Safari 27.0 ships with a Model Cooperation Protocol (MCP) server that lets coding agents like Claude control your browser to test code, plus major improvements to form controls and 3D model support. The real story is 844 quality fixes addressing compatibility, standards alignment, and feature interactions that were previously broken.

• Safari MCP lets AI coding agents see how your code renders in real-time, check accessibility issues, and test across browsers without you manually sharing screenshots or jumping between windows
• The customizable `<select>` element now supports full CSS styling and custom HTML content inside options, with improved default styles that don't require extra work to make usable
• The release includes 844 bug fixes (up from 525 announced at WWDC), with deep work on SVG (66 fixes), HTML tables, CSS Zoom rebuild, and fixes for feature interactions like `-webkit-line-clamp` combined with `text-wrap: balance`

Safari 27’s customizable select lets you fully style <select> controls without JavaScript, but you must include text or accessible labels for each option. Skipping text breaks keyboard navigation, screen readers, and fallbacks in unsupported browsers—icons or swatches must supplement, not replace, option text.

• Safari 27's customizable select allows full CSS styling of dropdowns while keeping native keyboard/accessibility behavior, but only if every option retains real text or an aria-label.
• Icon-only options (e.g., a hummingbird icon with no label) leave screen readers silent and sighted users guessing, since nothing conveys which option is selected or what it means.
• If CSS fails or a browser lacks support, the control falls back to a default select—so text-less options degrade into a list of blank entries.
• Best practice: wrap custom styles in @supports(appearance: base-select), design with plain text as the foundation, and add icons/swatches as supplements—visually hidden if needed—never as replacements for text.