STUPID SEXY TIMELINE (#16420)

packages/app/e2e/actions.ts

@@ -7,6 +7,7 @@ import { createSdk, modKey, resolveDirectory, serverUrl } from "./utils"
 import {
   dropdownMenuTriggerSelector,
   dropdownMenuContentSelector,
+  sessionTimelineHeaderSelector,
   projectMenuTriggerSelector,
   projectCloseMenuSelector,
   projectWorkspacesToggleSelector,
@@ -243,7 +244,9 @@ export async function openSessionMoreMenu(page: Page, sessionID: string) {
 
   const scroller = page.locator(".scroll-view__viewport").first()
   await expect(scroller).toBeVisible()
-  await expect(scroller.getByRole("heading", { level: 1 }).first()).toBeVisible({ timeout: 30_000 })
+  const header = page.locator(sessionTimelineHeaderSelector).first()
+  await expect(header).toBeVisible({ timeout: 30_000 })
+  await expect(header.getByRole("heading", { level: 1 }).first()).toBeVisible({ timeout: 30_000 })
 
   const menu = page
     .locator(dropdownMenuContentSelector)
@@ -259,7 +262,7 @@ export async function openSessionMoreMenu(page: Page, sessionID: string) {
 
   if (opened) return menu
 
-  const menuTrigger = scroller.getByRole("button", { name: /more options/i }).first()
+  const menuTrigger = header.getByRole("button", { name: /more options/i }).first()
   await expect(menuTrigger).toBeVisible()
   await menuTrigger.click()
 

packages/app/e2e/selectors.ts

@@ -53,6 +53,8 @@ export const dropdownMenuContentSelector = '[data-component="dropdown-menu-conte
 
 export const inlineInputSelector = '[data-component="inline-input"]'
 
+export const sessionTimelineHeaderSelector = "[data-session-title]"
+
 export const sessionItemSelector = (sessionID: string) => `${sidebarNavSelector} [data-session-id="${sessionID}"]`
 
 export const workspaceItemSelector = (slug: string) =>

packages/app/e2e/session/session.spec.ts

@@ -7,7 +7,7 @@ import {
   openSharePopover,
   withSession,
 } from "../actions"
-import { sessionItemSelector, inlineInputSelector } from "../selectors"
+import { sessionItemSelector, inlineInputSelector, sessionTimelineHeaderSelector } from "../selectors"
 
 const shareDisabled = process.env.OPENCODE_DISABLE_SHARE === "true" || process.env.OPENCODE_DISABLE_SHARE === "1"
 
@@ -39,12 +39,14 @@ test("session can be renamed via header menu", async ({ page, sdk, gotoSession }
   await withSession(sdk, originalTitle, async (session) => {
     await seedMessage(sdk, session.id)
     await gotoSession(session.id)
-    await expect(page.getByRole("heading", { level: 1 }).first()).toHaveText(originalTitle)
+    await expect(page.locator(sessionTimelineHeaderSelector).getByRole("heading", { level: 1 }).first()).toHaveText(
+      originalTitle,
+    )
 
     const menu = await openSessionMoreMenu(page, session.id)
     await clickMenuItem(menu, /rename/i)
 
-    const input = page.locator(".scroll-view__viewport").locator(inlineInputSelector).first()
+    const input = page.locator(sessionTimelineHeaderSelector).locator(inlineInputSelector).first()
     await expect(input).toBeVisible()
     await expect(input).toBeFocused()
     await input.fill(renamedTitle)
@@ -61,7 +63,9 @@ test("session can be renamed via header menu", async ({ page, sdk, gotoSession }
       )
       .toBe(renamedTitle)
 
-    await expect(page.getByRole("heading", { level: 1 }).first()).toHaveText(renamedTitle)
+    await expect(page.locator(sessionTimelineHeaderSelector).getByRole("heading", { level: 1 }).first()).toHaveText(
+      renamedTitle,
+    )
   })
 })
 

packages/app/src/pages/session.tsx

@@ -121,13 +121,9 @@ function createSessionHistoryWindow(input: SessionHistoryWindowInput) {
       return
     }
     const beforeTop = el.scrollTop
-    const beforeHeight = el.scrollHeight
     fn()
-    requestAnimationFrame(() => {
-      const delta = el.scrollHeight - beforeHeight
-      if (!delta) return
-      el.scrollTop = beforeTop + delta
-    })
+    void el.scrollHeight
+    el.scrollTop = beforeTop
   }
 
   const backfillTurns = () => {
@@ -210,7 +206,7 @@ function createSessionHistoryWindow(input: SessionHistoryWindowInput) {
     if (!input.userScrolled()) return
     const el = input.scroller()
     if (!el) return
-    if (el.scrollTop >= turnScrollThreshold) return
+    if (el.scrollHeight - el.clientHeight + el.scrollTop >= turnScrollThreshold) return
 
     const start = turnStart()
     if (start > 0) {
@@ -1110,7 +1106,7 @@ export default function Page() {
   const updateScrollState = (el: HTMLDivElement) => {
     const max = el.scrollHeight - el.clientHeight
     const overflow = max > 1
-    const bottom = !overflow || el.scrollTop >= max - 2
+    const bottom = !overflow || Math.abs(el.scrollTop) <= 2 || !autoScroll.userScrolled()
 
     if (ui.scroll.overflow === overflow && ui.scroll.bottom === bottom) return
     setUi("scroll", { overflow, bottom })
@@ -1133,7 +1129,7 @@ export default function Page() {
 
   const resumeScroll = () => {
     setStore("messageId", undefined)
-    autoScroll.forceScrollToBottom()
+    autoScroll.smoothScrollToBottom()
     clearMessageHash()
 
     const el = scroller
@@ -1201,13 +1197,11 @@ export default function Page() {
 
       const el = scroller
       const delta = next - dockHeight
-      const stick = el
-        ? !autoScroll.userScrolled() || el.scrollHeight - el.clientHeight - el.scrollTop < 10 + Math.max(0, delta)
-        : false
+      const stick = el ? Math.abs(el.scrollTop) < 10 + Math.max(0, delta) : false
 
       dockHeight = next
 
-      if (stick) autoScroll.forceScrollToBottom()
+      if (stick) autoScroll.smoothScrollToBottom()
 
       if (el) scheduleScrollState(el)
       scrollSpy.markDirty()
@@ -1293,6 +1287,7 @@ export default function Page() {
                     onScrollSpyScroll={scrollSpy.onScroll}
                     onTurnBackfillScroll={historyWindow.onScrollerScroll}
                     onAutoScrollInteraction={autoScroll.handleInteraction}
+                    onPreserveScrollAnchor={autoScroll.preserve}
                     centered={centered()}
                     setContentRef={(el) => {
                       content = el

packages/app/src/pages/session/message-timeline.tsx

@@ -1,27 +1,31 @@
-import { For, createEffect, createMemo, on, onCleanup, Show, Index, type JSX } from "solid-js"
-import { createStore, produce } from "solid-js/store"
-import { useNavigate, useParams } from "@solidjs/router"
+import {
+  For,
+  Index,
+  createEffect,
+  createMemo,
+  createSignal,
+  on,
+  onCleanup,
+  Show,
+  startTransition,
+  type JSX,
+} from "solid-js"
+import { createStore } from "solid-js/store"
+import { useParams } from "@solidjs/router"
 import { Button } from "@opencode-ai/ui/button"
 import { FileIcon } from "@opencode-ai/ui/file-icon"
 import { Icon } from "@opencode-ai/ui/icon"
-import { IconButton } from "@opencode-ai/ui/icon-button"
-import { DropdownMenu } from "@opencode-ai/ui/dropdown-menu"
-import { Dialog } from "@opencode-ai/ui/dialog"
-import { InlineInput } from "@opencode-ai/ui/inline-input"
 import { SessionTurn } from "@opencode-ai/ui/session-turn"
 import { ScrollView } from "@opencode-ai/ui/scroll-view"
 import type { AssistantMessage, Message as MessageType, Part, TextPart, UserMessage } from "@opencode-ai/sdk/v2"
-import { showToast } from "@opencode-ai/ui/toast"
 import { Binary } from "@opencode-ai/util/binary"
 import { getFilename } from "@opencode-ai/util/path"
 import { shouldMarkBoundaryGesture, normalizeWheelDelta } from "@/pages/session/message-gesture"
-import { SessionContextUsage } from "@/components/session-context-usage"
-import { useDialog } from "@opencode-ai/ui/context/dialog"
 import { useLanguage } from "@/context/language"
 import { useSettings } from "@/context/settings"
-import { useSDK } from "@/context/sdk"
 import { useSync } from "@/context/sync"
 import { parseCommentNote, readCommentMetadata } from "@/utils/comment-note"
+import { SessionTimelineHeader } from "@/pages/session/session-timeline-header"
 
 type MessageComment = {
   path: string
@@ -33,7 +37,9 @@ type MessageComment = {
 }
 
 const emptyMessages: MessageType[] = []
-const idle = { type: "idle" as const }
+
+const isDefaultSessionTitle = (title?: string) =>
+  !!title && /^(New session - |Child session - )\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}\.\d{3}Z$/.test(title)
 
 const messageComments = (parts: Part[]): MessageComment[] =>
   parts.flatMap((part) => {
@@ -110,6 +116,8 @@ function createTimelineStaging(input: TimelineStageInput) {
     completedSession: "",
     count: 0,
   })
+  const [readySession, setReadySession] = createSignal("")
+  let active = ""
 
   const stagedCount = createMemo(() => {
     const total = input.messages().length
@@ -134,23 +142,46 @@ function createTimelineStaging(input: TimelineStageInput) {
     cancelAnimationFrame(frame)
     frame = undefined
   }
+  const scheduleReady = (sessionKey: string) => {
+    if (input.sessionKey() !== sessionKey) return
+    if (readySession() === sessionKey) return
+    setReadySession(sessionKey)
+  }
 
   createEffect(
     on(
       () => [input.sessionKey(), input.turnStart() > 0, input.messages().length] as const,
       ([sessionKey, isWindowed, total]) => {
+        const switched = active !== sessionKey
+        if (switched) {
+          active = sessionKey
+          setReadySession("")
+        }
+
+        const staging = state.activeSession === sessionKey && state.completedSession !== sessionKey
+        const shouldStage = isWindowed && total > input.config.init && state.completedSession !== sessionKey
+
+        if (staging && !switched && shouldStage && frame !== undefined) return
+
         cancel()
-        const shouldStage =
-          isWindowed &&
-          total > input.config.init &&
-          state.completedSession !== sessionKey &&
-          state.activeSession !== sessionKey
+
+        if (shouldStage) setReadySession("")
         if (!shouldStage) {
-          setState({ activeSession: "", count: total })
+          setState({
+            activeSession: "",
+            completedSession: isWindowed ? sessionKey : state.completedSession,
+            count: total,
+          })
+          if (total <= 0) {
+            setReadySession("")
+            return
+          }
+          if (readySession() !== sessionKey) scheduleReady(sessionKey)
           return
         }
 
         let count = Math.min(total, input.config.init)
+        if (staging) count = Math.min(total, Math.max(count, state.count))
         setState({ activeSession: sessionKey, count })
 
         const step = () => {
@@ -160,10 +191,11 @@ function createTimelineStaging(input: TimelineStageInput) {
           }
           const currentTotal = input.messages().length
           count = Math.min(currentTotal, count + input.config.batch)
-          setState("count", count)
+          startTransition(() => setState("count", count))
           if (count >= currentTotal) {
             setState({ completedSession: sessionKey, activeSession: "" })
             frame = undefined
+            scheduleReady(sessionKey)
             return
           }
           frame = requestAnimationFrame(step)
@@ -177,9 +209,12 @@ function createTimelineStaging(input: TimelineStageInput) {
     const key = input.sessionKey()
     return state.activeSession === key && state.completedSession !== key
   })
+  const ready = createMemo(() => readySession() === input.sessionKey())
 
-  onCleanup(cancel)
-  return { messages: stagedUserMessages, isStaging }
+  onCleanup(() => {
+    cancel()
+  })
+  return { messages: stagedUserMessages, isStaging, ready }
 }
 
 export function MessageTimeline(props: {
@@ -196,6 +231,7 @@ export function MessageTimeline(props: {
   onScrollSpyScroll: () => void
   onTurnBackfillScroll: () => void
   onAutoScrollInteraction: (event: MouseEvent) => void
+  onPreserveScrollAnchor: (target: HTMLElement) => void
   centered: boolean
   setContentRef: (el: HTMLDivElement) => void
   turnStart: number
@@ -210,14 +246,19 @@ export function MessageTimeline(props: {
   let touchGesture: number | undefined
 
   const params = useParams()
-  const navigate = useNavigate()
-  const sdk = useSDK()
   const sync = useSync()
   const settings = useSettings()
-  const dialog = useDialog()
   const language = useLanguage()
 
-  const rendered = createMemo(() => props.renderedUserMessages.map((message) => message.id))
+  const trigger = (target: EventTarget | null) => {
+    const next =
+      target instanceof Element
+        ? target.closest('[data-slot="collapsible-trigger"], [data-slot="accordion-trigger"], [data-scroll-preserve]')
+        : undefined
+    if (!(next instanceof HTMLElement)) return
+    return next
+  }
+
   const sessionKey = createMemo(() => `${params.dir}${params.id ? "/" + params.id : ""}`)
   const sessionID = createMemo(() => params.id)
   const sessionMessages = createMemo(() => {
@@ -230,28 +271,20 @@ export function MessageTimeline(props: {
       (item): item is AssistantMessage => item.role === "assistant" && typeof item.time.completed !== "number",
     ),
   )
-  const sessionStatus = createMemo(() => {
-    const id = sessionID()
-    if (!id) return idle
-    return sync.data.session_status[id] ?? idle
-  })
+  const sessionStatus = createMemo(() => sync.data.session_status[sessionID() ?? ""]?.type ?? "idle")
   const activeMessageID = createMemo(() => {
-    const parentID = pending()?.parentID
-    if (parentID) {
-      const messages = sessionMessages()
-      const result = Binary.search(messages, parentID, (message) => message.id)
-      const message = result.found ? messages[result.index] : messages.find((item) => item.id === parentID)
-      if (message && message.role === "user") return message.id
+    const messages = sessionMessages()
+    const message = pending()
+    if (message?.parentID) {
+      const result = Binary.search(messages, message.parentID, (item) => item.id)
+      const parent = result.found ? messages[result.index] : messages.find((item) => item.id === message.parentID)
+      if (parent?.role === "user") return parent.id
     }
 
-    const status = sessionStatus()
-    if (status.type !== "idle") {
-      const messages = sessionMessages()
-      for (let i = messages.length - 1; i >= 0; i--) {
-        if (messages[i].role === "user") return messages[i].id
-      }
+    if (sessionStatus() === "idle") return undefined
+    for (let i = messages.length - 1; i >= 0; i--) {
+      if (messages[i].role === "user") return messages[i].id
     }
-
     return undefined
   })
   const info = createMemo(() => {
@@ -259,9 +292,19 @@ export function MessageTimeline(props: {
     if (!id) return
     return sync.session.get(id)
   })
-  const titleValue = createMemo(() => info()?.title)
+  const titleValue = createMemo(() => {
+    const title = info()?.title
+    if (!title) return
+    if (isDefaultSessionTitle(title)) return language.t("command.session.new")
+    return title
+  })
+  const defaultTitle = createMemo(() => isDefaultSessionTitle(info()?.title))
+  const headerTitle = createMemo(
+    () => titleValue() ?? (props.renderedUserMessages.length ? language.t("command.session.new") : undefined),
+  )
+  const placeholderTitle = createMemo(() => defaultTitle() || (!info()?.title && props.renderedUserMessages.length > 0))
   const parentID = createMemo(() => info()?.parentID)
-  const showHeader = createMemo(() => !!(titleValue() || parentID()))
+  const showHeader = createMemo(() => !!(headerTitle() || parentID()))
   const stageCfg = { init: 1, batch: 3 }
   const staging = createTimelineStaging({
     sessionKey,
@@ -269,212 +312,7 @@ export function MessageTimeline(props: {
     messages: () => props.renderedUserMessages,
     config: stageCfg,
   })
-
-  const [title, setTitle] = createStore({
-    draft: "",
-    editing: false,
-    saving: false,
-    menuOpen: false,
-    pendingRename: false,
-  })
-  let titleRef: HTMLInputElement | undefined
-
-  const errorMessage = (err: unknown) => {
-    if (err && typeof err === "object" && "data" in err) {
-      const data = (err as { data?: { message?: string } }).data
-      if (data?.message) return data.message
-    }
-    if (err instanceof Error) return err.message
-    return language.t("common.requestFailed")
-  }
-
-  createEffect(
-    on(
-      sessionKey,
-      () => setTitle({ draft: "", editing: false, saving: false, menuOpen: false, pendingRename: false }),
-      { defer: true },
-    ),
-  )
-
-  const openTitleEditor = () => {
-    if (!sessionID()) return
-    setTitle({ editing: true, draft: titleValue() ?? "" })
-    requestAnimationFrame(() => {
-      titleRef?.focus()
-      titleRef?.select()
-    })
-  }
-
-  const closeTitleEditor = () => {
-    if (title.saving) return
-    setTitle({ editing: false, saving: false })
-  }
-
-  const saveTitleEditor = async () => {
-    const id = sessionID()
-    if (!id) return
-    if (title.saving) return
-
-    const next = title.draft.trim()
-    if (!next || next === (titleValue() ?? "")) {
-      setTitle({ editing: false, saving: false })
-      return
-    }
-
-    setTitle("saving", true)
-    await sdk.client.session
-      .update({ sessionID: id, title: next })
-      .then(() => {
-        sync.set(
-          produce((draft) => {
-            const index = draft.session.findIndex((s) => s.id === id)
-            if (index !== -1) draft.session[index].title = next
-          }),
-        )
-        setTitle({ editing: false, saving: false })
-      })
-      .catch((err) => {
-        setTitle("saving", false)
-        showToast({
-          title: language.t("common.requestFailed"),
-          description: errorMessage(err),
-        })
-      })
-  }
-
-  const navigateAfterSessionRemoval = (sessionID: string, parentID?: string, nextSessionID?: string) => {
-    if (params.id !== sessionID) return
-    if (parentID) {
-      navigate(`/${params.dir}/session/${parentID}`)
-      return
-    }
-    if (nextSessionID) {
-      navigate(`/${params.dir}/session/${nextSessionID}`)
-      return
-    }
-    navigate(`/${params.dir}/session`)
-  }
-
-  const archiveSession = async (sessionID: string) => {
-    const session = sync.session.get(sessionID)
-    if (!session) return
-
-    const sessions = sync.data.session ?? []
-    const index = sessions.findIndex((s) => s.id === sessionID)
-    const nextSession = index === -1 ? undefined : (sessions[index + 1] ?? sessions[index - 1])
-
-    await sdk.client.session
-      .update({ sessionID, time: { archived: Date.now() } })
-      .then(() => {
-        sync.set(
-          produce((draft) => {
-            const index = draft.session.findIndex((s) => s.id === sessionID)
-            if (index !== -1) draft.session.splice(index, 1)
-          }),
-        )
-        navigateAfterSessionRemoval(sessionID, session.parentID, nextSession?.id)
-      })
-      .catch((err) => {
-        showToast({
-          title: language.t("common.requestFailed"),
-          description: errorMessage(err),
-        })
-      })
-  }
-
-  const deleteSession = async (sessionID: string) => {
-    const session = sync.session.get(sessionID)
-    if (!session) return false
-
-    const sessions = (sync.data.session ?? []).filter((s) => !s.parentID && !s.time?.archived)
-    const index = sessions.findIndex((s) => s.id === sessionID)
-    const nextSession = index === -1 ? undefined : (sessions[index + 1] ?? sessions[index - 1])
-
-    const result = await sdk.client.session
-      .delete({ sessionID })
-      .then((x) => x.data)
-      .catch((err) => {
-        showToast({
-          title: language.t("session.delete.failed.title"),
-          description: errorMessage(err),
-        })
-        return false
-      })
-
-    if (!result) return false
-
-    sync.set(
-      produce((draft) => {
-        const removed = new Set<string>([sessionID])
-
-        const byParent = new Map<string, string[]>()
-        for (const item of draft.session) {
-          const parentID = item.parentID
-          if (!parentID) continue
-          const existing = byParent.get(parentID)
-          if (existing) {
-            existing.push(item.id)
-            continue
-          }
-          byParent.set(parentID, [item.id])
-        }
-
-        const stack = [sessionID]
-        while (stack.length) {
-          const parentID = stack.pop()
-          if (!parentID) continue
-
-          const children = byParent.get(parentID)
-          if (!children) continue
-
-          for (const child of children) {
-            if (removed.has(child)) continue
-            removed.add(child)
-            stack.push(child)
-          }
-        }
-
-        draft.session = draft.session.filter((s) => !removed.has(s.id))
-      }),
-    )
-
-    navigateAfterSessionRemoval(sessionID, session.parentID, nextSession?.id)
-    return true
-  }
-
-  const navigateParent = () => {
-    const id = parentID()
-    if (!id) return
-    navigate(`/${params.dir}/session/${id}`)
-  }
-
-  function DialogDeleteSession(props: { sessionID: string }) {
-    const name = createMemo(() => sync.session.get(props.sessionID)?.title ?? language.t("command.session.new"))
-    const handleDelete = async () => {
-      await deleteSession(props.sessionID)
-      dialog.close()
-    }
-
-    return (
-      <Dialog title={language.t("session.delete.title")} fit>
-        <div class="flex flex-col gap-4 pl-6 pr-2.5 pb-3">
-          <div class="flex flex-col gap-1">
-            <span class="text-14-regular text-text-strong">
-              {language.t("session.delete.confirm", { name: name() })}
-            </span>
-          </div>
-          <div class="flex justify-end gap-2">
-            <Button variant="ghost" size="large" onClick={() => dialog.close()}>
-              {language.t("common.cancel")}
-            </Button>
-            <Button variant="primary" size="large" onClick={handleDelete}>
-              {language.t("session.delete.button")}
-            </Button>
-          </div>
-        </div>
-      </Dialog>
-    )
-  }
+  const rendered = createMemo(() => staging.messages().map((message) => message.id))
 
   return (
     <Show
@@ -498,6 +336,16 @@ export function MessageTimeline(props: {
             <Icon name="arrow-down-to-line" />
           </button>
         </div>
+        <SessionTimelineHeader
+          centered={props.centered}
+          showHeader={showHeader}
+          sessionKey={sessionKey}
+          sessionID={sessionID}
+          parentID={parentID}
+          titleValue={titleValue}
+          headerTitle={headerTitle}
+          placeholderTitle={placeholderTitle}
+        />
         <ScrollView
           viewportRef={props.setScrollRef}
           onWheel={(e) => {
@@ -532,9 +380,18 @@ export function MessageTimeline(props: {
             touchGesture = undefined
           }}
           onPointerDown={(e) => {
+            const next = trigger(e.target)
+            if (next) props.onPreserveScrollAnchor(next)
+
             if (e.target !== e.currentTarget) return
             props.onMarkScrollGesture(e.currentTarget)
           }}
+          onKeyDown={(e) => {
+            if (e.key !== "Enter" && e.key !== " ") return
+            const next = trigger(e.target)
+            if (!next) return
+            props.onPreserveScrollAnchor(next)
+          }}
           onScroll={(e) => {
             props.onScheduleScrollState(e.currentTarget)
             props.onTurnBackfillScroll()
@@ -543,131 +400,21 @@ export function MessageTimeline(props: {
             props.onMarkScrollGesture(e.currentTarget)
             if (props.isDesktop) props.onScrollSpyScroll()
           }}
-          onClick={props.onAutoScrollInteraction}
+          onClick={(e) => {
+            props.onAutoScrollInteraction(e)
+          }}
           class="relative min-w-0 w-full h-full"
           style={{
-            "--session-title-height": showHeader() ? "40px" : "0px",
+            "--session-title-height": showHeader() ? "72px" : "0px",
             "--sticky-accordion-top": showHeader() ? "48px" : "0px",
           }}
         >
-          <div ref={props.setContentRef} class="min-w-0 w-full">
-            <Show when={showHeader()}>
-              <div
-                data-session-title
-                classList={{
-                  "sticky top-0 z-30 bg-[linear-gradient(to_bottom,var(--background-stronger)_48px,transparent)]": true,
-                  "w-full": true,
-                  "pb-4": true,
-                  "pl-2 pr-3 md:pl-4 md:pr-3": true,
-                  "md:max-w-200 md:mx-auto 2xl:max-w-[1000px]": props.centered,
-                }}
-              >
-                <div class="h-12 w-full flex items-center justify-between gap-2">
-                  <div class="flex items-center gap-1 min-w-0 flex-1 pr-3">
-                    <Show when={parentID()}>
-                      <IconButton
-                        tabIndex={-1}
-                        icon="arrow-left"
-                        variant="ghost"
-                        onClick={navigateParent}
-                        aria-label={language.t("common.goBack")}
-                      />
-                    </Show>
-                    <Show when={titleValue() || title.editing}>
-                      <Show
-                        when={title.editing}
-                        fallback={
-                          <h1
-                            class="text-14-medium text-text-strong truncate grow-1 min-w-0 pl-2"
-                            onDblClick={openTitleEditor}
-                          >
-                            {titleValue()}
-                          </h1>
-                        }
-                      >
-                        <InlineInput
-                          ref={(el) => {
-                            titleRef = el
-                          }}
-                          value={title.draft}
-                          disabled={title.saving}
-                          class="text-14-medium text-text-strong grow-1 min-w-0 pl-2 rounded-[6px]"
-                          style={{ "--inline-input-shadow": "var(--shadow-xs-border-select)" }}
-                          onInput={(event) => setTitle("draft", event.currentTarget.value)}
-                          onKeyDown={(event) => {
-                            event.stopPropagation()
-                            if (event.key === "Enter") {
-                              event.preventDefault()
-                              void saveTitleEditor()
-                              return
-                            }
-                            if (event.key === "Escape") {
-                              event.preventDefault()
-                              closeTitleEditor()
-                            }
-                          }}
-                          onBlur={closeTitleEditor}
-                        />
-                      </Show>
-                    </Show>
-                  </div>
-                  <Show when={sessionID()}>
-                    {(id) => (
-                      <div class="shrink-0 flex items-center gap-3">
-                        <SessionContextUsage placement="bottom" />
-                        <DropdownMenu
-                          gutter={4}
-                          placement="bottom-end"
-                          open={title.menuOpen}
-                          onOpenChange={(open) => setTitle("menuOpen", open)}
-                        >
-                          <DropdownMenu.Trigger
-                            as={IconButton}
-                            icon="dot-grid"
-                            variant="ghost"
-                            class="size-6 rounded-md data-[expanded]:bg-surface-base-active"
-                            aria-label={language.t("common.moreOptions")}
-                          />
-                          <DropdownMenu.Portal>
-                            <DropdownMenu.Content
-                              style={{ "min-width": "104px" }}
-                              onCloseAutoFocus={(event) => {
-                                if (!title.pendingRename) return
-                                event.preventDefault()
-                                setTitle("pendingRename", false)
-                                openTitleEditor()
-                              }}
-                            >
-                              <DropdownMenu.Item
-                                onSelect={() => {
-                                  setTitle("pendingRename", true)
-                                  setTitle("menuOpen", false)
-                                }}
-                              >
-                                <DropdownMenu.ItemLabel>{language.t("common.rename")}</DropdownMenu.ItemLabel>
-                              </DropdownMenu.Item>
-                              <DropdownMenu.Item onSelect={() => void archiveSession(id())}>
-                                <DropdownMenu.ItemLabel>{language.t("common.archive")}</DropdownMenu.ItemLabel>
-                              </DropdownMenu.Item>
-                              <DropdownMenu.Separator />
-                              <DropdownMenu.Item
-                                onSelect={() => dialog.show(() => <DialogDeleteSession sessionID={id()} />)}
-                              >
-                                <DropdownMenu.ItemLabel>{language.t("common.delete")}</DropdownMenu.ItemLabel>
-                              </DropdownMenu.Item>
-                            </DropdownMenu.Content>
-                          </DropdownMenu.Portal>
-                        </DropdownMenu>
-                      </div>
-                    )}
-                  </Show>
-                </div>
-              </div>
-            </Show>
-
+          <div>
             <div
+              ref={props.setContentRef}
               role="log"
-              class="flex flex-col gap-12 items-start justify-start pb-16 transition-[margin]"
+              class="flex flex-col gap-0 items-start justify-start pb-16 transition-[margin]"
+              style={{ "padding-top": "var(--session-title-height)" }}
               classList={{
                 "w-full": true,
                 "md:max-w-200 md:mx-auto 2xl:max-w-[1000px]": props.centered,
@@ -692,6 +439,15 @@ export function MessageTimeline(props: {
               </Show>
               <For each={rendered()}>
                 {(messageID) => {
+                  // Capture at creation time: animate only messages added after the
+                  // timeline finishes its initial backfill staging, plus the first
+                  // turn while a brand new session is still using its default title.
+                  const isNew =
+                    staging.ready() ||
+                    (defaultTitle() &&
+                      sessionStatus() !== "idle" &&
+                      props.renderedUserMessages.length === 1 &&
+                      messageID === props.renderedUserMessages[0]?.id)
                   const active = createMemo(() => activeMessageID() === messageID)
                   const queued = createMemo(() => {
                     if (active()) return false
@@ -700,7 +456,10 @@ export function MessageTimeline(props: {
                     return false
                   })
                   const comments = createMemo(() => messageComments(sync.data.part[messageID] ?? []), [], {
-                    equals: (a, b) => JSON.stringify(a) === JSON.stringify(b),
+                    equals: (a, b) => {
+                      if (a.length !== b.length) return false
+                      return a.every((x, i) => x.path === b[i].path && x.comment === b[i].comment)
+                    },
                   })
                   const commentCount = createMemo(() => comments().length)
                   return (
@@ -757,7 +516,7 @@ export function MessageTimeline(props: {
                         messageID={messageID}
                         active={active()}
                         queued={queued()}
-                        status={active() ? sessionStatus() : undefined}
+                        animate={isNew || active()}
                         showReasoningSummaries={settings.general.showReasoningSummaries()}
                         shellToolDefaultOpen={settings.general.shellToolPartsExpanded()}
                         editToolDefaultOpen={settings.general.editToolPartsExpanded()}

packages/app/src/pages/session/session-timeline-header.tsx

@@ -0,0 +1,522 @@
+import { createEffect, createMemo, on, onCleanup, Show } from "solid-js"
+import { createStore, produce } from "solid-js/store"
+import { useNavigate, useParams } from "@solidjs/router"
+import { Button } from "@opencode-ai/ui/button"
+import { IconButton } from "@opencode-ai/ui/icon-button"
+import { DropdownMenu } from "@opencode-ai/ui/dropdown-menu"
+import { Dialog } from "@opencode-ai/ui/dialog"
+import { prefersReducedMotion } from "@opencode-ai/ui/hooks"
+import { InlineInput } from "@opencode-ai/ui/inline-input"
+import { animate, type AnimationPlaybackControls, clearFadeStyles, FAST_SPRING } from "@opencode-ai/ui/motion"
+import { showToast } from "@opencode-ai/ui/toast"
+import { errorMessage } from "@/pages/layout/helpers"
+import { SessionContextUsage } from "@/components/session-context-usage"
+import { useDialog } from "@opencode-ai/ui/context/dialog"
+import { useLanguage } from "@/context/language"
+import { useSDK } from "@/context/sdk"
+import { useSync } from "@/context/sync"
+
+export function SessionTimelineHeader(props: {
+  centered: boolean
+  showHeader: () => boolean
+  sessionKey: () => string
+  sessionID: () => string | undefined
+  parentID: () => string | undefined
+  titleValue: () => string | undefined
+  headerTitle: () => string | undefined
+  placeholderTitle: () => boolean
+}) {
+  const navigate = useNavigate()
+  const params = useParams()
+  const sdk = useSDK()
+  const sync = useSync()
+  const dialog = useDialog()
+  const language = useLanguage()
+  const reduce = prefersReducedMotion
+
+  const [title, setTitle] = createStore({
+    draft: "",
+    editing: false,
+    saving: false,
+    menuOpen: false,
+    pendingRename: false,
+  })
+  const [headerText, setHeaderText] = createStore({
+    session: props.sessionKey(),
+    value: props.headerTitle(),
+    prev: undefined as string | undefined,
+    muted: props.placeholderTitle(),
+    prevMuted: false,
+  })
+  let headerAnim: AnimationPlaybackControls | undefined
+  let enterAnim: AnimationPlaybackControls | undefined
+  let leaveAnim: AnimationPlaybackControls | undefined
+  let titleRef: HTMLInputElement | undefined
+  let headerRef: HTMLDivElement | undefined
+  let enterRef: HTMLSpanElement | undefined
+  let leaveRef: HTMLSpanElement | undefined
+
+  const clearHeaderAnim = () => {
+    headerAnim?.stop()
+    headerAnim = undefined
+  }
+
+  const animateHeader = () => {
+    const el = headerRef
+    if (!el) return
+
+    clearHeaderAnim()
+    if (!headerText.muted || reduce()) {
+      el.style.opacity = "1"
+      return
+    }
+
+    headerAnim = animate(el, { opacity: [0, 1] }, { type: "spring", visualDuration: 1.0, bounce: 0 })
+    headerAnim.finished.then(() => {
+      if (headerRef !== el) return
+      clearFadeStyles(el)
+    })
+  }
+
+  const clearTitleAnims = () => {
+    enterAnim?.stop()
+    enterAnim = undefined
+    leaveAnim?.stop()
+    leaveAnim = undefined
+  }
+
+  const settleTitleEnter = () => {
+    if (enterRef) clearFadeStyles(enterRef)
+  }
+
+  const hideLeave = () => {
+    if (!leaveRef) return
+    leaveRef.style.opacity = "0"
+    leaveRef.style.filter = ""
+    leaveRef.style.transform = ""
+  }
+
+  const animateEnterSpan = () => {
+    if (!enterRef) return
+    if (reduce()) {
+      settleTitleEnter()
+      return
+    }
+    enterAnim = animate(
+      enterRef,
+      { opacity: [0, 1], filter: ["blur(2px)", "blur(0px)"], transform: ["translateY(-2px)", "translateY(0)"] },
+      FAST_SPRING,
+    )
+    enterAnim.finished.then(() => settleTitleEnter())
+  }
+
+  const crossfadeTitle = (nextTitle: string, nextMuted: boolean) => {
+    clearTitleAnims()
+    setHeaderText({ prev: headerText.value, prevMuted: headerText.muted })
+    setHeaderText({ value: nextTitle, muted: nextMuted })
+
+    if (reduce()) {
+      setHeaderText({ prev: undefined, prevMuted: false })
+      hideLeave()
+      settleTitleEnter()
+      return
+    }
+
+    if (leaveRef) {
+      leaveAnim = animate(
+        leaveRef,
+        { opacity: [1, 0], filter: ["blur(0px)", "blur(2px)"], transform: ["translateY(0)", "translateY(2px)"] },
+        FAST_SPRING,
+      )
+      leaveAnim.finished.then(() => {
+        setHeaderText({ prev: undefined, prevMuted: false })
+        hideLeave()
+      })
+    }
+
+    animateEnterSpan()
+  }
+
+  const fadeInTitle = (nextTitle: string, nextMuted: boolean) => {
+    clearTitleAnims()
+    setHeaderText({ value: nextTitle, muted: nextMuted, prev: undefined, prevMuted: false })
+    animateEnterSpan()
+  }
+
+  const snapTitle = (nextTitle: string | undefined, nextMuted: boolean) => {
+    clearTitleAnims()
+    setHeaderText({ value: nextTitle, muted: nextMuted, prev: undefined, prevMuted: false })
+    settleTitleEnter()
+  }
+
+  createEffect(
+    on(props.showHeader, (show, prev) => {
+      if (!show) {
+        clearHeaderAnim()
+        return
+      }
+      if (show === prev) return
+      animateHeader()
+    }),
+  )
+
+  createEffect(
+    on(
+      () => [props.sessionKey(), props.headerTitle(), props.placeholderTitle()] as const,
+      ([nextSession, nextTitle, nextMuted]) => {
+        if (nextSession !== headerText.session) {
+          setHeaderText("session", nextSession)
+          if (nextTitle && nextMuted) {
+            fadeInTitle(nextTitle, nextMuted)
+            return
+          }
+          snapTitle(nextTitle, nextMuted)
+          return
+        }
+        if (nextTitle === headerText.value && nextMuted === headerText.muted) return
+        if (!nextTitle) {
+          snapTitle(undefined, false)
+          return
+        }
+        if (!headerText.value) {
+          fadeInTitle(nextTitle, nextMuted)
+          return
+        }
+        if (title.saving || title.editing) {
+          snapTitle(nextTitle, nextMuted)
+          return
+        }
+        crossfadeTitle(nextTitle, nextMuted)
+      },
+    ),
+  )
+
+  onCleanup(() => {
+    clearHeaderAnim()
+    clearTitleAnims()
+  })
+
+  const toastError = (err: unknown) => errorMessage(err, language.t("common.requestFailed"))
+
+  createEffect(
+    on(
+      props.sessionKey,
+      () => setTitle({ draft: "", editing: false, saving: false, menuOpen: false, pendingRename: false }),
+      { defer: true },
+    ),
+  )
+
+  const openTitleEditor = () => {
+    if (!props.sessionID()) return
+    setTitle({ editing: true, draft: props.titleValue() ?? "" })
+    requestAnimationFrame(() => {
+      titleRef?.focus()
+      titleRef?.select()
+    })
+  }
+
+  const closeTitleEditor = () => {
+    if (title.saving) return
+    setTitle({ editing: false, saving: false })
+  }
+
+  const saveTitleEditor = async () => {
+    const id = props.sessionID()
+    if (!id) return
+    if (title.saving) return
+
+    const next = title.draft.trim()
+    if (!next || next === (props.titleValue() ?? "")) {
+      setTitle({ editing: false, saving: false })
+      return
+    }
+
+    setTitle("saving", true)
+    await sdk.client.session
+      .update({ sessionID: id, title: next })
+      .then(() => {
+        sync.set(
+          produce((draft) => {
+            const index = draft.session.findIndex((session) => session.id === id)
+            if (index !== -1) draft.session[index].title = next
+          }),
+        )
+        setTitle({ editing: false, saving: false })
+      })
+      .catch((err) => {
+        setTitle("saving", false)
+        showToast({
+          title: language.t("common.requestFailed"),
+          description: toastError(err),
+        })
+      })
+  }
+
+  const navigateAfterSessionRemoval = (sessionID: string, parentID?: string, nextSessionID?: string) => {
+    if (params.id !== sessionID) return
+    if (parentID) {
+      navigate(`/${params.dir}/session/${parentID}`)
+      return
+    }
+    if (nextSessionID) {
+      navigate(`/${params.dir}/session/${nextSessionID}`)
+      return
+    }
+    navigate(`/${params.dir}/session`)
+  }
+
+  const archiveSession = async (sessionID: string) => {
+    const session = sync.session.get(sessionID)
+    if (!session) return
+
+    const sessions = sync.data.session ?? []
+    const index = sessions.findIndex((item) => item.id === sessionID)
+    const nextSession = index === -1 ? undefined : (sessions[index + 1] ?? sessions[index - 1])
+
+    await sdk.client.session
+      .update({ sessionID, time: { archived: Date.now() } })
+      .then(() => {
+        sync.set(
+          produce((draft) => {
+            const index = draft.session.findIndex((item) => item.id === sessionID)
+            if (index !== -1) draft.session.splice(index, 1)
+          }),
+        )
+        navigateAfterSessionRemoval(sessionID, session.parentID, nextSession?.id)
+      })
+      .catch((err) => {
+        showToast({
+          title: language.t("common.requestFailed"),
+          description: toastError(err),
+        })
+      })
+  }
+
+  const deleteSession = async (sessionID: string) => {
+    const session = sync.session.get(sessionID)
+    if (!session) return false
+
+    const sessions = (sync.data.session ?? []).filter((item) => !item.parentID && !item.time?.archived)
+    const index = sessions.findIndex((item) => item.id === sessionID)
+    const nextSession = index === -1 ? undefined : (sessions[index + 1] ?? sessions[index - 1])
+
+    const result = await sdk.client.session
+      .delete({ sessionID })
+      .then((x) => x.data)
+      .catch((err) => {
+        showToast({
+          title: language.t("session.delete.failed.title"),
+          description: toastError(err),
+        })
+        return false
+      })
+
+    if (!result) return false
+
+    sync.set(
+      produce((draft) => {
+        const removed = new Set<string>([sessionID])
+        const byParent = new Map<string, string[]>()
+
+        for (const item of draft.session) {
+          const parentID = item.parentID
+          if (!parentID) continue
+
+          const existing = byParent.get(parentID)
+          if (existing) {
+            existing.push(item.id)
+            continue
+          }
+          byParent.set(parentID, [item.id])
+        }
+
+        const stack = [sessionID]
+        while (stack.length) {
+          const parentID = stack.pop()
+          if (!parentID) continue
+
+          const children = byParent.get(parentID)
+          if (!children) continue
+
+          for (const child of children) {
+            if (removed.has(child)) continue
+            removed.add(child)
+            stack.push(child)
+          }
+        }
+
+        draft.session = draft.session.filter((item) => !removed.has(item.id))
+      }),
+    )
+
+    navigateAfterSessionRemoval(sessionID, session.parentID, nextSession?.id)
+    return true
+  }
+
+  const navigateParent = () => {
+    const id = props.parentID()
+    if (!id) return
+    navigate(`/${params.dir}/session/${id}`)
+  }
+
+  function DialogDeleteSession(input: { sessionID: string }) {
+    const name = createMemo(() => sync.session.get(input.sessionID)?.title ?? language.t("command.session.new"))
+
+    const handleDelete = async () => {
+      await deleteSession(input.sessionID)
+      dialog.close()
+    }
+
+    return (
+      <Dialog title={language.t("session.delete.title")} fit>
+        <div class="flex flex-col gap-4 pl-6 pr-2.5 pb-3">
+          <div class="flex flex-col gap-1">
+            <span class="text-14-regular text-text-strong">
+              {language.t("session.delete.confirm", { name: name() })}
+            </span>
+          </div>
+          <div class="flex justify-end gap-2">
+            <Button variant="ghost" size="large" onClick={() => dialog.close()}>
+              {language.t("common.cancel")}
+            </Button>
+            <Button variant="primary" size="large" onClick={handleDelete}>
+              {language.t("session.delete.button")}
+            </Button>
+          </div>
+        </div>
+      </Dialog>
+    )
+  }
+
+  return (
+    <Show when={props.showHeader()}>
+      <div
+        data-session-title
+        ref={(el) => {
+          headerRef = el
+          el.style.opacity = "0"
+        }}
+        class="pointer-events-none absolute inset-x-0 top-0 z-30"
+      >
+        <div
+          classList={{
+            "bg-[linear-gradient(to_bottom,var(--background-stronger)_38px,transparent)]": true,
+            "w-full": true,
+            "pb-10": true,
+            "px-4 md:px-5": true,
+            "md:max-w-200 md:mx-auto 2xl:max-w-[1000px]": props.centered,
+          }}
+        >
+          <div class="pointer-events-auto h-12 w-full flex items-center justify-between gap-2">
+            <div class="flex items-center gap-1 min-w-0 flex-1">
+              <Show when={props.parentID()}>
+                <div>
+                  <IconButton
+                    tabIndex={-1}
+                    icon="arrow-left"
+                    variant="ghost"
+                    onClick={navigateParent}
+                    aria-label={language.t("common.goBack")}
+                  />
+                </div>
+              </Show>
+              <Show when={!!headerText.value || title.editing}>
+                <Show
+                  when={title.editing}
+                  fallback={
+                    <h1 class="text-14-medium text-text-strong grow-1 min-w-0" onDblClick={openTitleEditor}>
+                      <span class="grid min-w-0" style={{ overflow: "clip" }}>
+                        <span ref={enterRef} class="col-start-1 row-start-1 min-w-0 truncate">
+                          <span classList={{ "opacity-60": headerText.muted }}>{headerText.value}</span>
+                        </span>
+                        <span
+                          ref={leaveRef}
+                          class="col-start-1 row-start-1 min-w-0 truncate pointer-events-none"
+                          style={{ opacity: "0" }}
+                        >
+                          <span classList={{ "opacity-60": headerText.prevMuted }}>{headerText.prev}</span>
+                        </span>
+                      </span>
+                    </h1>
+                  }
+                >
+                  <InlineInput
+                    ref={(el) => {
+                      titleRef = el
+                    }}
+                    value={title.draft}
+                    disabled={title.saving}
+                    class="text-14-medium text-text-strong grow-1 min-w-0 rounded-[6px]"
+                    style={{ "--inline-input-shadow": "var(--shadow-xs-border-select)" }}
+                    onInput={(event) => setTitle("draft", event.currentTarget.value)}
+                    onKeyDown={(event) => {
+                      event.stopPropagation()
+                      if (event.key === "Enter") {
+                        event.preventDefault()
+                        void saveTitleEditor()
+                        return
+                      }
+                      if (event.key === "Escape") {
+                        event.preventDefault()
+                        closeTitleEditor()
+                      }
+                    }}
+                    onBlur={closeTitleEditor}
+                  />
+                </Show>
+              </Show>
+            </div>
+            <Show when={props.sessionID()}>
+              {(id) => (
+                <div class="shrink-0 flex items-center gap-3">
+                  <SessionContextUsage placement="bottom" />
+                  <DropdownMenu
+                    gutter={4}
+                    placement="bottom-end"
+                    open={title.menuOpen}
+                    onOpenChange={(open) => setTitle("menuOpen", open)}
+                  >
+                    <DropdownMenu.Trigger
+                      as={IconButton}
+                      icon="dot-grid"
+                      variant="ghost"
+                      class="size-6 rounded-md data-[expanded]:bg-surface-base-active"
+                      aria-label={language.t("common.moreOptions")}
+                    />
+                    <DropdownMenu.Portal>
+                      <DropdownMenu.Content
+                        style={{ "min-width": "104px" }}
+                        onCloseAutoFocus={(event) => {
+                          if (!title.pendingRename) return
+                          event.preventDefault()
+                          setTitle("pendingRename", false)
+                          openTitleEditor()
+                        }}
+                      >
+                        <DropdownMenu.Item
+                          onSelect={() => {
+                            setTitle("pendingRename", true)
+                            setTitle("menuOpen", false)
+                          }}
+                        >
+                          <DropdownMenu.ItemLabel>{language.t("common.rename")}</DropdownMenu.ItemLabel>
+                        </DropdownMenu.Item>
+                        <DropdownMenu.Item onSelect={() => void archiveSession(id())}>
+                          <DropdownMenu.ItemLabel>{language.t("common.archive")}</DropdownMenu.ItemLabel>
+                        </DropdownMenu.Item>
+                        <DropdownMenu.Separator />
+                        <DropdownMenu.Item onSelect={() => dialog.show(() => <DialogDeleteSession sessionID={id()} />)}>
+                          <DropdownMenu.ItemLabel>{language.t("common.delete")}</DropdownMenu.ItemLabel>
+                        </DropdownMenu.Item>
+                      </DropdownMenu.Content>
+                    </DropdownMenu.Portal>
+                  </DropdownMenu>
+                </div>
+              )}
+            </Show>
+          </div>
+        </div>
+      </div>
+    </Show>
+  )
+}

packages/app/src/pages/session/use-session-hash-scroll.ts

@@ -1,6 +1,5 @@
 import type { UserMessage } from "@opencode-ai/sdk/v2"
-import { useLocation, useNavigate } from "@solidjs/router"
-import { createEffect, createMemo, onMount } from "solid-js"
+import { createEffect, createMemo, onCleanup, onMount } from "solid-js"
 import { messageIdFromHash } from "./message-id-from-hash"
 
 export { messageIdFromHash } from "./message-id-from-hash"
@@ -16,7 +15,7 @@ export const useSessionHashScroll = (input: {
   setPendingMessage: (value: string | undefined) => void
   setActiveMessage: (message: UserMessage | undefined) => void
   setTurnStart: (value: number) => void
-  autoScroll: { pause: () => void; forceScrollToBottom: () => void }
+  autoScroll: { pause: () => void; snapToBottom: () => void }
   scroller: () => HTMLDivElement | undefined
   anchor: (id: string) => string
   scheduleScrollState: (el: HTMLDivElement) => void
@@ -27,18 +26,13 @@ export const useSessionHashScroll = (input: {
   const messageIndex = createMemo(() => new Map(visibleUserMessages().map((m, i) => [m.id, i])))
   let pendingKey = ""
 
-  const location = useLocation()
-  const navigate = useNavigate()
-
   const clearMessageHash = () => {
-    if (!location.hash) return
-    navigate(location.pathname + location.search, { replace: true })
+    if (!window.location.hash) return
+    window.history.replaceState(null, "", window.location.pathname + window.location.search)
   }
 
   const updateHash = (id: string) => {
-    navigate(location.pathname + location.search + `#${input.anchor(id)}`, {
-      replace: true,
-    })
+    window.history.replaceState(null, "", `${window.location.pathname}${window.location.search}#${input.anchor(id)}`)
   }
 
   const scrollToElement = (el: HTMLElement, behavior: ScrollBehavior) => {
@@ -47,15 +41,15 @@ export const useSessionHashScroll = (input: {
 
     const a = el.getBoundingClientRect()
     const b = root.getBoundingClientRect()
-    const sticky = root.querySelector("[data-session-title]")
-    const inset = sticky instanceof HTMLElement ? sticky.offsetHeight : 0
-    const top = Math.max(0, a.top - b.top + root.scrollTop - inset)
+    const title = parseFloat(getComputedStyle(root).getPropertyValue("--session-title-height"))
+    const inset = Number.isNaN(title) ? 0 : title
+    // With column-reverse, scrollTop is negative — don't clamp to 0
+    const top = a.top - b.top + root.scrollTop - inset
     root.scrollTo({ top, behavior })
     return true
   }
 
   const scrollToMessage = (message: UserMessage, behavior: ScrollBehavior = "smooth") => {
-    console.log({ message, behavior })
     if (input.currentMessageId() !== message.id) input.setActiveMessage(message)
 
     const index = messageIndex().get(message.id) ?? -1
@@ -103,9 +97,9 @@ export const useSessionHashScroll = (input: {
   }
 
   const applyHash = (behavior: ScrollBehavior) => {
-    const hash = location.hash.slice(1)
+    const hash = window.location.hash.slice(1)
     if (!hash) {
-      input.autoScroll.forceScrollToBottom()
+      input.autoScroll.snapToBottom()
       const el = input.scroller()
       if (el) input.scheduleScrollState(el)
       return
@@ -129,13 +123,26 @@ export const useSessionHashScroll = (input: {
       return
     }
 
-    input.autoScroll.forceScrollToBottom()
+    input.autoScroll.snapToBottom()
     const el = input.scroller()
     if (el) input.scheduleScrollState(el)
   }
 
+  onMount(() => {
+    if (typeof window !== "undefined" && "scrollRestoration" in window.history) {
+      window.history.scrollRestoration = "manual"
+    }
+
+    const handler = () => {
+      if (!input.sessionID() || !input.messagesReady()) return
+      requestAnimationFrame(() => applyHash("auto"))
+    }
+
+    window.addEventListener("hashchange", handler)
+    onCleanup(() => window.removeEventListener("hashchange", handler))
+  })
+
   createEffect(() => {
-    location.hash
     if (!input.sessionID() || !input.messagesReady()) return
     requestAnimationFrame(() => applyHash("auto"))
   })
@@ -159,7 +166,6 @@ export const useSessionHashScroll = (input: {
       }
     }
 
-    if (!targetId) targetId = messageIdFromHash(location.hash)
     if (!targetId) return
     if (input.currentMessageId() === targetId) return
 
@@ -171,12 +177,6 @@ export const useSessionHashScroll = (input: {
     requestAnimationFrame(() => scrollToMessage(msg, "auto"))
   })
 
-  onMount(() => {
-    if (typeof window !== "undefined" && "scrollRestoration" in window.history) {
-      window.history.scrollRestoration = "manual"
-    }
-  })
-
   return {
     clearMessageHash,
     scrollToMessage,

packages/ui/src/components/animated-number.css

@@ -9,19 +9,20 @@
     display: inline-flex;
     flex-direction: row-reverse;
     align-items: baseline;
-    justify-content: flex-end;
+    justify-content: flex-start;
     line-height: inherit;
     width: var(--animated-number-width, 1ch);
-    overflow: hidden;
-    transition: width var(--tool-motion-spring-ms, 560ms) var(--tool-motion-ease, cubic-bezier(0.22, 1, 0.36, 1));
+    overflow: clip;
+    transition: width var(--tool-motion-spring-ms, 800ms) var(--tool-motion-ease, cubic-bezier(0.22, 1, 0.36, 1));
   }
 
   [data-slot="animated-number-digit"] {
     display: inline-block;
+    flex-shrink: 0;
     width: 1ch;
     height: 1em;
     line-height: 1em;
-    overflow: hidden;
+    overflow: clip;
     vertical-align: baseline;
     -webkit-mask-image: linear-gradient(
       to bottom,
@@ -46,7 +47,7 @@
     flex-direction: column;
     transform: translateY(calc(var(--animated-number-offset, 10) * -1em));
     transition-property: transform;
-    transition-duration: var(--animated-number-duration, 560ms);
+    transition-duration: var(--animated-number-duration, 600ms);
     transition-timing-function: var(--tool-motion-ease, cubic-bezier(0.22, 1, 0.36, 1));
   }
 

packages/ui/src/components/animated-number.tsx

@@ -1,7 +1,7 @@
 import { For, Index, createEffect, createMemo, createSignal, on } from "solid-js"
 
 const TRACK = Array.from({ length: 30 }, (_, index) => index % 10)
-const DURATION = 600
+const DURATION = 800
 
 function normalize(value: number) {
   return ((value % 10) + 10) % 10
@@ -90,10 +90,35 @@ export function AnimatedNumber(props: { value: number; class?: string }) {
   )
   const width = createMemo(() => `${digits().length}ch`)
 
+  const [exitingDigits, setExitingDigits] = createSignal<number[]>([])
+  let exitTimer: number | undefined
+
+  createEffect(
+    on(
+      digits,
+      (current, prev) => {
+        if (prev && current.length < prev.length) {
+          setExitingDigits(prev.slice(current.length))
+          clearTimeout(exitTimer)
+          exitTimer = window.setTimeout(() => setExitingDigits([]), DURATION)
+        } else {
+          clearTimeout(exitTimer)
+          setExitingDigits([])
+        }
+      },
+      { defer: true },
+    ),
+  )
+
+  const displayDigits = createMemo(() => {
+    const exiting = exitingDigits()
+    return exiting.length ? [...digits(), ...exiting] : digits()
+  })
+
   return (
     <span data-component="animated-number" class={props.class} aria-label={label()}>
       <span data-slot="animated-number-value" style={{ "--animated-number-width": width() }}>
-        <Index each={digits()}>{(digit) => <Digit value={digit()} direction={direction()} />}</Index>
+        <Index each={displayDigits()}>{(digit) => <Digit value={digit()} direction={direction()} />}</Index>
       </span>
     </span>
   )

packages/ui/src/components/basic-tool.css

@@ -8,54 +8,28 @@
   justify-content: flex-start;
 
   [data-slot="basic-tool-tool-trigger-content"] {
-    width: auto;
+    width: 100%;
+    min-width: 0;
     display: flex;
     align-items: center;
     align-self: stretch;
     gap: 8px;
   }
 
-  [data-slot="basic-tool-tool-indicator"] {
-    width: 16px;
-    height: 16px;
-    display: inline-flex;
-    align-items: center;
-    justify-content: center;
-    flex-shrink: 0;
-
-    [data-component="spinner"] {
-      width: 16px;
-      height: 16px;
-    }
-  }
-
-  [data-slot="basic-tool-tool-spinner"] {
-    width: 16px;
-    height: 16px;
-    display: inline-flex;
-    align-items: center;
-    justify-content: center;
-    flex-shrink: 0;
-    color: var(--text-weak);
-
-    [data-component="spinner"] {
-      width: 16px;
-      height: 16px;
-    }
-  }
-
   [data-slot="icon-svg"] {
     flex-shrink: 0;
   }
 
   [data-slot="basic-tool-tool-info"] {
-    flex: 0 1 auto;
+    flex: 1 1 auto;
     min-width: 0;
     font-size: 14px;
   }
 
   [data-slot="basic-tool-tool-info-structured"] {
     width: auto;
+    max-width: 100%;
+    min-width: 0;
     display: flex;
     align-items: center;
     gap: 8px;
@@ -63,11 +37,12 @@
   }
 
   [data-slot="basic-tool-tool-info-main"] {
+    flex: 0 1 auto;
     display: flex;
-    align-items: baseline;
+    align-items: center;
     gap: 8px;
     min-width: 0;
-    overflow: hidden;
+    overflow: clip;
   }
 
   [data-slot="basic-tool-tool-title"] {
@@ -80,21 +55,14 @@
     letter-spacing: var(--letter-spacing-normal);
     color: var(--text-strong);
 
-    &.capitalize {
-      text-transform: capitalize;
-    }
-
-    &.agent-title {
-      color: var(--text-strong);
-      font-weight: var(--font-weight-medium);
-    }
   }
 
   [data-slot="basic-tool-tool-subtitle"] {
-    flex-shrink: 1;
+    display: inline-block;
+    flex: 0 1 auto;
+    max-width: 100%;
     min-width: 0;
-    overflow: hidden;
-    text-overflow: ellipsis;
+    overflow: clip;
     white-space: nowrap;
     font-family: var(--font-family-sans);
     font-size: 14px;
@@ -138,8 +106,7 @@
   [data-slot="basic-tool-tool-arg"] {
     flex-shrink: 1;
     min-width: 0;
-    overflow: hidden;
-    text-overflow: ellipsis;
+    overflow: clip;
     white-space: nowrap;
     font-family: var(--font-family-sans);
     font-size: 14px;

packages/ui/src/components/basic-tool.tsx

@@ -1,8 +1,20 @@
-import { createEffect, createSignal, For, Match, on, onCleanup, Show, Switch, type JSX } from "solid-js"
-import { animate, type AnimationPlaybackControls } from "motion"
+import {
+  createEffect,
+  createSignal,
+  For,
+  Match,
+  on,
+  onCleanup,
+  onMount,
+  Show,
+  splitProps,
+  Switch,
+  type JSX,
+} from "solid-js"
+import { animate, type AnimationPlaybackControls, tunableSpringValue, COLLAPSIBLE_SPRING } from "./motion"
 import { Collapsible } from "./collapsible"
-import type { IconProps } from "./icon"
 import { TextShimmer } from "./text-shimmer"
+import { hold } from "./tool-utils"
 
 export type TriggerTitle = {
   title: string
@@ -20,26 +32,99 @@ const isTriggerTitle = (val: any): val is TriggerTitle => {
   )
 }
 
-export interface BasicToolProps {
-  icon: IconProps["name"]
+interface ToolCallPanelBaseProps {
+  icon: string
   trigger: TriggerTitle | JSX.Element
   children?: JSX.Element
   status?: string
+  animate?: boolean
   hideDetails?: boolean
   defaultOpen?: boolean
   forceOpen?: boolean
   defer?: boolean
   locked?: boolean
-  animated?: boolean
+  watchDetails?: boolean
+  springContent?: boolean
   onSubtitleClick?: () => void
 }
 
-const SPRING = { type: "spring" as const, visualDuration: 0.35, bounce: 0 }
+function ToolCallTriggerBody(props: {
+  trigger: TriggerTitle | JSX.Element
+  pending: boolean
+  onSubtitleClick?: () => void
+  arrow?: boolean
+}) {
+  return (
+    <div data-component="tool-trigger" data-arrow={props.arrow ? "" : undefined}>
+      <div data-slot="basic-tool-tool-trigger-content">
+        <div data-slot="basic-tool-tool-info">
+          <Switch>
+            <Match when={isTriggerTitle(props.trigger) && props.trigger}>
+              {(trigger) => (
+                <div data-slot="basic-tool-tool-info-structured">
+                  <div data-slot="basic-tool-tool-info-main">
+                    <span
+                      data-slot="basic-tool-tool-title"
+                      classList={{
+                        [trigger().titleClass ?? ""]: !!trigger().titleClass,
+                      }}
+                    >
+                      <TextShimmer text={trigger().title} active={props.pending} />
+                    </span>
+                    <Show when={!props.pending}>
+                      <Show when={trigger().subtitle}>
+                        <span
+                          data-slot="basic-tool-tool-subtitle"
+                          classList={{
+                            [trigger().subtitleClass ?? ""]: !!trigger().subtitleClass,
+                            clickable: !!props.onSubtitleClick,
+                          }}
+                          onClick={(e) => {
+                            if (!props.onSubtitleClick) return
+                            e.stopPropagation()
+                            props.onSubtitleClick()
+                          }}
+                        >
+                          {trigger().subtitle}
+                        </span>
+                      </Show>
+                      <Show when={trigger().args?.length}>
+                        <For each={trigger().args}>
+                          {(arg) => (
+                            <span
+                              data-slot="basic-tool-tool-arg"
+                              classList={{
+                                [trigger().argsClass ?? ""]: !!trigger().argsClass,
+                              }}
+                            >
+                              {arg}
+                            </span>
+                          )}
+                        </For>
+                      </Show>
+                    </Show>
+                  </div>
+                  <Show when={!props.pending && trigger().action}>{trigger().action}</Show>
+                </div>
+              )}
+            </Match>
+            <Match when={true}>{props.trigger as JSX.Element}</Match>
+          </Switch>
+        </div>
+      </div>
+      <Show when={props.arrow}>
+        <Collapsible.Arrow />
+      </Show>
+    </div>
+  )
+}
 
-export function BasicTool(props: BasicToolProps) {
+function ToolCallPanel(props: ToolCallPanelBaseProps) {
   const [open, setOpen] = createSignal(props.defaultOpen ?? false)
   const [ready, setReady] = createSignal(open())
-  const pending = () => props.status === "pending" || props.status === "running"
+  const pendingRaw = () => props.status === "pending" || props.status === "running"
+  const pending = hold(pendingRaw, 1000)
+  const watchDetails = () => props.watchDetails !== false
 
   let frame: number | undefined
 
@@ -59,7 +144,7 @@ export function BasicTool(props: BasicToolProps) {
     on(
       open,
       (value) => {
-        if (!props.defer) return
+        if (!props.defer || props.springContent) return
         if (!value) {
           cancel()
           setReady(false)
@@ -77,36 +162,110 @@ export function BasicTool(props: BasicToolProps) {
     ),
   )
 
-  // Animated height for collapsible open/close
+  // Animated content height — single springValue drives all height changes
   let contentRef: HTMLDivElement | undefined
-  let heightAnim: AnimationPlaybackControls | undefined
+  let bodyRef: HTMLDivElement | undefined
+  let fadeAnim: AnimationPlaybackControls | undefined
+  let observer: ResizeObserver | undefined
+  let resizeFrame: number | undefined
   const initialOpen = open()
+  const heightSpring = tunableSpringValue<number>(0, COLLAPSIBLE_SPRING)
+
+  const read = () => Math.max(0, Math.ceil(bodyRef?.getBoundingClientRect().height ?? 0))
+
+  const doOpen = () => {
+    if (!contentRef || !bodyRef) return
+    contentRef.style.display = ""
+    // Ensure fade starts from 0 if content was hidden (first open or after close cleared styles)
+    if (bodyRef.style.opacity === "") {
+      bodyRef.style.opacity = "0"
+      bodyRef.style.filter = "blur(2px)"
+    }
+    const next = read()
+    fadeAnim?.stop()
+    fadeAnim = animate(bodyRef, { opacity: 1, filter: "blur(0px)" }, COLLAPSIBLE_SPRING)
+    fadeAnim.finished.then(() => {
+      if (!bodyRef) return
+      bodyRef.style.opacity = ""
+      bodyRef.style.filter = ""
+    })
+    heightSpring.set(next)
+  }
+
+  const doClose = () => {
+    if (!contentRef || !bodyRef) return
+    fadeAnim?.stop()
+    fadeAnim = animate(bodyRef, { opacity: 0, filter: "blur(2px)" }, COLLAPSIBLE_SPRING)
+    fadeAnim.finished.then(() => {
+      if (!contentRef || open()) return
+      contentRef.style.display = "none"
+    })
+    heightSpring.set(0)
+  }
+
+  const grow = () => {
+    if (!contentRef || !open()) return
+    const next = read()
+    if (Math.abs(next - heightSpring.get()) < 1) return
+    heightSpring.set(next)
+  }
+
+  onMount(() => {
+    if (!props.springContent || props.animate === false || !contentRef || !bodyRef) return
+
+    const offChange = heightSpring.on("change", (v) => {
+      if (!contentRef) return
+      contentRef.style.height = `${Math.max(0, Math.ceil(v))}px`
+    })
+    onCleanup(() => {
+      offChange()
+    })
+
+    if (watchDetails()) {
+      observer = new ResizeObserver(() => {
+        if (resizeFrame !== undefined) return
+        resizeFrame = requestAnimationFrame(() => {
+          resizeFrame = undefined
+          grow()
+        })
+      })
+      observer.observe(bodyRef)
+    }
+
+    if (!open()) return
+    if (contentRef.style.display !== "none") {
+      const next = read()
+      heightSpring.jump(next)
+      contentRef.style.height = `${next}px`
+      return
+    }
+    let mountFrame: number | undefined = requestAnimationFrame(() => {
+      mountFrame = undefined
+      if (!open()) return
+      doOpen()
+    })
+    onCleanup(() => {
+      if (mountFrame !== undefined) cancelAnimationFrame(mountFrame)
+    })
+  })
 
   createEffect(
     on(
       open,
       (isOpen) => {
-        if (!props.animated || !contentRef) return
-        heightAnim?.stop()
-        if (isOpen) {
-          contentRef.style.overflow = "hidden"
-          heightAnim = animate(contentRef, { height: "auto" }, SPRING)
-          heightAnim.finished.then(() => {
-            if (!contentRef || !open()) return
-            contentRef.style.overflow = "visible"
-            contentRef.style.height = "auto"
-          })
-        } else {
-          contentRef.style.overflow = "hidden"
-          heightAnim = animate(contentRef, { height: "0px" }, SPRING)
-        }
+        if (!props.springContent || props.animate === false || !contentRef) return
+        if (isOpen) doOpen()
+        else doClose()
       },
       { defer: true },
     ),
   )
 
   onCleanup(() => {
-    heightAnim?.stop()
+    if (resizeFrame !== undefined) cancelAnimationFrame(resizeFrame)
+    observer?.disconnect()
+    fadeAnim?.stop()
+    heightSpring.destroy()
   })
 
   const handleOpenChange = (value: boolean) => {
@@ -118,85 +277,34 @@ export function BasicTool(props: BasicToolProps) {
   return (
     <Collapsible open={open()} onOpenChange={handleOpenChange} class="tool-collapsible">
       <Collapsible.Trigger>
-        <div data-component="tool-trigger">
-          <div data-slot="basic-tool-tool-trigger-content">
-            <div data-slot="basic-tool-tool-info">
-              <Switch>
-                <Match when={isTriggerTitle(props.trigger) && props.trigger}>
-                  {(trigger) => (
-                    <div data-slot="basic-tool-tool-info-structured">
-                      <div data-slot="basic-tool-tool-info-main">
-                        <span
-                          data-slot="basic-tool-tool-title"
-                          classList={{
-                            [trigger().titleClass ?? ""]: !!trigger().titleClass,
-                          }}
-                        >
-                          <TextShimmer text={trigger().title} active={pending()} />
-                        </span>
-                        <Show when={!pending()}>
-                          <Show when={trigger().subtitle}>
-                            <span
-                              data-slot="basic-tool-tool-subtitle"
-                              classList={{
-                                [trigger().subtitleClass ?? ""]: !!trigger().subtitleClass,
-                                clickable: !!props.onSubtitleClick,
-                              }}
-                              onClick={(e) => {
-                                if (props.onSubtitleClick) {
-                                  e.stopPropagation()
-                                  props.onSubtitleClick()
-                                }
-                              }}
-                            >
-                              {trigger().subtitle}
-                            </span>
-                          </Show>
-                          <Show when={trigger().args?.length}>
-                            <For each={trigger().args}>
-                              {(arg) => (
-                                <span
-                                  data-slot="basic-tool-tool-arg"
-                                  classList={{
-                                    [trigger().argsClass ?? ""]: !!trigger().argsClass,
-                                  }}
-                                >
-                                  {arg}
-                                </span>
-                              )}
-                            </For>
-                          </Show>
-                        </Show>
-                      </div>
-                      <Show when={!pending() && trigger().action}>{trigger().action}</Show>
-                    </div>
-                  )}
-                </Match>
-                <Match when={true}>{props.trigger as JSX.Element}</Match>
-              </Switch>
-            </div>
-          </div>
-          <Show when={props.children && !props.hideDetails && !props.locked && !pending()}>
-            <Collapsible.Arrow />
-          </Show>
-        </div>
+        <ToolCallTriggerBody
+          trigger={props.trigger}
+          pending={pending()}
+          onSubtitleClick={props.onSubtitleClick}
+          arrow={!!props.children && !props.hideDetails && !props.locked && !pending()}
+        />
       </Collapsible.Trigger>
-      <Show when={props.animated && props.children && !props.hideDetails}>
+      <Show when={props.springContent && props.animate !== false && props.children && !props.hideDetails}>
         <div
           ref={contentRef}
           data-slot="collapsible-content"
-          data-animated
+          data-spring-content
           style={{
             height: initialOpen ? "auto" : "0px",
-            overflow: initialOpen ? "visible" : "hidden",
+            overflow: "hidden",
+            display: initialOpen ? undefined : "none",
           }}
         >
-          {props.children}
+          <div ref={bodyRef} data-slot="basic-tool-content-inner">
+            {props.children}
+          </div>
         </div>
       </Show>
-      <Show when={!props.animated && props.children && !props.hideDetails}>
+      <Show when={(!props.springContent || props.animate === false) && props.children && !props.hideDetails}>
         <Collapsible.Content>
-          <Show when={!props.defer || ready()}>{props.children}</Show>
+          <Show when={!props.defer || ready()}>
+            <div data-slot="basic-tool-content-inner">{props.children}</div>
+          </Show>
         </Collapsible.Content>
       </Show>
     </Collapsible>
@@ -222,6 +330,60 @@ function args(input: Record<string, unknown> | undefined) {
     .slice(0, 3)
 }
 
+export interface ToolCallRowProps {
+  variant: "row"
+  icon: string
+  trigger: TriggerTitle | JSX.Element
+  status?: string
+  animate?: boolean
+  onSubtitleClick?: () => void
+  open?: boolean
+  showArrow?: boolean
+  onOpenChange?: (value: boolean) => void
+}
+export interface ToolCallPanelProps extends Omit<ToolCallPanelBaseProps, "hideDetails"> {
+  variant: "panel"
+}
+export type ToolCallProps = ToolCallRowProps | ToolCallPanelProps
+function ToolCallRoot(props: ToolCallProps) {
+  const pending = () => props.status === "pending" || props.status === "running"
+  if (props.variant === "row") {
+    return (
+      <Show
+        when={props.onOpenChange}
+        fallback={
+          <div data-component="collapsible" data-variant="normal" class="tool-collapsible">
+            <div data-slot="collapsible-trigger">
+              <ToolCallTriggerBody
+                trigger={props.trigger}
+                pending={pending()}
+                onSubtitleClick={props.onSubtitleClick}
+              />
+            </div>
+          </div>
+        }
+      >
+        {(onOpenChange) => (
+          <Collapsible open={props.open ?? true} onOpenChange={onOpenChange()} class="tool-collapsible">
+            <Collapsible.Trigger>
+              <ToolCallTriggerBody
+                trigger={props.trigger}
+                pending={pending()}
+                onSubtitleClick={props.onSubtitleClick}
+                arrow={!!props.showArrow}
+              />
+            </Collapsible.Trigger>
+          </Collapsible>
+        )}
+      </Show>
+    )
+  }
+
+  const [, rest] = splitProps(props, ["variant"])
+  return <ToolCallPanel {...rest} />
+}
+export const ToolCall = ToolCallRoot
+
 export function GenericTool(props: {
   tool: string
   status?: string
@@ -229,7 +391,8 @@ export function GenericTool(props: {
   input?: Record<string, unknown>
 }) {
   return (
-    <BasicTool
+    <ToolCall
+      variant={props.hideDetails ? "row" : "panel"}
       icon="mcp"
       status={props.status}
       trigger={{
@@ -237,7 +400,6 @@ export function GenericTool(props: {
         subtitle: label(props.input),
         args: args(props.input),
       }}
-      hideDetails={props.hideDetails}
     />
   )
 }

packages/ui/src/components/collapsible.css

@@ -8,14 +8,18 @@
   border-radius: var(--radius-md);
   overflow: visible;
 
-  &.tool-collapsible {
-    gap: 8px;
+  &.tool-collapsible [data-slot="collapsible-trigger"] {
+    height: 37px;
+  }
+
+  &.tool-collapsible [data-slot="basic-tool-content-inner"] {
+    padding-top: 0;
   }
 
   [data-slot="collapsible-trigger"] {
     width: 100%;
     display: flex;
-    height: 32px;
+    height: 36px;
     padding: 0;
     align-items: center;
     align-self: stretch;
@@ -23,6 +27,17 @@
     user-select: none;
     color: var(--text-base);
 
+    > [data-component="tool-trigger"][data-arrow] {
+      width: auto;
+      max-width: 100%;
+      flex: 0 1 auto;
+
+      [data-slot="basic-tool-tool-trigger-content"] {
+        width: auto;
+        max-width: 100%;
+      }
+    }
+
     [data-slot="collapsible-arrow"] {
       opacity: 0;
       transition: opacity 0.15s ease;
@@ -50,9 +65,6 @@
     line-height: var(--line-height-large); /* 166.667% */
     letter-spacing: var(--letter-spacing-normal);
 
-    /* &:hover { */
-    /*   background-color: var(--surface-base); */
-    /* } */
     &:focus-visible {
       outline: none;
       background-color: var(--surface-raised-base-hover);
@@ -82,16 +94,16 @@
   }
 
   [data-slot="collapsible-content"] {
-    overflow: hidden;
-    /* animation: slideUp 250ms ease-out; */
+    overflow: clip;
 
     &[data-expanded] {
       overflow: visible;
     }
 
-    /* &[data-expanded] { */
-    /*   animation: slideDown 250ms ease-out; */
-    /* } */
+    /* JS-animated content: overflow managed by animate() */
+    &[data-spring-content] {
+      overflow: clip;
+    }
   }
 
   &[data-variant="ghost"] {
@@ -103,9 +115,6 @@
       border: none;
       padding: 0;
 
-      /* &:hover { */
-      /*   color: var(--text-strong); */
-      /* } */
       &:focus-visible {
         outline: none;
         background-color: var(--surface-raised-base-hover);
@@ -122,21 +131,3 @@
     }
   }
 }
-
-@keyframes slideDown {
-  from {
-    height: 0;
-  }
-  to {
-    height: var(--kb-collapsible-content-height);
-  }
-}
-
-@keyframes slideUp {
-  from {
-    height: var(--kb-collapsible-content-height);
-  }
-  to {
-    height: 0;
-  }
-}

packages/ui/src/components/context-tool-results.tsx

@@ -0,0 +1,199 @@
+import { createMemo, createSignal, For, onMount } from "solid-js"
+import type { ToolPart } from "@opencode-ai/sdk/v2"
+import { getFilename } from "@opencode-ai/util/path"
+import { useI18n } from "../context/i18n"
+import { prefersReducedMotion } from "../hooks/use-reduced-motion"
+import { ToolCall } from "./basic-tool"
+import { ToolStatusTitle } from "./tool-status-title"
+import { AnimatedCountList } from "./tool-count-summary"
+import { RollingResults } from "./rolling-results"
+import { GROW_SPRING } from "./motion"
+import { useSpring } from "./motion-spring"
+import { busy, updateScrollMask, useCollapsible, useRowWipe } from "./tool-utils"
+
+function contextToolLabel(part: ToolPart): { action: string; detail: string } {
+  const state = part.state
+  const title = "title" in state ? (state.title as string | undefined) : undefined
+  const input = state.input
+  if (part.tool === "read") {
+    const path = input?.filePath as string | undefined
+    return { action: "Read", detail: title || (path ? getFilename(path) : "") }
+  }
+  if (part.tool === "grep") {
+    const pattern = input?.pattern as string | undefined
+    return { action: "Search", detail: title || (pattern ? `"${pattern}"` : "") }
+  }
+  if (part.tool === "glob") {
+    const pattern = input?.pattern as string | undefined
+    return { action: "Find", detail: title || (pattern ?? "") }
+  }
+  if (part.tool === "list") {
+    const path = input?.path as string | undefined
+    return { action: "List", detail: title || (path ? getFilename(path) : "") }
+  }
+  return { action: part.tool, detail: title || "" }
+}
+
+function contextToolSummary(parts: ToolPart[]) {
+  let read = 0
+  let search = 0
+  let list = 0
+  for (const part of parts) {
+    if (part.tool === "read") read++
+    else if (part.tool === "glob" || part.tool === "grep") search++
+    else if (part.tool === "list") list++
+  }
+  return { read, search, list }
+}
+
+export function ContextToolGroupHeader(props: {
+  parts: ToolPart[]
+  pending: boolean
+  open: boolean
+  onOpenChange: (value: boolean) => void
+}) {
+  const i18n = useI18n()
+  const summary = createMemo(() => contextToolSummary(props.parts))
+  return (
+    <ToolCall
+      variant="row"
+      icon="magnifying-glass-menu"
+      open={!props.pending && props.open}
+      showArrow={!props.pending}
+      onOpenChange={(v) => {
+        if (!props.pending) props.onOpenChange(v)
+      }}
+      trigger={
+        <div data-component="context-tool-group-trigger" data-pending={props.pending || undefined}>
+          <span
+            data-slot="context-tool-group-title"
+            class="min-w-0 flex items-center gap-2 text-14-medium text-text-strong"
+          >
+            <span data-slot="context-tool-group-label" class="shrink-0">
+              <ToolStatusTitle
+                active={props.pending}
+                activeText={i18n.t("ui.sessionTurn.status.gatheringContext")}
+                doneText={i18n.t("ui.sessionTurn.status.gatheredContext")}
+                split={false}
+              />
+            </span>
+            <span
+              data-slot="context-tool-group-summary"
+              class="min-w-0 overflow-hidden text-ellipsis whitespace-nowrap font-normal text-text-base"
+            >
+              <AnimatedCountList
+                items={[
+                  {
+                    key: "read",
+                    count: summary().read,
+                    one: i18n.t("ui.messagePart.context.read.one"),
+                    other: i18n.t("ui.messagePart.context.read.other"),
+                  },
+                  {
+                    key: "search",
+                    count: summary().search,
+                    one: i18n.t("ui.messagePart.context.search.one"),
+                    other: i18n.t("ui.messagePart.context.search.other"),
+                  },
+                  {
+                    key: "list",
+                    count: summary().list,
+                    one: i18n.t("ui.messagePart.context.list.one"),
+                    other: i18n.t("ui.messagePart.context.list.other"),
+                  },
+                ]}
+                fallback=""
+              />
+            </span>
+          </span>
+        </div>
+      }
+    />
+  )
+}
+
+export function ContextToolExpandedList(props: { parts: ToolPart[]; expanded: boolean }) {
+  let contentRef: HTMLDivElement | undefined
+  let bodyRef: HTMLDivElement | undefined
+  let scrollRef: HTMLDivElement | undefined
+  const updateMask = () => {
+    if (scrollRef) updateScrollMask(scrollRef)
+  }
+
+  useCollapsible({
+    content: () => contentRef,
+    body: () => bodyRef,
+    open: () => props.expanded,
+    onOpen: updateMask,
+  })
+
+  return (
+    <div ref={contentRef} style={{ overflow: "clip", height: "0px", display: "none" }}>
+      <div ref={bodyRef}>
+        <div ref={scrollRef} data-component="context-tool-expanded-list" onScroll={updateMask}>
+          <For each={props.parts}>
+            {(part) => {
+              const label = createMemo(() => contextToolLabel(part))
+              return (
+                <div data-component="context-tool-expanded-row">
+                  <span data-slot="context-tool-expanded-action">{label().action}</span>
+                  <span data-slot="context-tool-expanded-detail">{label().detail}</span>
+                </div>
+              )
+            }}
+          </For>
+        </div>
+      </div>
+    </div>
+  )
+}
+
+export function ContextToolRollingResults(props: { parts: ToolPart[]; pending: boolean }) {
+  const wiped = new Set<string>()
+  const [mounted, setMounted] = createSignal(false)
+  onMount(() => setMounted(true))
+  const reduce = prefersReducedMotion
+  const show = () => mounted() && props.pending
+  const opacity = useSpring(() => (show() ? 1 : 0), GROW_SPRING)
+  const blur = useSpring(() => (show() ? 0 : 2), GROW_SPRING)
+  return (
+    <div style={{ opacity: reduce() ? (show() ? 1 : 0) : opacity(), filter: `blur(${reduce() ? 0 : blur()}px)` }}>
+      <RollingResults
+        items={props.parts}
+        rows={5}
+        rowHeight={22}
+        rowGap={0}
+        open={props.pending}
+        animate
+        getKey={(part) => part.callID || part.id}
+        render={(part) => {
+          const label = createMemo(() => contextToolLabel(part))
+          const k = part.callID || part.id
+          return (
+            <div data-component="context-tool-rolling-row">
+              <span data-slot="context-tool-rolling-action">{label().action}</span>
+              {(() => {
+                const [detailRef, setDetailRef] = createSignal<HTMLSpanElement>()
+                useRowWipe({
+                  id: () => k,
+                  text: () => label().detail,
+                  ref: detailRef,
+                  seen: wiped,
+                })
+                return (
+                  <span
+                    ref={setDetailRef}
+                    data-slot="context-tool-rolling-detail"
+                    style={{ display: label().detail ? undefined : "none" }}
+                  >
+                    {label().detail}
+                  </span>
+                )
+              })()}
+            </div>
+          )
+        }}
+      />
+    </div>
+  )
+}

packages/ui/src/components/grow-box.tsx

@@ -0,0 +1,426 @@
+import { createEffect, on, type JSX, onMount, onCleanup } from "solid-js"
+import { animate, tunableSpringValue, type AnimationPlaybackControls, GROW_SPRING, type SpringConfig } from "./motion"
+import { prefersReducedMotion } from "../hooks/use-reduced-motion"
+
+export interface GrowBoxProps {
+  children: JSX.Element
+  /** Enable animation. When false, content shows immediately at full height. */
+  animate?: boolean
+  /** Animate height from 0 to content height. Default: true. */
+  grow?: boolean
+  /** Keep watching body size and animate subsequent height changes. Default: false. */
+  watch?: boolean
+  /** Fade in body content (opacity + blur). Default: true. */
+  fade?: boolean
+  /** Top padding in px on the body wrapper. Default: 0. */
+  gap?: number
+  /** Reset to height:auto after grow completes, or stay at fixed px. Default: true. */
+  autoHeight?: boolean
+  /** Controlled visibility for animating open/close without unmounting children. */
+  open?: boolean
+  /** Animate controlled open/close changes after mount. Default: true. */
+  animateToggle?: boolean
+  /** data-slot attribute on the root div. */
+  slot?: string
+  /** CSS class on the root div. */
+  class?: string
+  /** Override mount and resize spring config. Default: GROW_SPRING. */
+  spring?: SpringConfig
+  /** Override controlled open/close spring config. Default: spring. */
+  toggleSpring?: SpringConfig
+  /** Show a temporary bottom edge fade while height animation is running. */
+  edge?: boolean
+  /** Edge fade height in px. Default: 20. */
+  edgeHeight?: number
+  /** Edge fade opacity (0-1). Default: 1. */
+  edgeOpacity?: number
+  /** Delay before edge fades out after height settles. Default: 320. */
+  edgeIdle?: number
+  /** Edge fade-out duration in seconds. Default: 0.24. */
+  edgeFade?: number
+  /** Edge fade-in duration in seconds. Default: 0.2. */
+  edgeRise?: number
+}
+
+/**
+ * Wraps children in a container that animates from zero height on mount.
+ *
+ * Includes a ResizeObserver so content changes after mount are also spring-animated.
+ * Used for timeline turns, assistant part groups, and user messages.
+ */
+export function GrowBox(props: GrowBoxProps) {
+  const reduce = prefersReducedMotion
+  const spring = () => props.spring ?? GROW_SPRING
+  const toggleSpring = () => props.toggleSpring ?? spring()
+  let mode: "mount" | "toggle" = "mount"
+  let root: HTMLDivElement | undefined
+  let body: HTMLDivElement | undefined
+  let fadeAnim: AnimationPlaybackControls | undefined
+  let edgeRef: HTMLDivElement | undefined
+  let edgeAnim: AnimationPlaybackControls | undefined
+  let edgeTimer: ReturnType<typeof setTimeout> | undefined
+  let edgeOn = false
+  let mountFrame: number | undefined
+  let resizeFrame: number | undefined
+  let observer: ResizeObserver | undefined
+  let springTarget = -1
+  const height = tunableSpringValue<number>(0, {
+    type: "spring",
+    get visualDuration() {
+      return (mode === "toggle" ? toggleSpring() : spring()).visualDuration
+    },
+    get bounce() {
+      return (mode === "toggle" ? toggleSpring() : spring()).bounce
+    },
+  })
+
+  const gap = () => Math.max(0, props.gap ?? 0)
+  const grow = () => props.grow !== false
+  const watch = () => props.watch === true
+  const open = () => props.open !== false
+  const animateToggle = () => props.animateToggle !== false
+  const edge = () => props.edge === true
+  const edgeHeight = () => Math.max(0, props.edgeHeight ?? 20)
+  const edgeOpacity = () => Math.min(1, Math.max(0, props.edgeOpacity ?? 1))
+  const edgeIdle = () => Math.max(0, props.edgeIdle ?? 320)
+  const edgeFade = () => Math.max(0.05, props.edgeFade ?? 0.24)
+  const edgeRise = () => Math.max(0.05, props.edgeRise ?? 0.2)
+  const animated = () => props.animate !== false && !reduce()
+  const edgeReady = () => animated() && open() && edge() && edgeHeight() > 0
+
+  const stopEdgeTimer = () => {
+    if (edgeTimer === undefined) return
+    clearTimeout(edgeTimer)
+    edgeTimer = undefined
+  }
+
+  const hideEdge = (instant = false) => {
+    stopEdgeTimer()
+    if (!edgeRef) {
+      edgeOn = false
+      return
+    }
+    edgeAnim?.stop()
+    edgeAnim = undefined
+    if (instant || reduce()) {
+      edgeRef.style.opacity = "0"
+      edgeOn = false
+      return
+    }
+    if (!edgeOn) {
+      edgeRef.style.opacity = "0"
+      return
+    }
+    const current = animate(edgeRef, { opacity: 0 }, { type: "spring", visualDuration: edgeFade(), bounce: 0 })
+    edgeAnim = current
+    current.finished
+      .catch(() => {})
+      .finally(() => {
+        if (edgeAnim !== current) return
+        edgeAnim = undefined
+        if (!edgeRef) return
+        edgeRef.style.opacity = "0"
+        edgeOn = false
+      })
+  }
+
+  const showEdge = () => {
+    stopEdgeTimer()
+    if (!edgeRef) return
+    if (reduce()) {
+      edgeRef.style.opacity = `${edgeOpacity()}`
+      edgeOn = true
+      return
+    }
+    if (edgeOn && edgeAnim === undefined) {
+      edgeRef.style.opacity = `${edgeOpacity()}`
+      return
+    }
+    edgeAnim?.stop()
+    edgeAnim = undefined
+    if (!edgeOn) edgeRef.style.opacity = "0"
+    const current = animate(
+      edgeRef,
+      { opacity: edgeOpacity() },
+      { type: "spring", visualDuration: edgeRise(), bounce: 0 },
+    )
+    edgeAnim = current
+    edgeOn = true
+    current.finished
+      .catch(() => {})
+      .finally(() => {
+        if (edgeAnim !== current) return
+        edgeAnim = undefined
+        if (!edgeRef) return
+        edgeRef.style.opacity = `${edgeOpacity()}`
+      })
+  }
+
+  const queueEdgeHide = () => {
+    stopEdgeTimer()
+    if (!edgeOn) return
+    if (edgeIdle() <= 0) {
+      hideEdge()
+      return
+    }
+    edgeTimer = setTimeout(() => {
+      edgeTimer = undefined
+      hideEdge()
+    }, edgeIdle())
+  }
+
+  const hideBody = () => {
+    if (!body) return
+    body.style.opacity = "0"
+    body.style.filter = "blur(2px)"
+  }
+
+  const clearBody = () => {
+    if (!body) return
+    body.style.opacity = ""
+    body.style.filter = ""
+  }
+
+  const fadeBodyIn = (nextMode: "mount" | "toggle" = "mount") => {
+    if (props.fade === false || !body) return
+    if (reduce()) {
+      clearBody()
+      return
+    }
+    hideBody()
+    fadeAnim?.stop()
+    fadeAnim = animate(body, { opacity: 1, filter: "blur(0px)" }, nextMode === "toggle" ? toggleSpring() : spring())
+    fadeAnim.finished.then(() => {
+      if (!body || !open()) return
+      clearBody()
+    })
+  }
+
+  const setInstant = (visible: boolean) => {
+    const next = visible ? targetHeight() : 0
+    springTarget = next
+    height.jump(next)
+    root!.style.height = visible ? "" : "0px"
+    root!.style.overflow = visible ? "" : "clip"
+    hideEdge(true)
+    if (visible || props.fade === false) clearBody()
+    else hideBody()
+  }
+
+  const currentHeight = () => {
+    if (!root) return 0
+    const v = root.style.height
+    if (v && v !== "auto") {
+      const n = Number.parseFloat(v)
+      if (!Number.isNaN(n)) return n
+    }
+    return Math.max(0, root.getBoundingClientRect().height)
+  }
+
+  const targetHeight = () => Math.max(0, Math.ceil(body?.getBoundingClientRect().height ?? 0))
+
+  const setHeight = (nextMode: "mount" | "toggle" = "mount") => {
+    if (!root || !open()) return
+    const next = targetHeight()
+    if (reduce()) {
+      springTarget = next
+      height.jump(next)
+      if (props.autoHeight === false || watch()) {
+        root.style.height = `${next}px`
+        root.style.overflow = next > 0 ? "visible" : "clip"
+        return
+      }
+      root.style.height = "auto"
+      root.style.overflow = next > 0 ? "visible" : "clip"
+      return
+    }
+    if (next === springTarget) return
+    const prev = currentHeight()
+    if (Math.abs(next - prev) < 1) {
+      springTarget = next
+      if (props.autoHeight === false || watch()) {
+        root.style.height = `${next}px`
+        root.style.overflow = next > 0 ? "visible" : "clip"
+      }
+      return
+    }
+    root.style.overflow = "clip"
+    springTarget = next
+    mode = nextMode
+    height.set(next)
+  }
+
+  onMount(() => {
+    if (!root || !body) return
+
+    const offChange = height.on("change", (next) => {
+      if (!root) return
+      root.style.height = `${Math.max(0, next)}px`
+    })
+    const offStart = height.on("animationStart", () => {
+      if (!root) return
+      root.style.overflow = "clip"
+      root.style.willChange = "height"
+      root.style.contain = "layout style"
+      if (edgeReady()) showEdge()
+    })
+    const offComplete = height.on("animationComplete", () => {
+      if (!root) return
+      root.style.willChange = ""
+      root.style.contain = ""
+      if (!open()) {
+        springTarget = 0
+        root.style.height = "0px"
+        root.style.overflow = "clip"
+        return
+      }
+      const next = targetHeight()
+      springTarget = next
+      if (props.autoHeight === false || watch()) {
+        root.style.height = `${next}px`
+        root.style.overflow = next > 0 ? "visible" : "clip"
+        if (edgeReady()) queueEdgeHide()
+        return
+      }
+      root.style.height = "auto"
+      root.style.overflow = "visible"
+      if (edgeReady()) queueEdgeHide()
+    })
+
+    onCleanup(() => {
+      offComplete()
+      offStart()
+      offChange()
+    })
+
+    if (!animated()) {
+      setInstant(open())
+      return
+    }
+
+    if (props.fade !== false) hideBody()
+    hideEdge(true)
+
+    if (!open()) {
+      root.style.height = "0px"
+      root.style.overflow = "clip"
+    } else {
+      if (grow()) {
+        root.style.height = "0px"
+        root.style.overflow = "clip"
+      } else {
+        root.style.height = "auto"
+        root.style.overflow = "visible"
+      }
+      mountFrame = requestAnimationFrame(() => {
+        mountFrame = undefined
+        fadeBodyIn("mount")
+        if (grow()) setHeight("mount")
+      })
+    }
+    if (watch()) {
+      observer = new ResizeObserver(() => {
+        if (!open()) return
+        if (resizeFrame !== undefined) return
+        resizeFrame = requestAnimationFrame(() => {
+          resizeFrame = undefined
+          setHeight("mount")
+        })
+      })
+      observer.observe(body)
+    }
+  })
+
+  createEffect(
+    on(
+      () => props.open,
+      (value) => {
+        if (value === undefined) return
+        if (!root || !body) return
+        if (!animateToggle() || reduce()) {
+          setInstant(value)
+          return
+        }
+        fadeAnim?.stop()
+        if (!value) hideEdge(true)
+        if (!value) {
+          const next = currentHeight()
+          if (Math.abs(next - height.get()) >= 1) {
+            springTarget = next
+            height.jump(next)
+            root.style.height = `${next}px`
+          }
+          if (props.fade !== false) {
+            fadeAnim = animate(body, { opacity: 0, filter: "blur(2px)" }, toggleSpring())
+          }
+          root.style.overflow = "clip"
+          springTarget = 0
+          mode = "toggle"
+          height.set(0)
+          return
+        }
+        fadeBodyIn("toggle")
+        setHeight("toggle")
+      },
+      { defer: true },
+    ),
+  )
+
+  createEffect(() => {
+    if (!edgeRef) return
+    edgeRef.style.height = `${edgeHeight()}px`
+    if (!animated() || !open() || edgeHeight() <= 0) {
+      hideEdge(true)
+      return
+    }
+    if (edge()) return
+    hideEdge()
+  })
+
+  createEffect(() => {
+    if (!root || !body) return
+    if (!reduce()) return
+    fadeAnim?.stop()
+    edgeAnim?.stop()
+    setInstant(open())
+  })
+
+  onCleanup(() => {
+    stopEdgeTimer()
+    if (mountFrame !== undefined) cancelAnimationFrame(mountFrame)
+    if (resizeFrame !== undefined) cancelAnimationFrame(resizeFrame)
+    observer?.disconnect()
+    height.destroy()
+    fadeAnim?.stop()
+    edgeAnim?.stop()
+    edgeAnim = undefined
+    edgeOn = false
+  })
+
+  return (
+    <div
+      ref={root}
+      data-slot={props.slot}
+      class={props.class}
+      style={{ transform: "translateZ(0)", position: "relative" }}
+    >
+      <div ref={body} style={{ "padding-top": gap() > 0 ? `${gap()}px` : undefined }}>
+        {props.children}
+      </div>
+      <div
+        ref={edgeRef}
+        data-slot="grow-box-edge"
+        style={{
+          position: "absolute",
+          left: "0",
+          right: "0",
+          bottom: "0",
+          height: `${edgeHeight()}px`,
+          opacity: 0,
+          "pointer-events": "none",
+          background: "linear-gradient(to bottom, transparent 0%, var(--background-stronger) 100%)",
+        }}
+      />
+    </div>
+  )
+}

packages/ui/src/components/message-part.css

@@ -1,10 +1,20 @@
 [data-component="assistant-message"] {
   content-visibility: auto;
   width: 100%;
+}
+
+[data-component="assistant-parts"] {
+  width: 100%;
+  min-width: 0;
   display: flex;
   flex-direction: column;
   align-items: flex-start;
-  gap: 12px;
+  gap: 0;
+}
+
+[data-component="assistant-part-item"] {
+  width: 100%;
+  min-width: 0;
 }
 
 [data-component="user-message"] {
@@ -27,6 +37,14 @@
     color: var(--text-weak);
   }
 
+  [data-slot="user-message-inner"] {
+    position: relative;
+    display: flex;
+    flex-direction: column;
+    align-items: flex-end;
+    width: 100%;
+    gap: 4px;
+  }
   [data-slot="user-message-attachments"] {
     display: flex;
     flex-wrap: wrap;
@@ -35,6 +53,7 @@
     width: fit-content;
     max-width: min(82%, 64ch);
     margin-left: auto;
+    margin-bottom: 4px;
   }
 
   [data-slot="user-message-attachment"] {
@@ -134,7 +153,7 @@
 
   [data-slot="user-message-copy-wrapper"] {
     min-height: 24px;
-    margin-top: 4px;
+    margin-top: 0;
     display: flex;
     align-items: center;
     justify-content: flex-end;
@@ -144,7 +163,6 @@
     pointer-events: none;
     transition: opacity 0.15s ease;
     will-change: opacity;
-
     [data-component="tooltip-trigger"] {
       display: inline-flex;
       width: fit-content;
@@ -187,56 +205,21 @@
     opacity: 1;
     pointer-events: auto;
   }
-
-  .text-text-strong {
-    color: var(--text-strong);
-  }
-
-  .font-medium {
-    font-weight: var(--font-weight-medium);
-  }
 }
 
 [data-component="text-part"] {
   width: 100%;
-  margin-top: 24px;
+  margin-top: 0;
+  padding-block: 4px;
+  position: relative;
 
   [data-slot="text-part-body"] {
     margin-top: 0;
   }
 
-  [data-slot="text-part-copy-wrapper"] {
-    min-height: 24px;
-    margin-top: 4px;
-    display: flex;
-    align-items: center;
-    justify-content: flex-start;
-    gap: 10px;
-    opacity: 0;
-    pointer-events: none;
-    transition: opacity 0.15s ease;
-    will-change: opacity;
-
-    [data-component="tooltip-trigger"] {
-      display: inline-flex;
-      width: fit-content;
-    }
-  }
-
-  [data-slot="text-part-meta"] {
-    user-select: none;
-  }
-
-  [data-slot="text-part-copy-wrapper"][data-interrupted] {
+  [data-slot="text-part-turn-summary"] {
     width: 100%;
-    justify-content: flex-end;
-    gap: 12px;
-  }
-
-  &:hover [data-slot="text-part-copy-wrapper"],
-  &:focus-within [data-slot="text-part-copy-wrapper"] {
-    opacity: 1;
-    pointer-events: auto;
+    min-width: 0;
   }
 
   [data-component="markdown"] {
@@ -245,6 +228,10 @@
   }
 }
 
+[data-component="assistant-part-item"][data-kind="text"][data-last="true"] [data-component="text-part"] {
+  padding-bottom: 0;
+}
+
 [data-component="compaction-part"] {
   width: 100%;
   display: flex;
@@ -278,7 +265,6 @@
   line-height: var(--line-height-normal);
 
   [data-component="markdown"] {
-    margin-top: 24px;
     font-style: normal;
     font-size: inherit;
     color: var(--text-weak);
@@ -372,13 +358,16 @@
     height: auto;
     max-height: 240px;
     overflow-y: auto;
+    overscroll-behavior: contain;
     scrollbar-width: none;
     -ms-overflow-style: none;
-
+    -webkit-mask-image: linear-gradient(to bottom, transparent 0, black 6px, black calc(100% - 6px), transparent 100%);
+    mask-image: linear-gradient(to bottom, transparent 0, black 6px, black calc(100% - 6px), transparent 100%);
+    -webkit-mask-repeat: no-repeat;
+    mask-repeat: no-repeat;
     &::-webkit-scrollbar {
       display: none;
     }
-
     [data-component="markdown"] {
       overflow: visible;
     }
@@ -448,7 +437,7 @@
 [data-component="write-trigger"] {
   display: flex;
   align-items: center;
-  justify-content: space-between;
+  justify-content: flex-start;
   gap: 8px;
   width: 100%;
 
@@ -461,7 +450,8 @@
   }
 
   [data-slot="message-part-title"] {
-    flex-shrink: 0;
+    flex-shrink: 1;
+    min-width: 0;
     display: flex;
     align-items: center;
     gap: 8px;
@@ -493,40 +483,45 @@
   [data-slot="message-part-title-text"] {
     text-transform: capitalize;
     color: var(--text-strong);
+    flex-shrink: 0;
   }
 
-  [data-slot="message-part-title-filename"] {
-    /* No text-transform - preserve original filename casing */
+  [data-slot="message-part-meta-line"],
+  .message-part-meta-line {
+    min-width: 0;
+    display: inline-flex;
+    align-items: center;
+    gap: 6px;
     font-weight: var(--font-weight-regular);
+
+    [data-component="diff-changes"] {
+      flex-shrink: 0;
+      gap: 6px;
+    }
   }
 
-  [data-slot="message-part-path"] {
-    display: flex;
-    flex-grow: 1;
-    min-width: 0;
-    font-weight: var(--font-weight-regular);
+  .message-part-meta-line.soft {
+    [data-slot="message-part-title-filename"] {
+      color: var(--text-base);
+    }
   }
 
-  [data-slot="message-part-directory"] {
+  [data-slot="message-part-title-filename"] {
+    /* No text-transform - preserve original filename casing */
+    color: var(--text-strong);
+    flex-shrink: 0;
+  }
+
+  [data-slot="message-part-directory-inline"] {
     color: var(--text-weak);
+    min-width: 0;
+    max-width: min(48vw, 36ch);
     text-overflow: ellipsis;
     overflow: hidden;
     white-space: nowrap;
     direction: rtl;
     text-align: left;
   }
-
-  [data-slot="message-part-filename"] {
-    color: var(--text-strong);
-    flex-shrink: 0;
-  }
-
-  [data-slot="message-part-actions"] {
-    display: flex;
-    gap: 16px;
-    align-items: center;
-    justify-content: flex-end;
-  }
 }
 
 [data-component="edit-content"] {
@@ -617,6 +612,17 @@
   }
 }
 
+[data-slot="webfetch-meta"] {
+  min-width: 0;
+  display: inline-flex;
+  align-items: center;
+  gap: 8px;
+
+  [data-component="tool-action"] {
+    flex-shrink: 0;
+  }
+}
+
 [data-component="todos"] {
   padding: 10px 0 24px 0;
   display: flex;
@@ -639,7 +645,6 @@
 }
 
 [data-component="context-tool-group-trigger"] {
-  width: 100%;
   min-height: 24px;
   display: flex;
   align-items: center;
@@ -647,28 +652,352 @@
   gap: 0px;
   cursor: pointer;
 
+  &[data-pending] {
+    cursor: default;
+  }
+
   [data-slot="context-tool-group-title"] {
     flex-shrink: 1;
     min-width: 0;
   }
+}
 
-  [data-slot="collapsible-arrow"] {
-    color: var(--icon-weaker);
+/* Prevent the trigger content from stretching full-width so the arrow sits after the text */
+[data-slot="basic-tool-tool-trigger-content"]:has([data-component="context-tool-group-trigger"]) {
+  width: auto;
+  flex: 0 1 auto;
+
+  [data-slot="basic-tool-tool-info"] {
+    flex: 0 1 auto;
   }
 }
 
-[data-component="context-tool-group-list"] {
-  padding: 6px 0 4px 0;
+[data-component="context-tool-step"] {
+  width: 100%;
+  min-width: 0;
+  padding-left: 12px;
+}
+
+[data-component="context-tool-expanded-list"] {
   display: flex;
   flex-direction: column;
-  gap: 2px;
+  padding: 4px 0 4px 12px;
+  max-height: 200px;
+  overflow-y: auto;
+  overscroll-behavior: contain;
+  scrollbar-width: none;
+  -ms-overflow-style: none;
+  -webkit-mask-repeat: no-repeat;
+  mask-repeat: no-repeat;
 
-  [data-slot="context-tool-group-item"] {
+  &::-webkit-scrollbar {
+    display: none;
+  }
+}
+
+[data-component="context-tool-expanded-row"] {
+  display: flex;
+  align-items: center;
+  gap: 6px;
+  min-width: 0;
+  height: 22px;
+  flex-shrink: 0;
+  white-space: nowrap;
+  overflow: hidden;
+
+  [data-slot="context-tool-expanded-action"] {
+    flex-shrink: 0;
+    font-size: var(--font-size-base);
+    font-weight: 500;
+    color: var(--text-base);
+  }
+
+  [data-slot="context-tool-expanded-detail"] {
+    flex-shrink: 1;
     min-width: 0;
-    padding: 6px 0;
+    overflow: hidden;
+    text-overflow: ellipsis;
+    font-size: var(--font-size-base);
+    color: var(--text-base);
+    opacity: 0.75;
   }
 }
 
+[data-component="context-tool-rolling-row"] {
+  display: inline-flex;
+  align-items: center;
+  gap: 6px;
+  width: 100%;
+  min-width: 0;
+  white-space: nowrap;
+  overflow: hidden;
+  padding-left: 12px;
+
+  [data-slot="context-tool-rolling-action"] {
+    flex-shrink: 0;
+    font-size: var(--font-size-base);
+    font-weight: 500;
+    color: var(--text-base);
+  }
+
+  [data-slot="context-tool-rolling-detail"] {
+    flex-shrink: 1;
+    min-width: 0;
+    overflow: hidden;
+    text-overflow: ellipsis;
+    font-size: var(--font-size-base);
+    color: var(--text-weak);
+  }
+}
+
+[data-component="shell-rolling-results"] {
+  width: 100%;
+  min-width: 0;
+  display: flex;
+  flex-direction: column;
+
+  [data-slot="shell-rolling-header-clip"] {
+    &:hover [data-slot="shell-rolling-actions"] {
+      opacity: 1;
+    }
+
+    &[data-clickable="true"] {
+      cursor: pointer;
+    }
+  }
+
+  [data-slot="shell-rolling-header"] {
+    display: inline-flex;
+    align-items: center;
+    gap: 8px;
+    min-width: 0;
+    max-width: 100%;
+    height: 37px;
+    box-sizing: border-box;
+  }
+
+  [data-slot="shell-rolling-title"] {
+    flex-shrink: 0;
+    font-family: var(--font-family-sans);
+    font-size: 14px;
+    font-style: normal;
+    font-weight: var(--font-weight-medium);
+    line-height: var(--line-height-large);
+    letter-spacing: var(--letter-spacing-normal);
+    color: var(--text-strong);
+  }
+
+  [data-slot="shell-rolling-subtitle"] {
+    flex: 0 1 auto;
+    min-width: 0;
+    overflow: hidden;
+    text-overflow: ellipsis;
+    white-space: nowrap;
+    font-family: var(--font-family-sans);
+    font-size: 14px;
+    font-weight: var(--font-weight-normal);
+    line-height: var(--line-height-large);
+    color: var(--text-weak);
+  }
+
+  [data-slot="shell-rolling-actions"] {
+    flex-shrink: 0;
+    display: inline-flex;
+    align-items: center;
+    gap: 2px;
+    opacity: 0;
+    transition: opacity 0.15s ease;
+  }
+
+  .shell-rolling-copy {
+    border: none !important;
+    outline: none !important;
+    box-shadow: none !important;
+    background: transparent !important;
+
+    [data-slot="icon-svg"] {
+      color: var(--icon-weaker);
+    }
+
+    &:hover:not(:disabled) {
+      background: color-mix(in srgb, var(--text-base) 8%, transparent) !important;
+      box-shadow: 0 0 0 1px color-mix(in srgb, var(--icon-weaker) 40%, transparent) !important;
+      border-radius: var(--radius-sm);
+
+      [data-slot="icon-svg"] {
+        color: var(--icon-base);
+      }
+    }
+  }
+
+  [data-slot="shell-rolling-arrow"] {
+    display: inline-flex;
+    align-items: center;
+    justify-content: center;
+    color: var(--icon-weaker);
+    transform: rotate(-90deg);
+    transition: transform 0.15s ease;
+  }
+
+  [data-slot="shell-rolling-arrow"][data-open="true"] {
+    transform: rotate(0deg);
+  }
+}
+
+[data-component="shell-rolling-output"] {
+  width: 100%;
+  min-width: 0;
+}
+
+[data-slot="shell-rolling-preview"] {
+  width: 100%;
+  min-width: 0;
+}
+
+[data-component="shell-expanded-output"] {
+  width: 100%;
+  max-width: 100%;
+  overflow-y: auto;
+  overflow-x: hidden;
+  scrollbar-width: none;
+  -ms-overflow-style: none;
+
+  &::-webkit-scrollbar {
+    display: none;
+  }
+}
+
+[data-component="shell-expanded-shell"] {
+  position: relative;
+  width: 100%;
+  min-width: 0;
+  border: 1px solid var(--border-weak-base);
+  border-radius: 6px;
+  background: transparent;
+  overflow: hidden;
+}
+
+[data-slot="shell-expanded-body"] {
+  position: relative;
+  width: 100%;
+  min-width: 0;
+}
+
+[data-slot="shell-expanded-top"] {
+  position: relative;
+  width: 100%;
+  min-width: 0;
+  padding: 9px 44px 9px 16px;
+  box-sizing: border-box;
+}
+
+[data-slot="shell-expanded-command"] {
+  display: flex;
+  align-items: flex-start;
+  gap: 8px;
+  width: 100%;
+  min-width: 0;
+  font-family: var(--font-family-mono);
+  font-feature-settings: var(--font-family-mono--font-feature-settings);
+  font-size: 13px;
+  line-height: 1.45;
+}
+
+[data-slot="shell-expanded-prompt"] {
+  flex-shrink: 0;
+  color: var(--text-weaker);
+}
+
+[data-slot="shell-expanded-input"] {
+  min-width: 0;
+  color: var(--text-strong);
+  white-space: pre-wrap;
+  overflow-wrap: anywhere;
+}
+
+[data-slot="shell-expanded-actions"] {
+  position: absolute;
+  top: 50%;
+  right: 8px;
+  z-index: 1;
+  transform: translateY(-50%);
+}
+
+.shell-expanded-copy {
+  border: none !important;
+  outline: none !important;
+  box-shadow: none !important;
+  background: transparent !important;
+
+  [data-slot="icon-svg"] {
+    color: var(--icon-weaker);
+  }
+
+  &:hover:not(:disabled) {
+    background: color-mix(in srgb, var(--text-base) 8%, transparent) !important;
+    box-shadow: 0 0 0 1px color-mix(in srgb, var(--icon-weaker) 40%, transparent) !important;
+    border-radius: var(--radius-sm);
+
+    [data-slot="icon-svg"] {
+      color: var(--icon-base);
+    }
+  }
+}
+
+[data-slot="shell-expanded-divider"] {
+  width: 100%;
+  height: 1px;
+  background: var(--border-weak-base);
+}
+
+[data-slot="shell-expanded-pre"] {
+  margin: 0;
+  padding: 12px 16px;
+  white-space: pre-wrap;
+  overflow-wrap: anywhere;
+
+  code {
+    font-family: var(--font-family-mono);
+    font-feature-settings: var(--font-family-mono--font-feature-settings);
+    font-size: 13px;
+    line-height: 1.45;
+    color: var(--text-base);
+  }
+}
+
+[data-component="shell-rolling-command"],
+[data-component="shell-rolling-row"] {
+  display: inline-flex;
+  align-items: center;
+  width: 100%;
+  min-width: 0;
+  overflow: hidden;
+  white-space: pre;
+  padding-left: 12px;
+}
+
+[data-slot="shell-rolling-text"] {
+  min-width: 0;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  font-family: var(--font-family-mono);
+  font-feature-settings: var(--font-family-mono--font-feature-settings);
+  font-size: var(--font-size-small);
+  line-height: var(--line-height-large);
+}
+
+[data-component="shell-rolling-command"] [data-slot="shell-rolling-text"] {
+  color: var(--text-base);
+}
+
+[data-component="shell-rolling-command"] [data-slot="shell-rolling-prompt"] {
+  color: var(--text-weaker);
+}
+
+[data-component="shell-rolling-row"] [data-slot="shell-rolling-text"] {
+  color: var(--text-weak);
+}
+
 [data-component="diagnostics"] {
   display: flex;
   flex-direction: column;
@@ -729,6 +1058,30 @@
   width: 100%;
 }
 
+[data-slot="assistant-part-grow"] {
+  width: 100%;
+  min-width: 0;
+  overflow: visible;
+}
+
+[data-component="tool-part-wrapper"][data-tool="bash"] {
+  [data-component="tool-trigger"] {
+    width: auto;
+    max-width: 100%;
+  }
+
+  [data-slot="basic-tool-tool-info-main"] {
+    align-items: center;
+  }
+
+  [data-slot="basic-tool-tool-title"],
+  [data-slot="basic-tool-tool-subtitle"] {
+    display: inline-flex;
+    align-items: center;
+    line-height: var(--line-height-large);
+  }
+}
+
 [data-component="dock-prompt"][data-kind="permission"] {
   position: relative;
   display: flex;
@@ -1187,8 +1540,7 @@
     position: sticky;
     top: var(--sticky-accordion-top, 0px);
     z-index: 20;
-    height: 40px;
-    padding-bottom: 8px;
+    height: 37px;
     background-color: var(--background-stronger);
   }
 }
@@ -1199,11 +1551,12 @@
   }
 
   [data-slot="apply-patch-trigger-content"] {
-    display: flex;
+    display: inline-flex;
     align-items: center;
-    justify-content: space-between;
-    width: 100%;
-    gap: 20px;
+    justify-content: flex-start;
+    max-width: 100%;
+    min-width: 0;
+    gap: 8px;
   }
 
   [data-slot="apply-patch-file-info"] {
@@ -1237,9 +1590,9 @@
   [data-slot="apply-patch-trigger-actions"] {
     flex-shrink: 0;
     display: flex;
-    gap: 16px;
+    gap: 8px;
     align-items: center;
-    justify-content: flex-end;
+    justify-content: flex-start;
   }
 
   [data-slot="apply-patch-change"] {
@@ -1279,10 +1632,11 @@
 }
 
 [data-component="tool-loaded-file"] {
+  min-width: 0;
   display: flex;
   align-items: center;
   gap: 8px;
-  padding: 4px 0 4px 28px;
+  padding: 4px 0 4px 12px;
   font-family: var(--font-family-sans);
   font-size: var(--font-size-small);
   font-weight: var(--font-weight-regular);
@@ -1293,4 +1647,11 @@
     flex-shrink: 0;
     color: var(--icon-weak);
   }
+
+  span {
+    min-width: 0;
+    overflow: hidden;
+    text-overflow: ellipsis;
+    white-space: nowrap;
+  }
 }

packages/ui/src/components/motion-spring.tsx

@@ -1,8 +1,9 @@
 import { attachSpring, motionValue } from "motion"
 import type { SpringOptions } from "motion"
 import { createEffect, createSignal, onCleanup } from "solid-js"
+import { prefersReducedMotion } from "../hooks/use-reduced-motion"
 
-type Opt = Partial<Pick<SpringOptions, "visualDuration" | "bounce" | "stiffness" | "damping" | "mass" | "velocity">>
+type Opt = Pick<SpringOptions, "visualDuration" | "bounce" | "stiffness" | "damping" | "mass" | "velocity">
 const eq = (a: Opt | undefined, b: Opt | undefined) =>
   a?.visualDuration === b?.visualDuration &&
   a?.bounce === b?.bounce &&
@@ -13,24 +14,41 @@ const eq = (a: Opt | undefined, b: Opt | undefined) =>
 
 export function useSpring(target: () => number, options?: Opt | (() => Opt)) {
   const read = () => (typeof options === "function" ? options() : options)
+  const reduce = prefersReducedMotion
   const [value, setValue] = createSignal(target())
   const source = motionValue(value())
   const spring = motionValue(value())
   let config = read()
-  let stop = attachSpring(spring, source, config)
-  let off = spring.on("change", (next: number) => setValue(next))
+  let reduced = reduce()
+  let stop = reduced ? () => {} : attachSpring(spring, source, config)
+  let off = spring.on("change", (next) => setValue(next))
 
   createEffect(() => {
-    source.set(target())
+    const next = target()
+    if (reduced) {
+      source.set(next)
+      spring.set(next)
+      setValue(next)
+      return
+    }
+    source.set(next)
   })
 
   createEffect(() => {
-    if (!options) return
     const next = read()
-    if (eq(config, next)) return
+    const skip = reduce()
+    if (eq(config, next) && reduced === skip) return
     config = next
+    reduced = skip
     stop()
-    stop = attachSpring(spring, source, next)
+    stop = skip ? () => {} : attachSpring(spring, source, next)
+    if (skip) {
+      const value = target()
+      source.set(value)
+      spring.set(value)
+      setValue(value)
+      return
+    }
     setValue(spring.get())
   })
 

packages/ui/src/components/motion.tsx

@@ -0,0 +1,77 @@
+import { followValue } from "motion"
+import type { MotionValue } from "motion"
+
+export { animate, springValue } from "motion"
+export type { AnimationPlaybackControls } from "motion"
+
+/**
+ * Like `springValue` but preserves getters on the config object.
+ * `springValue` spreads config at creation, snapshotting getter values.
+ * This passes the config through to `followValue` intact, so getters
+ * on `visualDuration` etc. fire on every `.set()` call.
+ */
+export function tunableSpringValue<T extends string | number>(initial: T, config: SpringConfig): MotionValue<T> {
+  return followValue(initial, config as any)
+}
+
+let _growDuration = 0.5
+let _collapsibleDuration = 0.3
+
+export const GROW_SPRING = {
+  type: "spring" as const,
+  get visualDuration() {
+    return _growDuration
+  },
+  bounce: 0,
+}
+
+export const COLLAPSIBLE_SPRING = {
+  type: "spring" as const,
+  get visualDuration() {
+    return _collapsibleDuration
+  },
+  bounce: 0,
+}
+
+export const setGrowDuration = (v: number) => {
+  _growDuration = v
+}
+export const setCollapsibleDuration = (v: number) => {
+  _collapsibleDuration = v
+}
+export const getGrowDuration = () => _growDuration
+export const getCollapsibleDuration = () => _collapsibleDuration
+
+export type SpringConfig = { type: "spring"; visualDuration: number; bounce: number }
+
+export const FAST_SPRING = {
+  type: "spring" as const,
+  visualDuration: 0.35,
+  bounce: 0,
+}
+
+export const GLOW_SPRING = {
+  type: "spring" as const,
+  visualDuration: 0.4,
+  bounce: 0.15,
+}
+
+export const WIPE_MASK =
+  "linear-gradient(to right, rgba(0,0,0,1) 0%, rgba(0,0,0,1) 45%, rgba(0,0,0,0) 60%, rgba(0,0,0,0) 100%)"
+
+export const clearMaskStyles = (el: HTMLElement) => {
+  el.style.maskImage = ""
+  el.style.webkitMaskImage = ""
+  el.style.maskSize = ""
+  el.style.webkitMaskSize = ""
+  el.style.maskRepeat = ""
+  el.style.webkitMaskRepeat = ""
+  el.style.maskPosition = ""
+  el.style.webkitMaskPosition = ""
+}
+
+export const clearFadeStyles = (el: HTMLElement) => {
+  el.style.opacity = ""
+  el.style.filter = ""
+  el.style.transform = ""
+}

packages/ui/src/components/rolling-results.css

@@ -0,0 +1,92 @@
+[data-component="rolling-results"] {
+  --rolling-results-row-height: 22px;
+  --rolling-results-fixed-height: var(--rolling-results-row-height);
+  --rolling-results-fixed-gap: 0px;
+  --rolling-results-row-gap: 0px;
+
+  display: block;
+  width: 100%;
+  min-width: 0;
+
+  [data-slot="rolling-results-viewport"] {
+    position: relative;
+    min-width: 0;
+    height: 0;
+    overflow: clip;
+  }
+
+  &[data-overflowing="true"]:not([data-scrollable="true"]) [data-slot="rolling-results-window"] {
+    mask-image: linear-gradient(
+      to bottom,
+      transparent 0%,
+      black var(--rolling-results-fade),
+      black calc(100% - calc(var(--rolling-results-fade) * 0.5)),
+      transparent 100%
+    );
+    -webkit-mask-image: linear-gradient(
+      to bottom,
+      transparent 0%,
+      black var(--rolling-results-fade),
+      black calc(100% - calc(var(--rolling-results-fade) * 0.5)),
+      transparent 100%
+    );
+  }
+
+  [data-slot="rolling-results-fixed"] {
+    min-width: 0;
+    height: var(--rolling-results-fixed-height);
+    min-height: var(--rolling-results-fixed-height);
+    display: flex;
+    align-items: center;
+  }
+
+  [data-slot="rolling-results-window"] {
+    min-width: 0;
+    margin-top: var(--rolling-results-fixed-gap);
+    height: calc(100% - var(--rolling-results-fixed-height) - var(--rolling-results-fixed-gap));
+    overflow: clip;
+  }
+
+  &[data-scrollable="true"] [data-slot="rolling-results-window"] {
+    scrollbar-width: none;
+    -ms-overflow-style: none;
+
+    &::-webkit-scrollbar {
+      display: none;
+    }
+  }
+
+  &[data-scrollable="true"] [data-slot="rolling-results-track"] {
+    transform: none !important;
+    will-change: auto;
+  }
+
+  [data-slot="rolling-results-body"] {
+    min-width: 0;
+  }
+
+  [data-slot="rolling-results-track"] {
+    display: flex;
+    min-width: 0;
+    flex-direction: column;
+    gap: var(--rolling-results-row-gap);
+    will-change: transform;
+  }
+
+  [data-slot="rolling-results-row"],
+  [data-slot="rolling-results-empty"] {
+    min-width: 0;
+    height: var(--rolling-results-row-height);
+    min-height: var(--rolling-results-row-height);
+    display: flex;
+    align-items: center;
+  }
+
+  [data-slot="rolling-results-row"] {
+    color: var(--text-base);
+  }
+
+  [data-slot="rolling-results-empty"] {
+    color: var(--text-weaker);
+  }
+}

packages/ui/src/components/rolling-results.tsx

@@ -0,0 +1,326 @@
+import { For, Show, batch, createEffect, createMemo, createSignal, on, onCleanup, onMount, type JSX } from "solid-js"
+import { animate, clearMaskStyles, GROW_SPRING, type AnimationPlaybackControls, type SpringConfig } from "./motion"
+import { prefersReducedMotion } from "../hooks/use-reduced-motion"
+
+export type RollingResultsProps<T> = {
+  items: T[]
+  render: (item: T, index: number) => JSX.Element
+  fixed?: JSX.Element
+  getKey?: (item: T, index: number) => string
+  rows?: number
+  rowHeight?: number
+  fixedHeight?: number
+  rowGap?: number
+  open?: boolean
+  scrollable?: boolean
+  spring?: SpringConfig
+  animate?: boolean
+  class?: string
+  empty?: JSX.Element
+  noFadeOnCollapse?: boolean
+}
+
+export function RollingResults<T>(props: RollingResultsProps<T>) {
+  let view: HTMLDivElement | undefined
+  let track: HTMLDivElement | undefined
+  let windowEl: HTMLDivElement | undefined
+  let shift: AnimationPlaybackControls | undefined
+  let resize: AnimationPlaybackControls | undefined
+  let edgeFade: AnimationPlaybackControls | undefined
+
+  const reducedMotion = prefersReducedMotion
+
+  const rows = createMemo(() => Math.max(1, Math.round(props.rows ?? 3)))
+  const rowHeight = createMemo(() => Math.max(16, Math.round(props.rowHeight ?? 22)))
+  const fixedHeight = createMemo(() => Math.max(0, Math.round(props.fixedHeight ?? rowHeight())))
+  const rowGap = createMemo(() => Math.max(0, Math.round(props.rowGap ?? 0)))
+  const fixed = createMemo(() => props.fixed !== undefined)
+  const list = createMemo(() => props.items ?? [])
+  const count = createMemo(() => list().length)
+
+  // scrollReady is the internal "transition complete" state.
+  // It only becomes true after props.scrollable is true AND the offset animation has settled.
+  const [scrollReady, setScrollReady] = createSignal(false)
+
+  const backstop = createMemo(() => Math.max(rows() * 2, 12))
+  const rendered = createMemo(() => {
+    const items = list()
+    if (scrollReady()) return items
+    const max = backstop()
+    return items.length > max ? items.slice(-max) : items
+  })
+  const skipped = createMemo(() => {
+    if (scrollReady()) return 0
+    return count() - rendered().length
+  })
+  const open = createMemo(() => props.open !== false)
+  const active = createMemo(() => (props.animate !== false || props.spring !== undefined) && !reducedMotion())
+  const noFade = () => props.noFadeOnCollapse === true
+  const overflowing = createMemo(() => count() > rows())
+  const shown = createMemo(() => Math.min(rows(), count()))
+  const step = createMemo(() => rowHeight() + rowGap())
+  const offset = createMemo(() => Math.max(0, count() - shown()) * step())
+  const body = createMemo(() => {
+    if (shown() > 0) {
+      return shown() * rowHeight() + Math.max(0, shown() - 1) * rowGap()
+    }
+    if (props.empty === undefined) return 0
+    return rowHeight()
+  })
+  const gap = createMemo(() => {
+    if (!fixed()) return 0
+    if (body() <= 0) return 0
+    return rowGap()
+  })
+  const height = createMemo(() => {
+    if (!open()) return 0
+    if (!fixed()) return body()
+    return fixedHeight() + gap() + body()
+  })
+
+  const key = (item: T, index: number) => {
+    const value = props.getKey
+    if (value) return value(item, index)
+    return String(index)
+  }
+
+  const setTrack = (value: number) => {
+    if (!track) return
+    track.style.transform = `translateY(${-Math.round(value)}px)`
+  }
+
+  const setView = (value: number) => {
+    if (!view) return
+    view.style.height = `${Math.max(0, Math.round(value))}px`
+  }
+
+  onMount(() => {
+    setTrack(offset())
+  })
+
+  // Original WAAPI offset animation — untouched rolling behavior.
+  createEffect(
+    on(
+      offset,
+      (next) => {
+        if (!track) return
+        if (scrollReady()) return
+        if (props.scrollable) return
+        if (!active()) {
+          shift?.stop()
+          shift = undefined
+          setTrack(next)
+          return
+        }
+        shift?.stop()
+        const anim = animate(track, { transform: `translateY(${-next}px)` }, props.spring ?? GROW_SPRING)
+        shift = anim
+        anim.finished
+          .catch(() => {})
+          .finally(() => {
+            if (shift !== anim) return
+            setTrack(next)
+            shift = undefined
+          })
+      },
+      { defer: true },
+    ),
+  )
+
+  // Scrollable transition: wait for the offset animation to finish,
+  // then batch all DOM changes in one synchronous pass.
+  createEffect(
+    on(
+      () => props.scrollable === true,
+      (isScrollable) => {
+        if (!isScrollable) {
+          setScrollReady(false)
+          if (windowEl) {
+            windowEl.style.overflowY = ""
+            windowEl.style.maskImage = ""
+            windowEl.style.webkitMaskImage = ""
+          }
+          return
+        }
+        // Wait for the current offset animation to settle (if any).
+        const done = shift?.finished ?? Promise.resolve()
+        done
+          .catch(() => {})
+          .then(() => {
+            if (props.scrollable !== true) return
+
+            // Batch the signal update — Solid updates the DOM synchronously:
+            // rendered() returns all items, skipped() returns 0, padding-top removed,
+            // data-scrollable becomes "true".
+            batch(() => setScrollReady(true))
+
+            // Now the DOM has all items. Safe to switch layout strategy.
+            // CSS handles `transform: none !important` on [data-scrollable="true"].
+            if (windowEl) {
+              windowEl.style.overflowY = "auto"
+              windowEl.scrollTop = windowEl.scrollHeight
+            }
+            updateScrollMask()
+          })
+      },
+    ),
+  )
+
+  // Auto-scroll to bottom when new items arrive in scrollable mode
+  const [userScrolled, setUserScrolled] = createSignal(false)
+
+  const updateScrollMask = () => {
+    if (!windowEl) return
+    if (!scrollReady()) {
+      windowEl.style.maskImage = ""
+      windowEl.style.webkitMaskImage = ""
+      return
+    }
+    const { scrollTop, scrollHeight, clientHeight } = windowEl
+    const atBottom = scrollHeight - scrollTop - clientHeight < 8
+    // Top fade is always present in scrollable mode (matches rolling mode appearance).
+    // Bottom fade only when not scrolled to the end.
+    const mask = atBottom
+      ? "linear-gradient(to bottom, transparent 0, black 8px)"
+      : "linear-gradient(to bottom, transparent 0, black 8px, black calc(100% - 8px), transparent 100%)"
+    windowEl.style.maskImage = mask
+    windowEl.style.webkitMaskImage = mask
+  }
+
+  createEffect(() => {
+    if (!scrollReady()) {
+      setUserScrolled(false)
+      return
+    }
+    const _n = count()
+    const scrolled = userScrolled()
+    if (scrolled) return
+    if (windowEl) {
+      windowEl.scrollTop = windowEl.scrollHeight
+      updateScrollMask()
+    }
+  })
+
+  const onWindowScroll = () => {
+    if (!windowEl || !scrollReady()) return
+    const atBottom = windowEl.scrollHeight - windowEl.scrollTop - windowEl.clientHeight < 8
+    setUserScrolled(!atBottom)
+    updateScrollMask()
+  }
+
+  const EDGE_MASK = "linear-gradient(to top, transparent 0%, black 8px)"
+  const applyEdge = () => {
+    if (!view) return
+    edgeFade?.stop()
+    edgeFade = undefined
+    view.style.maskImage = EDGE_MASK
+    view.style.webkitMaskImage = EDGE_MASK
+    view.style.maskSize = "100% 100%"
+    view.style.maskRepeat = "no-repeat"
+  }
+  const clearEdge = () => {
+    if (!view) return
+    if (!active()) {
+      clearMaskStyles(view)
+      return
+    }
+    edgeFade?.stop()
+    const anim = animate(view, { maskSize: "100% 200%" }, props.spring ?? GROW_SPRING)
+    edgeFade = anim
+    anim.finished
+      .catch(() => {})
+      .then(() => {
+        if (edgeFade !== anim || !view) return
+        clearMaskStyles(view)
+        edgeFade = undefined
+      })
+  }
+
+  createEffect(
+    on(height, (next, prev) => {
+      if (!view) return
+      if (!active()) {
+        resize?.stop()
+        resize = undefined
+        setView(next)
+        view.style.opacity = ""
+        clearEdge()
+        return
+      }
+      const collapsing = next === 0 && prev !== undefined && prev > 0
+      const expanding = prev === 0 && next > 0
+      resize?.stop()
+      view.style.opacity = ""
+      applyEdge()
+      const spring = props.spring ?? GROW_SPRING
+      const anim = collapsing
+        ? animate(view, noFade() ? { height: `${next}px` } : { height: `${next}px`, opacity: 0 }, spring)
+        : expanding
+          ? animate(view, noFade() ? { height: `${next}px` } : { height: `${next}px`, opacity: [0, 1] }, spring)
+          : animate(view, { height: `${next}px` }, spring)
+      resize = anim
+      anim.finished
+        .catch(() => {})
+        .finally(() => {
+          view.style.opacity = ""
+          if (resize !== anim) return
+          setView(next)
+          resize = undefined
+          clearEdge()
+        })
+    }),
+  )
+
+  onCleanup(() => {
+    shift?.stop()
+    resize?.stop()
+    edgeFade?.stop()
+    shift = undefined
+    resize = undefined
+    edgeFade = undefined
+  })
+
+  return (
+    <div
+      data-component="rolling-results"
+      class={props.class}
+      data-open={open() ? "true" : "false"}
+      data-overflowing={overflowing() ? "true" : "false"}
+      data-scrollable={scrollReady() ? "true" : "false"}
+      data-fixed={fixed() ? "true" : "false"}
+      style={{
+        "--rolling-results-row-height": `${rowHeight()}px`,
+        "--rolling-results-fixed-height": `${fixed() ? fixedHeight() : 0}px`,
+        "--rolling-results-fixed-gap": `${gap()}px`,
+        "--rolling-results-row-gap": `${rowGap()}px`,
+        "--rolling-results-fade": `${Math.round(rowHeight() * 0.6)}px`,
+      }}
+    >
+      <div ref={view} data-slot="rolling-results-viewport" aria-live="polite">
+        <Show when={fixed()}>
+          <div data-slot="rolling-results-fixed">{props.fixed}</div>
+        </Show>
+        <div ref={windowEl} data-slot="rolling-results-window" onScroll={onWindowScroll}>
+          <div data-slot="rolling-results-body">
+            <Show when={list().length === 0 && props.empty !== undefined}>
+              <div data-slot="rolling-results-empty">{props.empty}</div>
+            </Show>
+            <div
+              ref={track}
+              data-slot="rolling-results-track"
+              style={{ "padding-top": scrollReady() ? undefined : `${skipped() * step()}px` }}
+            >
+              <For each={rendered()}>
+                {(item, index) => (
+                  <div data-slot="rolling-results-row" data-key={key(item, index())}>
+                    {props.render(item, index())}
+                  </div>
+                )}
+              </For>
+            </div>
+          </div>
+        </div>
+      </div>
+    </div>
+  )
+}

packages/ui/src/components/scroll-view.css

@@ -9,6 +9,9 @@
   overflow-y: auto;
   scrollbar-width: none;
   outline: none;
+  display: flex;
+  flex-direction: column-reverse;
+  overflow-anchor: none;
 }
 
 .scroll-view__viewport::-webkit-scrollbar {
@@ -45,18 +48,6 @@
   background-color: var(--border-strong-base);
 }
 
-.dark .scroll-view__thumb::after,
-[data-theme="dark"] .scroll-view__thumb::after {
-  background-color: var(--border-weak-base);
-}
-
-.dark .scroll-view__thumb:hover::after,
-[data-theme="dark"] .scroll-view__thumb:hover::after,
-.dark .scroll-view__thumb[data-dragging="true"]::after,
-[data-theme="dark"] .scroll-view__thumb[data-dragging="true"]::after {
-  background-color: var(--border-strong-base);
-}
-
 .scroll-view__thumb[data-visible="true"] {
   opacity: 1;
 }

packages/ui/src/components/scroll-view.tsx

@@ -1,17 +1,17 @@
-import { createSignal, onCleanup, onMount, splitProps, type ComponentProps, Show, mergeProps } from "solid-js"
+import { createSignal, onCleanup, onMount, splitProps, type ComponentProps, Show } from "solid-js"
+import { animate, type AnimationPlaybackControls } from "motion"
 import { useI18n } from "../context/i18n"
+import { FAST_SPRING } from "./motion"
 
 export interface ScrollViewProps extends ComponentProps<"div"> {
   viewportRef?: (el: HTMLDivElement) => void
-  orientation?: "vertical" | "horizontal" // currently only vertical is fully implemented for thumb
 }
 
 export function ScrollView(props: ScrollViewProps) {
   const i18n = useI18n()
-  const merged = mergeProps({ orientation: "vertical" }, props)
   const [local, events, rest] = splitProps(
-    merged,
-    ["class", "children", "viewportRef", "orientation", "style"],
+    props,
+    ["class", "children", "viewportRef", "style"],
     [
       "onScroll",
       "onWheel",
@@ -25,9 +25,9 @@ export function ScrollView(props: ScrollViewProps) {
     ],
   )
 
-  let rootRef!: HTMLDivElement
   let viewportRef!: HTMLDivElement
   let thumbRef!: HTMLDivElement
+  let anim: AnimationPlaybackControls | undefined
 
   const [isHovered, setIsHovered] = createSignal(false)
   const [isDragging, setIsDragging] = createSignal(false)
@@ -57,9 +57,12 @@ export function ScrollView(props: ScrollViewProps) {
     const maxScrollTop = scrollHeight - clientHeight
     const maxThumbTop = trackHeight - height
 
-    const top = maxScrollTop > 0 ? (scrollTop / maxScrollTop) * maxThumbTop : 0
+    // With column-reverse: scrollTop=0 is at bottom, negative = scrolled up
+    // Normalize so 0 = at top, maxScrollTop = at bottom
+    const normalizedScrollTop = maxScrollTop + scrollTop
+    const top = maxScrollTop > 0 ? (normalizedScrollTop / maxScrollTop) * maxThumbTop : 0
 
-    // Ensure thumb stays within bounds (shouldn't be necessary due to math above, but good for safety)
+    // Ensure thumb stays within bounds
     const boundedTop = trackPadding + Math.max(0, Math.min(top, maxThumbTop))
 
     setThumbHeight(height)
@@ -82,6 +85,7 @@ export function ScrollView(props: ScrollViewProps) {
     }
 
     onCleanup(() => {
+      stop()
       observer.disconnect()
     })
 
@@ -123,6 +127,30 @@ export function ScrollView(props: ScrollViewProps) {
     thumbRef.addEventListener("pointerup", onPointerUp)
   }
 
+  const stop = () => {
+    if (!anim) return
+    anim.stop()
+    anim = undefined
+  }
+
+  const limit = (top: number) => {
+    const max = viewportRef.scrollHeight - viewportRef.clientHeight
+    return Math.max(-max, Math.min(0, top))
+  }
+
+  const glide = (top: number) => {
+    stop()
+    anim = animate(viewportRef.scrollTop, limit(top), {
+      ...FAST_SPRING,
+      onUpdate: (v) => {
+        viewportRef.scrollTop = v
+      },
+      onComplete: () => {
+        anim = undefined
+      },
+    })
+  }
+
   // Keybinds implementation
   // We ensure the viewport has a tabindex so it can receive focus
   // We can also explicitly catch PageUp/Down if we want smooth scroll or specific behavior,
@@ -147,11 +175,13 @@ export function ScrollView(props: ScrollViewProps) {
         break
       case "Home":
         e.preventDefault()
-        viewportRef.scrollTo({ top: 0, behavior: "smooth" })
+        // With column-reverse, top of content = -(scrollHeight - clientHeight)
+        glide(-(viewportRef.scrollHeight - viewportRef.clientHeight))
         break
       case "End":
         e.preventDefault()
-        viewportRef.scrollTo({ top: viewportRef.scrollHeight, behavior: "smooth" })
+        // With column-reverse, bottom of content = 0
+        glide(0)
         break
       case "ArrowUp":
         e.preventDefault()
@@ -166,7 +196,6 @@ export function ScrollView(props: ScrollViewProps) {
 
   return (
     <div
-      ref={rootRef}
       class={`scroll-view ${local.class || ""}`}
       style={local.style}
       onPointerEnter={() => setIsHovered(true)}
@@ -181,12 +210,21 @@ export function ScrollView(props: ScrollViewProps) {
           updateThumb()
           if (typeof events.onScroll === "function") events.onScroll(e as any)
         }}
-        onWheel={events.onWheel as any}
-        onTouchStart={events.onTouchStart as any}
+        onWheel={(e) => {
+          if (e.deltaY) stop()
+          if (typeof events.onWheel === "function") events.onWheel(e as any)
+        }}
+        onTouchStart={(e) => {
+          stop()
+          if (typeof events.onTouchStart === "function") events.onTouchStart(e as any)
+        }}
         onTouchMove={events.onTouchMove as any}
         onTouchEnd={events.onTouchEnd as any}
         onTouchCancel={events.onTouchCancel as any}
-        onPointerDown={events.onPointerDown as any}
+        onPointerDown={(e) => {
+          stop()
+          if (typeof events.onPointerDown === "function") events.onPointerDown(e as any)
+        }}
         onClick={events.onClick as any}
         tabIndex={0}
         role="region"

packages/ui/src/components/session-turn.css

@@ -1,5 +1,4 @@
 [data-component="session-turn"] {
-  --sticky-header-height: calc(var(--session-title-height, 0px) + 24px);
   height: 100%;
   min-height: 0;
   min-width: 0;
@@ -26,7 +25,7 @@
     align-items: flex-start;
     align-self: stretch;
     min-width: 0;
-    gap: 18px;
+    gap: 0px;
     overflow-anchor: none;
   }
 
@@ -43,30 +42,127 @@
     align-self: stretch;
   }
 
+  [data-slot="session-turn-assistant-lane"] {
+    width: 100%;
+    min-width: 0;
+    display: flex;
+    flex-direction: column;
+    align-self: stretch;
+  }
+
   [data-slot="session-turn-thinking"] {
     display: flex;
+    flex-wrap: nowrap;
     align-items: center;
     gap: 8px;
     width: 100%;
     min-width: 0;
+    white-space: nowrap;
     color: var(--text-weak);
     font-family: var(--font-family-sans);
     font-size: var(--font-size-base);
     font-weight: var(--font-weight-medium);
-    line-height: 20px;
-    min-height: 20px;
+    line-height: var(--line-height-large);
+    height: 36px;
 
     [data-component="spinner"] {
       width: 16px;
       height: 16px;
     }
+
+    > [data-component="text-shimmer"] {
+      flex: 0 0 auto;
+      white-space: nowrap;
+    }
+  }
+
+  [data-slot="session-turn-handoff-wrap"] {
+    width: 100%;
+    min-width: 0;
+    overflow: visible;
+  }
+
+  [data-slot="session-turn-handoff"] {
+    width: 100%;
+    min-width: 0;
+    min-height: 37px;
+    position: relative;
+  }
+
+  [data-slot="session-turn-thinking"] {
+    position: absolute;
+    inset: 0;
+    will-change: opacity, filter;
+    transition:
+      opacity 180ms ease-out,
+      filter 180ms ease-out,
+      transform 180ms ease-out;
+  }
+
+  [data-slot="session-turn-thinking"][data-visible="false"] {
+    opacity: 0;
+    filter: blur(2px);
+    transform: translateY(1px);
+    pointer-events: none;
+  }
+
+  [data-slot="session-turn-thinking"][data-visible="true"] {
+    opacity: 1;
+    filter: blur(0px);
+    transform: translateY(0px);
+  }
+
+  [data-slot="session-turn-meta"] {
+    position: absolute;
+    inset: 0;
+    min-height: 37px;
+    display: flex;
+    align-items: center;
+    justify-content: flex-start;
+    gap: 10px;
+    opacity: 0;
+    pointer-events: none;
+    transition: opacity 0.15s ease;
+  }
+
+  [data-slot="session-turn-meta"][data-interrupted] {
+    gap: 12px;
+  }
+
+  [data-slot="session-turn-meta"] [data-component="tooltip-trigger"] {
+    display: inline-flex;
+    width: fit-content;
+  }
+
+  [data-slot="session-turn-message-container"]:hover [data-slot="session-turn-meta"][data-visible="true"],
+  [data-slot="session-turn-message-container"]:focus-within [data-slot="session-turn-meta"][data-visible="true"] {
+    opacity: 1;
+    pointer-events: auto;
+  }
+
+  [data-slot="session-turn-meta-label"] {
+    user-select: none;
+    min-width: 0;
+    overflow: clip;
+    white-space: nowrap;
+    text-overflow: ellipsis;
   }
 
   [data-component="text-reveal"].session-turn-thinking-heading {
     flex: 1 1 auto;
     min-width: 0;
+    overflow: clip;
+    white-space: nowrap;
+    line-height: inherit;
     color: var(--text-weaker);
     font-weight: var(--font-weight-regular);
+
+    [data-slot="text-reveal-track"],
+    [data-slot="text-reveal-entering"],
+    [data-slot="text-reveal-leaving"] {
+      min-height: 0;
+      line-height: inherit;
+    }
   }
 
   .error-card {
@@ -84,7 +180,7 @@
     display: flex;
     flex-direction: column;
     align-self: stretch;
-    gap: 12px;
+    gap: 0px;
 
     > :first-child > [data-component="markdown"]:first-child {
       margin-top: 0;
@@ -109,6 +205,7 @@
 
   [data-component="session-turn-diffs-trigger"] {
     width: 100%;
+    height: 36px;
     display: flex;
     align-items: center;
     justify-content: flex-start;
@@ -118,7 +215,7 @@
 
   [data-slot="session-turn-diffs-title"] {
     display: inline-flex;
-    align-items: baseline;
+    align-items: center;
     gap: 8px;
   }
 
@@ -135,7 +232,7 @@
     font-family: var(--font-family-sans);
     font-size: var(--font-size-base);
     font-weight: var(--font-weight-regular);
-    line-height: var(--line-height-x-large);
+    line-height: var(--line-height-large);
   }
 
   [data-slot="session-turn-diffs-meta"] {
@@ -171,8 +268,10 @@
 
   [data-slot="session-turn-diff-path"] {
     display: flex;
-    flex-grow: 1;
     min-width: 0;
+    align-items: baseline;
+    overflow: clip;
+    white-space: nowrap;
 
     font-family: var(--font-family-sans);
     font-size: var(--font-size-small);
@@ -180,16 +279,22 @@
   }
 
   [data-slot="session-turn-diff-directory"] {
-    color: var(--text-base);
-    overflow: hidden;
-    text-overflow: ellipsis;
+    flex: 1 1 auto;
+    color: var(--text-weak);
+    min-width: 0;
+    overflow: clip;
     white-space: nowrap;
     direction: rtl;
+    unicode-bidi: plaintext;
     text-align: left;
   }
 
   [data-slot="session-turn-diff-filename"] {
     flex-shrink: 0;
+    max-width: 100%;
+    min-width: 0;
+    overflow: clip;
+    white-space: nowrap;
     color: var(--text-strong);
     font-weight: var(--font-weight-medium);
   }

packages/ui/src/components/session-turn.tsx

@@ -3,23 +3,27 @@ import type { SessionStatus } from "@opencode-ai/sdk/v2"
 import { useData } from "../context"
 import { useFileComponent } from "../context/file"
 
+import { same } from "@opencode-ai/util/array"
 import { Binary } from "@opencode-ai/util/binary"
 import { getDirectory, getFilename } from "@opencode-ai/util/path"
-import { createEffect, createMemo, createSignal, For, on, ParentProps, Show } from "solid-js"
+import { createEffect, createMemo, createSignal, For, on, onCleanup, ParentProps, Show } from "solid-js"
 import { Dynamic } from "solid-js/web"
-import { AssistantParts, Message, Part, PART_MAPPING } from "./message-part"
+import { GrowBox } from "./grow-box"
+import { AssistantParts, UserMessageDisplay, Part, PART_MAPPING } from "./message-part"
 import { Card } from "./card"
 import { Accordion } from "./accordion"
 import { StickyAccordionHeader } from "./sticky-accordion-header"
 import { Collapsible } from "./collapsible"
 import { DiffChanges } from "./diff-changes"
 import { Icon } from "./icon"
+import { IconButton } from "./icon-button"
 import { TextShimmer } from "./text-shimmer"
-import { SessionRetry } from "./session-retry"
 import { TextReveal } from "./text-reveal"
+import { list } from "./text-utils"
+import { SessionRetry } from "./session-retry"
+import { Tooltip } from "./tooltip"
 import { createAutoScroll } from "../hooks"
 import { useI18n } from "../context/i18n"
-
 function record(value: unknown): value is Record<string, unknown> {
   return !!value && typeof value === "object" && !Array.isArray(value)
 }
@@ -73,18 +77,12 @@ function unwrap(message: string) {
   return message
 }
 
-function same<T>(a: readonly T[], b: readonly T[]) {
-  if (a === b) return true
-  if (a.length !== b.length) return false
-  return a.every((x, i) => x === b[i])
-}
-
-function list<T>(value: T[] | undefined | null, fallback: T[]) {
-  if (Array.isArray(value)) return value
-  return fallback
-}
-
 const hidden = new Set(["todowrite", "todoread"])
+const emptyMessages: MessageType[] = []
+const emptyAssistant: AssistantMessage[] = []
+const emptyDiffs: FileDiff[] = []
+const idle: SessionStatus = { type: "idle" as const }
+const handoffHoldMs = 120
 
 function partState(part: PartType, showReasoningSummaries: boolean) {
   if (part.type === "tool") {
@@ -141,6 +139,7 @@ export function SessionTurn(
   props: ParentProps<{
     sessionID: string
     messageID: string
+    animate?: boolean
     showReasoningSummaries?: boolean
     shellToolDefaultOpen?: boolean
     editToolDefaultOpen?: boolean
@@ -159,11 +158,7 @@ export function SessionTurn(
   const i18n = useI18n()
   const fileComponent = useFileComponent()
 
-  const emptyMessages: MessageType[] = []
   const emptyParts: PartType[] = []
-  const emptyAssistant: AssistantMessage[] = []
-  const emptyDiffs: FileDiff[] = []
-  const idle = { type: "idle" as const }
 
   const allMessages = createMemo(() => list(data.store.message?.[props.sessionID], emptyMessages))
 
@@ -191,42 +186,8 @@ export function SessionTurn(
     return msg
   })
 
-  const pending = createMemo(() => {
-    if (typeof props.active === "boolean" && typeof props.queued === "boolean") return
-    const messages = allMessages() ?? emptyMessages
-    return messages.findLast(
-      (item): item is AssistantMessage => item.role === "assistant" && typeof item.time.completed !== "number",
-    )
-  })
-
-  const pendingUser = createMemo(() => {
-    const item = pending()
-    if (!item?.parentID) return
-    const messages = allMessages() ?? emptyMessages
-    const result = Binary.search(messages, item.parentID, (m) => m.id)
-    const msg = result.found ? messages[result.index] : messages.find((m) => m.id === item.parentID)
-    if (!msg || msg.role !== "user") return
-    return msg
-  })
-
-  const active = createMemo(() => {
-    if (typeof props.active === "boolean") return props.active
-    const msg = message()
-    const parent = pendingUser()
-    if (!msg || !parent) return false
-    return parent.id === msg.id
-  })
-
-  const queued = createMemo(() => {
-    if (typeof props.queued === "boolean") return props.queued
-    const id = message()?.id
-    if (!id) return false
-    if (!pendingUser()) return false
-    const item = pending()
-    if (!item) return false
-    return id > item.id
-  })
-
+  const active = createMemo(() => props.active ?? false)
+  const queued = createMemo(() => props.queued ?? false)
   const parts = createMemo(() => {
     const msg = message()
     if (!msg) return emptyParts
@@ -289,7 +250,7 @@ export function SessionTurn(
   const error = createMemo(
     () => assistantMessages().find((m) => m.error && m.error.name !== "MessageAbortedError")?.error,
   )
-  const showAssistantCopyPartID = createMemo(() => {
+  const assistantCopyPart = createMemo(() => {
     const messages = assistantMessages()
 
     for (let i = messages.length - 1; i >= 0; i--) {
@@ -299,13 +260,18 @@ export function SessionTurn(
       const parts = list(data.store.part?.[message.id], emptyParts)
       for (let j = parts.length - 1; j >= 0; j--) {
         const part = parts[j]
-        if (!part || part.type !== "text" || !part.text?.trim()) continue
-        return part.id
+        if (!part || part.type !== "text") continue
+        const text = part.text?.trim()
+        if (!text) continue
+        return {
+          id: part.id,
+          text,
+          message,
+        }
       }
     }
-
-    return undefined
   })
+  const assistantCopyPartID = createMemo(() => assistantCopyPart()?.id ?? null)
   const errorText = createMemo(() => {
     const msg = error()?.data?.message
     if (typeof msg === "string") return unwrap(msg)
@@ -313,18 +279,14 @@ export function SessionTurn(
     return unwrap(String(msg))
   })
 
-  const status = createMemo(() => {
-    if (props.status !== undefined) return props.status
-    if (typeof props.active === "boolean" && !props.active) return idle
-    return data.store.session_status[props.sessionID] ?? idle
+  const status = createMemo(() => data.store.session_status[props.sessionID] ?? idle)
+  const working = createMemo(() => {
+    if (status().type === "idle") return false
+    if (!message()) return false
+    return active()
   })
-  const working = createMemo(() => status().type !== "idle" && active())
   const showReasoningSummaries = createMemo(() => props.showReasoningSummaries ?? true)
-
-  const assistantCopyPartID = createMemo(() => {
-    if (working()) return null
-    return showAssistantCopyPartID() ?? null
-  })
+  const showDiffSummary = createMemo(() => edited() > 0 && !working())
   const turnDurationMs = createMemo(() => {
     const start = message()?.time.created
     if (typeof start !== "number") return undefined
@@ -364,13 +326,109 @@ export function SessionTurn(
       .filter((text): text is string => !!text)
       .at(-1),
   )
-  const showThinking = createMemo(() => {
+  const thinking = createMemo(() => {
     if (!working() || !!error()) return false
     if (queued()) return false
     if (status().type === "retry") return false
     if (showReasoningSummaries()) return assistantVisible() === 0
     return true
   })
+  const hasAssistant = createMemo(() => assistantMessages().length > 0)
+  const animateEnabled = createMemo(() => props.animate !== false)
+  const [live, setLive] = createSignal(false)
+  const thinkingOpen = createMemo(() => thinking() && (live() || !animateEnabled()))
+  const metaOpen = createMemo(() => !working() && !!assistantCopyPart())
+  const duration = createMemo(() => {
+    const ms = turnDurationMs()
+    if (typeof ms !== "number" || ms < 0) return ""
+
+    const total = Math.round(ms / 1000)
+    if (total < 60) return `${total}s`
+
+    const minutes = Math.floor(total / 60)
+    const seconds = total % 60
+    return `${minutes}m ${seconds}s`
+  })
+  const meta = createMemo(() => {
+    const item = assistantCopyPart()
+    if (!item) return ""
+
+    const agent = item.message.agent ? item.message.agent[0]?.toUpperCase() + item.message.agent.slice(1) : ""
+    const model = item.message.modelID
+      ? (data.store.provider?.all?.find((provider) => provider.id === item.message.providerID)?.models?.[
+          item.message.modelID
+        ]?.name ?? item.message.modelID)
+      : ""
+    return [agent, model, duration()].filter((value) => !!value).join("\u00A0\u00B7\u00A0")
+  })
+  const [copied, setCopied] = createSignal(false)
+  const [handoffHold, setHandoffHold] = createSignal(false)
+  const thinkingVisible = createMemo(() => thinkingOpen() || handoffHold())
+  const handoffOpen = createMemo(() => thinkingVisible() || metaOpen())
+  const lane = createMemo(() => hasAssistant() || handoffOpen())
+
+  let liveFrame: number | undefined
+  let copiedTimer: ReturnType<typeof setTimeout> | undefined
+  let handoffTimer: ReturnType<typeof setTimeout> | undefined
+
+  const copyAssistant = async () => {
+    const text = assistantCopyPart()?.text
+    if (!text) return
+
+    await navigator.clipboard.writeText(text)
+    setCopied(true)
+    if (copiedTimer !== undefined) clearTimeout(copiedTimer)
+    copiedTimer = setTimeout(() => {
+      copiedTimer = undefined
+      setCopied(false)
+    }, 2000)
+  }
+
+  createEffect(
+    on(
+      () => [animateEnabled(), working()] as const,
+      ([enabled, isWorking]) => {
+        if (liveFrame !== undefined) {
+          cancelAnimationFrame(liveFrame)
+          liveFrame = undefined
+        }
+        if (!enabled || !isWorking || live()) return
+        liveFrame = requestAnimationFrame(() => {
+          liveFrame = undefined
+          setLive(true)
+        })
+      },
+    ),
+  )
+
+  createEffect(
+    on(
+      () => [thinkingOpen(), metaOpen()] as const,
+      ([thinkingNow, metaNow]) => {
+        if (handoffTimer !== undefined) {
+          clearTimeout(handoffTimer)
+          handoffTimer = undefined
+        }
+
+        if (thinkingNow) {
+          setHandoffHold(true)
+          return
+        }
+
+        if (metaNow) {
+          setHandoffHold(false)
+          return
+        }
+
+        if (!handoffHold()) return
+        handoffTimer = setTimeout(() => {
+          handoffTimer = undefined
+          setHandoffHold(false)
+        }, handoffHoldMs)
+      },
+      { defer: true },
+    ),
+  )
 
   const autoScroll = createAutoScroll({
     working,
@@ -378,6 +436,119 @@ export function SessionTurn(
     overflowAnchor: "dynamic",
   })
 
+  onCleanup(() => {
+    if (liveFrame !== undefined) cancelAnimationFrame(liveFrame)
+    if (copiedTimer !== undefined) clearTimeout(copiedTimer)
+    if (handoffTimer !== undefined) clearTimeout(handoffTimer)
+  })
+
+  const turnDiffSummary = () => (
+    <div data-slot="session-turn-diffs">
+      <Collapsible open={open()} onOpenChange={setOpen} variant="ghost">
+        <Collapsible.Trigger>
+          <div data-component="session-turn-diffs-trigger">
+            <div data-slot="session-turn-diffs-title">
+              <span data-slot="session-turn-diffs-label">{i18n.t("ui.sessionReview.change.modified")}</span>
+              <span data-slot="session-turn-diffs-count">
+                {edited()} {i18n.t(edited() === 1 ? "ui.common.file.one" : "ui.common.file.other")}
+              </span>
+              <div data-slot="session-turn-diffs-meta">
+                <DiffChanges changes={diffs()} variant="bars" />
+                <Collapsible.Arrow />
+              </div>
+            </div>
+          </div>
+        </Collapsible.Trigger>
+        <Collapsible.Content>
+          <Show when={open()}>
+            <div data-component="session-turn-diffs-content">
+              <Accordion
+                multiple
+                style={{ "--sticky-accordion-offset": "37px" }}
+                value={expanded()}
+                onChange={(value) => setExpanded(Array.isArray(value) ? value : value ? [value] : [])}
+              >
+                <For each={diffs()}>
+                  {(diff) => {
+                    const active = createMemo(() => expanded().includes(diff.file))
+                    const [visible, setVisible] = createSignal(false)
+
+                    createEffect(
+                      on(
+                        active,
+                        (value) => {
+                          if (!value) {
+                            setVisible(false)
+                            return
+                          }
+
+                          requestAnimationFrame(() => {
+                            if (!active()) return
+                            setVisible(true)
+                          })
+                        },
+                        { defer: true },
+                      ),
+                    )
+
+                    return (
+                      <Accordion.Item value={diff.file}>
+                        <StickyAccordionHeader>
+                          <Accordion.Trigger>
+                            <div data-slot="session-turn-diff-trigger">
+                              <span data-slot="session-turn-diff-path">
+                                <Show when={diff.file.includes("/")}>
+                                  <span data-slot="session-turn-diff-directory">{`\u202A${getDirectory(diff.file)}\u202C`}</span>
+                                </Show>
+                                <span data-slot="session-turn-diff-filename">{getFilename(diff.file)}</span>
+                              </span>
+                              <div data-slot="session-turn-diff-meta">
+                                <span data-slot="session-turn-diff-changes">
+                                  <DiffChanges changes={diff} />
+                                </span>
+                                <span data-slot="session-turn-diff-chevron">
+                                  <Icon name="chevron-down" size="small" />
+                                </span>
+                              </div>
+                            </div>
+                          </Accordion.Trigger>
+                        </StickyAccordionHeader>
+                        <Accordion.Content>
+                          <Show when={visible()}>
+                            <div data-slot="session-turn-diff-view" data-scrollable>
+                              <Dynamic
+                                component={fileComponent}
+                                mode="diff"
+                                before={{ name: diff.file, contents: diff.before }}
+                                after={{ name: diff.file, contents: diff.after }}
+                              />
+                            </div>
+                          </Show>
+                        </Accordion.Content>
+                      </Accordion.Item>
+                    )
+                  }}
+                </For>
+              </Accordion>
+            </div>
+          </Show>
+        </Collapsible.Content>
+      </Collapsible>
+    </div>
+  )
+
+  const divider = (label: string) => (
+    <div data-component="compaction-part">
+      <div data-slot="compaction-part-divider">
+        <span data-slot="compaction-part-line" />
+        <span data-slot="compaction-part-label" class="text-12-regular text-text-weak">
+          {label}
+        </span>
+        <span data-slot="compaction-part-line" />
+      </div>
+    </div>
+  )
+
   return (
     <div data-component="session-turn" class={props.classes?.root}>
       <div
@@ -388,149 +559,120 @@ export function SessionTurn(
       >
         <div onClick={autoScroll.handleInteraction}>
           <Show when={message()}>
-            <div
-              ref={autoScroll.contentRef}
-              data-message={message()!.id}
-              data-slot="session-turn-message-container"
-              class={props.classes?.container}
-            >
-              <div data-slot="session-turn-message-content" aria-live="off">
-                <Message message={message()!} parts={parts()} interrupted={interrupted()} queued={queued()} />
-              </div>
-              <Show when={compaction()}>
-                <div data-slot="session-turn-compaction">
-                  <Part part={compaction()!} message={message()!} hideDetails />
-                </div>
-              </Show>
-              <Show when={assistantMessages().length > 0}>
-                <div data-slot="session-turn-assistant-content" aria-hidden={working()}>
-                  <AssistantParts
-                    messages={assistantMessages()}
-                    showAssistantCopyPartID={assistantCopyPartID()}
-                    turnDurationMs={turnDurationMs()}
-                    working={working()}
-                    showReasoningSummaries={showReasoningSummaries()}
-                    shellToolDefaultOpen={props.shellToolDefaultOpen}
-                    editToolDefaultOpen={props.editToolDefaultOpen}
+            {(msg) => (
+              <div
+                ref={autoScroll.contentRef}
+                data-message={msg().id}
+                data-slot="session-turn-message-container"
+                class={props.classes?.container}
+              >
+                <div data-slot="session-turn-message-content" aria-live="off">
+                  <UserMessageDisplay
+                    message={msg()}
+                    parts={parts()}
+                    interrupted={interrupted()}
+                    animate={props.animate}
+                    queued={queued()}
                   />
                 </div>
-              </Show>
-              <Show when={showThinking()}>
-                <div data-slot="session-turn-thinking">
-                  <TextShimmer text={i18n.t("ui.sessionTurn.status.thinking")} />
-                  <Show when={!showReasoningSummaries()}>
-                    <TextReveal
-                      text={reasoningHeading()}
-                      class="session-turn-thinking-heading"
-                      travel={25}
-                      duration={700}
-                    />
+                <Show when={compaction()}>
+                  {(part) => (
+                    <GrowBox animate={props.animate !== false} fade gap={8} class="w-full min-w-0">
+                      <div data-slot="session-turn-compaction">
+                        <Part part={part()} message={msg()} hideDetails />
+                      </div>
+                    </GrowBox>
+                  )}
+                </Show>
+                <div data-slot="session-turn-assistant-lane" aria-hidden={!lane()}>
+                  <Show when={hasAssistant()}>
+                    <div
+                      data-slot="session-turn-assistant-content"
+                      aria-hidden={working()}
+                      style={{ contain: "layout paint" }}
+                    >
+                      <AssistantParts
+                        messages={assistantMessages()}
+                        showAssistantCopyPartID={assistantCopyPartID()}
+                        showTurnDiffSummary={showDiffSummary()}
+                        turnDiffSummary={turnDiffSummary}
+                        working={working()}
+                        animate={live()}
+                        showReasoningSummaries={showReasoningSummaries()}
+                        shellToolDefaultOpen={props.shellToolDefaultOpen}
+                        editToolDefaultOpen={props.editToolDefaultOpen}
+                      />
+                    </div>
                   </Show>
-                </div>
-              </Show>
-              <SessionRetry status={status()} show={active()} />
-              <Show when={edited() > 0 && !working()}>
-                <div data-slot="session-turn-diffs">
-                  <Collapsible open={open()} onOpenChange={setOpen} variant="ghost">
-                    <Collapsible.Trigger>
-                      <div data-component="session-turn-diffs-trigger">
-                        <div data-slot="session-turn-diffs-title">
-                          <span data-slot="session-turn-diffs-label">{i18n.t("ui.sessionReview.change.modified")}</span>
-                          <span data-slot="session-turn-diffs-count">
-                            {edited()} {i18n.t(edited() === 1 ? "ui.common.file.one" : "ui.common.file.other")}
-                          </span>
-                          <div data-slot="session-turn-diffs-meta">
-                            <DiffChanges changes={diffs()} variant="bars" />
-                            <Collapsible.Arrow />
-                          </div>
-                        </div>
+                  <GrowBox
+                    animate={live()}
+                    animateToggle={live()}
+                    open={handoffOpen()}
+                    fade
+                    slot="session-turn-handoff-wrap"
+                  >
+                    <div data-slot="session-turn-handoff">
+                      <div data-slot="session-turn-thinking" data-visible={thinkingVisible() ? "true" : "false"}>
+                        <TextShimmer text={i18n.t("ui.sessionTurn.status.thinking")} />
+                        <TextReveal
+                          text={!showReasoningSummaries() ? (reasoningHeading() ?? "") : ""}
+                          class="session-turn-thinking-heading"
+                          travel={25}
+                          duration={900}
+                        />
                       </div>
-                    </Collapsible.Trigger>
-                    <Collapsible.Content>
-                      <Show when={open()}>
-                        <div data-component="session-turn-diffs-content">
-                          <Accordion
-                            multiple
-                            style={{ "--sticky-accordion-offset": "40px" }}
-                            value={expanded()}
-                            onChange={(value) => setExpanded(Array.isArray(value) ? value : value ? [value] : [])}
+                      <Show when={metaOpen()}>
+                        <div
+                          data-slot="session-turn-meta"
+                          data-visible={thinkingVisible() ? "false" : "true"}
+                          data-interrupted={interrupted() ? "" : undefined}
+                        >
+                          <Tooltip
+                            value={copied() ? i18n.t("ui.message.copied") : i18n.t("ui.message.copyResponse")}
+                            placement="top"
+                            gutter={4}
                           >
-                            <For each={diffs()}>
-                              {(diff) => {
-                                const active = createMemo(() => expanded().includes(diff.file))
-                                const [visible, setVisible] = createSignal(false)
-
-                                createEffect(
-                                  on(
-                                    active,
-                                    (value) => {
-                                      if (!value) {
-                                        setVisible(false)
-                                        return
-                                      }
-
-                                      requestAnimationFrame(() => {
-                                        if (!active()) return
-                                        setVisible(true)
-                                      })
-                                    },
-                                    { defer: true },
-                                  ),
-                                )
-
-                                return (
-                                  <Accordion.Item value={diff.file}>
-                                    <StickyAccordionHeader>
-                                      <Accordion.Trigger>
-                                        <div data-slot="session-turn-diff-trigger">
-                                          <span data-slot="session-turn-diff-path">
-                                            <Show when={diff.file.includes("/")}>
-                                              <span data-slot="session-turn-diff-directory">
-                                                {`\u202A${getDirectory(diff.file)}\u202C`}
-                                              </span>
-                                            </Show>
-                                            <span data-slot="session-turn-diff-filename">{getFilename(diff.file)}</span>
-                                          </span>
-                                          <div data-slot="session-turn-diff-meta">
-                                            <span data-slot="session-turn-diff-changes">
-                                              <DiffChanges changes={diff} />
-                                            </span>
-                                            <span data-slot="session-turn-diff-chevron">
-                                              <Icon name="chevron-down" size="small" />
-                                            </span>
-                                          </div>
-                                        </div>
-                                      </Accordion.Trigger>
-                                    </StickyAccordionHeader>
-                                    <Accordion.Content>
-                                      <Show when={visible()}>
-                                        <div data-slot="session-turn-diff-view" data-scrollable>
-                                          <Dynamic
-                                            component={fileComponent}
-                                            mode="diff"
-                                            before={{ name: diff.file, contents: diff.before }}
-                                            after={{ name: diff.file, contents: diff.after }}
-                                          />
-                                        </div>
-                                      </Show>
-                                    </Accordion.Content>
-                                  </Accordion.Item>
-                                )
-                              }}
-                            </For>
-                          </Accordion>
+                            <IconButton
+                              icon={copied() ? "check" : "copy"}
+                              size="normal"
+                              variant="ghost"
+                              onMouseDown={(event) => event.preventDefault()}
+                              onClick={() => void copyAssistant()}
+                              aria-label={copied() ? i18n.t("ui.message.copied") : i18n.t("ui.message.copyResponse")}
+                            />
+                          </Tooltip>
+                          <Show when={meta()}>
+                            <span
+                              data-slot="session-turn-meta-label"
+                              class="text-12-regular text-text-weak cursor-default"
+                            >
+                              {meta()}
+                            </span>
+                          </Show>
                         </div>
                       </Show>
-                    </Collapsible.Content>
-                  </Collapsible>
+                    </div>
+                  </GrowBox>
                 </div>
-              </Show>
-              <Show when={error()}>
-                <Card variant="error" class="error-card">
-                  {errorText()}
-                </Card>
-              </Show>
-            </div>
+                <GrowBox animate={props.animate !== false} fade gap={0} open={interrupted()} class="w-full min-w-0">
+                  {divider(i18n.t("ui.message.interrupted"))}
+                </GrowBox>
+                <SessionRetry status={status()} show={active()} />
+                <GrowBox
+                  animate={props.animate !== false}
+                  fade
+                  gap={0}
+                  open={showDiffSummary() && !assistantCopyPartID()}
+                >
+                  {turnDiffSummary()}
+                </GrowBox>
+                <Show when={error()}>
+                  <Card variant="error" class="error-card">
+                    {errorText()}
+                  </Card>
+                </Show>
+              </div>
+            )}
           </Show>
           {props.children}
         </div>

packages/ui/src/components/shell-rolling-results.tsx

@@ -0,0 +1,310 @@
+import { createEffect, createMemo, createSignal, onCleanup, onMount, Show } from "solid-js"
+import stripAnsi from "strip-ansi"
+import type { ToolPart } from "@opencode-ai/sdk/v2"
+import { prefersReducedMotion } from "../hooks/use-reduced-motion"
+import { useI18n } from "../context/i18n"
+import { RollingResults } from "./rolling-results"
+import { Icon } from "./icon"
+import { IconButton } from "./icon-button"
+import { TextShimmer } from "./text-shimmer"
+import { Tooltip } from "./tooltip"
+import { GROW_SPRING } from "./motion"
+import { useSpring } from "./motion-spring"
+import {
+  busy,
+  createThrottledValue,
+  hold,
+  updateScrollMask,
+  useCollapsible,
+  useRowWipe,
+  useToolFade,
+} from "./tool-utils"
+
+function ShellRollingSubtitle(props: { text: string; animate?: boolean }) {
+  let ref: HTMLSpanElement | undefined
+  useToolFade(() => ref, { wipe: true, animate: props.animate })
+
+  return (
+    <span data-slot="shell-rolling-subtitle">
+      <span ref={ref}>{props.text}</span>
+    </span>
+  )
+}
+
+function firstLine(text: string) {
+  return text
+    .split(/\r\n|\n|\r/g)
+    .map((item) => item.trim())
+    .find((item) => item.length > 0)
+}
+
+function shellRows(output: string) {
+  const rows: { id: string; text: string }[] = []
+  const lines = output
+    .split(/\r\n|\n|\r/g)
+    .map((item) => item.trimEnd())
+    .filter((item) => item.length > 0)
+  const start = Math.max(0, lines.length - 80)
+  for (let i = start; i < lines.length; i++) {
+    rows.push({ id: `line:${i}`, text: lines[i]! })
+  }
+
+  return rows
+}
+
+function ShellRollingCommand(props: { text: string; animate?: boolean }) {
+  let ref: HTMLSpanElement | undefined
+  useToolFade(() => ref, { wipe: true, animate: props.animate })
+
+  return (
+    <div data-component="shell-rolling-command">
+      <span ref={ref} data-slot="shell-rolling-text">
+        <span data-slot="shell-rolling-prompt">$</span> {props.text}
+      </span>
+    </div>
+  )
+}
+
+function ShellExpanded(props: { cmd: string; out: string; open: boolean }) {
+  const i18n = useI18n()
+  const rows = 10
+  const rowHeight = 22
+  const max = rows * rowHeight
+
+  let contentRef: HTMLDivElement | undefined
+  let bodyRef: HTMLDivElement | undefined
+  let scrollRef: HTMLDivElement | undefined
+  let topRef: HTMLDivElement | undefined
+  const [copied, setCopied] = createSignal(false)
+  const [cap, setCap] = createSignal(max)
+
+  const updateMask = () => {
+    if (scrollRef) updateScrollMask(scrollRef)
+  }
+
+  const resize = () => {
+    const top = Math.ceil(topRef?.getBoundingClientRect().height ?? 0)
+    setCap(Math.max(rowHeight * 2, max - top - (props.out ? 1 : 0)))
+  }
+
+  const measure = () => {
+    resize()
+    return Math.ceil(bodyRef?.getBoundingClientRect().height ?? 0)
+  }
+
+  onMount(() => {
+    resize()
+    if (!topRef) return
+    const obs = new ResizeObserver(resize)
+    obs.observe(topRef)
+    onCleanup(() => obs.disconnect())
+  })
+
+  createEffect(() => {
+    props.cmd
+    props.out
+    queueMicrotask(() => {
+      resize()
+      updateMask()
+    })
+  })
+
+  useCollapsible({
+    content: () => contentRef,
+    body: () => bodyRef,
+    open: () => props.open,
+    measure,
+    onOpen: updateMask,
+  })
+
+  const handleCopy = async (e: MouseEvent) => {
+    e.stopPropagation()
+    const cmd = props.cmd ? `$ ${props.cmd}` : ""
+    const text = `${cmd}${props.out ? `${cmd ? "\n\n" : ""}${props.out}` : ""}`
+    if (!text) return
+    await navigator.clipboard.writeText(text)
+    setCopied(true)
+    setTimeout(() => setCopied(false), 2000)
+  }
+
+  return (
+    <div ref={contentRef} style={{ overflow: "clip", height: "0px", display: "none" }}>
+      <div ref={bodyRef} data-component="shell-expanded-shell">
+        <div data-slot="shell-expanded-body">
+          <div ref={topRef} data-slot="shell-expanded-top">
+            <div data-slot="shell-expanded-command">
+              <span data-slot="shell-expanded-prompt">$</span>
+              <span data-slot="shell-expanded-input">{props.cmd}</span>
+            </div>
+            <div data-slot="shell-expanded-actions">
+              <Tooltip
+                value={copied() ? i18n.t("ui.message.copied") : i18n.t("ui.message.copy")}
+                placement="top"
+                gutter={4}
+              >
+                <IconButton
+                  icon={copied() ? "check" : "copy"}
+                  size="small"
+                  variant="ghost"
+                  class="shell-expanded-copy"
+                  onMouseDown={(e: MouseEvent) => e.preventDefault()}
+                  onClick={handleCopy}
+                  aria-label={copied() ? i18n.t("ui.message.copied") : i18n.t("ui.message.copy")}
+                />
+              </Tooltip>
+            </div>
+          </div>
+          <Show when={props.out}>
+            <>
+              <div data-slot="shell-expanded-divider" />
+              <div
+                ref={scrollRef}
+                data-component="shell-expanded-output"
+                data-scrollable
+                onScroll={updateMask}
+                style={{ "max-height": `${cap()}px` }}
+              >
+                <pre data-slot="shell-expanded-pre">
+                  <code>{props.out}</code>
+                </pre>
+              </div>
+            </>
+          </Show>
+        </div>
+      </div>
+    </div>
+  )
+}
+
+export function ShellRollingResults(props: { part: ToolPart; animate?: boolean }) {
+  const i18n = useI18n()
+  const wiped = new Set<string>()
+  const [mounted, setMounted] = createSignal(false)
+  const [userToggled, setUserToggled] = createSignal(false)
+  const [userOpen, setUserOpen] = createSignal(false)
+  onMount(() => setMounted(true))
+  const state = createMemo(() => props.part.state as Record<string, any>)
+  const pending = createMemo(() => busy(props.part.state.status))
+  const autoOpen = hold(pending, 2000)
+  const effectiveOpen = createMemo(() => {
+    if (pending()) return true
+    if (userToggled()) return userOpen()
+    return autoOpen()
+  })
+  const expanded = createMemo(() => !pending() && !autoOpen() && userToggled() && userOpen())
+  const previewOpen = createMemo(() => effectiveOpen() && !expanded())
+  const command = createMemo(() => {
+    const value = state().input?.command ?? state().metadata?.command
+    if (typeof value === "string") return value
+    return ""
+  })
+  const subtitle = createMemo(() => {
+    const value = state().input?.description ?? state().metadata?.description
+    if (typeof value === "string" && value.trim().length > 0) return value
+    return firstLine(command()) ?? ""
+  })
+  const output = createMemo(() => {
+    const value = state().output ?? state().metadata?.output
+    if (typeof value === "string") return value
+    return ""
+  })
+  const reduce = prefersReducedMotion
+  const skip = () => reduce() || props.animate === false
+  const opacity = useSpring(() => (mounted() ? 1 : 0), GROW_SPRING)
+  const blur = useSpring(() => (mounted() ? 0 : 2), GROW_SPRING)
+  const previewOpacity = useSpring(() => (previewOpen() ? 1 : 0), GROW_SPRING)
+  const previewBlur = useSpring(() => (previewOpen() ? 0 : 2), GROW_SPRING)
+  const headerHeight = useSpring(() => (mounted() ? 37 : 0), GROW_SPRING)
+  let headerClipRef: HTMLDivElement | undefined
+  const handleHeaderClick = () => {
+    if (pending()) return
+    const el = headerClipRef
+    const viewport = el?.closest(".scroll-view__viewport") as HTMLElement | null
+    const beforeY = el?.getBoundingClientRect().top ?? 0
+    setUserToggled(true)
+    setUserOpen((prev) => !prev)
+    if (viewport && el) {
+      requestAnimationFrame(() => {
+        const afterY = el.getBoundingClientRect().top
+        const delta = afterY - beforeY
+        if (delta !== 0) viewport.scrollTop += delta
+      })
+    }
+  }
+  const line = createMemo(() => firstLine(command()))
+  const fixed = createMemo(() => {
+    const value = line()
+    if (!value) return
+    return <ShellRollingCommand text={value} animate={props.animate} />
+  })
+  const text = createThrottledValue(() => stripAnsi(output()))
+  const rows = createMemo(() => shellRows(text()))
+
+  return (
+    <div
+      data-component="shell-rolling-results"
+      style={{ opacity: skip() ? (mounted() ? 1 : 0) : opacity(), filter: `blur(${skip() ? 0 : blur()}px)` }}
+    >
+      <div
+        ref={headerClipRef}
+        data-slot="shell-rolling-header-clip"
+        data-scroll-preserve
+        data-clickable={!pending() ? "true" : "false"}
+        onClick={handleHeaderClick}
+        style={{ height: `${skip() ? (mounted() ? 37 : 0) : headerHeight()}px`, overflow: "clip" }}
+      >
+        <div data-slot="shell-rolling-header">
+          <span data-slot="shell-rolling-title">
+            <TextShimmer text={i18n.t("ui.tool.shell")} active={pending()} />
+          </span>
+          <Show when={subtitle()}>{(text) => <ShellRollingSubtitle text={text()} animate={props.animate} />}</Show>
+          <Show when={!pending()}>
+            <span data-slot="shell-rolling-actions">
+              <span data-slot="shell-rolling-arrow" data-open={effectiveOpen() ? "true" : "false"}>
+                <Icon name="chevron-down" size="small" />
+              </span>
+            </span>
+          </Show>
+        </div>
+      </div>
+      <div
+        data-slot="shell-rolling-preview"
+        style={{
+          opacity: skip() ? (previewOpen() ? 1 : 0) : previewOpacity(),
+          filter: `blur(${skip() ? 0 : previewBlur()}px)`,
+        }}
+      >
+        <RollingResults
+          class="shell-rolling-output"
+          noFadeOnCollapse
+          items={rows()}
+          fixed={fixed()}
+          fixedHeight={22}
+          rows={5}
+          rowHeight={22}
+          rowGap={0}
+          open={previewOpen()}
+          animate={props.animate !== false}
+          getKey={(row) => row.id}
+          render={(row) => {
+            const [textRef, setTextRef] = createSignal<HTMLSpanElement>()
+            useRowWipe({
+              id: () => row.id,
+              text: () => row.text,
+              ref: textRef,
+              seen: wiped,
+            })
+            return (
+              <div data-component="shell-rolling-row">
+                <span ref={setTextRef} data-slot="shell-rolling-text">
+                  {row.text}
+                </span>
+              </div>
+            )
+          }}
+        />
+      </div>
+      <ShellExpanded cmd={command()} out={text()} open={expanded()} />
+    </div>
+  )
+}

packages/ui/src/components/shell-submessage.css

@@ -1,23 +1,13 @@
 [data-component="shell-submessage"] {
   min-width: 0;
   max-width: 100%;
-  display: inline-flex;
-  align-items: baseline;
+  display: inline-block;
   vertical-align: baseline;
 }
 
-[data-component="shell-submessage"] [data-slot="shell-submessage-width"] {
-  min-width: 0;
-  max-width: 100%;
-  display: inline-flex;
-  align-items: baseline;
-  overflow: hidden;
-}
-
 [data-component="shell-submessage"] [data-slot="shell-submessage-value"] {
   display: inline-block;
   vertical-align: baseline;
   min-width: 0;
-  line-height: inherit;
   white-space: nowrap;
 }

packages/ui/src/components/text-reveal.css

@@ -4,14 +4,14 @@
  * Instead of sliding text through a fixed mask (odometer style),
  * the mask itself sweeps across each span to reveal/hide text.
  *
- * Direction: top-to-bottom. New text drops in from above, old text exits downward.
+ * Direction: bottom-to-top. New text rises in from below, old text exits upward.
  *
- * Entering: gradient reveals top-to-bottom (top of text appears first).
+ * Entering: gradient reveals bottom-to-top (bottom of text appears first).
  *   gradient(to bottom, white 33%, transparent 33%+edge)
  *   pos 0 100% = transparent covers element = hidden
  *   pos 0 0%   = white covers element       = visible
  *
- * Leaving: gradient hides top-to-bottom (top of text disappears first).
+ * Leaving: gradient hides bottom-to-top (bottom of text disappears first).
  *   gradient(to top, white 33%, transparent 33%+edge)
  *   pos 0 100% = white covers element       = visible
  *   pos 0 0%   = transparent covers element = hidden
@@ -56,17 +56,17 @@
     transition-timing-function: var(--_spring);
   }
 
-  /* ── entering: reveal top-to-bottom ──
-   * Gradient(to top): white at bottom, transparent at top of mask.
-   * Settled pos 0 100% = white covers element   = visible
-   * Swap    pos 0 0%   = transparent covers      = hidden
-   * Slides from above: translateY(-travel) → translateY(0)
+  /* ── entering: reveal bottom-to-top ──
+   * Gradient(to bottom): white at top, transparent at bottom of mask.
+   * Settled pos 0 0%   = white covers element   = visible
+   * Swap    pos 0 100% = transparent covers      = hidden
+   * Rises from below: translateY(travel) → translateY(0)
    */
   [data-slot="text-reveal-entering"] {
-    mask-image: linear-gradient(to top, white 33%, transparent calc(33% + var(--_edge)));
-    -webkit-mask-image: linear-gradient(to top, white 33%, transparent calc(33% + var(--_edge)));
-    mask-position: 0 100%;
-    -webkit-mask-position: 0 100%;
+    mask-image: linear-gradient(to bottom, white 33%, transparent calc(33% + var(--_edge)));
+    -webkit-mask-image: linear-gradient(to bottom, white 33%, transparent calc(33% + var(--_edge)));
+    mask-position: 0 0%;
+    -webkit-mask-position: 0 0%;
     transition-property:
       mask-position,
       -webkit-mask-position,
@@ -74,37 +74,37 @@
     transform: translateY(0);
   }
 
-  /* ── leaving: hide top-to-bottom + slide downward ──
-   * Gradient(to bottom): white at top, transparent at bottom of mask.
-   * Swap    pos 0 0%   = white covers element   = visible
-   * Settled pos 0 100% = transparent covers      = hidden
-   * Slides down: translateY(0) → translateY(travel)
+  /* ── leaving: hide bottom-to-top + slide upward ──
+   * Gradient(to top): white at bottom, transparent at top of mask.
+   * Swap    pos 0 100% = white covers element   = visible
+   * Settled pos 0 0%   = transparent covers      = hidden
+   * Slides up: translateY(0) → translateY(-travel)
    */
   [data-slot="text-reveal-leaving"] {
-    mask-image: linear-gradient(to bottom, white 33%, transparent calc(33% + var(--_edge)));
-    -webkit-mask-image: linear-gradient(to bottom, white 33%, transparent calc(33% + var(--_edge)));
-    mask-position: 0 100%;
-    -webkit-mask-position: 0 100%;
+    mask-image: linear-gradient(to top, white 33%, transparent calc(33% + var(--_edge)));
+    -webkit-mask-image: linear-gradient(to top, white 33%, transparent calc(33% + var(--_edge)));
+    mask-position: 0 0%;
+    -webkit-mask-position: 0 0%;
     transition-property:
       mask-position,
       -webkit-mask-position,
       transform;
-    transform: translateY(var(--_travel));
+    transform: translateY(calc(var(--_travel) * -1));
   }
 
   /* ── swapping: instant reset ──
-   * Snap entering to hidden (above), leaving to visible (center).
+   * Snap entering to hidden (below), leaving to visible (center).
    */
   &[data-swapping="true"] [data-slot="text-reveal-entering"] {
-    mask-position: 0 0%;
-    -webkit-mask-position: 0 0%;
-    transform: translateY(calc(var(--_travel) * -1));
+    mask-position: 0 100%;
+    -webkit-mask-position: 0 100%;
+    transform: translateY(var(--_travel));
     transition-duration: 0ms !important;
   }
 
   &[data-swapping="true"] [data-slot="text-reveal-leaving"] {
-    mask-position: 0 0%;
-    -webkit-mask-position: 0 0%;
+    mask-position: 0 100%;
+    -webkit-mask-position: 0 100%;
     transform: translateY(0);
     transition-duration: 0ms !important;
   }
@@ -126,15 +126,14 @@
   &[data-truncate="true"] [data-slot="text-reveal-track"] {
     width: 100%;
     min-width: 0;
-    overflow: hidden;
+    overflow: clip;
   }
 
   &[data-truncate="true"] [data-slot="text-reveal-entering"],
   &[data-truncate="true"] [data-slot="text-reveal-leaving"] {
     min-width: 0;
     width: 100%;
-    overflow: hidden;
-    text-overflow: ellipsis;
+    overflow: clip;
   }
 }
 

packages/ui/src/components/text-reveal.tsx

@@ -1,4 +1,6 @@
 import { createEffect, createSignal, on, onCleanup, onMount } from "solid-js"
+import { animate, type AnimationPlaybackControls, clearFadeStyles, clearMaskStyles, GROW_SPRING, WIPE_MASK } from "./motion"
+import { prefersReducedMotion } from "../hooks/use-reduced-motion"
 
 const px = (value: number | string | undefined, fallback: number) => {
   if (typeof value === "number") return `${value}px`
@@ -17,6 +19,11 @@ const pct = (value: number | undefined, fallback: number) => {
   return `${v}%`
 }
 
+const clearWipe = (el: HTMLElement) => {
+  clearFadeStyles(el)
+  clearMaskStyles(el)
+}
+
 export function TextReveal(props: {
   text?: string
   class?: string
@@ -39,10 +46,8 @@ export function TextReveal(props: {
   let outRef: HTMLSpanElement | undefined
   let rootRef: HTMLSpanElement | undefined
   let frame: number | undefined
-
   const win = () => inRef?.scrollWidth ?? 0
   const wout = () => outRef?.scrollWidth ?? 0
-
   const widen = (next: number) => {
     if (next <= 0) return
     if (props.growOnly ?? true) {
@@ -51,21 +56,14 @@ export function TextReveal(props: {
     }
     setWidth(`${next}px`)
   }
-
   createEffect(
     on(
       () => props.text,
       (next, prev) => {
         if (next === prev) return
-        if (typeof next === "string" && typeof prev === "string" && next.startsWith(prev)) {
-          setCur(next)
-          widen(win())
-          return
-        }
         setSwapping(true)
         setOld(prev)
         setCur(next)
-
         if (typeof requestAnimationFrame !== "function") {
           widen(Math.max(win(), wout()))
           rootRef?.offsetHeight
@@ -133,3 +131,94 @@ export function TextReveal(props: {
     </span>
   )
 }
+
+export function TextWipe(props: { text?: string; class?: string; delay?: number; animate?: boolean }) {
+  let ref: HTMLSpanElement | undefined
+  let frame: number | undefined
+  let anim: AnimationPlaybackControls | undefined
+
+  const run = () => {
+    if (props.animate === false) return
+    const el = ref
+    if (!el || !props.text || typeof window === "undefined") return
+    if (prefersReducedMotion()) return
+
+    const mask =
+      typeof CSS !== "undefined" &&
+      (CSS.supports("mask-image", "linear-gradient(to right, black, transparent)") ||
+        CSS.supports("-webkit-mask-image", "linear-gradient(to right, black, transparent)"))
+
+    anim?.stop()
+    if (frame !== undefined && typeof cancelAnimationFrame === "function") {
+      cancelAnimationFrame(frame)
+      frame = undefined
+    }
+
+    el.style.opacity = "0"
+    el.style.filter = "blur(3px)"
+    el.style.transform = "translateX(-0.06em)"
+
+    if (mask) {
+      el.style.maskImage = WIPE_MASK
+      el.style.webkitMaskImage = WIPE_MASK
+      el.style.maskSize = "240% 100%"
+      el.style.webkitMaskSize = "240% 100%"
+      el.style.maskRepeat = "no-repeat"
+      el.style.webkitMaskRepeat = "no-repeat"
+      el.style.maskPosition = "100% 0%"
+      el.style.webkitMaskPosition = "100% 0%"
+    }
+
+    if (typeof requestAnimationFrame !== "function") {
+      clearWipe(el)
+      return
+    }
+
+    frame = requestAnimationFrame(() => {
+      frame = undefined
+      const node = ref
+      if (!node) return
+      anim = mask
+        ? animate(
+            node,
+            { opacity: 1, filter: "blur(0px)", transform: "translateX(0)", maskPosition: "0% 0%" },
+            { ...GROW_SPRING, delay: props.delay ?? 0 },
+          )
+        : animate(
+            node,
+            { opacity: 1, filter: "blur(0px)", transform: "translateX(0)" },
+            { ...GROW_SPRING, delay: props.delay ?? 0 },
+          )
+
+      anim?.finished.then(() => {
+        const value = ref
+        if (!value) return
+        clearWipe(value)
+      })
+    })
+  }
+
+  createEffect(
+    on(
+      () => [props.text, props.animate] as const,
+      ([text, enabled]) => {
+        if (!text || enabled === false) {
+          if (ref) clearWipe(ref)
+          return
+        }
+        run()
+      },
+    ),
+  )
+
+  onCleanup(() => {
+    if (frame !== undefined && typeof cancelAnimationFrame === "function") cancelAnimationFrame(frame)
+    anim?.stop()
+  })
+
+  return (
+    <span ref={ref} class={props.class} aria-label={props.text ?? ""}>
+      {props.text ?? "\u00A0"}
+    </span>
+  )
+}

packages/ui/src/components/text-shimmer.css

@@ -1,11 +1,11 @@
 [data-component="text-shimmer"] {
   --text-shimmer-step: 45ms;
-  --text-shimmer-duration: 1200ms;
+  --text-shimmer-duration: 2000ms;
   --text-shimmer-swap: 220ms;
   --text-shimmer-index: 0;
   --text-shimmer-angle: 90deg;
   --text-shimmer-spread: 5.2ch;
-  --text-shimmer-size: 360%;
+  --text-shimmer-size: 600%;
   --text-shimmer-base-color: var(--text-weak);
   --text-shimmer-peak-color: var(--text-strong);
   --text-shimmer-sweep: linear-gradient(
@@ -16,15 +16,17 @@
   );
   --text-shimmer-base: linear-gradient(var(--text-shimmer-base-color), var(--text-shimmer-base-color));
 
-  display: inline-flex;
-  align-items: baseline;
+  display: inline-block;
+  vertical-align: baseline;
   font: inherit;
   letter-spacing: inherit;
   line-height: inherit;
 }
 
 [data-component="text-shimmer"] [data-slot="text-shimmer-char"] {
-  display: inline-grid;
+  display: inline-block;
+  position: relative;
+  vertical-align: baseline;
   white-space: pre;
   font: inherit;
   letter-spacing: inherit;
@@ -33,7 +35,7 @@
 
 [data-component="text-shimmer"] [data-slot="text-shimmer-char-base"],
 [data-component="text-shimmer"] [data-slot="text-shimmer-char-shimmer"] {
-  grid-area: 1 / 1;
+  display: inline-block;
   white-space: pre;
   transition: opacity var(--text-shimmer-swap) ease-out;
   font: inherit;
@@ -42,11 +44,14 @@
 }
 
 [data-component="text-shimmer"] [data-slot="text-shimmer-char-base"] {
+  position: relative;
   color: inherit;
   opacity: 1;
 }
 
 [data-component="text-shimmer"] [data-slot="text-shimmer-char-shimmer"] {
+  position: absolute;
+  inset: 0;
   color: var(--text-weaker);
   opacity: 0;
 }

packages/ui/src/components/text-shimmer.tsx

@@ -36,6 +36,19 @@ export const TextShimmer = <T extends ValidComponent = "span">(props: {
     clearTimeout(timer)
   })
 
+  const shimmerSize = createMemo(() => {
+    const len = Math.max(props.text.length, 1)
+    return Math.max(300, Math.round(200 + 1400 / len))
+  })
+
+  // duration = len × (size - 1) / velocity → uniform perceived sweep speed
+  const VELOCITY = 0.01375 // ch per ms, ~10% faster than original 0.0125 baseline
+  const shimmerDuration = createMemo(() => {
+    const len = Math.max(props.text.length, 1)
+    const s = shimmerSize() / 100
+    return Math.max(1000, Math.min(2500, Math.round((len * (s - 1)) / VELOCITY)))
+  })
+
   return (
     <Dynamic
       component={props.as ?? "span"}
@@ -46,6 +59,8 @@ export const TextShimmer = <T extends ValidComponent = "span">(props: {
       style={{
         "--text-shimmer-swap": `${swap}ms`,
         "--text-shimmer-index": `${offset()}`,
+        "--text-shimmer-size": `${shimmerSize()}%`,
+        "--text-shimmer-duration": `${shimmerDuration()}ms`,
       }}
     >
       <span data-slot="text-shimmer-char">

packages/ui/src/components/text-utils.ts

@@ -0,0 +1,17 @@
+/** Find the longest common character prefix between two strings. */
+export function commonPrefix(a: string, b: string) {
+  const ac = Array.from(a)
+  const bc = Array.from(b)
+  let i = 0
+  while (i < ac.length && i < bc.length && ac[i] === bc[i]) i++
+  return {
+    prefix: ac.slice(0, i).join(""),
+    aSuffix: ac.slice(i).join(""),
+    bSuffix: bc.slice(i).join(""),
+  }
+}
+
+export function list<T>(value: T[] | undefined | null, fallback: T[]): T[] {
+  if (Array.isArray(value)) return value
+  return fallback
+}

packages/ui/src/components/tool-count-label.css

@@ -27,10 +27,10 @@
     grid-template-columns: 0fr;
     opacity: 0;
     filter: blur(calc(var(--tool-motion-blur, 2px) * 0.42));
-    overflow: hidden;
+    overflow: clip;
     transform: translateX(-0.04em);
     transition-property: grid-template-columns, opacity, filter, transform;
-    transition-duration: 250ms, 250ms, 250ms, 250ms;
+    transition-duration: 800ms, 400ms, 400ms, 800ms;
     transition-timing-function:
       var(--tool-motion-ease, cubic-bezier(0.22, 1, 0.36, 1)), ease-out, ease-out,
       var(--tool-motion-ease, cubic-bezier(0.22, 1, 0.36, 1));
@@ -45,7 +45,7 @@
 
   [data-slot="tool-count-label-suffix-inner"] {
     min-width: 0;
-    overflow: hidden;
+    overflow: clip;
     white-space: pre;
   }
 }

packages/ui/src/components/tool-count-label.tsx

@@ -1,5 +1,6 @@
 import { createMemo } from "solid-js"
 import { AnimatedNumber } from "./animated-number"
+import { commonPrefix } from "./text-utils"
 
 function split(text: string) {
   const match = /{{\s*count\s*}}/.exec(text)
@@ -11,35 +12,23 @@ function split(text: string) {
   }
 }
 
-function common(one: string, other: string) {
-  const a = Array.from(one)
-  const b = Array.from(other)
-  let i = 0
-  while (i < a.length && i < b.length && a[i] === b[i]) i++
-  return {
-    stem: a.slice(0, i).join(""),
-    one: a.slice(i).join(""),
-    other: b.slice(i).join(""),
-  }
-}
-
 export function AnimatedCountLabel(props: { count: number; one: string; other: string; class?: string }) {
   const one = createMemo(() => split(props.one))
   const other = createMemo(() => split(props.other))
   const singular = createMemo(() => Math.round(props.count) === 1)
   const active = createMemo(() => (singular() ? one() : other()))
-  const suffix = createMemo(() => common(one().after, other().after))
+  const suffix = createMemo(() => commonPrefix(one().after, other().after))
   const splitSuffix = createMemo(
     () =>
       one().before === other().before &&
       (one().after.startsWith(other().after) || other().after.startsWith(one().after)),
   )
   const before = createMemo(() => (splitSuffix() ? one().before : active().before))
-  const stem = createMemo(() => (splitSuffix() ? suffix().stem : active().after))
+  const stem = createMemo(() => (splitSuffix() ? suffix().prefix : active().after))
   const tail = createMemo(() => {
     if (!splitSuffix()) return ""
-    if (singular()) return suffix().one
-    return suffix().other
+    if (singular()) return suffix().aSuffix
+    return suffix().bSuffix
   })
   const showTail = createMemo(() => splitSuffix() && tail().length > 0)
 

packages/ui/src/components/tool-count-summary.css

@@ -10,12 +10,12 @@
     opacity: 1;
     filter: blur(0);
     transform: translateY(0) scale(1);
-    overflow: hidden;
+    overflow: clip;
     transform-origin: left center;
     transition-property: grid-template-columns, opacity, filter, transform;
     transition-duration:
-      var(--tool-motion-spring-ms, 480ms), var(--tool-motion-fade-ms, 240ms), var(--tool-motion-fade-ms, 280ms),
-      var(--tool-motion-spring-ms, 480ms);
+      var(--tool-motion-spring-ms, 800ms), var(--tool-motion-fade-ms, 400ms), var(--tool-motion-fade-ms, 400ms),
+      var(--tool-motion-spring-ms, 800ms);
     transition-timing-function:
       var(--tool-motion-ease, cubic-bezier(0.22, 1, 0.36, 1)), ease-out, ease-out,
       var(--tool-motion-ease, cubic-bezier(0.22, 1, 0.36, 1));
@@ -35,12 +35,12 @@
     opacity: 0;
     filter: blur(var(--tool-motion-blur, 2px));
     transform: translateY(0.06em) scale(0.985);
-    overflow: hidden;
+    overflow: clip;
     transform-origin: left center;
     transition-property: grid-template-columns, opacity, filter, transform;
     transition-duration:
-      var(--tool-motion-spring-ms, 480ms), var(--tool-motion-fade-ms, 280ms), var(--tool-motion-fade-ms, 320ms),
-      var(--tool-motion-spring-ms, 480ms);
+      var(--tool-motion-spring-ms, 800ms), var(--tool-motion-fade-ms, 400ms), var(--tool-motion-fade-ms, 400ms),
+      var(--tool-motion-spring-ms, 800ms);
     transition-timing-function:
       var(--tool-motion-ease, cubic-bezier(0.22, 1, 0.36, 1)), ease-out, ease-out,
       var(--tool-motion-ease, cubic-bezier(0.22, 1, 0.36, 1));
@@ -55,7 +55,7 @@
 
   [data-slot="tool-count-summary-empty-inner"] {
     min-width: 0;
-    overflow: hidden;
+    overflow: clip;
     white-space: nowrap;
   }
 
@@ -63,7 +63,7 @@
     display: inline-flex;
     align-items: baseline;
     min-width: 0;
-    overflow: hidden;
+    overflow: clip;
     white-space: nowrap;
   }
 
@@ -75,12 +75,12 @@
     margin-right: 0;
     opacity: 0;
     filter: blur(calc(var(--tool-motion-blur, 2px) * 0.55));
-    overflow: hidden;
+    overflow: clip;
     transform: translateX(-0.08em);
     transition-property: opacity, filter, transform;
     transition-duration:
-      calc(var(--tool-motion-fade-ms, 200ms) * 0.75), calc(var(--tool-motion-fade-ms, 220ms) * 0.75),
-      calc(var(--tool-motion-fade-ms, 220ms) * 0.6);
+      var(--tool-motion-fade-ms, 400ms), var(--tool-motion-fade-ms, 400ms),
+      var(--tool-motion-fade-ms, 400ms);
     transition-timing-function: ease-out, ease-out, ease-out;
   }
 

packages/ui/src/components/tool-status-title.css

@@ -18,9 +18,8 @@
   [data-slot="tool-status-swap"],
   [data-slot="tool-status-tail"] {
     display: inline-grid;
-    overflow: hidden;
+    overflow: clip;
     justify-items: start;
-    transition: width var(--tool-motion-spring-ms, 480ms) var(--tool-motion-ease, cubic-bezier(0.22, 1, 0.36, 1));
   }
 
   [data-slot="tool-status-active"],
@@ -31,8 +30,8 @@
     text-align: start;
     transition-property: opacity, filter, transform;
     transition-duration:
-      var(--tool-motion-fade-ms, 240ms), calc(var(--tool-motion-fade-ms, 240ms) * 0.8),
-      calc(var(--tool-motion-fade-ms, 240ms) * 0.8);
+      var(--tool-motion-fade-ms, 400ms), calc(var(--tool-motion-fade-ms, 400ms) * 0.8),
+      calc(var(--tool-motion-fade-ms, 400ms) * 0.8);
     transition-timing-function: ease-out, ease-out, ease-out;
   }
 

packages/ui/src/components/tool-status-title.tsx

@@ -1,17 +1,8 @@
 import { Show, createEffect, createMemo, createSignal, on, onCleanup, onMount } from "solid-js"
+import { animate, type AnimationPlaybackControls, GROW_SPRING } from "./motion"
 import { TextShimmer } from "./text-shimmer"
-
-function common(active: string, done: string) {
-  const a = Array.from(active)
-  const b = Array.from(done)
-  let i = 0
-  while (i < a.length && i < b.length && a[i] === b[i]) i++
-  return {
-    prefix: a.slice(0, i).join(""),
-    active: a.slice(i).join(""),
-    done: b.slice(i).join(""),
-  }
-}
+import { commonPrefix } from "./text-utils"
+import { prefersReducedMotion } from "../hooks/use-reduced-motion"
 
 function contentWidth(el: HTMLSpanElement | undefined) {
   if (!el) return 0
@@ -27,25 +18,58 @@ export function ToolStatusTitle(props: {
   class?: string
   split?: boolean
 }) {
-  const split = createMemo(() => common(props.activeText, props.doneText))
+  const split = createMemo(() => commonPrefix(props.activeText, props.doneText))
   const suffix = createMemo(
-    () => (props.split ?? true) && split().prefix.length >= 2 && split().active.length > 0 && split().done.length > 0,
+    () => (props.split ?? true) && split().prefix.length >= 2 && split().aSuffix.length > 0 && split().bSuffix.length > 0,
   )
   const prefixLen = createMemo(() => Array.from(split().prefix).length)
-  const activeTail = createMemo(() => (suffix() ? split().active : props.activeText))
-  const doneTail = createMemo(() => (suffix() ? split().done : props.doneText))
+  const activeTail = createMemo(() => (suffix() ? split().aSuffix : props.activeText))
+  const doneTail = createMemo(() => (suffix() ? split().bSuffix : props.doneText))
 
-  const [width, setWidth] = createSignal("auto")
   const [ready, setReady] = createSignal(false)
   let activeRef: HTMLSpanElement | undefined
   let doneRef: HTMLSpanElement | undefined
+  let swapRef: HTMLSpanElement | undefined
+  let tailRef: HTMLSpanElement | undefined
   let frame: number | undefined
   let readyFrame: number | undefined
+  let widthAnim: AnimationPlaybackControls | undefined
+
+  const node = () => (suffix() ? tailRef : swapRef)
+
+  const reduce = prefersReducedMotion
+
+  const setNodeWidth = (width: string) => {
+    if (swapRef) swapRef.style.width = width
+    if (tailRef) tailRef.style.width = width
+  }
 
   const measure = () => {
     const target = props.active ? activeRef : doneRef
-    const px = contentWidth(target)
-    if (px > 0) setWidth(`${px}px`)
+    const next = contentWidth(target)
+    if (next <= 0) return
+
+    const ref = node()
+    if (!ref || !ready() || reduce()) {
+      widthAnim?.stop()
+      setNodeWidth(`${next}px`)
+      return
+    }
+
+    const prev = Math.max(0, Math.ceil(ref.getBoundingClientRect().width))
+    if (Math.abs(next - prev) < 1) {
+      ref.style.width = `${next}px`
+      return
+    }
+
+    ref.style.width = `${prev}px`
+    widthAnim?.stop()
+    widthAnim = animate(ref, { width: `${next}px` }, GROW_SPRING)
+    widthAnim.finished.then(() => {
+      const el = node()
+      if (!el) return
+      el.style.width = `${next}px`
+    })
   }
 
   const schedule = () => {
@@ -90,6 +114,7 @@ export function ToolStatusTitle(props: {
   onCleanup(() => {
     if (frame !== undefined) cancelAnimationFrame(frame)
     if (readyFrame !== undefined) cancelAnimationFrame(readyFrame)
+    widthAnim?.stop()
   })
 
   return (
@@ -104,7 +129,7 @@ export function ToolStatusTitle(props: {
       <Show
         when={suffix()}
         fallback={
-          <span data-slot="tool-status-swap" style={{ width: width() }}>
+          <span data-slot="tool-status-swap" ref={swapRef}>
             <span data-slot="tool-status-active" ref={activeRef}>
               <TextShimmer text={activeTail()} active={props.active} offset={0} />
             </span>
@@ -118,7 +143,7 @@ export function ToolStatusTitle(props: {
           <span data-slot="tool-status-prefix">
             <TextShimmer text={split().prefix} active={props.active} offset={0} />
           </span>
-          <span data-slot="tool-status-tail" style={{ width: width() }}>
+          <span data-slot="tool-status-tail" ref={tailRef}>
             <span data-slot="tool-status-active" ref={activeRef}>
               <TextShimmer text={activeTail()} active={props.active} offset={prefixLen()} />
             </span>

packages/ui/src/components/tool-utils.ts

@@ -0,0 +1,325 @@
+import { createEffect, createMemo, createSignal, on, onCleanup, onMount } from "solid-js"
+import {
+  animate,
+  type AnimationPlaybackControls,
+  clearFadeStyles,
+  clearMaskStyles,
+  COLLAPSIBLE_SPRING,
+  GROW_SPRING,
+  WIPE_MASK,
+} from "./motion"
+import { prefersReducedMotion } from "../hooks/use-reduced-motion"
+import type { ToolPart } from "@opencode-ai/sdk/v2"
+
+export const TEXT_RENDER_THROTTLE_MS = 100
+
+export function createThrottledValue(getValue: () => string) {
+  const [value, setValue] = createSignal(getValue())
+  let timeout: ReturnType<typeof setTimeout> | undefined
+  let last = 0
+
+  createEffect(() => {
+    const next = getValue()
+    const now = Date.now()
+
+    const remaining = TEXT_RENDER_THROTTLE_MS - (now - last)
+    if (remaining <= 0) {
+      if (timeout) {
+        clearTimeout(timeout)
+        timeout = undefined
+      }
+      last = now
+      setValue(next)
+      return
+    }
+    if (timeout) clearTimeout(timeout)
+    timeout = setTimeout(() => {
+      last = Date.now()
+      setValue(next)
+      timeout = undefined
+    }, remaining)
+  })
+
+  onCleanup(() => {
+    if (timeout) clearTimeout(timeout)
+  })
+
+  return value
+}
+
+export function busy(status: string | undefined) {
+  return status === "pending" || status === "running"
+}
+
+export function hold(state: () => boolean, wait = 2000) {
+  const [live, setLive] = createSignal(state())
+  let timer: ReturnType<typeof setTimeout> | undefined
+
+  createEffect(() => {
+    if (state()) {
+      if (timer) clearTimeout(timer)
+      timer = undefined
+      setLive(true)
+      return
+    }
+
+    if (timer) clearTimeout(timer)
+    timer = setTimeout(() => {
+      timer = undefined
+      setLive(false)
+    }, wait)
+  })
+
+  onCleanup(() => {
+    if (timer) clearTimeout(timer)
+  })
+
+  return live
+}
+
+export function updateScrollMask(el: HTMLElement, fade = 12) {
+  const { scrollTop, scrollHeight, clientHeight } = el
+  const overflow = scrollHeight - clientHeight
+  if (overflow <= 1) {
+    el.style.maskImage = ""
+    el.style.webkitMaskImage = ""
+    return
+  }
+  const top = scrollTop > 1
+  const bottom = scrollTop < overflow - 1
+  const mask =
+    top && bottom
+      ? `linear-gradient(to bottom, transparent 0, black ${fade}px, black calc(100% - ${fade}px), transparent 100%)`
+      : top
+        ? `linear-gradient(to bottom, transparent 0, black ${fade}px)`
+        : bottom
+          ? `linear-gradient(to bottom, black calc(100% - ${fade}px), transparent 100%)`
+          : ""
+  el.style.maskImage = mask
+  el.style.webkitMaskImage = mask
+}
+
+export function useCollapsible(options: {
+  content: () => HTMLElement | undefined
+  body: () => HTMLElement | undefined
+  open: () => boolean
+  measure?: () => number
+  onOpen?: () => void
+}) {
+  let heightAnim: AnimationPlaybackControls | undefined
+  let fadeAnim: AnimationPlaybackControls | undefined
+  let gen = 0
+
+  createEffect(
+    on(
+      options.open,
+      (isOpen) => {
+        const content = options.content()
+        const body = options.body()
+        if (!content || !body) return
+        heightAnim?.stop()
+        fadeAnim?.stop()
+        const id = ++gen
+        if (isOpen) {
+          content.style.display = ""
+          content.style.height = "0px"
+          body.style.opacity = "0"
+          body.style.filter = "blur(2px)"
+          fadeAnim = animate(body, { opacity: [0, 1], filter: ["blur(2px)", "blur(0px)"] }, COLLAPSIBLE_SPRING)
+          queueMicrotask(() => {
+            if (gen !== id) return
+            const c = options.content()
+            if (!c) return
+            const h = options.measure?.() ?? Math.ceil(body.getBoundingClientRect().height)
+            heightAnim = animate(c, { height: ["0px", `${h}px`] }, COLLAPSIBLE_SPRING)
+            heightAnim.finished.then(
+              () => {
+                if (gen !== id) return
+                c.style.height = "auto"
+                options.onOpen?.()
+              },
+              () => {},
+            )
+          })
+          return
+        }
+
+        const h = content.getBoundingClientRect().height
+        heightAnim = animate(content, { height: [`${h}px`, "0px"] }, COLLAPSIBLE_SPRING)
+        fadeAnim = animate(body, { opacity: [1, 0], filter: ["blur(0px)", "blur(2px)"] }, COLLAPSIBLE_SPRING)
+        heightAnim.finished.then(
+          () => {
+            if (gen !== id) return
+            content.style.display = "none"
+          },
+          () => {},
+        )
+      },
+      { defer: true },
+    ),
+  )
+
+  onCleanup(() => {
+    ++gen
+    heightAnim?.stop()
+    fadeAnim?.stop()
+  })
+}
+
+export function useContextToolPending(parts: () => ToolPart[], working?: () => boolean) {
+  const anyRunning = createMemo(() => parts().some((part) => busy(part.state.status)))
+  const [settled, setSettled] = createSignal(false)
+  createEffect(() => {
+    if (!anyRunning() && !working?.()) setSettled(true)
+  })
+  return createMemo(() => !settled() && (!!working?.() || anyRunning()))
+}
+
+export function useRowWipe(opts: {
+  id: () => string
+  text: () => string | undefined
+  ref: () => HTMLElement | undefined
+  seen: Set<string>
+}) {
+  const reduce = prefersReducedMotion
+
+  createEffect(() => {
+    const id = opts.id()
+    const txt = opts.text()
+    const el = opts.ref()
+    if (!el) return
+    if (!txt) {
+      clearFadeStyles(el)
+      clearMaskStyles(el)
+      return
+    }
+    if (reduce() || typeof window === "undefined") {
+      clearFadeStyles(el)
+      clearMaskStyles(el)
+      return
+    }
+    if (opts.seen.has(id)) {
+      clearFadeStyles(el)
+      clearMaskStyles(el)
+      return
+    }
+    opts.seen.add(id)
+
+    el.style.maskImage = WIPE_MASK
+    el.style.webkitMaskImage = WIPE_MASK
+    el.style.maskSize = "240% 100%"
+    el.style.webkitMaskSize = "240% 100%"
+    el.style.maskRepeat = "no-repeat"
+    el.style.webkitMaskRepeat = "no-repeat"
+    el.style.maskPosition = "100% 0%"
+    el.style.webkitMaskPosition = "100% 0%"
+    el.style.opacity = "0"
+    el.style.filter = "blur(2px)"
+    el.style.transform = "translateX(-0.06em)"
+
+    let done = false
+    const clear = () => {
+      if (done) return
+      done = true
+      clearFadeStyles(el)
+      clearMaskStyles(el)
+    }
+    if (typeof requestAnimationFrame !== "function") {
+      clear()
+      return
+    }
+    let anim: AnimationPlaybackControls | undefined
+    let frame: number | undefined = requestAnimationFrame(() => {
+      frame = undefined
+      const node = opts.ref()
+      if (!node) return
+      anim = animate(
+        node,
+        {
+          opacity: [0, 1],
+          filter: ["blur(2px)", "blur(0px)"],
+          transform: ["translateX(-0.06em)", "translateX(0)"],
+          maskPosition: "0% 0%",
+        },
+        GROW_SPRING,
+      )
+
+      anim.finished.catch(() => {}).finally(clear)
+    })
+
+    onCleanup(() => {
+      if (frame !== undefined) {
+        cancelAnimationFrame(frame)
+        clear()
+      }
+    })
+  })
+}
+
+export function useToolFade(
+  ref: () => HTMLElement | undefined,
+  options?: { delay?: number; wipe?: boolean; animate?: boolean },
+) {
+  let anim: AnimationPlaybackControls | undefined
+  let frame: number | undefined
+  const delay = options?.delay ?? 0
+  const wipe = options?.wipe ?? false
+  const active = options?.animate !== false
+
+  onMount(() => {
+    if (!active) return
+
+    const el = ref()
+    if (!el || typeof window === "undefined") return
+    if (prefersReducedMotion()) return
+
+    const mask =
+      wipe &&
+      typeof CSS !== "undefined" &&
+      (CSS.supports("mask-image", "linear-gradient(to right, black, transparent)") ||
+        CSS.supports("-webkit-mask-image", "linear-gradient(to right, black, transparent)"))
+
+    el.style.opacity = "0"
+    el.style.filter = wipe ? "blur(3px)" : "blur(2px)"
+    el.style.transform = wipe ? "translateX(-0.06em)" : "translateY(0.04em)"
+
+    if (mask) {
+      el.style.maskImage = WIPE_MASK
+      el.style.webkitMaskImage = WIPE_MASK
+      el.style.maskSize = "240% 100%"
+      el.style.webkitMaskSize = "240% 100%"
+      el.style.maskRepeat = "no-repeat"
+      el.style.webkitMaskRepeat = "no-repeat"
+      el.style.maskPosition = "100% 0%"
+      el.style.webkitMaskPosition = "100% 0%"
+    }
+
+    frame = requestAnimationFrame(() => {
+      frame = undefined
+      const node = ref()
+      if (!node) return
+
+      anim = wipe
+        ? mask
+          ? animate(
+              node,
+              { opacity: 1, filter: "blur(0px)", transform: "translateX(0)", maskPosition: "0% 0%" },
+              { ...GROW_SPRING, delay },
+            )
+          : animate(node, { opacity: 1, filter: "blur(0px)", transform: "translateX(0)" }, { ...GROW_SPRING, delay })
+        : animate(node, { opacity: 1, filter: "blur(0px)", transform: "translateY(0)" }, { ...GROW_SPRING, delay })
+
+      anim?.finished.then(() => {
+        const value = ref()
+        if (!value) return
+        clearFadeStyles(value)
+        if (mask) clearMaskStyles(value)
+      })
+    })
+  })
+
+  onCleanup(() => {
+    if (frame !== undefined) cancelAnimationFrame(frame)
+    anim?.stop()
+  })
+}

packages/ui/src/hooks/create-auto-scroll.tsx

@@ -1,6 +1,8 @@
 import { createEffect, on, onCleanup } from "solid-js"
 import { createStore } from "solid-js/store"
 import { createResizeObserver } from "@solid-primitives/resize-observer"
+import { animate, type AnimationPlaybackControls } from "motion"
+import { FAST_SPRING } from "../components/motion"
 
 export interface AutoScrollOptions {
   working: () => boolean
@@ -9,13 +11,28 @@ export interface AutoScrollOptions {
   bottomThreshold?: number
 }
 
+const SETTLE_MS = 500
+const AUTO_SCROLL_GRACE_MS = 120
+const AUTO_SCROLL_EPSILON = 0.5
+const MANUAL_ANCHOR_MS = 3000
+const MANUAL_ANCHOR_QUIET_FRAMES = 24
+
 export function createAutoScroll(options: AutoScrollOptions) {
   let scroll: HTMLElement | undefined
   let settling = false
   let settleTimer: ReturnType<typeof setTimeout> | undefined
-  let autoTimer: ReturnType<typeof setTimeout> | undefined
   let cleanup: (() => void) | undefined
-  let auto: { top: number; time: number } | undefined
+  let programmaticUntil = 0
+  let scrollAnim: AnimationPlaybackControls | undefined
+  let hold:
+    | {
+        el: HTMLElement
+        top: number
+        until: number
+        quiet: number
+        frame: number | undefined
+      }
+    | undefined
 
   const threshold = () => options.bottomThreshold ?? 10
 
@@ -27,77 +44,160 @@ export function createAutoScroll(options: AutoScrollOptions) {
   const active = () => options.working() || settling
 
   const distanceFromBottom = (el: HTMLElement) => {
-    return el.scrollHeight - el.clientHeight - el.scrollTop
+    // With column-reverse, scrollTop=0 is at the bottom, negative = scrolled up
+    return Math.abs(el.scrollTop)
   }
 
   const canScroll = (el: HTMLElement) => {
     return el.scrollHeight - el.clientHeight > 1
   }
 
-  // Browsers can dispatch scroll events asynchronously. If new content arrives
-  // between us calling `scrollTo()` and the subsequent `scroll` event firing,
-  // the handler can see a non-zero `distanceFromBottom` and incorrectly assume
-  // the user scrolled.
-  const markAuto = (el: HTMLElement) => {
-    auto = {
-      top: Math.max(0, el.scrollHeight - el.clientHeight),
-      time: Date.now(),
-    }
+  const markProgrammatic = () => {
+    programmaticUntil = Date.now() + AUTO_SCROLL_GRACE_MS
+  }
 
-    if (autoTimer) clearTimeout(autoTimer)
-    autoTimer = setTimeout(() => {
-      auto = undefined
-      autoTimer = undefined
-    }, 1500)
+  const clearHold = () => {
+    const next = hold
+    if (!next) return
+    if (next.frame !== undefined) cancelAnimationFrame(next.frame)
+    hold = undefined
   }
 
-  const isAuto = (el: HTMLElement) => {
-    const a = auto
-    if (!a) return false
+  const tickHold = () => {
+    const next = hold
+    const el = scroll
+    if (!next || !el) return false
+    if (Date.now() > next.until) {
+      clearHold()
+      return false
+    }
+    if (!next.el.isConnected) {
+      clearHold()
+      return false
+    }
 
-    if (Date.now() - a.time > 1500) {
-      auto = undefined
+    const current = next.el.getBoundingClientRect().top
+    if (!Number.isFinite(current)) {
+      clearHold()
       return false
     }
 
-    return Math.abs(el.scrollTop - a.top) < 2
+    const delta = current - next.top
+    if (Math.abs(delta) <= AUTO_SCROLL_EPSILON) {
+      next.quiet += 1
+      if (next.quiet > MANUAL_ANCHOR_QUIET_FRAMES) {
+        clearHold()
+        return false
+      }
+      return true
+    }
+
+    next.quiet = 0
+    if (!store.userScrolled) {
+      setStore("userScrolled", true)
+      options.onUserInteracted?.()
+    }
+    el.scrollTop += delta
+    markProgrammatic()
+    return true
+  }
+
+  const scheduleHold = () => {
+    const next = hold
+    if (!next) return
+    if (next.frame !== undefined) return
+
+    next.frame = requestAnimationFrame(() => {
+      const value = hold
+      if (!value) return
+      value.frame = undefined
+      if (!tickHold()) return
+      scheduleHold()
+    })
   }
 
-  const scrollToBottomNow = (behavior: ScrollBehavior) => {
+  const preserve = (target: HTMLElement) => {
     const el = scroll
     if (!el) return
-    markAuto(el)
-    if (behavior === "smooth") {
-      el.scrollTo({ top: el.scrollHeight, behavior })
-      return
+
+    if (!store.userScrolled) {
+      setStore("userScrolled", true)
+      options.onUserInteracted?.()
     }
 
-    // `scrollTop` assignment bypasses any CSS `scroll-behavior: smooth`.
-    el.scrollTop = el.scrollHeight
+    const top = target.getBoundingClientRect().top
+    if (!Number.isFinite(top)) return
+
+    clearHold()
+    hold = {
+      el: target,
+      top,
+      until: Date.now() + MANUAL_ANCHOR_MS,
+      quiet: 0,
+      frame: undefined,
+    }
+    scheduleHold()
   }
 
   const scrollToBottom = (force: boolean) => {
     if (!force && !active()) return
 
+    clearHold()
+
     if (force && store.userScrolled) setStore("userScrolled", false)
 
     const el = scroll
     if (!el) return
 
+    if (scrollAnim) cancelSmooth()
     if (!force && store.userScrolled) return
 
-    const distance = distanceFromBottom(el)
-    if (distance < 2) {
-      markAuto(el)
+    // With column-reverse, scrollTop=0 is at the bottom
+    if (Math.abs(el.scrollTop) <= AUTO_SCROLL_EPSILON) {
+      markProgrammatic()
       return
     }
 
-    // For auto-following content we prefer immediate updates to avoid
-    // visible "catch up" animations while content is still settling.
-    scrollToBottomNow("auto")
+    el.scrollTop = 0
+    markProgrammatic()
+  }
+
+  const cancelSmooth = () => {
+    if (scrollAnim) {
+      scrollAnim.stop()
+      scrollAnim = undefined
+    }
   }
 
-  const stop = () => {
+  const smoothScrollToBottom = () => {
+    const el = scroll
+    if (!el) return
+
+    cancelSmooth()
+    if (store.userScrolled) setStore("userScrolled", false)
+
+    // With column-reverse, scrollTop=0 is at the bottom
+    if (Math.abs(el.scrollTop) <= AUTO_SCROLL_EPSILON) {
+      markProgrammatic()
+      return
+    }
+
+    scrollAnim = animate(el.scrollTop, 0, {
+      ...FAST_SPRING,
+      onUpdate: (v) => {
+        markProgrammatic()
+        el.scrollTop = v
+      },
+      onComplete: () => {
+        scrollAnim = undefined
+        markProgrammatic()
+      },
+    })
+  }
+
+  const stop = (input?: { hold?: boolean }) => {
+    if (input?.hold !== false) clearHold()
+
     const el = scroll
     if (!el) return
     if (!canScroll(el)) {
@@ -106,15 +206,25 @@ export function createAutoScroll(options: AutoScrollOptions) {
     }
     if (store.userScrolled) return
 
+    markProgrammatic()
     setStore("userScrolled", true)
     options.onUserInteracted?.()
   }
 
   const handleWheel = (e: WheelEvent) => {
+    if (e.deltaY !== 0) clearHold()
+
+    if (e.deltaY > 0) {
+      const el = scroll
+      if (!el) return
+      if (distanceFromBottom(el) >= threshold()) return
+      if (store.userScrolled) setStore("userScrolled", false)
+      markProgrammatic()
+      return
+    }
+
     if (e.deltaY >= 0) return
-    // If the user is scrolling within a nested scrollable region (tool output,
-    // code block, etc), don't treat it as leaving the "follow bottom" mode.
-    // Those regions opt in via `data-scrollable`.
+    cancelSmooth()
     const el = scroll
     const target = e.target instanceof Element ? e.target : undefined
     const nested = target?.closest("[data-scrollable]")
@@ -126,23 +236,27 @@ export function createAutoScroll(options: AutoScrollOptions) {
     const el = scroll
     if (!el) return
 
+    if (hold) {
+      if (Date.now() < programmaticUntil) return
+      clearHold()
+    }
+
     if (!canScroll(el)) {
       if (store.userScrolled) setStore("userScrolled", false)
+      markProgrammatic()
       return
     }
 
     if (distanceFromBottom(el) < threshold()) {
+      if (Date.now() < programmaticUntil) return
       if (store.userScrolled) setStore("userScrolled", false)
+      markProgrammatic()
       return
     }
 
-    // Ignore scroll events triggered by our own scrollToBottom calls.
-    if (!store.userScrolled && isAuto(el)) {
-      scrollToBottom(false)
-      return
-    }
+    if (!store.userScrolled && Date.now() < programmaticUntil) return
 
-    stop()
+    stop({ hold: false })
   }
 
   const handleInteraction = () => {
@@ -154,6 +268,11 @@ export function createAutoScroll(options: AutoScrollOptions) {
   }
 
   const updateOverflowAnchor = (el: HTMLElement) => {
+    if (hold) {
+      el.style.overflowAnchor = "none"
+      return
+    }
+
     const mode = options.overflowAnchor ?? "dynamic"
 
     if (mode === "none") {
@@ -173,15 +292,17 @@ export function createAutoScroll(options: AutoScrollOptions) {
     () => store.contentRef,
     () => {
       const el = scroll
+      if (hold) {
+        scheduleHold()
+        return
+      }
       if (el && !canScroll(el)) {
         if (store.userScrolled) setStore("userScrolled", false)
+        markProgrammatic()
         return
       }
       if (!active()) return
       if (store.userScrolled) return
-      // ResizeObserver fires after layout, before paint.
-      // Keep the bottom locked in the same frame to avoid visible
-      // "jump up then catch up" artifacts while streaming content.
       scrollToBottom(false)
     },
   )
@@ -200,13 +321,11 @@ export function createAutoScroll(options: AutoScrollOptions) {
       settling = true
       settleTimer = setTimeout(() => {
         settling = false
-      }, 300)
+      }, SETTLE_MS)
     }),
   )
 
   createEffect(() => {
-    // Track `userScrolled` even before `scrollRef` is attached, so we can
-    // update overflow anchoring once the element exists.
     store.userScrolled
     const el = scroll
     if (!el) return
@@ -215,7 +334,8 @@ export function createAutoScroll(options: AutoScrollOptions) {
 
   onCleanup(() => {
     if (settleTimer) clearTimeout(settleTimer)
-    if (autoTimer) clearTimeout(autoTimer)
+    clearHold()
+    cancelSmooth()
     if (cleanup) cleanup()
   })
 
@@ -228,8 +348,12 @@ export function createAutoScroll(options: AutoScrollOptions) {
 
       scroll = el
 
-      if (!el) return
+      if (!el) {
+        clearHold()
+        return
+      }
 
+      markProgrammatic()
       updateOverflowAnchor(el)
       el.addEventListener("wheel", handleWheel, { passive: true })
 
@@ -240,13 +364,18 @@ export function createAutoScroll(options: AutoScrollOptions) {
     contentRef: (el: HTMLElement | undefined) => setStore("contentRef", el),
     handleScroll,
     handleInteraction,
+    preserve,
     pause: stop,
-    resume: () => {
+    forceScrollToBottom: () => scrollToBottom(true),
+    smoothScrollToBottom,
+    snapToBottom: () => {
+      const el = scroll
+      if (!el) return
       if (store.userScrolled) setStore("userScrolled", false)
-      scrollToBottom(true)
+      // With column-reverse, scrollTop=0 is at the bottom
+      el.scrollTop = 0
+      markProgrammatic()
     },
-    scrollToBottom: () => scrollToBottom(false),
-    forceScrollToBottom: () => scrollToBottom(true),
     userScrolled: () => store.userScrolled,
   }
 }

packages/ui/src/hooks/index.ts

@@ -1,2 +1,5 @@
 export * from "./use-filtered-list"
 export * from "./create-auto-scroll"
+export * from "./use-element-height"
+export * from "./use-reduced-motion"
+export * from "./use-page-visible"

packages/ui/src/hooks/use-element-height.ts

@@ -0,0 +1,25 @@
+import { createEffect, createSignal, onCleanup, type Accessor } from "solid-js"
+
+/**
+ * Tracks an element's height via ResizeObserver.
+ * Returns a reactive signal that updates whenever the element resizes.
+ */
+export function useElementHeight(
+  ref: Accessor<HTMLElement | undefined> | (() => HTMLElement | undefined),
+  initial = 0,
+): Accessor<number> {
+  const [height, setHeight] = createSignal(initial)
+
+  createEffect(() => {
+    const el = ref()
+    if (!el) return
+    setHeight(el.getBoundingClientRect().height)
+    const observer = new ResizeObserver(() => {
+      setHeight(el.getBoundingClientRect().height)
+    })
+    observer.observe(el)
+    onCleanup(() => observer.disconnect())
+  })
+
+  return height
+}

packages/ui/src/hooks/use-page-visible.ts

@@ -0,0 +1,11 @@
+import { createSignal } from "solid-js"
+
+export const pageVisible = /* @__PURE__ */ (() => {
+  const [visible, setVisible] = createSignal(true)
+  if (typeof document !== "undefined") {
+    const sync = () => setVisible(document.visibilityState !== "hidden")
+    sync()
+    document.addEventListener("visibilitychange", sync)
+  }
+  return visible
+})()

packages/ui/src/hooks/use-reduced-motion.ts

@@ -0,0 +1,9 @@
+import { createSignal } from "solid-js"
+
+export const prefersReducedMotion = /* @__PURE__ */ (() => {
+  if (typeof window === "undefined") return () => false
+  const mql = window.matchMedia("(prefers-reduced-motion: reduce)")
+  const [reduced, setReduced] = createSignal(mql.matches)
+  mql.addEventListener("change", () => setReduced(mql.matches))
+  return reduced
+})()

packages/ui/src/styles/index.css

@@ -40,6 +40,7 @@
 @import "../components/progress-circle.css" layer(components);
 @import "../components/radio-group.css" layer(components);
 @import "../components/resize-handle.css" layer(components);
+@import "../components/rolling-results.css" layer(components);
 @import "../components/select.css" layer(components);
 @import "../components/spinner.css" layer(components);
 @import "../components/switch.css" layer(components);

packages/util/src/array.ts

@@ -1,3 +1,10 @@
+export function same<T>(a: readonly T[] | undefined, b: readonly T[] | undefined) {
+  if (a === b) return true
+  if (!a || !b) return false
+  if (a.length !== b.length) return false
+  return a.every((x, i) => x === b[i])
+}
+
 export function findLast<T>(
   items: readonly T[],
   predicate: (item: T, index: number, items: readonly T[]) => boolean,