Utility Hooks

Focused helpers for message parts, quotes, timing, and viewport behavior.

Utility hooks expose commonly needed slices of assistant-ui behavior without requiring a full primitive.

Message Helpers

useMessageQuote reads the quote state for the current message.
useMessageTiming reads timing metadata for the current message.

Message Part Helpers

useMessagePartText
useMessagePartReasoning
useMessagePartSource
useMessagePartFile
useMessagePartImage
useMessagePartData

These hooks are intended for custom message part renderers. They read the nearest message part context established by MessagePrimitive.Parts, MessagePartPrimitive, or the lower-level providers.

Viewport Helpers

useThreadViewport reads and controls the thread viewport.
useThreadViewportAutoScroll wires auto-scroll behavior for custom viewport compositions.
useScrollLock helps reasoning and grouped-part UIs preserve scroll behavior while content changes.

For primitive-specific prop APIs, see Primitives.