

For icon-only triggers, add aria-label for the accessible name:

<button type="button"
        aria-label="Delete item"
        aria-describedby="delete-tip">
  <!-- SVG icon, aria-hidden="true" focusable="false" -->
</button>
<div id="delete-tip" role="tooltip" hidden>
  Permanently removes this item from your account
</div>

Moderate: WCAG 1.4.13 — Content on Hover or Focus

Moderate: Touch / Mobile — Toggletip Pattern

Hover tooltips do not work on touch screens. Use the toggletip pattern:

<button type="button"
        aria-expanded="false"
        aria-controls="info-tip"
        aria-label="More information about password requirements">
  <span aria-hidden="true">ⓘ</span>
</button>
<div id="info-tip" hidden>
  Your password must be at least 12 characters and include a number.
</div>

Toggle aria-expanded and hidden together on click.

Moderate: Visual Design

• Tooltip text: 4.5:1 contrast against tooltip background
• Tooltip background: 3:1 contrast against adjacent surfaces
• Respect prefers-reduced-motion:

@media (prefers-reduced-motion: no-preference) {
  [role="tooltip"] { transition: opacity 0.15s ease; }
}

When NOT to Use a Tooltip

• Label of control is self-explanatory
• Information must be readable at all times → use persistent help text
• Touch-only interface → use toggletip or persistent help text
• Content is long → use a popover or disclosure
• Content contains interactive elements (links, buttons) → use a popover

Definition of Done Checklist

• [ ] role="tooltip" on tooltip element
• [ ] Trigger has aria-describedby pointing to tooltip id
• [ ] Tooltip appears on both hover and keyboard focus
• [ ] Escape dismisses without moving focus
• [ ] Tooltip hoverable (pointer can move over it without dismissal)
• [ ] Tooltip not focusable itself
• [ ] Text contrast 4.5:1; background 3:1 against surface
• [ ] Touch/mobile has toggletip fallback
• [ ] prefers-reduced-motion respected for animations
• [ ] Essential information not hidden tooltip-only

Key WCAG Criteria

• 1.4.3 Contrast Minimum (AA)
• 1.4.13 Content on Hover or Focus (AA) — Serious if hover-only
• 2.1.1 Keyboard (A) — Serious if keyboard cannot trigger tooltip
• 4.1.2 Name, Role, Value (A)

References

• Full best practices guide
• WCAG 2.2 Understanding 1.4.13 Content on Hover or Focus
• WAI-ARIA APG — Tooltip pattern

Standards horizon: WCAG 3.0 is in development; 1.4.13 requirements are expected to carry forward. Monitor: <https://www.w3.org/TR/wcag-3.0/>