- hidden
- Recommended in the original HTML on either the card or its dedicated data-stand-reveal wrapper so content cannot flash before the custom element upgrades.
- show-when
- Optional responder display filter: either (the default), rep, or standin. Empty or unsupported values fail closed. The filter does not change routing.
- greeting
- Opening greeting from the rep or Stand-in for a new conversation. An explicit action opens chat; the greeting does not replace an existing transcript.
- prompt
- Optional internal context attached when a new session starts. Visitors do not see it; reps can see it in history and AI Stand-ins use it as guidance. It does not update a session already in progress.
- analytics-id
- Optional attribution label included with the activation event so teams can compare cards or placements. Labels may be reused; spotlight dismissal is still remembered per card and page.
- spotlight
- Optional. When the fully visible card crosses the viewport midpoint in either scroll direction, it centers above a blurred glass layer while the page keeps its native momentum. After placement it stays fixed, moving only enough to remain visible when an on-screen keyboard or browser controls reduce the viewport. Its actions stay fixed through each pointer gesture. A visual imprint preserves the underlying layout. Dismissal or activation suppresses the spotlight for that card in the visitor browser on that website origin. It can appear again after site data is cleared or in another browser or device.
- dismiss-label
- Optional label for the generated spotlight dismissal action. Missing or empty values use Cancel. The attribute has no effect without spotlight.
- identity
- Optional space-separated generated identity fields: avatar, name, and title. Omit it to hide the generated identity header, including the AI badge. When identity is shown for an AI Stand-in, the header also includes the AI badge.
- data-stand-action
- Makes the card focusable and opens chat on click, Enter, or Space. Nested links and form controls keep their own behavior. Do not also mark a child action; conflicting markers disable activation.
- visitor-id / visitor-name
- Optional page-known visitor identity captured when a new session starts. visitor-id is required when visitor-name is present. The ID is private correlation metadata; authenticated reps can see the name in dashboard and history. These attributes do not authenticate the visitor or update an existing session.
- theme
- Optional space-separated style variants. Supported values are outlined, elevated, horizontal, cover-media, stretch-media, and divided-footer.
- class
- Optional standard HTML class. Use it with ::part() selectors and your own slotted content selectors to customize styling.
- style
- Optional standard HTML style attribute on the card host. The card fills its containing block by default; use max-width and margins here to constrain and align it without crossing the shadow boundary.