| Do | Compose messages using MessageList > Message > Bubble for consistent sender-aware styling and density. |
| Do | Set the density prop to control spacing globally: compact for sidebars, balanced for most views, spacious for long-form reading. Individual messages can override. |
| Do | Use gap when top-level rows are independent (for example, LLM tool events or streamed blocks) and list spacing needs to be tuned separately from density. |
| Do | Use the group prop on bubbles (first, middle, last) when a single sender sends multiple consecutive messages; it tightens corner radius to visually connect them. |
| Do | Use XDSChatSystemMessage with variant="divider" for date separators and default for inline status notices like joins, leaves, or topic changes. |
| Do | Put name on the first bubble and metadata on the last bubble in a message so they align with the bubble's inline padding. |
| Do | Provide an emptyState prop so new users see a clear prompt to start a conversation instead of a blank screen. |
| Do | Use the ghost bubble variant for AI-style responses that show rich content like code blocks or markdown without a visible boundary. |
| Don't | Don't use XDSChatSystemMessage for sender content; it has no avatar, alignment, or bubble. Use XDSChatMessage with a sender role instead. |
| Don't | Don't put long or multi-line content in a system message; keep it to a single short sentence. If you need more, use a bubble or a card. |
| Don't | Don't nest XDSChatMessage inside another XDSChatMessage; each message is a standalone article element with its own sender context. |
| Don't | Don't apply a fixed height directly on the message list; wrap it in a sized container and let the list fill with flex: 1. |
| Don't | Don't mix filled and ghost bubble variants within the same sender's messages; pick one style per side and use it consistently. |
| Don't | Don't place metadata or names on both the bubble and the message wrapper; pick one based on whether the content has a bubble boundary. |