WebKit's release notes for Safari 27.0 are its longest yet, and the headline addition is a tool for people who build sites with coding agents. The Safari MCP server, now in Safari 27.0, hands an agent such as Claude Code or Codex control of the browser window so it can see how code renders. It exposes the DOM, network requests, screenshots, and console output, and the server runs entirely on the local machine with no network calls of its own, according to WebKit.
Setting it up means enabling remote automation under Safari's Developer settings, then registering the server with a single command for Claude or Codex, or adding it to an agent's config file. WebKit says captured data goes to the agent being run rather than to Apple, and that the server has no access to personal information in Safari. The company frames the feature as a way to cut down on window switching and screenshot pasting while an agent verifies form states, compares computed styles against other browsers, checks accessibility issues, and reads navigation timing.
The release also makes the native select element fully restylable through Customizable Select, which WebKit says works without JavaScript or a stack of divs and keeps keyboard navigation, screen readers, form submission, and validation intact. New default styles, including 4px rounded corners and a drop shadow, arrive with this version and differ from the defaults in the first beta in June; WebKit says it took the design to the CSS Working Group for further discussion. New pseudo-elements such as ::picker-icon and ::checkmark target previously unstylable parts of the control.
The HTML model element, which shipped a year ago on visionOS, now reaches Safari on iOS, iPadOS, and macOS, embedding a 3D model much as video, audio, and img embed other media. It accepts multiple source files with a fallback image, plus attributes for custom lighting and default interaction behavior. Safari 27.0 also lets the CSS dynamic-range-limit property apply to the element, giving developers control over HDR tone mapping for 3D content on iOS and macOS.
WebKit is presenting the bulk of the work as quality rather than novelty. The team announced 525 fixes at WWDC and then added 60% more, for a total of 844. That includes 66 fixes to SVG alone, an end-to-end review of the SMIL animation engine, a systematic pass over HTML tables, and an all-new ES module loader. Compatibility work targeted specific sites, such as Hindi InScript typing in an online document editor and Pahawh Hmong text misrendering in an online encyclopedia.
One example shows how long-standing features can collide: -webkit-line-clamp shipped in WebKit in 2010 and text-wrap: balance arrived in 2024, but applying both to the same element meant the balancing never happened until this release. The feature count itself rose from 58 to 83 between the first beta in June and this version. The notes follow a run of Safari Technology Preview releases for macOS Golden Gate and macOS Tahoe, the most recent of which arrived in September.
WebKit points readers to the resolved-issue lists at the end of its post and to a video about the quality work behind this release.
