fix(ui): render image attachment preview in portal

packages/ui/src/components/message-item.tsx

@@ -1,4 +1,5 @@
 import { For, Show, createEffect, createSignal, onCleanup } from "solid-js"
+import { Portal } from "solid-js/web"
 import { Copy, ListStart, Split, Trash, Undo } from "lucide-solid"
 import type { MessageInfo, ClientPart, SDKAssistantMessageV2 } from "../types/message"
 import { partHasRenderableText } from "../types/message"
@@ -43,6 +44,57 @@ export default function MessageItem(props: MessageItemProps) {
   const [deletingMessage, setDeletingMessage] = createSignal(false)
   const [deletingUpTo, setDeletingUpTo] = createSignal(false)
 
+  type ImagePreviewState = {
+    url: string
+    name: string
+    anchor: HTMLElement
+  }
+
+  const [imagePreview, setImagePreview] = createSignal<ImagePreviewState | null>(null)
+
+  const clamp = (value: number, min: number, max: number) => Math.min(max, Math.max(min, value))
+
+  const getImagePreviewPosition = () => {
+    const state = imagePreview()
+    if (!state) return null
+
+    const rect = state.anchor.getBoundingClientRect()
+
+    // Outer box: 320px image + 8px padding on each side.
+    const padding = 8
+    const maxImage = 320
+    const gap = 8
+    const chrome = padding * 2
+    const outerWidth = maxImage + chrome
+    const outerHeight = maxImage + chrome
+
+    const viewportW = window.innerWidth
+    const viewportH = window.innerHeight
+
+    const left = clamp(rect.left, 8, Math.max(8, viewportW - outerWidth - 8))
+
+    const fitsAbove = rect.top >= outerHeight + gap + 8
+    const preferredTop = fitsAbove ? rect.top - outerHeight - gap : rect.bottom + gap
+    const top = clamp(preferredTop, 8, Math.max(8, viewportH - outerHeight - 8))
+
+    return { left, top }
+  }
+
+  createEffect(() => {
+    const active = imagePreview()
+    if (!active) return
+
+    // If the user scrolls (message stream scroll container) or resizes, the anchor moves.
+    // Hide the popover to avoid showing it in the wrong place.
+    const hide = () => setImagePreview(null)
+    window.addEventListener("scroll", hide, true)
+    window.addEventListener("resize", hide)
+    onCleanup(() => {
+      window.removeEventListener("scroll", hide, true)
+      window.removeEventListener("resize", hide)
+    })
+  })
+
   const isSelectedForDeletion = () => Boolean(props.selectedMessageIds?.().has(props.record.id))
 
   let topRowEl: HTMLDivElement | undefined
@@ -178,6 +230,11 @@ export default function MessageItem(props: MessageItemProps) {
     }
   }
 
+  const showImagePreview = (anchor: HTMLElement, url: string, name: string) => {
+    if (!url) return
+    setImagePreview({ anchor, url, name })
+  }
+
   const errorMessage = () => {
     const info = props.messageInfo
     if (!info || info.role !== "assistant" || !info.error) return null
@@ -521,6 +578,12 @@ export default function MessageItem(props: MessageItemProps) {
                   <div
                     class={`attachment-chip ${isImage ? "attachment-chip-image" : ""}`}
                     title={name}
+                    onMouseEnter={(e) => {
+                      if (!isImage) return
+                      const el = e.currentTarget as HTMLElement
+                      showImagePreview(el, attachment.url || "", name)
+                    }}
+                    onMouseLeave={() => setImagePreview(null)}
                   >
                     <Show when={isImage} fallback={
                       <svg class="h-3 w-3" fill="none" viewBox="0 0 24 24" stroke="currentColor">
@@ -549,11 +612,6 @@ export default function MessageItem(props: MessageItemProps) {
                         </svg>
                       </button>
                     </Show>
-                    <Show when={isImage}>
-                      <div class="attachment-chip-preview">
-                        <img src={attachment.url} alt={name} />
-                      </div>
-                    </Show>
                   </div>
                 )
               }}
@@ -561,6 +619,31 @@ export default function MessageItem(props: MessageItemProps) {
           </div>
         </Show>
 
+        <Show when={imagePreview()}>
+          {(stateAccessor) => {
+            const state = stateAccessor()
+            const pos = () => getImagePreviewPosition()
+            return (
+              <Portal>
+                <Show when={pos()}>
+                  {(posAccessor) => {
+                    const coords = posAccessor()
+                    return (
+                      <div
+                        class="attachment-image-popover"
+                        style={{ left: `${coords.left}px`, top: `${coords.top}px` }}
+                        aria-hidden="true"
+                      >
+                        <img src={state.url} alt={state.name} />
+                      </div>
+                    )
+                  }}
+                </Show>
+              </Portal>
+            )
+          }}
+        </Show>
+
         <Show when={props.record.status === "sending"}>
           <div class="message-sending">
             <span class="generating-spinner">●</span> {t("messageItem.status.sending")}

packages/ui/src/components/tool-call/renderers/task.tsx

@@ -178,28 +178,116 @@ export const taskRenderer: ToolRenderer = {
       void loadMessages(instanceId, id)
     })
 
-    const childToolKeys = createMemo(() => {
-      const id = childSessionId()
-      if (!id) return [] as string[]
-      if (!childSessionLoaded()) return [] as string[]
+    const [childToolKeys, setChildToolKeys] = createSignal<string[]>([])
 
-      // React to session changes, but do the scan untracked to avoid
-      // subscribing to every message/part node in the store.
+    let indexedSessionId = ""
+    let indexedMessageCount = 0
+    let indexedMessageTail = ""
+    const indexedPartCounts = new Map<string, number>()
+
+    function resetChildToolIndex(nextSessionId: string) {
+      indexedSessionId = nextSessionId
+      indexedMessageCount = 0
+      indexedMessageTail = ""
+      indexedPartCounts.clear()
+      setChildToolKeys([])
+    }
+
+    function scanMessageToolParts(messageId: string, startIndex: number) {
+      const record = store.getMessage(messageId)
+      if (!record) return [] as string[]
+
+      const partIds = record.partIds
+      const keys: string[] = []
+      for (let idx = startIndex; idx < partIds.length; idx += 1) {
+        const partId = partIds[idx]
+        const entry = record.parts?.[partId]
+        const data = entry?.data
+        if (!data || (data as any).type !== "tool") continue
+        keys.push(`${messageId}::${partId}`)
+      }
+      indexedPartCounts.set(messageId, partIds.length)
+      return keys
+    }
+
+    function fullRescanChildTools(sessionId: string, messageIds: string[]) {
+      indexedSessionId = sessionId
+      indexedMessageCount = messageIds.length
+      indexedMessageTail = messageIds[messageIds.length - 1] ?? ""
+      indexedPartCounts.clear()
+
+      const nextKeys: string[] = []
+      for (const messageId of messageIds) {
+        nextKeys.push(...scanMessageToolParts(messageId, 0))
+      }
+      setChildToolKeys(nextKeys)
+    }
+
+    createEffect(() => {
+      const id = childSessionId()
+      const loaded = childSessionLoaded()
+
+      if (!id || !loaded) {
+        if (indexedSessionId) {
+          resetChildToolIndex("")
+        }
+        return
+      }
+
+      // We use the session revision as the reactive change point, but avoid
+      // rescanning the entire session on every update.
       store.getSessionRevision(id)
-      return untrack(() => {
+
+      untrack(() => {
         const messageIds = store.getSessionMessageIds(id)
-        const keys: string[] = []
-        for (const messageId of messageIds) {
-          const record = store.getMessage(messageId)
-          if (!record) continue
-          for (const partId of record.partIds) {
-            const entry = record.parts?.[partId]
-            const data = entry?.data
-            if (!data || (data as any).type !== "tool") continue
-            keys.push(`${messageId}::${partId}`)
+
+        if (!indexedSessionId || indexedSessionId !== id) {
+          fullRescanChildTools(id, messageIds)
+          return
+        }
+
+        // Detect structural changes (reorder/shrink) and fall back to a full rescan.
+        if (messageIds.length < indexedMessageCount) {
+          fullRescanChildTools(id, messageIds)
+          return
+        }
+        if (indexedMessageCount > 0) {
+          const expectedTailIndex = indexedMessageCount - 1
+          if (expectedTailIndex >= 0 && messageIds[expectedTailIndex] !== indexedMessageTail) {
+            fullRescanChildTools(id, messageIds)
+            return
           }
         }
-        return keys
+
+        const appendedKeys: string[] = []
+
+        // Scan any new messages appended since last index.
+        for (let idx = indexedMessageCount; idx < messageIds.length; idx += 1) {
+          const messageId = messageIds[idx]
+          appendedKeys.push(...scanMessageToolParts(messageId, 0))
+        }
+
+        // Scan a small window of recent messages for newly appended parts.
+        // Deltas typically affect the most recent tool call, so this avoids
+        // iterating every message on every revision.
+        const existingCount = Math.min(indexedMessageCount, messageIds.length)
+        const windowStart = Math.max(0, existingCount - 3)
+        for (let idx = windowStart; idx < existingCount; idx += 1) {
+          const messageId = messageIds[idx]
+          const previousPartCount = indexedPartCounts.get(messageId) ?? 0
+          const record = store.getMessage(messageId)
+          const nextPartCount = record?.partIds.length ?? 0
+          if (nextPartCount > previousPartCount) {
+            appendedKeys.push(...scanMessageToolParts(messageId, previousPartCount))
+          }
+        }
+
+        indexedMessageCount = messageIds.length
+        indexedMessageTail = messageIds[messageIds.length - 1] ?? ""
+
+        if (appendedKeys.length > 0) {
+          setChildToolKeys((prev) => [...prev, ...appendedKeys])
+        }
       })
     })
     const promptContent = createMemo(() => {
@@ -354,7 +442,7 @@ export const taskRenderer: ToolRenderer = {
                     scrollHelpers ? (event) => scrollHelpers.handleScroll(event as Event & { currentTarget: HTMLDivElement }) : undefined
                   }
                 >
-                  <div class="tool-call-task-summary">
+                    <div class="tool-call-task-summary">
                     <For each={childToolKeys()}>
                       {(key) => (
                         <Show when={renderToolCall}>

packages/ui/src/stores/message-v2/bridge.ts

@@ -117,6 +117,7 @@ export function applyPartDeltaV2(
     partId: input.partId,
     field: input.field,
     delta: input.delta,
+    bumpSessionRevision: false,
   })
 }
 

packages/ui/src/stores/message-v2/instance-store.ts

@@ -189,7 +189,14 @@ export interface InstanceMessageStore {
   hydrateMessages: (sessionId: string, inputs: MessageUpsertInput[], infos?: Iterable<MessageInfo>) => void
   upsertMessage: (input: MessageUpsertInput) => void
   applyPartUpdate: (input: PartUpdateInput) => void
-  applyPartDelta: (input: { messageId: string; partId: string; field: string; delta: string; bumpRevision?: boolean }) => void
+  applyPartDelta: (input: {
+    messageId: string
+    partId: string
+    field: string
+    delta: string
+    bumpRevision?: boolean
+    bumpSessionRevision: boolean
+  }) => void
   removeMessage: (messageId: string) => void
   removeMessagePart: (messageId: string, partId: string) => void
   bufferPendingPart: (entry: PendingPartEntry) => void
@@ -598,7 +605,14 @@ export function createInstanceMessageStore(instanceId: string, hooks?: MessageSt
     bumpSessionRevision(message.sessionId)
   }
 
-  function applyPartDelta(input: { messageId: string; partId: string; field: string; delta: string; bumpRevision?: boolean }) {
+  function applyPartDelta(input: {
+    messageId: string
+    partId: string
+    field: string
+    delta: string
+    bumpRevision?: boolean
+    bumpSessionRevision?: boolean
+  }) {
     if (!input?.messageId || !input.partId || !input.field || typeof input.delta !== "string") {
       return
     }
@@ -632,7 +646,7 @@ export function createInstanceMessageStore(instanceId: string, hooks?: MessageSt
       }),
     )
 
-    if (applied) {
+    if (applied && (input.bumpSessionRevision ?? true)) {
       bumpSessionRevision(message.sessionId)
     }
   }
@@ -1165,4 +1179,3 @@ export function createInstanceMessageStore(instanceId: string, hooks?: MessageSt
       clearInstance,
     }
   }
-

packages/ui/src/styles/messaging/message-base.css

@@ -203,6 +203,27 @@
   border-top: 1px solid var(--border-base);
 }
 
+/* Image attachment preview popover.
+   Rendered via a Portal to avoid being clipped by the message stream scroller. */
+.attachment-image-popover {
+  position: fixed;
+  padding: 8px;
+  background-color: var(--surface-base);
+  border: 1px solid var(--border-base);
+  border-radius: 10px;
+  box-shadow: var(--popover-shadow);
+  z-index: 1000;
+  pointer-events: none;
+}
+
+.attachment-image-popover img {
+  display: block;
+  max-width: 320px;
+  max-height: 320px;
+  border-radius: 8px;
+  object-fit: contain;
+}
+
 .message-error {
   @apply text-xs mt-1;
   color: var(--status-error);