chore(ui): remove tool header button borders

.github/workflows/build-and-upload.yml

@@ -61,7 +61,21 @@ jobs:
 
       - name: Set workspace versions
         if: ${{ inputs.set_versions && inputs.version != '' }}
-        run: npm version ${VERSION} --workspaces --include-workspace-root --no-git-tag-version --allow-same-version
+        shell: bash
+        env:
+          NPM_CONFIG_FETCH_RETRIES: 5
+          NPM_CONFIG_FETCH_RETRY_MINTIMEOUT: 20000
+          NPM_CONFIG_FETCH_RETRY_MAXTIMEOUT: 120000
+        run: |
+          set -euo pipefail
+          for attempt in 1 2 3; do
+            if npm version "${VERSION}" --workspaces --include-workspace-root --no-git-tag-version --allow-same-version; then
+              exit 0
+            fi
+            echo "npm version failed (attempt $attempt/3); retrying..." >&2
+            sleep $((attempt * 10))
+          done
+          exit 1
 
       - name: Install dependencies
         run: npm ci --workspaces --include=optional
@@ -72,6 +86,37 @@ jobs:
       - name: Build macOS binaries (Electron)
         run: npm run build:mac --workspace @neuralnomads/codenomad-electron-app
 
+      - name: Ad-hoc sign Electron macOS app bundles (seal resources)
+        shell: bash
+        run: |
+          set -euo pipefail
+
+          release_root="packages/electron-app/release"
+          apps=()
+          while IFS= read -r -d '' app; do
+            apps+=("$app")
+          done < <(find "$release_root" -type d -name 'CodeNomad.app' -print0)
+
+          if [ "${#apps[@]}" -eq 0 ]; then
+            echo "No CodeNomad.app found under $release_root" >&2
+            exit 1
+          fi
+
+          # GitHub macOS runners typically have no signing identity. Without any signature,
+          # the shipped .app can fail Gatekeeper with:
+          #   code has no resources but signature indicates they must be present
+          # Ad-hoc signing seals bundle resources and makes the signature internally consistent.
+          if security find-identity -p codesigning -v | grep -q "0 valid identities found"; then
+            echo "No valid macOS codesigning identity found; applying ad-hoc signature"
+            for app in "${apps[@]}"; do
+              echo "codesign (adhoc): $app"
+              codesign --force --deep --sign - "$app"
+              codesign --verify --deep --strict --verbose=2 "$app"
+            done
+          else
+            echo "macOS codesigning identity present; skipping ad-hoc signing"
+          fi
+
       - name: Repackage Electron macOS zips (ditto)
         shell: bash
         run: |
@@ -114,13 +159,6 @@ jobs:
           set -euo pipefail
           shopt -s nullglob
 
-          # Dev CI builds typically don't have a macOS signing identity available.
-          # When no identity is present, electron-builder skips signing and strict verification will fail.
-          if security find-identity -p codesigning -v | grep -q "0 valid identities found"; then
-            echo "No valid macOS codesigning identity found; skipping codesign verification"
-            exit 0
-          fi
-
           tmp_dir=$(mktemp -d)
           trap 'rm -rf "$tmp_dir"' EXIT
 

packages/opencode-config/package.json

@@ -4,6 +4,6 @@
   "private": true,
   "license": "MIT",
   "dependencies": {
-    "@opencode-ai/plugin": "1.2.10"
+    "@opencode-ai/plugin": "1.2.14"
   }
 }

packages/ui/src/components/instance/shell/right-panel/RightPanel.tsx

@@ -7,7 +7,7 @@ import {
   type Accessor,
   type Component,
 } from "solid-js"
-import type { ToolState } from "@opencode-ai/sdk"
+import type { ToolState } from "@opencode-ai/sdk/v2"
 import type { FileContent, FileNode, File as GitFileStatus } from "@opencode-ai/sdk/v2/client"
 import IconButton from "@suid/material/IconButton"
 import MenuOpenIcon from "@suid/icons-material/MenuOpen"

packages/ui/src/components/instance/shell/right-panel/tabs/StatusTab.tsx

@@ -1,5 +1,5 @@
 import { For, Show, type Accessor, type Component } from "solid-js"
-import type { ToolState } from "@opencode-ai/sdk"
+import type { ToolState } from "@opencode-ai/sdk/v2"
 import { Accordion } from "@kobalte/core"
 import { Tooltip } from "@kobalte/core/tooltip"
 

packages/ui/src/components/instance/shell/useInstanceSessionContext.ts

@@ -1,5 +1,5 @@
 import { batch, createMemo, type Accessor } from "solid-js"
-import type { ToolState } from "@opencode-ai/sdk"
+import type { ToolState } from "@opencode-ai/sdk/v2"
 import type { Session } from "../../../types/session"
 import {
   activeParentSessionId,

packages/ui/src/components/message-block-list.tsx

@@ -2,6 +2,7 @@ import { Index, type Accessor } from "solid-js"
 import VirtualItem from "./virtual-item"
 import MessageBlock from "./message-block"
 import type { InstanceMessageStore } from "../stores/message-v2/instance-store"
+import type { DeleteHoverState } from "../types/delete-hover"
 
 export function getMessageAnchorId(messageId: string) {
   return `message-anchor-${messageId}`
@@ -21,8 +22,13 @@ interface MessageBlockListProps {
   scrollContainer: Accessor<HTMLDivElement | undefined>
   loading?: boolean
   onRevert?: (messageId: string) => void
+  onDeleteMessagesUpTo?: (messageId: string) => void | Promise<void>
   onFork?: (messageId?: string) => void
   onContentRendered?: () => void
+  deleteHover?: Accessor<DeleteHoverState>
+  onDeleteHoverChange?: (state: DeleteHoverState) => void
+  selectedMessageIds?: Accessor<Set<string>>
+  onToggleSelectedMessage?: (messageId: string, selected: boolean) => void
   setBottomSentinel: (element: HTMLDivElement | null) => void
   suspendMeasurements?: () => boolean
 }
@@ -51,7 +57,12 @@ export default function MessageBlockList(props: MessageBlockListProps) {
               showThinking={props.showThinking}
               thinkingDefaultExpanded={props.thinkingDefaultExpanded}
               showUsageMetrics={props.showUsageMetrics}
+              deleteHover={props.deleteHover}
+              onDeleteHoverChange={props.onDeleteHoverChange}
+              selectedMessageIds={props.selectedMessageIds}
+              onToggleSelectedMessage={props.onToggleSelectedMessage}
               onRevert={props.onRevert}
+              onDeleteMessagesUpTo={props.onDeleteMessagesUpTo}
               onFork={props.onFork}
               onContentRendered={props.onContentRendered}
             />

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

@@ -1,5 +1,5 @@
-import { For, Match, Show, Switch, createEffect, createMemo, createSignal, untrack } from "solid-js"
-import { ChevronsDownUp, ChevronsUpDown, ExternalLink, FoldVertical, Trash2 } from "lucide-solid"
+import { For, Match, Show, Switch, createEffect, createMemo, createSignal, onCleanup, untrack } from "solid-js"
+import { ChevronsDownUp, ChevronsUpDown, ExternalLink, FoldVertical, ListStart, Trash } from "lucide-solid"
 import MessageItem from "./message-item"
 import ToolCall from "./tool-call"
 import type { InstanceMessageStore } from "../stores/message-v2/instance-store"
@@ -12,8 +12,17 @@ import { formatTokenTotal } from "../lib/formatters"
 import { sessions, setActiveParentSession, setActiveSession } from "../stores/sessions"
 import { setActiveInstanceId } from "../stores/instances"
 import { showAlertDialog } from "../stores/alerts"
-import { deleteMessagePart } from "../stores/session-actions"
+import { deleteMessage } from "../stores/session-actions"
 import { useI18n } from "../lib/i18n"
+import type { DeleteHoverState } from "../types/delete-hover"
+
+function DeleteUpToIcon() {
+  return (
+    <span class="relative inline-block w-3.5 h-3.5" aria-hidden="true">
+      <ListStart class="absolute inset-0 w-3.5 h-3.5" aria-hidden="true" />
+    </span>
+  )
+}
 
 const TOOL_ICON = "🔧"
 const USER_BORDER_COLOR = "var(--message-user-border)"
@@ -23,10 +32,10 @@ const TOOL_BORDER_COLOR = "var(--message-tool-border)"
 type ToolCallPart = Extract<ClientPart, { type: "tool" }>
 
 
-type ToolState = import("@opencode-ai/sdk").ToolState
-type ToolStateRunning = import("@opencode-ai/sdk").ToolStateRunning
-type ToolStateCompleted = import("@opencode-ai/sdk").ToolStateCompleted
-type ToolStateError = import("@opencode-ai/sdk").ToolStateError
+type ToolState = import("@opencode-ai/sdk/v2").ToolState
+type ToolStateRunning = import("@opencode-ai/sdk/v2").ToolStateRunning
+type ToolStateCompleted = import("@opencode-ai/sdk/v2").ToolStateCompleted
+type ToolStateError = import("@opencode-ai/sdk/v2").ToolStateError
 
 function isToolStateRunning(state: ToolState | undefined): state is ToolStateRunning {
   return Boolean(state && state.status === "running")
@@ -194,8 +203,13 @@ interface MessageContentItemProps {
   messageIndex: number
   lastAssistantIndex: () => number
   onRevert?: (messageId: string) => void
+  onDeleteMessagesUpTo?: (messageId: string) => void | Promise<void>
   onFork?: (messageId?: string) => void
   onContentRendered?: () => void
+  showDeleteMessage?: boolean
+  onDeleteHoverChange?: (state: DeleteHoverState) => void
+  selectedMessageIds?: () => Set<string>
+  onToggleSelectedMessage?: (messageId: string, selected: boolean) => void
 }
 
 function isSupportedPartType(part: unknown): boolean {
@@ -282,7 +296,12 @@ function MessageContentItem(props: MessageContentItemProps) {
           sessionId={props.sessionId}
           isQueued={isQueued()}
           showAgentMeta={showAgentMeta()}
+          showDeleteMessage={props.showDeleteMessage}
+          onDeleteHoverChange={props.onDeleteHoverChange}
+          selectedMessageIds={props.selectedMessageIds}
+          onToggleSelectedMessage={props.onToggleSelectedMessage}
           onRevert={props.onRevert}
+          onDeleteMessagesUpTo={props.onDeleteMessagesUpTo}
           onFork={props.onFork}
           onContentRendered={props.onContentRendered}
         />
@@ -298,11 +317,19 @@ interface ToolCallItemProps {
   messageId: string
   partId: string
   onContentRendered?: () => void
+  showDeleteMessage?: boolean
+  onDeleteHoverChange?: (state: DeleteHoverState) => void
+  onDeleteMessagesUpTo?: (messageId: string) => void | Promise<void>
+  selectedMessageIds?: () => Set<string>
+  onToggleSelectedMessage?: (messageId: string, selected: boolean) => void
 }
 
 function ToolCallItem(props: ToolCallItemProps) {
   const { t } = useI18n()
-  const [deleting, setDeleting] = createSignal(false)
+  const [deletingMessage, setDeletingMessage] = createSignal(false)
+  const [deletingUpTo, setDeletingUpTo] = createSignal(false)
+
+  const isSelectedForDeletion = () => Boolean(props.selectedMessageIds?.().has(props.messageId))
 
   const record = createMemo(() => props.store().getMessage(props.messageId))
   const messageInfo = createMemo(() => props.store().getMessageInfo(props.messageId))
@@ -319,14 +346,6 @@ function ToolCallItem(props: ToolCallItemProps) {
   const messageVersion = createMemo(() => record()?.revision ?? 0)
   const partVersion = createMemo(() => partEntry()?.revision ?? 0)
 
-  const deleteDisabled = createMemo(() => {
-    if (deleting()) return true
-    // Avoid deleting while a tool is actively running to prevent confusing UI states.
-    if (isToolStateRunning(toolState())) return true
-    // Avoid deleting permission prompts from here; those are interactive.
-    return Boolean(toolPart()?.pendingPermission)
-  })
-
   const taskSessionId = createMemo(() => {
     const state = toolState()
     if (!state) return ""
@@ -350,38 +369,72 @@ function ToolCallItem(props: ToolCallItemProps) {
     navigateToTaskSession(location)
   }
 
-  const handleDeleteToolPart = async (event: MouseEvent) => {
+  const handleDeleteMessage = async (event: MouseEvent) => {
     event.preventDefault()
     event.stopPropagation()
 
-    if (deleteDisabled()) return
+    if (!props.showDeleteMessage) return
+    if (deletingMessage()) return
 
-    setDeleting(true)
+    setDeletingMessage(true)
     try {
-      await deleteMessagePart(props.instanceId, props.sessionId, props.messageId, props.partId)
+      await deleteMessage(props.instanceId, props.sessionId, props.messageId)
     } catch (error) {
-      showAlertDialog(t("messageBlock.tool.deletePart.failed.message"), {
-        title: t("messageBlock.tool.deletePart.failed.title"),
+      showAlertDialog(t("messageItem.actions.deleteMessageFailedMessage"), {
+        title: t("messageItem.actions.deleteMessageFailedTitle"),
         detail: error instanceof Error ? error.message : String(error),
         variant: "error",
       })
     } finally {
-      setDeleting(false)
+      setDeletingMessage(false)
+    }
+  }
+
+  const handleDeleteUpTo = async (event: MouseEvent) => {
+    event.preventDefault()
+    event.stopPropagation()
+    if (!props.showDeleteMessage) return
+    if (!props.onDeleteMessagesUpTo) return
+    if (deletingUpTo()) return
+
+    setDeletingUpTo(true)
+    try {
+      await props.onDeleteMessagesUpTo(props.messageId)
+    } finally {
+      setDeletingUpTo(false)
     }
   }
 
   return (
     <Show when={toolPart()}>
       {(resolvedToolPart) => (
-        <>
+        <div class="delete-hover-scope">
           <div class="tool-call-header-label">
             <div class="tool-call-header-meta">
+              <Show when={props.showDeleteMessage}>
+                <input
+                  class="message-select-checkbox"
+                  type="checkbox"
+                  checked={isSelectedForDeletion()}
+                  onClick={(event) => {
+                    event.stopPropagation()
+                  }}
+                  onChange={(event) => {
+                    event.stopPropagation()
+                    const next = Boolean((event.currentTarget as HTMLInputElement).checked)
+                    props.onToggleSelectedMessage?.(props.messageId, next)
+                  }}
+                  aria-label={t("messageItem.selection.checkboxAriaLabel")}
+                  title={t("messageItem.selection.checkboxAriaLabel")}
+                />
+              </Show>
+
               <span class="tool-call-icon">{TOOL_ICON}</span>
               <span>{t("messageBlock.tool.header")}</span>
               <span class="tool-name">{toolName() || t("messageBlock.tool.unknown")}</span>
             </div>
 
-            <div class="flex items-center gap-2">
+            <div class="flex items-center gap-0">
               <Show when={taskSessionId()}>
                 <button
                   class="tool-call-header-button"
@@ -395,16 +448,33 @@ function ToolCallItem(props: ToolCallItemProps) {
                 </button>
               </Show>
 
-              <button
-                class="tool-call-header-button"
-                type="button"
-                disabled={deleteDisabled()}
-                onClick={handleDeleteToolPart}
-                title={deleting() ? t("messageBlock.tool.deletePart.deleting") : t("messageBlock.tool.deletePart.label")}
-                aria-label={deleting() ? t("messageBlock.tool.deletePart.deleting") : t("messageBlock.tool.deletePart.label")}
-              >
-                <Trash2 class="w-3.5 h-3.5" aria-hidden="true" />
-              </button>
+              <Show when={props.showDeleteMessage}>
+                <button
+                  class="tool-call-header-button"
+                  type="button"
+                  disabled={!props.onDeleteMessagesUpTo || deletingUpTo()}
+                  onClick={handleDeleteUpTo}
+                  onMouseEnter={() => props.onDeleteHoverChange?.({ kind: "deleteUpTo", messageId: props.messageId })}
+                  onMouseLeave={() => props.onDeleteHoverChange?.({ kind: "none" })}
+                  title={t("messageItem.actions.deleteMessagesUpTo")}
+                  aria-label={t("messageItem.actions.deleteMessagesUpTo")}
+                >
+                  <DeleteUpToIcon />
+                </button>
+
+                <button
+                  class="tool-call-header-button"
+                  type="button"
+                  disabled={deletingMessage()}
+                  onClick={handleDeleteMessage}
+                  onMouseEnter={() => props.onDeleteHoverChange?.({ kind: "message", messageId: props.messageId })}
+                  onMouseLeave={() => props.onDeleteHoverChange?.({ kind: "none" })}
+                  title={deletingMessage() ? t("messageItem.actions.deletingMessage") : t("messageItem.actions.deleteMessage")}
+                  aria-label={deletingMessage() ? t("messageItem.actions.deletingMessage") : t("messageItem.actions.deleteMessage")}
+                >
+                  <Trash class="w-3.5 h-3.5" aria-hidden="true" />
+                </button>
+              </Show>
             </div>
           </div>
 
@@ -418,7 +488,7 @@ function ToolCallItem(props: ToolCallItemProps) {
             sessionId={props.sessionId}
             onContentRendered={props.onContentRendered}
           />
-        </>
+        </div>
       )}
     </Show>
   )
@@ -470,7 +540,12 @@ interface MessageBlockProps {
   showThinking: () => boolean
   thinkingDefaultExpanded: () => boolean
   showUsageMetrics: () => boolean
+  deleteHover?: () => DeleteHoverState
+  onDeleteHoverChange?: (state: DeleteHoverState) => void
+  selectedMessageIds?: () => Set<string>
+  onToggleSelectedMessage?: (messageId: string, selected: boolean) => void
   onRevert?: (messageId: string) => void
+  onDeleteMessagesUpTo?: (messageId: string) => void | Promise<void>
   onFork?: (messageId?: string) => void
   onContentRendered?: () => void
 }
@@ -481,6 +556,30 @@ export default function MessageBlock(props: MessageBlockProps) {
   const messageInfo = createMemo(() => props.store().getMessageInfo(props.messageId))
   const sessionCache = getSessionRenderCache(props.instanceId, props.sessionId)
 
+  const isDeleteMessageHovered = () => {
+    const hover = props.deleteHover?.() ?? ({ kind: "none" } as DeleteHoverState)
+
+    const selected = props.selectedMessageIds?.() ?? new Set<string>()
+    if (selected.has(props.messageId)) {
+      return true
+    }
+
+    if (hover.kind === "message") {
+      return hover.messageId === props.messageId
+    }
+
+    if (hover.kind === "deleteUpTo") {
+      const ids = props.store().getSessionMessageIds(props.sessionId)
+      const targetIndex = ids.indexOf(hover.messageId)
+      if (targetIndex === -1) return false
+      const currentIndex = ids.indexOf(props.messageId)
+      if (currentIndex === -1) return false
+      return currentIndex >= targetIndex
+    }
+
+    return false
+  }
+
   const block = createMemo<MessageDisplayBlock | null>(() => {
     const current = record()
     if (!current) return null
@@ -668,9 +767,13 @@ export default function MessageBlock(props: MessageBlockProps) {
   return (
     <Show when={block()}>
       {(resolvedBlock) => (
-        <div class="message-stream-block" data-message-id={resolvedBlock().record.id}>
+        <div
+          class="message-stream-block"
+          data-message-id={resolvedBlock().record.id}
+          data-delete-message-hover={isDeleteMessageHovered() ? "true" : undefined}
+        >
           <For each={resolvedBlock().items}>
-            {(item) => (
+            {(item, index) => (
               <Switch>
                 <Match when={item.type === "content"}>
                   <MessageContentItem
@@ -681,7 +784,12 @@ export default function MessageBlock(props: MessageBlockProps) {
                     startPartId={(item as ContentDisplayItem).startPartId}
                     messageIndex={props.messageIndex}
                     lastAssistantIndex={props.lastAssistantIndex}
+                    showDeleteMessage={index() === 0}
+                    onDeleteHoverChange={props.onDeleteHoverChange}
                     onRevert={props.onRevert}
+                    onDeleteMessagesUpTo={props.onDeleteMessagesUpTo}
+                    selectedMessageIds={props.selectedMessageIds}
+                    onToggleSelectedMessage={props.onToggleSelectedMessage}
                     onFork={props.onFork}
                     onContentRendered={props.onContentRendered}
                   />
@@ -697,6 +805,11 @@ export default function MessageBlock(props: MessageBlockProps) {
                           store={props.store}
                           messageId={toolItem.messageId}
                           partId={toolItem.partId}
+                          showDeleteMessage={index() === 0}
+                          onDeleteHoverChange={props.onDeleteHoverChange}
+                          onDeleteMessagesUpTo={props.onDeleteMessagesUpTo}
+                          selectedMessageIds={props.selectedMessageIds}
+                          onToggleSelectedMessage={props.onToggleSelectedMessage}
                           onContentRendered={props.onContentRendered}
                         />
                       </div>
@@ -709,6 +822,14 @@ export default function MessageBlock(props: MessageBlockProps) {
                     part={(item as StepDisplayItem).part}
                     messageInfo={(item as StepDisplayItem).messageInfo}
                     showAgentMeta
+                    showDeleteMessage={index() === 0}
+                    instanceId={props.instanceId}
+                    sessionId={props.sessionId}
+                    messageId={props.messageId}
+                    onDeleteHoverChange={props.onDeleteHoverChange}
+                    onDeleteMessagesUpTo={props.onDeleteMessagesUpTo}
+                    selectedMessageIds={props.selectedMessageIds}
+                    onToggleSelectedMessage={props.onToggleSelectedMessage}
                   />
                 </Match>
                 <Match when={item.type === "step-finish"}>
@@ -718,6 +839,14 @@ export default function MessageBlock(props: MessageBlockProps) {
                     messageInfo={(item as StepDisplayItem).messageInfo}
                     showUsage={props.showUsageMetrics()}
                     borderColor={(item as StepDisplayItem).accentColor}
+                    showDeleteMessage={index() === 0}
+                    instanceId={props.instanceId}
+                    sessionId={props.sessionId}
+                    messageId={props.messageId}
+                    onDeleteHoverChange={props.onDeleteHoverChange}
+                    onDeleteMessagesUpTo={props.onDeleteMessagesUpTo}
+                    selectedMessageIds={props.selectedMessageIds}
+                    onToggleSelectedMessage={props.onToggleSelectedMessage}
                   />
                 </Match>
                 <Match when={item.type === "compaction"}>
@@ -728,7 +857,11 @@ export default function MessageBlock(props: MessageBlockProps) {
                     instanceId={props.instanceId}
                     sessionId={props.sessionId}
                     messageId={(item as CompactionDisplayItem).messageId}
-                    partId={(item as CompactionDisplayItem).partId}
+                    showDeleteMessage={index() === 0}
+                    onDeleteHoverChange={props.onDeleteHoverChange}
+                    onDeleteMessagesUpTo={props.onDeleteMessagesUpTo}
+                    selectedMessageIds={props.selectedMessageIds}
+                    onToggleSelectedMessage={props.onToggleSelectedMessage}
                   />
                 </Match>
                 <Match when={item.type === "reasoning"}>
@@ -738,9 +871,13 @@ export default function MessageBlock(props: MessageBlockProps) {
                     instanceId={props.instanceId}
                     sessionId={props.sessionId}
                     messageId={(item as ReasoningDisplayItem).messageId}
-                    partId={(item as ReasoningDisplayItem).partId}
                     showAgentMeta={(item as ReasoningDisplayItem).showAgentMeta}
                     defaultExpanded={(item as ReasoningDisplayItem).defaultExpanded}
+                    showDeleteMessage={index() === 0}
+                    onDeleteHoverChange={props.onDeleteHoverChange}
+                    onDeleteMessagesUpTo={props.onDeleteMessagesUpTo}
+                    selectedMessageIds={props.selectedMessageIds}
+                    onToggleSelectedMessage={props.onToggleSelectedMessage}
                   />
                 </Match>
               </Switch>
@@ -759,6 +896,14 @@ interface StepCardProps {
   showAgentMeta?: boolean
   showUsage?: boolean
   borderColor?: string
+  showDeleteMessage?: boolean
+  instanceId?: string
+  sessionId?: string
+  messageId?: string
+  onDeleteHoverChange?: (state: DeleteHoverState) => void
+  onDeleteMessagesUpTo?: (messageId: string) => void | Promise<void>
+  selectedMessageIds?: () => Set<string>
+  onToggleSelectedMessage?: (messageId: string, selected: boolean) => void
 }
 
 interface CompactionCardProps {
@@ -768,12 +913,18 @@ interface CompactionCardProps {
   instanceId: string
   sessionId: string
   messageId: string
-  partId: string
+  showDeleteMessage?: boolean
+  onDeleteHoverChange?: (state: DeleteHoverState) => void
+  onDeleteMessagesUpTo?: (messageId: string) => void | Promise<void>
+  selectedMessageIds?: () => Set<string>
+  onToggleSelectedMessage?: (messageId: string, selected: boolean) => void
 }
 
 function CompactionCard(props: CompactionCardProps) {
   const { t } = useI18n()
-  const [deleting, setDeleting] = createSignal(false)
+  const [deletingMessage, setDeletingMessage] = createSignal(false)
+  const [deletingUpTo, setDeletingUpTo] = createSignal(false)
+  const isSelectedForDeletion = () => Boolean(props.selectedMessageIds?.().has(props.messageId))
   const isAuto = () => Boolean((props.part as any)?.auto)
   const label = () => (isAuto() ? t("messageBlock.compaction.autoLabel") : t("messageBlock.compaction.manualLabel"))
   const borderColor = () => props.borderColor ?? (isAuto() ? "var(--session-status-compacting-fg)" : USER_BORDER_COLOR)
@@ -781,44 +932,98 @@ function CompactionCard(props: CompactionCardProps) {
   const containerClass = () =>
     `message-compaction-card ${isAuto() ? "message-compaction-card--auto" : "message-compaction-card--manual"}`
 
-  const canDelete = () => Boolean(props.partId) && !deleting()
+  const canDeleteMessage = () => Boolean(props.showDeleteMessage) && !deletingMessage()
 
-  const handleDelete = async (event: MouseEvent) => {
+  const handleDeleteMessage = async (event: MouseEvent) => {
     event.preventDefault()
     event.stopPropagation()
-    if (!canDelete()) return
-    setDeleting(true)
+    if (!props.showDeleteMessage) return
+    if (!canDeleteMessage()) return
+    setDeletingMessage(true)
     try {
-      await deleteMessagePart(props.instanceId, props.sessionId, props.messageId, props.partId)
+      await deleteMessage(props.instanceId, props.sessionId, props.messageId)
     } catch (error) {
-      showAlertDialog(t("messagePart.actions.deleteFailedMessage"), {
-        title: t("messagePart.actions.deleteFailedTitle"),
+      showAlertDialog(t("messageItem.actions.deleteMessageFailedMessage"), {
+        title: t("messageItem.actions.deleteMessageFailedTitle"),
         detail: error instanceof Error ? error.message : String(error),
         variant: "error",
       })
     } finally {
-      setDeleting(false)
+      setDeletingMessage(false)
+    }
+  }
+
+  const handleDeleteUpTo = async (event: MouseEvent) => {
+    event.preventDefault()
+    event.stopPropagation()
+    if (!props.showDeleteMessage) return
+    if (!props.onDeleteMessagesUpTo) return
+    if (deletingUpTo()) return
+
+    setDeletingUpTo(true)
+    try {
+      await props.onDeleteMessagesUpTo(props.messageId)
+    } finally {
+      setDeletingUpTo(false)
     }
   }
 
   return (
     <div
-      class={`${containerClass()} relative`}
+      class={`delete-hover-scope ${containerClass()} relative`}
       style={{ "border-left": `4px solid ${borderColor()}` }}
       role="status"
       aria-label={t("messageBlock.compaction.ariaLabel")}
     >
-      <button
-        type="button"
-        class="tool-call-header-button absolute right-2 top-1/2 -translate-y-1/2"
-        disabled={!canDelete()}
-        onClick={handleDelete}
-        title={t("messagePart.actions.deleteTitle")}
-      >
-        {deleting() ? t("messagePart.actions.deleting") : t("messagePart.actions.delete")}
-      </button>
+      <div class="absolute right-2 top-1/2 -translate-y-1/2 flex items-center gap-1">
+        <Show when={props.showDeleteMessage}>
+          <button
+            type="button"
+            class="tool-call-header-button"
+            disabled={!props.onDeleteMessagesUpTo || deletingUpTo()}
+            onClick={handleDeleteUpTo}
+            onMouseEnter={() => props.onDeleteHoverChange?.({ kind: "deleteUpTo", messageId: props.messageId })}
+            onMouseLeave={() => props.onDeleteHoverChange?.({ kind: "none" })}
+            title={t("messageItem.actions.deleteMessagesUpTo")}
+            aria-label={t("messageItem.actions.deleteMessagesUpTo")}
+          >
+            <DeleteUpToIcon />
+          </button>
+
+          <button
+            type="button"
+            class="tool-call-header-button"
+            disabled={!canDeleteMessage()}
+            onClick={handleDeleteMessage}
+            onMouseEnter={() => props.onDeleteHoverChange?.({ kind: "message", messageId: props.messageId })}
+            onMouseLeave={() => props.onDeleteHoverChange?.({ kind: "none" })}
+            title={deletingMessage() ? t("messageItem.actions.deletingMessage") : t("messageItem.actions.deleteMessage")}
+            aria-label={deletingMessage() ? t("messageItem.actions.deletingMessage") : t("messageItem.actions.deleteMessage")}
+          >
+            <Trash class="w-3.5 h-3.5" aria-hidden="true" />
+          </button>
+        </Show>
+      </div>
 
       <div class="message-compaction-row">
+        <Show when={props.showDeleteMessage}>
+          <input
+            class="message-select-checkbox"
+            type="checkbox"
+            checked={isSelectedForDeletion()}
+            onClick={(event) => {
+              event.stopPropagation()
+            }}
+            onChange={(event) => {
+              event.stopPropagation()
+              const next = Boolean((event.currentTarget as HTMLInputElement).checked)
+              props.onToggleSelectedMessage?.(props.messageId, next)
+            }}
+            aria-label={t("messageItem.selection.checkboxAriaLabel")}
+            title={t("messageItem.selection.checkboxAriaLabel")}
+          />
+        </Show>
+
         <FoldVertical class="message-compaction-icon w-4 h-4" aria-hidden="true" />
         <span class="message-compaction-label">{label()}</span>
       </div>
@@ -828,6 +1033,9 @@ function CompactionCard(props: CompactionCardProps) {
 
 function StepCard(props: StepCardProps) {
   const { t } = useI18n()
+  const [deletingMessage, setDeletingMessage] = createSignal(false)
+  const [deletingUpTo, setDeletingUpTo] = createSignal(false)
+  const isSelectedForDeletion = () => Boolean(props.messageId && props.selectedMessageIds?.().has(props.messageId))
   const timestamp = () => {
     const value = props.messageInfo?.time?.created ?? (props.part as any)?.time?.start ?? Date.now()
     const date = new Date(value)
@@ -872,6 +1080,42 @@ function StepCard(props: StepCardProps) {
 
   const finishStyle = () => (props.borderColor ? { "border-left-color": props.borderColor } : undefined)
 
+  const canDeleteMessage = () =>
+    Boolean(props.showDeleteMessage && props.instanceId && props.sessionId && props.messageId) && !deletingMessage()
+
+  const handleDeleteMessage = async (event: MouseEvent) => {
+    event.preventDefault()
+    event.stopPropagation()
+    if (!canDeleteMessage()) return
+    setDeletingMessage(true)
+    try {
+      await deleteMessage(props.instanceId!, props.sessionId!, props.messageId!)
+    } catch (error) {
+      showAlertDialog(t("messageItem.actions.deleteMessageFailedMessage"), {
+        title: t("messageItem.actions.deleteMessageFailedTitle"),
+        detail: error instanceof Error ? error.message : String(error),
+        variant: "error",
+      })
+    } finally {
+      setDeletingMessage(false)
+    }
+  }
+
+  const handleDeleteUpTo = async (event: MouseEvent) => {
+    event.preventDefault()
+    event.stopPropagation()
+    if (!props.messageId) return
+    if (!props.onDeleteMessagesUpTo) return
+    if (deletingUpTo()) return
+
+    setDeletingUpTo(true)
+    try {
+      await props.onDeleteMessagesUpTo(props.messageId)
+    } finally {
+      setDeletingUpTo(false)
+    }
+  }
+
 
   const renderUsageChips = (usage: NonNullable<ReturnType<typeof usageStats>>) => {
     const entries = [
@@ -902,17 +1146,83 @@ function StepCard(props: StepCardProps) {
       return null
     }
     return (
-      <div class={`message-step-card message-step-finish message-step-finish-flush`} style={finishStyle()}>
+      <div class={`message-step-card message-step-finish message-step-finish-flush relative`} style={finishStyle()}>
+        <Show when={props.showDeleteMessage && props.messageId}>
+          <input
+            class="message-select-checkbox absolute left-2 top-1/2 -translate-y-1/2"
+            type="checkbox"
+            checked={isSelectedForDeletion()}
+            onClick={(event) => {
+              event.stopPropagation()
+            }}
+            onChange={(event) => {
+              event.stopPropagation()
+              const next = Boolean((event.currentTarget as HTMLInputElement).checked)
+              props.onToggleSelectedMessage?.(props.messageId!, next)
+            }}
+            aria-label={t("messageItem.selection.checkboxAriaLabel")}
+            title={t("messageItem.selection.checkboxAriaLabel")}
+          />
+        </Show>
+
+        <Show when={props.showDeleteMessage}>
+          <div class="absolute right-2 top-1/2 -translate-y-1/2 flex items-center gap-1">
+            <button
+              type="button"
+              class="message-action-button"
+              disabled={!props.onDeleteMessagesUpTo || deletingUpTo()}
+              onClick={handleDeleteUpTo}
+              onMouseEnter={() => props.onDeleteHoverChange?.({ kind: "deleteUpTo", messageId: props.messageId! })}
+              onMouseLeave={() => props.onDeleteHoverChange?.({ kind: "none" })}
+              title={t("messageItem.actions.deleteMessagesUpTo")}
+              aria-label={t("messageItem.actions.deleteMessagesUpTo")}
+            >
+              <DeleteUpToIcon />
+            </button>
+
+            <button
+              type="button"
+              class="message-action-button"
+              disabled={!canDeleteMessage()}
+              onClick={handleDeleteMessage}
+              onMouseEnter={() => props.onDeleteHoverChange?.({ kind: "message", messageId: props.messageId! })}
+              onMouseLeave={() => props.onDeleteHoverChange?.({ kind: "none" })}
+              title={deletingMessage() ? t("messageItem.actions.deletingMessage") : t("messageItem.actions.deleteMessage")}
+              aria-label={deletingMessage() ? t("messageItem.actions.deletingMessage") : t("messageItem.actions.deleteMessage")}
+            >
+              <Trash class="w-3.5 h-3.5" aria-hidden="true" />
+            </button>
+          </div>
+        </Show>
+
         {renderUsageChips(usage)}
       </div>
     )
   }
 
   return (
-    <div class={`message-step-card message-step-start`}>
+    <div class={`message-step-card message-step-start relative`}>
       <div class="message-step-heading">
         <div class="message-step-title">
           <div class="message-step-title-left">
+            <Show when={props.showDeleteMessage && props.messageId}>
+              <input
+                class="message-select-checkbox"
+                type="checkbox"
+                checked={isSelectedForDeletion()}
+                onClick={(event) => {
+                  event.stopPropagation()
+                }}
+                onChange={(event) => {
+                  event.stopPropagation()
+                  const next = Boolean((event.currentTarget as HTMLInputElement).checked)
+                  props.onToggleSelectedMessage?.(props.messageId!, next)
+                }}
+                aria-label={t("messageItem.selection.checkboxAriaLabel")}
+                title={t("messageItem.selection.checkboxAriaLabel")}
+              />
+            </Show>
+
             <Show when={props.showAgentMeta && (agentIdentifier() || modelIdentifier())}>
               <span class="message-step-meta-inline">
                 <Show when={agentIdentifier()}>{(value) => <span>{t("messageBlock.step.agentLabel", { agent: value() })}</span>}</Show>
@@ -939,15 +1249,27 @@ interface ReasoningCardProps {
   instanceId: string
   sessionId: string
   messageId: string
-  partId: string
   showAgentMeta?: boolean
   defaultExpanded?: boolean
+  showDeleteMessage?: boolean
+  onDeleteHoverChange?: (state: DeleteHoverState) => void
+  onDeleteMessagesUpTo?: (messageId: string) => void | Promise<void>
+  selectedMessageIds?: () => Set<string>
+  onToggleSelectedMessage?: (messageId: string, selected: boolean) => void
 }
 
 function ReasoningCard(props: ReasoningCardProps) {
   const { t } = useI18n()
   const [expanded, setExpanded] = createSignal(Boolean(props.defaultExpanded))
-  const [deleting, setDeleting] = createSignal(false)
+  const [deletingMessage, setDeletingMessage] = createSignal(false)
+  const [deletingUpTo, setDeletingUpTo] = createSignal(false)
+  const isSelectedForDeletion = () => Boolean(props.selectedMessageIds?.().has(props.messageId))
+
+  let headerEl: HTMLDivElement | undefined
+  let actionsEl: HTMLDivElement | undefined
+  let primaryEl: HTMLSpanElement | undefined
+  let metaMeasureEl: HTMLSpanElement | undefined
+  const [showMetaInline, setShowMetaInline] = createSignal(true)
 
   createEffect(() => {
     setExpanded(Boolean(props.defaultExpanded))
@@ -974,6 +1296,35 @@ function ReasoningCard(props: ReasoningCardProps) {
     return modelID
   }
 
+  const hasMeta = () => Boolean(props.showAgentMeta && (agentIdentifier() || modelIdentifier()))
+
+  const updateMetaLayout = () => {
+    if (!hasMeta()) return
+    if (!headerEl || !actionsEl || !primaryEl || !metaMeasureEl) return
+
+    const headerWidth = headerEl.getBoundingClientRect().width
+    const actionsWidth = actionsEl.getBoundingClientRect().width
+    const primaryWidth = primaryEl.getBoundingClientRect().width
+    const metaWidth = metaMeasureEl.getBoundingClientRect().width
+
+    const availableLeft = Math.max(0, headerWidth - actionsWidth - 12)
+    setShowMetaInline(primaryWidth + metaWidth + 8 <= availableLeft)
+  }
+
+  createEffect(() => {
+    if (!hasMeta() || typeof ResizeObserver === "undefined") {
+      setShowMetaInline(true)
+      return
+    }
+
+    updateMetaLayout()
+    const observer = new ResizeObserver(() => updateMetaLayout())
+    if (headerEl) observer.observe(headerEl)
+    if (actionsEl) observer.observe(actionsEl)
+    if (primaryEl) observer.observe(primaryEl)
+    onCleanup(() => observer.disconnect())
+  })
+
   const reasoningText = () => {
     const part = props.part as any
     if (!part) return ""
@@ -1014,30 +1365,45 @@ function ReasoningCard(props: ReasoningCardProps) {
   const viewHideLabel = () =>
     expanded() ? t("messageBlock.reasoning.indicator.hide") : t("messageBlock.reasoning.indicator.view")
 
-  const hasDeleteTarget = () => Boolean(props.partId)
-  const canDelete = () => hasDeleteTarget() && !deleting()
+  const canDeleteMessage = () => Boolean(props.showDeleteMessage) && !deletingMessage()
 
-  const handleDelete = async (event: MouseEvent) => {
+  const handleDeleteMessage = async (event: MouseEvent) => {
     event.preventDefault()
     event.stopPropagation()
-    if (!canDelete()) return
-    setDeleting(true)
+    if (!props.showDeleteMessage) return
+    if (!canDeleteMessage()) return
+    setDeletingMessage(true)
     try {
-      await deleteMessagePart(props.instanceId, props.sessionId, props.messageId, props.partId)
+      await deleteMessage(props.instanceId, props.sessionId, props.messageId)
     } catch (error) {
-      showAlertDialog(t("messagePart.actions.deleteFailedMessage"), {
-        title: t("messagePart.actions.deleteFailedTitle"),
+      showAlertDialog(t("messageItem.actions.deleteMessageFailedMessage"), {
+        title: t("messageItem.actions.deleteMessageFailedTitle"),
         detail: error instanceof Error ? error.message : String(error),
         variant: "error",
       })
     } finally {
-      setDeleting(false)
+      setDeletingMessage(false)
+    }
+  }
+
+  const handleDeleteUpTo = async (event: MouseEvent) => {
+    event.preventDefault()
+    event.stopPropagation()
+    if (!props.showDeleteMessage) return
+    if (!props.onDeleteMessagesUpTo) return
+    if (deletingUpTo()) return
+
+    setDeletingUpTo(true)
+    try {
+      await props.onDeleteMessagesUpTo(props.messageId)
+    } finally {
+      setDeletingUpTo(false)
     }
   }
 
   return (
-    <div class="message-reasoning-card">
-      <div class="message-reasoning-header">
+    <div class="delete-hover-scope message-reasoning-card">
+      <div class="message-reasoning-header" ref={(el) => (headerEl = el)}>
         <button
           type="button"
           class="message-reasoning-toggle"
@@ -1045,9 +1411,30 @@ function ReasoningCard(props: ReasoningCardProps) {
           aria-expanded={expanded()}
           aria-label={expanded() ? t("messageBlock.reasoning.collapseAriaLabel") : t("messageBlock.reasoning.expandAriaLabel")}
         >
-          <span class="message-reasoning-label flex flex-wrap items-center gap-2">
-            <span>{t("messageBlock.reasoning.thinkingLabel")}</span>
-            <Show when={props.showAgentMeta && (agentIdentifier() || modelIdentifier())}>
+          <span class="message-reasoning-label">
+            <span class="message-reasoning-label-primary" ref={(el) => (primaryEl = el)}>
+              <Show when={props.showDeleteMessage}>
+                <input
+                  class="message-select-checkbox"
+                  type="checkbox"
+                  checked={isSelectedForDeletion()}
+                  onClick={(event) => {
+                    event.stopPropagation()
+                  }}
+                  onChange={(event) => {
+                    event.stopPropagation()
+                    const next = Boolean((event.currentTarget as HTMLInputElement).checked)
+                    props.onToggleSelectedMessage?.(props.messageId, next)
+                  }}
+                  aria-label={t("messageItem.selection.checkboxAriaLabel")}
+                  title={t("messageItem.selection.checkboxAriaLabel")}
+                />
+              </Show>
+
+              <span>{t("messageBlock.reasoning.thinkingLabel")}</span>
+            </span>
+
+            <Show when={hasMeta() && showMetaInline()}>
               <span class="message-step-meta-inline">
                 <Show when={agentIdentifier()}>
                   {(value) => (
@@ -1061,10 +1448,28 @@ function ReasoningCard(props: ReasoningCardProps) {
                 </Show>
               </span>
             </Show>
+
+            <Show when={hasMeta()}>
+              <span
+                ref={(el) => (metaMeasureEl = el)}
+                class="message-step-meta-inline message-step-meta-inline--measure"
+              >
+                <Show when={agentIdentifier()}>
+                  {(value) => (
+                    <span class="font-medium text-[var(--message-assistant-border)]">{t("messageBlock.step.agentLabel", { agent: value() })}</span>
+                  )}
+                </Show>
+                <Show when={modelIdentifier()}>
+                  {(value) => (
+                    <span class="font-medium text-[var(--message-assistant-border)]">{t("messageBlock.step.modelLabel", { model: value() })}</span>
+                  )}
+                </Show>
+              </span>
+            </Show>
           </span>
         </button>
 
-        <div class="message-reasoning-actions">
+        <div class="message-reasoning-actions" ref={(el) => (actionsEl = el)}>
           <button
             type="button"
             class="message-action-button"
@@ -1081,16 +1486,31 @@ function ReasoningCard(props: ReasoningCardProps) {
             </Show>
           </button>
 
-          <Show when={hasDeleteTarget()}>
+          <Show when={props.showDeleteMessage}>
             <button
               type="button"
               class="message-action-button"
-              onClick={handleDelete}
-              disabled={!canDelete()}
-              aria-label={t("messagePart.actions.deleteTitle")}
-              title={t("messagePart.actions.deleteTitle")}
+              onClick={handleDeleteUpTo}
+              disabled={!props.onDeleteMessagesUpTo || deletingUpTo()}
+              onMouseEnter={() => props.onDeleteHoverChange?.({ kind: "deleteUpTo", messageId: props.messageId })}
+              onMouseLeave={() => props.onDeleteHoverChange?.({ kind: "none" })}
+              aria-label={t("messageItem.actions.deleteMessagesUpTo")}
+              title={t("messageItem.actions.deleteMessagesUpTo")}
             >
-              <Trash2 class="w-3.5 h-3.5" aria-hidden="true" />
+              <DeleteUpToIcon />
+            </button>
+
+            <button
+              type="button"
+              class="message-action-button"
+              onClick={handleDeleteMessage}
+              disabled={!canDeleteMessage()}
+              onMouseEnter={() => props.onDeleteHoverChange?.({ kind: "message", messageId: props.messageId })}
+              onMouseLeave={() => props.onDeleteHoverChange?.({ kind: "none" })}
+              aria-label={deletingMessage() ? t("messageItem.actions.deletingMessage") : t("messageItem.actions.deleteMessage")}
+              title={deletingMessage() ? t("messageItem.actions.deletingMessage") : t("messageItem.actions.deleteMessage")}
+            >
+              <Trash class="w-3.5 h-3.5" aria-hidden="true" />
             </button>
           </Show>
 
@@ -1098,6 +1518,23 @@ function ReasoningCard(props: ReasoningCardProps) {
         </div>
       </div>
 
+      <Show when={hasMeta() && !showMetaInline()}>
+        <div class="message-reasoning-meta-row">
+          <span class="message-step-meta-inline">
+            <Show when={agentIdentifier()}>
+              {(value) => (
+                <span class="font-medium text-[var(--message-assistant-border)]">{t("messageBlock.step.agentLabel", { agent: value() })}</span>
+              )}
+            </Show>
+            <Show when={modelIdentifier()}>
+              {(value) => (
+                <span class="font-medium text-[var(--message-assistant-border)]">{t("messageBlock.step.modelLabel", { model: value() })}</span>
+              )}
+            </Show>
+          </span>
+        </div>
+      </Show>
+
       <Show when={expanded()}>
         <div class="message-reasoning-expanded">
           <div class="message-reasoning-body">

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

@@ -1,14 +1,23 @@
-import { For, Show, createSignal } from "solid-js"
-import { Copy, ExternalLink, Split, Trash2, Undo } from "lucide-solid"
-import type { MessageInfo, ClientPart } from "../types/message"
+import { For, Show, createEffect, createSignal, onCleanup } from "solid-js"
+import { Copy, ListStart, Split, Trash, Undo } from "lucide-solid"
+import type { MessageInfo, ClientPart, SDKAssistantMessageV2 } from "../types/message"
 import { partHasRenderableText } from "../types/message"
 import type { MessageRecord } from "../stores/message-v2/types"
 import MessagePart from "./message-part"
 import { copyToClipboard } from "../lib/clipboard"
 import { useI18n } from "../lib/i18n"
 import { showAlertDialog } from "../stores/alerts"
-import { deleteMessagePart } from "../stores/session-actions"
+import { deleteMessage } from "../stores/session-actions"
 import { isTauriHost } from "../lib/runtime-env"
+import type { DeleteHoverState } from "../types/delete-hover"
+
+function DeleteUpToIcon() {
+  return (
+    <span class="relative inline-block w-3.5 h-3.5" aria-hidden="true">
+      <ListStart class="absolute inset-0 w-3.5 h-3.5" aria-hidden="true" />
+    </span>
+  )
+}
 
 interface MessageItemProps {
   record: MessageRecord
@@ -18,15 +27,61 @@ interface MessageItemProps {
   isQueued?: boolean
   parts: ClientPart[]
   onRevert?: (messageId: string) => void
+  selectedMessageIds?: () => Set<string>
+  onToggleSelectedMessage?: (messageId: string, selected: boolean) => void
+  onDeleteMessagesUpTo?: (messageId: string) => void | Promise<void>
   onFork?: (messageId?: string) => void
   showAgentMeta?: boolean
   onContentRendered?: () => void
+  showDeleteMessage?: boolean
+  onDeleteHoverChange?: (state: DeleteHoverState) => void
 }
 
 export default function MessageItem(props: MessageItemProps) {
   const { t } = useI18n()
   const [copied, setCopied] = createSignal(false)
-  const [deletingParts, setDeletingParts] = createSignal<Set<string>>(new Set())
+  const [deletingMessage, setDeletingMessage] = createSignal(false)
+  const [deletingUpTo, setDeletingUpTo] = createSignal(false)
+
+  const isSelectedForDeletion = () => Boolean(props.selectedMessageIds?.().has(props.record.id))
+
+  let topRowEl: HTMLDivElement | undefined
+  let actionsEl: HTMLDivElement | undefined
+  let speakerPrimaryEl: HTMLDivElement | undefined
+  let metaMeasureEl: HTMLSpanElement | undefined
+  const [showMetaInline, setShowMetaInline] = createSignal(true)
+
+  const metaText = () => agentMeta()
+
+  const updateMetaLayout = () => {
+    const text = metaText()
+    if (!text) return
+    if (!topRowEl || !actionsEl || !speakerPrimaryEl || !metaMeasureEl) return
+
+    const rowWidth = topRowEl.getBoundingClientRect().width
+    const actionsWidth = actionsEl.getBoundingClientRect().width
+    const primaryWidth = speakerPrimaryEl.getBoundingClientRect().width
+    const metaWidth = metaMeasureEl.getBoundingClientRect().width
+
+    // Allow for the flex gap between left and actions.
+    const availableLeft = Math.max(0, rowWidth - actionsWidth - 12)
+    setShowMetaInline(primaryWidth + metaWidth + 8 <= availableLeft)
+  }
+
+  createEffect(() => {
+    const text = metaText()
+    if (!text || typeof ResizeObserver === "undefined") {
+      setShowMetaInline(true)
+      return
+    }
+
+    updateMetaLayout()
+    const observer = new ResizeObserver(() => updateMetaLayout())
+    if (topRowEl) observer.observe(topRowEl)
+    if (actionsEl) observer.observe(actionsEl)
+    if (speakerPrimaryEl) observer.observe(speakerPrimaryEl)
+    onCleanup(() => observer.disconnect())
+  })
 
   const isUser = () => props.record.role === "user"
   const createdTimestamp = () => props.messageInfo?.time?.created ?? props.record.createdAt
@@ -190,47 +245,30 @@ export default function MessageItem(props: MessageItemProps) {
     setTimeout(() => setCopied(false), 2000)
   }
 
-  const deletableTextPartId = () => {
-    const part = props.parts.find((candidate) => {
-      if (!candidate || candidate.type !== "text") return false
-      const id = (candidate as any).id
-      if (typeof id !== "string" || id.length === 0) return false
-      return !Boolean((candidate as any).synthetic)
-    })
-    return (part as any)?.id as string | undefined
-  }
-
-  const isDeletingPart = (partId?: string) => {
-    if (!partId) return false
-    return deletingParts().has(partId)
-  }
-
-  const setPartDeleting = (partId: string, value: boolean) => {
-    setDeletingParts((prev) => {
-      const next = new Set(prev)
-      if (value) {
-        next.add(partId)
-      } else {
-        next.delete(partId)
-      }
-      return next
-    })
-  }
-
-  const handleDeletePart = async (partId?: string) => {
-    if (!partId) return
-    if (isDeletingPart(partId)) return
-    setPartDeleting(partId, true)
+  const handleDeleteMessage = async () => {
+    if (deletingMessage()) return
+    setDeletingMessage(true)
     try {
-      await deleteMessagePart(props.instanceId, props.sessionId, props.record.id, partId)
+      await deleteMessage(props.instanceId, props.sessionId, props.record.id)
     } catch (error) {
-      showAlertDialog(t("messagePart.actions.deleteFailedMessage"), {
-        title: t("messagePart.actions.deleteFailedTitle"),
+      showAlertDialog(t("messageItem.actions.deleteMessageFailedMessage"), {
+        title: t("messageItem.actions.deleteMessageFailedTitle"),
         detail: error instanceof Error ? error.message : String(error),
         variant: "error",
       })
     } finally {
-      setPartDeleting(partId, false)
+      setDeletingMessage(false)
+    }
+  }
+
+  const handleDeleteUpTo = async () => {
+    if (!props.onDeleteMessagesUpTo) return
+    if (deletingUpTo()) return
+    setDeletingUpTo(true)
+    try {
+      await props.onDeleteMessagesUpTo(props.record.id)
+    } finally {
+      setDeletingUpTo(false)
     }
   }
 
@@ -258,8 +296,16 @@ export default function MessageItem(props: MessageItemProps) {
     if (!info || info.role !== "assistant") return ""
     const modelID = info.modelID || ""
     const providerID = info.providerID || ""
-    if (modelID && providerID) return `${providerID}/${modelID}`
-    return modelID
+
+    const base = modelID && providerID ? `${providerID}/${modelID}` : modelID
+    if (!base) return ""
+
+    const variant = (info as SDKAssistantMessageV2).variant
+    if (typeof variant === "string" && variant.trim().length > 0) {
+      return `${base} (${variant.trim()})`
+    }
+
+    return base
   }
 
   const agentMeta = () => {
@@ -280,26 +326,58 @@ export default function MessageItem(props: MessageItemProps) {
   return (
     <div class={containerClass()}>
       <header class={`message-item-header ${isUser() ? "pb-0.5" : "pb-0"}`}>
-        <div class="message-item-header-row message-item-header-row--top">
-          <div class="message-speaker">
-            <span class="message-speaker-label" data-role={isUser() ? "user" : "assistant"}>
-              {speakerLabel()}
-            </span>
+        <div class="message-item-header-row message-item-header-row--top" ref={(el) => (topRowEl = el)}>
+          <div class="message-header-left">
+            <div class="message-speaker-primary" ref={(el) => (speakerPrimaryEl = el)}>
+              <Show when={props.showDeleteMessage}>
+                <input
+                  class="message-select-checkbox"
+                  type="checkbox"
+                  checked={isSelectedForDeletion()}
+                  onClick={(event) => {
+                    event.stopPropagation()
+                  }}
+                  onChange={(event) => {
+                    event.stopPropagation()
+                    const next = Boolean((event.currentTarget as HTMLInputElement).checked)
+                    props.onToggleSelectedMessage?.(props.record.id, next)
+                  }}
+                  aria-label={t("messageItem.selection.checkboxAriaLabel")}
+                  title={t("messageItem.selection.checkboxAriaLabel")}
+                />
+              </Show>
+
+              <span class="message-speaker-label" data-role={isUser() ? "user" : "assistant"}>
+                {speakerLabel()}
+              </span>
+            </div>
+
+            <Show when={metaText() && showMetaInline()}>
+              <span class="message-agent-meta-inline">{metaText()}</span>
+            </Show>
+
+            <Show when={metaText()}>
+              <span
+                ref={(el) => (metaMeasureEl = el)}
+                class="message-agent-meta-inline message-agent-meta-inline--measure"
+              >
+                {metaText()}
+              </span>
+            </Show>
           </div>
 
-          <div class="message-item-actions">
+          <div class="message-item-actions" ref={(el) => (actionsEl = el)}>
             <Show when={isUser()}>
               <div class="message-action-group">
-                <Show when={props.onRevert}>
-                  <button
-                    class="message-action-button"
-                    onClick={handleRevert}
-                    title={t("messageItem.actions.revert")}
-                    aria-label={t("messageItem.actions.revert")}
-                  >
-                    <Undo class="w-3.5 h-3.5" aria-hidden="true" />
-                  </button>
-                </Show>
+                <button
+                  class="message-action-button"
+                  onClick={handleCopy}
+                  title={copyLabel()}
+                  aria-label={copyLabel()}
+                >
+                  <Copy class="w-3.5 h-3.5" aria-hidden="true" />
+                </button>
+
                 <Show when={props.onFork}>
                   <button
                     class="message-action-button"
@@ -310,14 +388,43 @@ export default function MessageItem(props: MessageItemProps) {
                     <Split class="w-3.5 h-3.5" aria-hidden="true" />
                   </button>
                 </Show>
-                <button
-                  class="message-action-button"
-                  onClick={handleCopy}
-                  title={copyLabel()}
-                  aria-label={copyLabel()}
-                >
-                  <Copy class="w-3.5 h-3.5" aria-hidden="true" />
-                </button>
+
+                <Show when={props.onRevert}>
+                  <button
+                    class="message-action-button"
+                    onClick={handleRevert}
+                    title={t("messageItem.actions.revertTitle")}
+                    aria-label={t("messageItem.actions.revertTitle")}
+                  >
+                    <Undo class="w-3.5 h-3.5" aria-hidden="true" />
+                  </button>
+                </Show>
+
+                <Show when={props.showDeleteMessage}>
+                  <button
+                    class="message-action-button"
+                    onClick={() => void handleDeleteUpTo()}
+                    disabled={!props.onDeleteMessagesUpTo || deletingUpTo()}
+                    onMouseEnter={() => props.onDeleteHoverChange?.({ kind: "deleteUpTo", messageId: props.record.id })}
+                    onMouseLeave={() => props.onDeleteHoverChange?.({ kind: "none" })}
+                    title={t("messageItem.actions.deleteMessagesUpTo")}
+                    aria-label={t("messageItem.actions.deleteMessagesUpTo")}
+                  >
+                    <DeleteUpToIcon />
+                  </button>
+
+                  <button
+                    class="message-action-button"
+                    onClick={handleDeleteMessage}
+                    disabled={deletingMessage()}
+                    onMouseEnter={() => props.onDeleteHoverChange?.({ kind: "message", messageId: props.record.id })}
+                    onMouseLeave={() => props.onDeleteHoverChange?.({ kind: "none" })}
+                    title={deletingMessage() ? t("messageItem.actions.deletingMessage") : t("messageItem.actions.deleteMessage")}
+                    aria-label={deletingMessage() ? t("messageItem.actions.deletingMessage") : t("messageItem.actions.deleteMessage")}
+                  >
+                    <Trash class="w-3.5 h-3.5" aria-hidden="true" />
+                  </button>
+                </Show>
               </div>
             </Show>
             <Show when={!isUser()}>
@@ -331,18 +438,30 @@ export default function MessageItem(props: MessageItemProps) {
                   <Copy class="w-3.5 h-3.5" aria-hidden="true" />
                 </button>
 
-                <Show when={deletableTextPartId()}>
-                  {(partId) => (
-                    <button
-                      class="message-action-button"
-                      onClick={() => void handleDeletePart(partId())}
-                      disabled={isDeletingPart(partId())}
-                      title={isDeletingPart(partId()) ? t("messagePart.actions.deleting") : t("messagePart.actions.delete")}
-                      aria-label={isDeletingPart(partId()) ? t("messagePart.actions.deleting") : t("messagePart.actions.delete")}
-                    >
-                      <Trash2 class="w-3.5 h-3.5" aria-hidden="true" />
-                    </button>
-                  )}
+                <Show when={props.showDeleteMessage}>
+                  <button
+                    class="message-action-button"
+                    onClick={() => void handleDeleteUpTo()}
+                    disabled={!props.onDeleteMessagesUpTo || deletingUpTo()}
+                    onMouseEnter={() => props.onDeleteHoverChange?.({ kind: "deleteUpTo", messageId: props.record.id })}
+                    onMouseLeave={() => props.onDeleteHoverChange?.({ kind: "none" })}
+                    title={t("messageItem.actions.deleteMessagesUpTo")}
+                    aria-label={t("messageItem.actions.deleteMessagesUpTo")}
+                  >
+                    <DeleteUpToIcon />
+                  </button>
+
+                  <button
+                    class="message-action-button"
+                    onClick={handleDeleteMessage}
+                    disabled={deletingMessage()}
+                    onMouseEnter={() => props.onDeleteHoverChange?.({ kind: "message", messageId: props.record.id })}
+                    onMouseLeave={() => props.onDeleteHoverChange?.({ kind: "none" })}
+                    title={deletingMessage() ? t("messageItem.actions.deletingMessage") : t("messageItem.actions.deleteMessage")}
+                    aria-label={deletingMessage() ? t("messageItem.actions.deletingMessage") : t("messageItem.actions.deleteMessage")}
+                  >
+                    <Trash class="w-3.5 h-3.5" aria-hidden="true" />
+                  </button>
                 </Show>
               </div>
             </Show>
@@ -350,12 +469,10 @@ export default function MessageItem(props: MessageItemProps) {
           </div>
         </div>
 
-        <Show when={agentMeta()}>
-          {(meta) => (
-            <div class="message-item-header-row message-item-header-row--bottom">
-              <span class="message-agent-meta">{meta()}</span>
-            </div>
-          )}
+        <Show when={metaText() && !showMetaInline()}>
+          <div class="message-item-header-row message-item-header-row--meta">
+            <span class="message-agent-meta-block">{metaText()}</span>
+          </div>
         </Show>
 
       </header>
@@ -378,16 +495,20 @@ export default function MessageItem(props: MessageItemProps) {
         </Show>
 
         <For each={messageParts()}>
-          {(part) => (
-            <MessagePart
-              part={part}
-              messageType={props.record.role}
-              instanceId={props.instanceId}
-              sessionId={props.sessionId}
-              primaryUserTextPartId={primaryUserTextPartId()}
-              onRendered={props.onContentRendered}
-            />
-          )}
+          {(part) => {
+            return (
+              <div class="message-part-shell">
+                <MessagePart
+                  part={part}
+                  messageType={props.record.role}
+                  instanceId={props.instanceId}
+                  sessionId={props.sessionId}
+                  primaryUserTextPartId={primaryUserTextPartId()}
+                  onRendered={props.onContentRendered}
+                />
+              </div>
+            )
+          }}
         </For>
 
         <Show when={fileAttachments().length > 0}>
@@ -397,7 +518,10 @@ export default function MessageItem(props: MessageItemProps) {
                 const name = getAttachmentName(attachment)
                 const isImage = isImageAttachment(attachment)
                 return (
-                  <div class={`attachment-chip ${isImage ? "attachment-chip-image" : ""}`} title={name}>
+                  <div
+                    class={`attachment-chip ${isImage ? "attachment-chip-image" : ""}`}
+                    title={name}
+                  >
                     <Show when={isImage} fallback={
                       <svg class="h-3 w-3" fill="none" viewBox="0 0 24 24" stroke="currentColor">
                         <path
@@ -425,19 +549,6 @@ export default function MessageItem(props: MessageItemProps) {
                         </svg>
                       </button>
                     </Show>
-
-                    <button
-                      type="button"
-                      onClick={() => void handleDeletePart(attachment.id)}
-                      class="attachment-remove"
-                      disabled={isDeletingPart(attachment.id)}
-                      aria-label={t("messagePart.actions.deleteTitle")}
-                      title={t("messagePart.actions.deleteTitle")}
-                    >
-                      <svg class="h-3 w-3" fill="none" viewBox="0 0 24 24" stroke="currentColor">
-                        <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M6 18L18 6M6 6l12 12" />
-                      </svg>
-                    </button>
                     <Show when={isImage}>
                       <div class="attachment-chip-preview">
                         <img src={attachment.url} alt={name} />

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

@@ -1,12 +1,18 @@
 import type { Component } from "solid-js"
 import MessageBlock from "./message-block"
 import type { InstanceMessageStore } from "../stores/message-v2/instance-store"
+import type { DeleteHoverState } from "../types/delete-hover"
 
 interface MessagePreviewProps {
   instanceId: string
   sessionId: string
   messageId: string
   store: () => InstanceMessageStore
+  deleteHover?: () => DeleteHoverState
+  onDeleteHoverChange?: (state: DeleteHoverState) => void
+  onDeleteMessagesUpTo?: (messageId: string) => void | Promise<void>
+  selectedMessageIds?: () => Set<string>
+  onToggleSelectedMessage?: (messageId: string, selected: boolean) => void
 }
 
 const MessagePreview: Component<MessagePreviewProps> = (props) => {
@@ -24,6 +30,11 @@ const MessagePreview: Component<MessagePreviewProps> = (props) => {
         showThinking={() => false}
         thinkingDefaultExpanded={() => false}
         showUsageMetrics={() => false}
+        deleteHover={props.deleteHover}
+        onDeleteHoverChange={props.onDeleteHoverChange}
+        onDeleteMessagesUpTo={props.onDeleteMessagesUpTo}
+        selectedMessageIds={props.selectedMessageIds}
+        onToggleSelectedMessage={props.onToggleSelectedMessage}
       />
     </div>
   )

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

@@ -1,4 +1,5 @@
 import { Show, createEffect, createMemo, createSignal, onCleanup, untrack } from "solid-js"
+import { CheckSquare, Trash, X } from "lucide-solid"
 import Kbd from "./kbd"
 import MessageBlockList, { getMessageAnchorId } from "./message-block-list"
 import MessageTimeline, { buildTimelineSegments, type TimelineSegment } from "./message-timeline"
@@ -9,7 +10,10 @@ import { useScrollCache } from "../lib/hooks/use-scroll-cache"
 import { useI18n } from "../lib/i18n"
 import { copyToClipboard } from "../lib/clipboard"
 import { showToastNotification } from "../lib/notifications"
+import { showAlertDialog } from "../stores/alerts"
+import { deleteMessage } from "../stores/session-actions"
 import type { InstanceMessageStore } from "../stores/message-v2/instance-store"
+import type { DeleteHoverState } from "../types/delete-hover"
 
 const SCROLL_SCOPE = "session"
 const SCROLL_SENTINEL_MARGIN_PX = 48
@@ -23,6 +27,7 @@ export interface MessageSectionProps {
   sessionId: string
   loading?: boolean
   onRevert?: (messageId: string) => void
+  onDeleteMessagesUpTo?: (messageId: string) => void | Promise<void>
   onFork?: (messageId?: string) => void
   registerScrollToBottom?: (fn: () => void) => void
   showSidebarToggle?: boolean
@@ -145,6 +150,63 @@ export default function MessageSection(props: MessageSectionProps) {
     }
   }
   const [activeMessageId, setActiveMessageId] = createSignal<string | null>(null)
+
+  const [deleteHover, setDeleteHover] = createSignal<DeleteHoverState>({ kind: "none" })
+
+  const [selectedForDeletion, setSelectedForDeletion] = createSignal<Set<string>>(new Set<string>())
+  const isDeleteMode = createMemo(() => selectedForDeletion().size > 0)
+  const selectedDeleteCount = createMemo(() => selectedForDeletion().size)
+
+  const isMessageSelectedForDeletion = (messageId: string) => selectedForDeletion().has(messageId)
+
+  const setMessageSelectedForDeletion = (messageId: string, selected: boolean) => {
+    if (!messageId) return
+    setSelectedForDeletion((prev) => {
+      const next = new Set(prev)
+      if (selected) {
+        next.add(messageId)
+      } else {
+        next.delete(messageId)
+      }
+      return next
+    })
+  }
+
+  const clearDeleteMode = () => {
+    setSelectedForDeletion(new Set<string>())
+    setDeleteHover({ kind: "none" })
+  }
+
+  const selectAllForDeletion = () => {
+    setSelectedForDeletion(new Set<string>(messageIds()))
+  }
+
+  const deleteSelectedMessages = async () => {
+    const selected = selectedForDeletion()
+    if (selected.size === 0) return
+
+    const idsInSessionOrder = messageIds()
+    const toDelete: string[] = []
+    for (let idx = idsInSessionOrder.length - 1; idx >= 0; idx -= 1) {
+      const id = idsInSessionOrder[idx]
+      if (selected.has(id)) {
+        toDelete.push(id)
+      }
+    }
+
+    try {
+      for (const messageId of toDelete) {
+        await deleteMessage(props.instanceId, props.sessionId, messageId)
+      }
+      clearDeleteMode()
+    } catch (error) {
+      showAlertDialog(t("messageSection.bulkDelete.failedMessage"), {
+        title: t("messageSection.bulkDelete.failedTitle"),
+        detail: error instanceof Error ? error.message : String(error),
+        variant: "error",
+      })
+    }
+  }
  
   const changeToken = createMemo(() => String(sessionRevision()))
   const isActive = createMemo(() => props.isActive !== false)
@@ -167,6 +229,7 @@ export default function MessageSection(props: MessageSectionProps) {
   const [autoScroll, setAutoScroll] = createSignal(true)
   const [showScrollTopButton, setShowScrollTopButton] = createSignal(false)
   const [showScrollBottomButton, setShowScrollBottomButton] = createSignal(false)
+  const scrollButtonsCount = createMemo(() => (showScrollTopButton() ? 1 : 0) + (showScrollBottomButton() ? 1 : 0))
   const [topSentinelVisible, setTopSentinelVisible] = createSignal(true)
   const [bottomSentinelVisible, setBottomSentinelVisible] = createSignal(true)
   const [quoteSelection, setQuoteSelection] = createSignal<{ text: string; top: number; left: number } | null>(null)
@@ -851,7 +914,10 @@ export default function MessageSection(props: MessageSectionProps) {
 
   return (
     <div class="message-stream-container">
-      <div class={`message-layout${hasTimelineSegments() ? " message-layout--with-timeline" : ""}`}>
+      <div
+        class={`message-layout${hasTimelineSegments() ? " message-layout--with-timeline" : ""}`}
+        data-scroll-buttons={scrollButtonsCount()}
+      >
         <div class="message-stream-shell" ref={setShellElement}>
           <div class="message-stream" ref={setContainerRef} onScroll={handleScroll} onMouseUp={handleStreamMouseUp}>
             <div ref={setTopSentinel} aria-hidden="true" style={{ height: "1px" }} />
@@ -897,8 +963,13 @@ export default function MessageSection(props: MessageSectionProps) {
               scrollContainer={scrollElement}
               loading={props.loading}
               onRevert={props.onRevert}
+              onDeleteMessagesUpTo={props.onDeleteMessagesUpTo}
               onFork={props.onFork}
               onContentRendered={handleContentRendered}
+              deleteHover={deleteHover}
+              onDeleteHoverChange={setDeleteHover}
+              selectedMessageIds={selectedForDeletion}
+              onToggleSelectedMessage={setMessageSelectedForDeletion}
               setBottomSentinel={setBottomSentinel}
               suspendMeasurements={() => !isActive()}
             />
@@ -957,9 +1028,56 @@ export default function MessageSection(props: MessageSectionProps) {
               instanceId={props.instanceId}
               sessionId={props.sessionId}
               showToolSegments={showTimelineToolsPreference()}
+              deleteHover={deleteHover}
+              onDeleteHoverChange={setDeleteHover}
+              onDeleteMessagesUpTo={props.onDeleteMessagesUpTo}
+              selectedMessageIds={selectedForDeletion}
+              onToggleSelectedMessage={setMessageSelectedForDeletion}
             />
           </div>
         </Show>
+
+        <Show when={isDeleteMode()}>
+          <div
+            class="message-delete-mode-toolbar"
+            role="toolbar"
+            aria-label={t("messageSection.bulkDelete.toolbarAriaLabel", { count: selectedDeleteCount() })}
+          >
+            <span class="message-delete-mode-count" aria-hidden="true">
+              {selectedDeleteCount()}
+            </span>
+
+            <button
+              type="button"
+              class="message-delete-mode-button"
+              onClick={() => void deleteSelectedMessages()}
+              title={t("messageSection.bulkDelete.deleteSelectedTitle")}
+              aria-label={t("messageSection.bulkDelete.deleteSelectedTitle")}
+            >
+              <Trash class="w-4 h-4" aria-hidden="true" />
+            </button>
+
+            <button
+              type="button"
+              class="message-delete-mode-button"
+              onClick={selectAllForDeletion}
+              title={t("messageSection.bulkDelete.selectAllTitle")}
+              aria-label={t("messageSection.bulkDelete.selectAllTitle")}
+            >
+              <CheckSquare class="w-4 h-4" aria-hidden="true" />
+            </button>
+
+            <button
+              type="button"
+              class="message-delete-mode-button"
+              onClick={clearDeleteMode}
+              title={t("messageSection.bulkDelete.cancelTitle")}
+              aria-label={t("messageSection.bulkDelete.cancelTitle")}
+            >
+              <X class="w-4 h-4" aria-hidden="true" />
+            </button>
+          </div>
+        </Show>
       </div>
 
     </div>

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

@@ -7,6 +7,7 @@ import { buildRecordDisplayData } from "../stores/message-v2/record-display-cach
 import { getToolIcon } from "./tool-call/utils"
 import { User as UserIcon, Bot as BotIcon, FoldVertical, ShieldAlert } from "lucide-solid"
 import { useI18n } from "../lib/i18n"
+import type { DeleteHoverState } from "../types/delete-hover"
 
 export type TimelineSegmentType = "user" | "assistant" | "tool" | "compaction"
 
@@ -19,6 +20,8 @@ export interface TimelineSegment {
   shortLabel?: string
   variant?: "auto" | "manual"
   toolPartIds?: string[]
+  partIds?: string[]
+  partId?: string
 }
 
 interface MessageTimelineProps {
@@ -28,6 +31,11 @@ interface MessageTimelineProps {
   instanceId: string
   sessionId: string
   showToolSegments?: boolean
+  deleteHover?: () => DeleteHoverState
+  onDeleteHoverChange?: (state: DeleteHoverState) => void
+  onDeleteMessagesUpTo?: (messageId: string) => void | Promise<void>
+  selectedMessageIds?: () => Set<string>
+  onToggleSelectedMessage?: (messageId: string, selected: boolean) => void
 }
 
 const MAX_TOOLTIP_LENGTH = 220
@@ -38,10 +46,7 @@ interface PendingSegment {
   type: TimelineSegmentType
   texts: string[]
   reasoningTexts: string[]
-  toolTitles: string[]
-  toolTypeLabels: string[]
-  toolIcons: string[]
-  toolPartIds: string[]
+  partIds: string[]
   hasPrimaryText: boolean
 }
 
@@ -171,17 +176,12 @@ export function buildTimelineSegments(
       pending = null
       return
     }
-    const isToolSegment = pending.type === "tool"
-    const label = isToolSegment
-      ? pending.toolTypeLabels[0] || segmentLabel("tool")
-      : segmentLabel(pending.type)
-    const shortLabel = isToolSegment ? pending.toolIcons[0] || getToolIcon("tool") : undefined
-    const tooltip = isToolSegment
-      ? formatToolTooltip(pending.toolTitles, t)
-      : formatTextsTooltip(
-          [...pending.texts, ...pending.reasoningTexts],
-          pending.type === "user" ? t("messageTimeline.tooltip.userFallback") : t("messageTimeline.tooltip.assistantFallback"),
-        )
+    const label = segmentLabel(pending.type)
+    const shortLabel = undefined
+    const tooltip = formatTextsTooltip(
+      [...pending.texts, ...pending.reasoningTexts],
+      pending.type === "user" ? t("messageTimeline.tooltip.userFallback") : t("messageTimeline.tooltip.assistantFallback"),
+    )
  
     result.push({
       id: `${record.id}:${segmentIndex}`,
@@ -190,7 +190,7 @@ export function buildTimelineSegments(
       label,
       tooltip,
       shortLabel,
-      toolPartIds: isToolSegment ? pending.toolPartIds : undefined,
+      partIds: pending.partIds,
     })
     segmentIndex += 1
     pending = null
@@ -199,7 +199,13 @@ export function buildTimelineSegments(
   const ensureSegment = (type: TimelineSegmentType): PendingSegment => {
     if (!pending || pending.type !== type) {
       flushPending()
-      pending = { type, texts: [], reasoningTexts: [], toolTitles: [], toolTypeLabels: [], toolIcons: [], toolPartIds: [], hasPrimaryText: type !== "assistant" }
+      pending = {
+        type,
+        texts: [],
+        reasoningTexts: [],
+        partIds: [],
+        hasPrimaryText: type !== "assistant",
+      }
     }
     return pending!
   }
@@ -211,14 +217,20 @@ export function buildTimelineSegments(
     if (!part || typeof part !== "object") continue
 
     if (part.type === "tool") {
-      const target = ensureSegment("tool")
+      flushPending()
       const toolPart = part as ToolCallPart
-      target.toolTitles.push(getToolTitle(toolPart, t))
-      target.toolTypeLabels.push(getToolTypeLabel(toolPart, t))
-      target.toolIcons.push(getToolIcon(typeof toolPart.tool === "string" ? toolPart.tool : "tool"))
-      if (typeof toolPart.id === "string" && toolPart.id.length > 0) {
-        target.toolPartIds.push(toolPart.id)
-      }
+      const partId = typeof toolPart.id === "string" ? toolPart.id : ""
+      const title = getToolTitle(toolPart, t)
+      result.push({
+        id: `${record.id}:${segmentIndex}`,
+        messageId: record.id,
+        type: "tool",
+        label: getToolTypeLabel(toolPart, t) || segmentLabel("tool"),
+        tooltip: formatToolTooltip([title], t),
+        shortLabel: getToolIcon(typeof toolPart.tool === "string" ? toolPart.tool : "tool"),
+        toolPartIds: partId ? [partId] : undefined,
+      })
+      segmentIndex += 1
       continue
     }
 
@@ -228,6 +240,9 @@ export function buildTimelineSegments(
       const target = ensureSegment(defaultContentType)
       if (target) {
         target.reasoningTexts.push(text)
+        if (typeof (part as any).id === "string" && (part as any).id.length > 0) {
+          target.partIds.push((part as any).id)
+        }
       }
       continue
     }
@@ -235,6 +250,7 @@ export function buildTimelineSegments(
     if (part.type === "compaction") {
       flushPending()
       const isAuto = Boolean((part as any)?.auto)
+      const partId = typeof (part as any)?.id === "string" ? ((part as any).id as string) : ""
       result.push({
         id: `${record.id}:${segmentIndex}`,
         messageId: record.id,
@@ -242,6 +258,7 @@ export function buildTimelineSegments(
         label: segmentLabel("compaction"),
         tooltip: isAuto ? t("messageTimeline.tooltip.compaction.auto") : t("messageTimeline.tooltip.compaction.manual"),
         variant: isAuto ? "auto" : "manual",
+        partId,
       })
       segmentIndex += 1
       continue
@@ -257,6 +274,9 @@ export function buildTimelineSegments(
     if (target) {
       target.texts.push(text)
       target.hasPrimaryText = true
+      if (typeof (part as any).id === "string" && (part as any).id.length > 0) {
+        target.partIds.push((part as any).id)
+      }
     }
   }
 
@@ -278,6 +298,7 @@ const MessageTimeline: Component<MessageTimelineProps> = (props) => {
   let hoverTimer: number | null = null
   let closeTimer: number | null = null
   const showTools = () => props.showToolSegments ?? true
+  const deleteHover = () => props.deleteHover?.() ?? { kind: "none" as const }
  
   const registerButtonRef = (segmentId: string, element: HTMLButtonElement | null) => {
     if (element) {
@@ -396,6 +417,28 @@ const MessageTimeline: Component<MessageTimelineProps> = (props) => {
           onCleanup(() => buttonRefs.delete(segment.id))
           const isActive = () => props.activeMessageId === segment.messageId
 
+          const isDeleteHovered = () => {
+            const hover = deleteHover() as DeleteHoverState
+            const selected = props.selectedMessageIds?.() ?? new Set<string>()
+            if (selected.has(segment.messageId)) {
+              return true
+            }
+            if (hover.kind === "message") {
+              return hover.messageId === segment.messageId
+            }
+
+            if (hover.kind === "deleteUpTo") {
+              const ids = store().getSessionMessageIds(props.sessionId)
+              const targetIndex = ids.indexOf(hover.messageId)
+              if (targetIndex === -1) return false
+              const segmentIndex = ids.indexOf(segment.messageId)
+              if (segmentIndex === -1) return false
+              return segmentIndex >= targetIndex
+            }
+
+            return false
+          }
+
           const hasActivePermission = () => {
             if (segment.type !== "tool") return false
             const partIds = segment.toolPartIds ?? []
@@ -407,7 +450,7 @@ const MessageTimeline: Component<MessageTimelineProps> = (props) => {
             return false
           }
 
-          const isHidden = () => segment.type === "tool" && !(showTools() || isActive() || hasActivePermission())
+          const isHidden = () => segment.type === "tool" && !(showTools() || isActive() || hasActivePermission() || isDeleteHovered())
 
            const shortLabelContent = () => {
              if (segment.type === "tool") {
@@ -427,15 +470,17 @@ const MessageTimeline: Component<MessageTimelineProps> = (props) => {
 
           return (
              <button
-               ref={(el) => registerButtonRef(segment.id, el)}
-               type="button"
-               data-variant={segment.variant}
-               class={`message-timeline-segment message-timeline-${segment.type} ${hasActivePermission() ? "message-timeline-segment-permission" : ""} ${segment.type === "compaction" ? `message-timeline-compaction-${segment.variant ?? "manual"}` : ""} ${isActive() ? "message-timeline-segment-active" : ""} ${isHidden() ? "message-timeline-segment-hidden" : ""}`}
+                ref={(el) => registerButtonRef(segment.id, el)}
+                type="button"
+                data-variant={segment.variant}
+                class={`message-timeline-segment message-timeline-${segment.type} ${hasActivePermission() ? "message-timeline-segment-permission" : ""} ${segment.type === "compaction" ? `message-timeline-compaction-${segment.variant ?? "manual"}` : ""} ${isActive() ? "message-timeline-segment-active" : ""} ${isHidden() ? "message-timeline-segment-hidden" : ""}`}
 
-              aria-current={isActive() ? "true" : undefined}
-              aria-hidden={isHidden() ? "true" : undefined}
-              onClick={() => props.onSegmentClick?.(segment)}
-              onMouseEnter={(event) => handleMouseEnter(segment, event)}
+                data-delete-hover={isDeleteHovered() ? "true" : undefined}
+
+               aria-current={isActive() ? "true" : undefined}
+               aria-hidden={isHidden() ? "true" : undefined}
+               onClick={() => props.onSegmentClick?.(segment)}
+               onMouseEnter={(event) => handleMouseEnter(segment, event)}
               onMouseLeave={handleMouseLeave}
             >
               <span class="message-timeline-label message-timeline-label-full">{segment.label}</span>
@@ -460,6 +505,10 @@ const MessageTimeline: Component<MessageTimelineProps> = (props) => {
                 instanceId={props.instanceId}
                 sessionId={props.sessionId}
                 store={store}
+                deleteHover={props.deleteHover}
+                onDeleteHoverChange={props.onDeleteHoverChange}
+                onDeleteMessagesUpTo={props.onDeleteMessagesUpTo}
+                selectedMessageIds={props.selectedMessageIds}
               />
             </div>
           )

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

@@ -10,6 +10,7 @@ import { getAttachments, removeAttachment } from "../../stores/attachments"
 import { instances } from "../../stores/instances"
 import { loadMessages, sendMessage, forkSession, renameSession, isSessionMessagesLoading, setActiveParentSession, setActiveSession, runShellCommand, abortSession } from "../../stores/sessions"
 import { isSessionBusy as getSessionBusyStatus } from "../../stores/session-status"
+import { deleteMessage } from "../../stores/session-actions"
 import { showAlertDialog } from "../../stores/alerts"
 import { getLogger } from "../../lib/logger"
 import { requestData } from "../../lib/opencode-api"
@@ -225,6 +226,35 @@ export const SessionView: Component<SessionViewProps> = (props) => {
     }
   }
 
+  async function handleDeleteMessagesUpTo(messageId: string) {
+    const ids = messageStore().getSessionMessageIds(props.sessionId)
+    const index = ids.indexOf(messageId)
+    if (index === -1) return
+
+    const restoredText = getUserMessageText(messageId)
+    const toDelete = ids.slice(index)
+
+    try {
+      for (let idx = toDelete.length - 1; idx >= 0; idx -= 1) {
+        await deleteMessage(props.instanceId, props.sessionId, toDelete[idx])
+      }
+    } catch (error) {
+      log.error("Failed to delete messages up to", error)
+      showAlertDialog(t("sessionView.alerts.deleteUpToFailed.message"), {
+        title: t("sessionView.alerts.deleteUpToFailed.title"),
+        variant: "error",
+      })
+    } finally {
+      if (restoredText) {
+        if (promptInputApi) {
+          promptInputApi.setPromptText(restoredText, { focus: true })
+        } else {
+          pendingPromptText = restoredText
+        }
+      }
+    }
+  }
+
   async function handleFork(messageId?: string) {
     if (!messageId) {
       log.warn("Fork requires a user message id")
@@ -283,10 +313,11 @@ export const SessionView: Component<SessionViewProps> = (props) => {
             <MessageSection
                instanceId={props.instanceId}
                sessionId={activeSession.id}
-               loading={messagesLoading()}
-               onRevert={handleRevert}
-               onFork={handleFork}
-               isActive={props.isActive}
+                loading={messagesLoading()}
+                onRevert={handleRevert}
+                onDeleteMessagesUpTo={handleDeleteMessagesUpTo}
+                onFork={handleFork}
+                isActive={props.isActive}
                 registerScrollToBottom={(fn) => {
                   scrollToBottomHandle = fn
                   if (props.isActive) {

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

@@ -44,7 +44,7 @@ import { getLogger } from "../lib/logger"
 
 const log = getLogger("session")
 
-type ToolState = import("@opencode-ai/sdk").ToolState
+type ToolState = import("@opencode-ai/sdk/v2").ToolState
 
 const TOOL_CALL_CACHE_SCOPE = "tool-call"
 const TOOL_SCROLL_SENTINEL_MARGIN_PX = 48

packages/ui/src/components/tool-call/diagnostics.ts

@@ -1,4 +1,4 @@
-import type { ToolState } from "@opencode-ai/sdk"
+import type { ToolState } from "@opencode-ai/sdk/v2"
 import { getRelativePath, isToolStateCompleted, isToolStateError, isToolStateRunning } from "./utils"
 import { tGlobal } from "../../lib/i18n"
 

packages/ui/src/components/tool-call/markdown-render.tsx

@@ -1,5 +1,5 @@
 import type { Accessor, JSXElement } from "solid-js"
-import type { ToolState } from "@opencode-ai/sdk"
+import type { ToolState } from "@opencode-ai/sdk/v2"
 import type { TextPart } from "../../types/message"
 import { Markdown } from "../markdown"
 import type { MarkdownRenderOptions, ToolScrollHelpers } from "./types"

packages/ui/src/components/tool-call/question-block.tsx

@@ -1,5 +1,5 @@
 import { createMemo, Show, For, createEffect, type Accessor } from "solid-js"
-import type { ToolState } from "@opencode-ai/sdk"
+import type { ToolState } from "@opencode-ai/sdk/v2"
 import type { QuestionRequest } from "@opencode-ai/sdk/v2"
 import { useI18n } from "../../lib/i18n"
 

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

@@ -1,5 +1,5 @@
 import { For, Show, createEffect, createMemo, createSignal, untrack } from "solid-js"
-import type { ToolState } from "@opencode-ai/sdk"
+import type { ToolState } from "@opencode-ai/sdk/v2"
 import type { ToolRenderer } from "../types"
 import { ensureMarkdownContent, getDefaultToolAction, getToolIcon, getToolName, readToolStatePayload } from "../utils"
 import { resolveTitleForTool } from "../tool-title"

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

@@ -1,5 +1,5 @@
 import { For, Show } from "solid-js"
-import type { ToolState } from "@opencode-ai/sdk"
+import type { ToolState } from "@opencode-ai/sdk/v2"
 import type { ToolRenderer } from "../types"
 import { readToolStatePayload } from "../utils"
 import { useI18n, tGlobal } from "../../../lib/i18n"

packages/ui/src/components/tool-call/tool-title.ts

@@ -1,4 +1,4 @@
-import type { ToolState } from "@opencode-ai/sdk"
+import type { ToolState } from "@opencode-ai/sdk/v2"
 import type { ToolRendererContext, ToolRenderer, ToolCallPart } from "./types"
 import { getDefaultToolAction, getToolName, isToolStateCompleted, isToolStateRunning } from "./utils"
 import { enMessages } from "../../lib/i18n/messages/en"

packages/ui/src/components/tool-call/types.ts

@@ -1,5 +1,5 @@
 import type { Accessor, JSXElement } from "solid-js"
-import type { ToolState } from "@opencode-ai/sdk"
+import type { ToolState } from "@opencode-ai/sdk/v2"
 import type { ClientPart } from "../../types/message"
 
 export type ToolCallPart = Extract<ClientPart, { type: "tool" }>

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

@@ -1,15 +1,15 @@
 import { isRenderableDiffText } from "../../lib/diff-utils"
 import { getLanguageFromPath } from "../../lib/markdown"
-import type { ToolState } from "@opencode-ai/sdk"
+import type { ToolState } from "@opencode-ai/sdk/v2"
 import type { DiffPayload } from "./types"
 import { getLogger } from "../../lib/logger"
 import { tGlobal } from "../../lib/i18n"
 const log = getLogger("session")
 
 
-export type ToolStateRunning = import("@opencode-ai/sdk").ToolStateRunning
-export type ToolStateCompleted = import("@opencode-ai/sdk").ToolStateCompleted
-export type ToolStateError = import("@opencode-ai/sdk").ToolStateError
+export type ToolStateRunning = import("@opencode-ai/sdk/v2").ToolStateRunning
+export type ToolStateCompleted = import("@opencode-ai/sdk/v2").ToolStateCompleted
+export type ToolStateError = import("@opencode-ai/sdk/v2").ToolStateError
 
 export const diffCapableTools = new Set(["edit", "patch"])
 

packages/ui/src/lib/i18n/messages/en/messaging.ts

@@ -41,7 +41,7 @@ export const messagingMessages = {
   "messageBlock.tool.goToSession.label": "Go to Session",
   "messageBlock.tool.goToSession.title": "Go to session",
   "messageBlock.tool.goToSession.unavailableTitle": "Session not available yet",
-  "messageBlock.tool.deletePart.label": "Delete",
+  "messageBlock.tool.deletePart.label": "Delete Part",
   "messageBlock.tool.deletePart.deleting": "Deleting...",
   "messageBlock.tool.deletePart.title": "Delete this tool call output",
   "messageBlock.tool.deletePart.failed.title": "Delete failed",
@@ -71,17 +71,31 @@ export const messagingMessages = {
   "messageItem.speaker.you": "You",
   "messageItem.speaker.assistant": "Assistant",
   "messageItem.actions.revert": "Revert",
-  "messageItem.actions.revertTitle": "Revert to this message",
+  "messageItem.actions.revertTitle": "Undo changes up to here (deletes messages)",
   "messageItem.actions.fork": "Fork",
   "messageItem.actions.forkTitle": "Fork from this message",
   "messageItem.actions.copy": "Copy",
   "messageItem.actions.copyTitle": "Copy message",
   "messageItem.actions.copied": "Copied!",
+  "messageItem.actions.deleteMessage": "Delete message (doesn't undo changes)",
+  "messageItem.actions.deleteMessagesUpTo": "Delete messages up to here (doesn't undo changes)",
+  "messageItem.actions.deletingMessage": "Deleting...",
+  "messageItem.actions.deleteMessageFailedTitle": "Delete failed",
+  "messageItem.actions.deleteMessageFailedMessage": "Failed to delete message",
+
+  "messageItem.selection.checkboxAriaLabel": "Select message for deletion",
+
+  "messageSection.bulkDelete.toolbarAriaLabel": "Selected messages ({count})",
+  "messageSection.bulkDelete.deleteSelectedTitle": "Delete selected messages",
+  "messageSection.bulkDelete.selectAllTitle": "Select all messages",
+  "messageSection.bulkDelete.cancelTitle": "Cancel selection",
+  "messageSection.bulkDelete.failedTitle": "Delete failed",
+  "messageSection.bulkDelete.failedMessage": "Failed to delete selected messages",
   "messageItem.status.queued": "QUEUED",
   "messageItem.status.generating": "Generating...",
   "messageItem.status.sending": "Sending...",
   "messageItem.status.failedToSend": "Message failed to send",
-  "messagePart.actions.delete": "Delete",
+  "messagePart.actions.delete": "Delete Part",
   "messagePart.actions.deleting": "Deleting...",
   "messagePart.actions.deleteTitle": "Delete this item",
   "messagePart.actions.deleteFailedTitle": "Delete failed",

packages/ui/src/lib/i18n/messages/en/session.ts

@@ -67,6 +67,8 @@ export const sessionMessages = {
   "sessionView.alerts.abortFailed.title": "Stop failed",
   "sessionView.alerts.revertFailed.message": "Failed to revert to message",
   "sessionView.alerts.revertFailed.title": "Revert failed",
+  "sessionView.alerts.deleteUpToFailed.message": "Failed to delete messages",
+  "sessionView.alerts.deleteUpToFailed.title": "Delete failed",
   "sessionView.alerts.forkFailed.message": "Failed to fork session",
   "sessionView.alerts.forkFailed.title": "Fork failed",
   "sessionView.attachments.expandPastedTextAriaLabel": "Expand pasted text",

packages/ui/src/lib/i18n/messages/es/messaging.ts

@@ -41,7 +41,7 @@ export const messagingMessages = {
   "messageBlock.tool.goToSession.label": "Ir a sesión",
   "messageBlock.tool.goToSession.title": "Ir a la sesión",
   "messageBlock.tool.goToSession.unavailableTitle": "La sesión aún no está disponible",
-  "messageBlock.tool.deletePart.label": "Eliminar",
+  "messageBlock.tool.deletePart.label": "Eliminar parte",
   "messageBlock.tool.deletePart.deleting": "Eliminando...",
   "messageBlock.tool.deletePart.title": "Eliminar esta salida de herramienta",
   "messageBlock.tool.deletePart.failed.title": "Error al eliminar",
@@ -71,17 +71,31 @@ export const messagingMessages = {
   "messageItem.speaker.you": "Tú",
   "messageItem.speaker.assistant": "Asistente",
   "messageItem.actions.revert": "Revertir",
-  "messageItem.actions.revertTitle": "Revertir a este mensaje",
+  "messageItem.actions.revertTitle": "Deshacer cambios hasta aqui (elimina mensajes)",
   "messageItem.actions.fork": "Fork",
   "messageItem.actions.forkTitle": "Fork desde este mensaje",
   "messageItem.actions.copy": "Copiar",
   "messageItem.actions.copyTitle": "Copiar mensaje",
   "messageItem.actions.copied": "¡Copiado!",
+  "messageItem.actions.deleteMessage": "Eliminar mensaje (no deshace cambios)",
+  "messageItem.actions.deleteMessagesUpTo": "Eliminar mensajes hasta aqui (no deshace cambios)",
+  "messageItem.actions.deletingMessage": "Eliminando...",
+  "messageItem.actions.deleteMessageFailedTitle": "Error al eliminar",
+  "messageItem.actions.deleteMessageFailedMessage": "No se pudo eliminar el mensaje",
+
+  "messageItem.selection.checkboxAriaLabel": "Seleccionar mensaje para eliminar",
+
+  "messageSection.bulkDelete.toolbarAriaLabel": "Mensajes seleccionados ({count})",
+  "messageSection.bulkDelete.deleteSelectedTitle": "Eliminar mensajes seleccionados",
+  "messageSection.bulkDelete.selectAllTitle": "Seleccionar todos los mensajes",
+  "messageSection.bulkDelete.cancelTitle": "Cancelar selección",
+  "messageSection.bulkDelete.failedTitle": "Error al eliminar",
+  "messageSection.bulkDelete.failedMessage": "No se pudieron eliminar los mensajes seleccionados",
   "messageItem.status.queued": "EN COLA",
   "messageItem.status.generating": "Generando...",
   "messageItem.status.sending": "Enviando...",
   "messageItem.status.failedToSend": "No se pudo enviar el mensaje",
-  "messagePart.actions.delete": "Eliminar",
+  "messagePart.actions.delete": "Eliminar parte",
   "messagePart.actions.deleting": "Eliminando...",
   "messagePart.actions.deleteTitle": "Eliminar este elemento",
   "messagePart.actions.deleteFailedTitle": "Error al eliminar",

packages/ui/src/lib/i18n/messages/es/session.ts

@@ -67,6 +67,8 @@ export const sessionMessages = {
   "sessionView.alerts.abortFailed.title": "No se pudo detener",
   "sessionView.alerts.revertFailed.message": "No se pudo revertir al mensaje",
   "sessionView.alerts.revertFailed.title": "No se pudo revertir",
+  "sessionView.alerts.deleteUpToFailed.message": "No se pudieron eliminar los mensajes",
+  "sessionView.alerts.deleteUpToFailed.title": "Error al eliminar",
   "sessionView.alerts.forkFailed.message": "No se pudo hacer fork de la sesión",
   "sessionView.alerts.forkFailed.title": "No se pudo hacer fork",
   "sessionView.attachments.expandPastedTextAriaLabel": "Expandir texto pegado",

packages/ui/src/lib/i18n/messages/fr/messaging.ts

@@ -41,7 +41,7 @@ export const messagingMessages = {
   "messageBlock.tool.goToSession.label": "Aller à la session",
   "messageBlock.tool.goToSession.title": "Aller à la session",
   "messageBlock.tool.goToSession.unavailableTitle": "Session pas encore disponible",
-  "messageBlock.tool.deletePart.label": "Supprimer",
+  "messageBlock.tool.deletePart.label": "Supprimer la partie",
   "messageBlock.tool.deletePart.deleting": "Suppression...",
   "messageBlock.tool.deletePart.title": "Supprimer cette sortie d'outil",
   "messageBlock.tool.deletePart.failed.title": "Échec de suppression",
@@ -71,17 +71,31 @@ export const messagingMessages = {
   "messageItem.speaker.you": "Vous",
   "messageItem.speaker.assistant": "Assistant",
   "messageItem.actions.revert": "Revenir",
-  "messageItem.actions.revertTitle": "Revenir à ce message",
+  "messageItem.actions.revertTitle": "Annuler les changements jusqu'ici (supprime les messages)",
   "messageItem.actions.fork": "Fork",
   "messageItem.actions.forkTitle": "Fork depuis ce message",
   "messageItem.actions.copy": "Copier",
   "messageItem.actions.copyTitle": "Copier le message",
   "messageItem.actions.copied": "Copié !",
+  "messageItem.actions.deleteMessage": "Supprimer le message (sans annuler les changements)",
+  "messageItem.actions.deleteMessagesUpTo": "Supprimer les messages jusqu'ici (sans annuler les changements)",
+  "messageItem.actions.deletingMessage": "Suppression...",
+  "messageItem.actions.deleteMessageFailedTitle": "Échec de suppression",
+  "messageItem.actions.deleteMessageFailedMessage": "Impossible de supprimer le message",
+
+  "messageItem.selection.checkboxAriaLabel": "Sélectionner le message pour suppression",
+
+  "messageSection.bulkDelete.toolbarAriaLabel": "Messages sélectionnés ({count})",
+  "messageSection.bulkDelete.deleteSelectedTitle": "Supprimer les messages sélectionnés",
+  "messageSection.bulkDelete.selectAllTitle": "Tout sélectionner",
+  "messageSection.bulkDelete.cancelTitle": "Annuler la sélection",
+  "messageSection.bulkDelete.failedTitle": "Échec de suppression",
+  "messageSection.bulkDelete.failedMessage": "Impossible de supprimer les messages sélectionnés",
   "messageItem.status.queued": "EN FILE",
   "messageItem.status.generating": "Génération...",
   "messageItem.status.sending": "Envoi...",
   "messageItem.status.failedToSend": "Échec de l'envoi du message",
-  "messagePart.actions.delete": "Supprimer",
+  "messagePart.actions.delete": "Supprimer la partie",
   "messagePart.actions.deleting": "Suppression...",
   "messagePart.actions.deleteTitle": "Supprimer cet élément",
   "messagePart.actions.deleteFailedTitle": "Échec de suppression",

packages/ui/src/lib/i18n/messages/fr/session.ts

@@ -67,6 +67,8 @@ export const sessionMessages = {
   "sessionView.alerts.abortFailed.title": "Échec de l'arrêt",
   "sessionView.alerts.revertFailed.message": "Impossible de revenir au message",
   "sessionView.alerts.revertFailed.title": "Échec du retour",
+  "sessionView.alerts.deleteUpToFailed.message": "Impossible de supprimer les messages",
+  "sessionView.alerts.deleteUpToFailed.title": "Échec de suppression",
   "sessionView.alerts.forkFailed.message": "Impossible de forker la session",
   "sessionView.alerts.forkFailed.title": "Échec du fork",
   "sessionView.attachments.expandPastedTextAriaLabel": "Développer le texte collé",

packages/ui/src/lib/i18n/messages/ja/messaging.ts

@@ -41,7 +41,7 @@ export const messagingMessages = {
   "messageBlock.tool.goToSession.label": "セッションへ移動",
   "messageBlock.tool.goToSession.title": "セッションへ移動",
   "messageBlock.tool.goToSession.unavailableTitle": "セッションはまだ利用できません",
-  "messageBlock.tool.deletePart.label": "削除",
+  "messageBlock.tool.deletePart.label": "パートを削除",
   "messageBlock.tool.deletePart.deleting": "削除中...",
   "messageBlock.tool.deletePart.title": "このツール出力を削除",
   "messageBlock.tool.deletePart.failed.title": "削除に失敗しました",
@@ -71,17 +71,31 @@ export const messagingMessages = {
   "messageItem.speaker.you": "あなた",
   "messageItem.speaker.assistant": "アシスタント",
   "messageItem.actions.revert": "戻す",
-  "messageItem.actions.revertTitle": "このメッセージまで戻す",
+  "messageItem.actions.revertTitle": "ここまでの変更を元に戻す（メッセージを削除）",
   "messageItem.actions.fork": "フォーク",
   "messageItem.actions.forkTitle": "このメッセージからフォーク",
   "messageItem.actions.copy": "コピー",
   "messageItem.actions.copyTitle": "メッセージをコピー",
   "messageItem.actions.copied": "コピーしました!",
+  "messageItem.actions.deleteMessage": "メッセージを削除（変更は元に戻さない）",
+  "messageItem.actions.deleteMessagesUpTo": "ここまでのメッセージを削除（変更は元に戻さない）",
+  "messageItem.actions.deletingMessage": "削除中...",
+  "messageItem.actions.deleteMessageFailedTitle": "削除に失敗しました",
+  "messageItem.actions.deleteMessageFailedMessage": "メッセージの削除に失敗しました",
+
+  "messageItem.selection.checkboxAriaLabel": "削除するメッセージを選択",
+
+  "messageSection.bulkDelete.toolbarAriaLabel": "選択したメッセージ（{count}）",
+  "messageSection.bulkDelete.deleteSelectedTitle": "選択したメッセージを削除",
+  "messageSection.bulkDelete.selectAllTitle": "すべて選択",
+  "messageSection.bulkDelete.cancelTitle": "選択をキャンセル",
+  "messageSection.bulkDelete.failedTitle": "削除に失敗しました",
+  "messageSection.bulkDelete.failedMessage": "選択したメッセージの削除に失敗しました",
   "messageItem.status.queued": "待機中",
   "messageItem.status.generating": "生成中...",
   "messageItem.status.sending": "送信中...",
   "messageItem.status.failedToSend": "メッセージの送信に失敗しました",
-  "messagePart.actions.delete": "削除",
+  "messagePart.actions.delete": "パートを削除",
   "messagePart.actions.deleting": "削除中...",
   "messagePart.actions.deleteTitle": "この項目を削除",
   "messagePart.actions.deleteFailedTitle": "削除に失敗しました",

packages/ui/src/lib/i18n/messages/ja/session.ts

@@ -67,6 +67,8 @@ export const sessionMessages = {
   "sessionView.alerts.abortFailed.title": "停止に失敗",
   "sessionView.alerts.revertFailed.message": "メッセージへ戻せませんでした",
   "sessionView.alerts.revertFailed.title": "復元に失敗",
+  "sessionView.alerts.deleteUpToFailed.message": "メッセージの削除に失敗しました",
+  "sessionView.alerts.deleteUpToFailed.title": "削除に失敗しました",
   "sessionView.alerts.forkFailed.message": "セッションのフォークに失敗しました",
   "sessionView.alerts.forkFailed.title": "フォークに失敗",
   "sessionView.attachments.expandPastedTextAriaLabel": "貼り付けたテキストを展開",

packages/ui/src/lib/i18n/messages/ru/messaging.ts

@@ -41,7 +41,7 @@ export const messagingMessages = {
   "messageBlock.tool.goToSession.label": "Перейти к сессии",
   "messageBlock.tool.goToSession.title": "Перейти к сессии",
   "messageBlock.tool.goToSession.unavailableTitle": "Сессия пока недоступна",
-  "messageBlock.tool.deletePart.label": "Удалить",
+  "messageBlock.tool.deletePart.label": "Удалить часть",
   "messageBlock.tool.deletePart.deleting": "Удаление...",
   "messageBlock.tool.deletePart.title": "Удалить этот вывод инструмента",
   "messageBlock.tool.deletePart.failed.title": "Ошибка удаления",
@@ -71,17 +71,31 @@ export const messagingMessages = {
   "messageItem.speaker.you": "Вы",
   "messageItem.speaker.assistant": "Ассистент",
   "messageItem.actions.revert": "Откатить",
-  "messageItem.actions.revertTitle": "Откатиться к этому сообщению",
+  "messageItem.actions.revertTitle": "Отменить изменения до этого места (удалит сообщения)",
   "messageItem.actions.fork": "Форк",
   "messageItem.actions.forkTitle": "Форкнуть от этого сообщения",
   "messageItem.actions.copy": "Копировать",
   "messageItem.actions.copyTitle": "Копировать сообщение",
   "messageItem.actions.copied": "Скопировано!",
+  "messageItem.actions.deleteMessage": "Удалить сообщение (без отката изменений)",
+  "messageItem.actions.deleteMessagesUpTo": "Удалить сообщения до этого места (без отката изменений)",
+  "messageItem.actions.deletingMessage": "Удаление...",
+  "messageItem.actions.deleteMessageFailedTitle": "Ошибка удаления",
+  "messageItem.actions.deleteMessageFailedMessage": "Не удалось удалить сообщение",
+
+  "messageItem.selection.checkboxAriaLabel": "Выбрать сообщение для удаления",
+
+  "messageSection.bulkDelete.toolbarAriaLabel": "Выбранные сообщения ({count})",
+  "messageSection.bulkDelete.deleteSelectedTitle": "Удалить выбранные сообщения",
+  "messageSection.bulkDelete.selectAllTitle": "Выбрать все сообщения",
+  "messageSection.bulkDelete.cancelTitle": "Отменить выбор",
+  "messageSection.bulkDelete.failedTitle": "Ошибка удаления",
+  "messageSection.bulkDelete.failedMessage": "Не удалось удалить выбранные сообщения",
   "messageItem.status.queued": "В ОЧЕРЕДИ",
   "messageItem.status.generating": "Генерация…",
   "messageItem.status.sending": "Отправка…",
   "messageItem.status.failedToSend": "Не удалось отправить сообщение",
-  "messagePart.actions.delete": "Удалить",
+  "messagePart.actions.delete": "Удалить часть",
   "messagePart.actions.deleting": "Удаление...",
   "messagePart.actions.deleteTitle": "Удалить этот элемент",
   "messagePart.actions.deleteFailedTitle": "Ошибка удаления",

packages/ui/src/lib/i18n/messages/ru/session.ts

@@ -67,6 +67,8 @@ export const sessionMessages = {
   "sessionView.alerts.abortFailed.title": "Не удалось остановить",
   "sessionView.alerts.revertFailed.message": "Не удалось откатиться к сообщению",
   "sessionView.alerts.revertFailed.title": "Не удалось откатиться",
+  "sessionView.alerts.deleteUpToFailed.message": "Не удалось удалить сообщения",
+  "sessionView.alerts.deleteUpToFailed.title": "Ошибка удаления",
   "sessionView.alerts.forkFailed.message": "Не удалось форкнуть сессию",
   "sessionView.alerts.forkFailed.title": "Не удалось форкнуть",
   "sessionView.attachments.expandPastedTextAriaLabel": "Развернуть вставленный текст",

packages/ui/src/lib/i18n/messages/zh-Hans/messaging.ts

@@ -41,7 +41,7 @@ export const messagingMessages = {
   "messageBlock.tool.goToSession.label": "前往会话",
   "messageBlock.tool.goToSession.title": "前往会话",
   "messageBlock.tool.goToSession.unavailableTitle": "会话尚不可用",
-  "messageBlock.tool.deletePart.label": "删除",
+  "messageBlock.tool.deletePart.label": "删除部分",
   "messageBlock.tool.deletePart.deleting": "正在删除...",
   "messageBlock.tool.deletePart.title": "删除此工具输出",
   "messageBlock.tool.deletePart.failed.title": "删除失败",
@@ -71,17 +71,31 @@ export const messagingMessages = {
   "messageItem.speaker.you": "你",
   "messageItem.speaker.assistant": "助手",
   "messageItem.actions.revert": "回退",
-  "messageItem.actions.revertTitle": "回退到这条消息",
+  "messageItem.actions.revertTitle": "撤销到此处的更改（会删除消息）",
   "messageItem.actions.fork": "分叉",
   "messageItem.actions.forkTitle": "从这条消息分叉",
   "messageItem.actions.copy": "复制",
   "messageItem.actions.copyTitle": "复制消息",
   "messageItem.actions.copied": "已复制！",
+  "messageItem.actions.deleteMessage": "删除消息（不会撤销更改）",
+  "messageItem.actions.deleteMessagesUpTo": "删除到此处的消息（不会撤销更改）",
+  "messageItem.actions.deletingMessage": "正在删除...",
+  "messageItem.actions.deleteMessageFailedTitle": "删除失败",
+  "messageItem.actions.deleteMessageFailedMessage": "无法删除消息",
+
+  "messageItem.selection.checkboxAriaLabel": "选择要删除的消息",
+
+  "messageSection.bulkDelete.toolbarAriaLabel": "已选择的消息（{count}）",
+  "messageSection.bulkDelete.deleteSelectedTitle": "删除已选择的消息",
+  "messageSection.bulkDelete.selectAllTitle": "全选消息",
+  "messageSection.bulkDelete.cancelTitle": "取消选择",
+  "messageSection.bulkDelete.failedTitle": "删除失败",
+  "messageSection.bulkDelete.failedMessage": "无法删除已选择的消息",
   "messageItem.status.queued": "排队中",
   "messageItem.status.generating": "正在生成...",
   "messageItem.status.sending": "正在发送...",
   "messageItem.status.failedToSend": "消息发送失败",
-  "messagePart.actions.delete": "删除",
+  "messagePart.actions.delete": "删除部分",
   "messagePart.actions.deleting": "正在删除...",
   "messagePart.actions.deleteTitle": "删除此项",
   "messagePart.actions.deleteFailedTitle": "删除失败",

packages/ui/src/lib/i18n/messages/zh-Hans/session.ts

@@ -67,6 +67,8 @@ export const sessionMessages = {
   "sessionView.alerts.abortFailed.title": "停止失败",
   "sessionView.alerts.revertFailed.message": "回退到消息失败",
   "sessionView.alerts.revertFailed.title": "回退失败",
+  "sessionView.alerts.deleteUpToFailed.message": "无法删除消息",
+  "sessionView.alerts.deleteUpToFailed.title": "删除失败",
   "sessionView.alerts.forkFailed.message": "分叉会话失败",
   "sessionView.alerts.forkFailed.title": "分叉失败",
   "sessionView.attachments.expandPastedTextAriaLabel": "展开粘贴的文本",

packages/ui/src/stores/session-actions.ts

@@ -7,7 +7,7 @@ import { providers, sessions, withSession } from "./session-state"
 import { getDefaultModel, isModelValid } from "./session-models"
 import { updateSessionInfo } from "./message-v2/session-info"
 import { messageStoreBus } from "./message-v2/bus"
-import { removeMessagePartV2 } from "./message-v2/bridge"
+import { removeMessagePartV2, removeMessageV2 } from "./message-v2/bridge"
 import { getLogger } from "../lib/logger"
 import { requestData } from "../lib/opencode-api"
 
@@ -439,8 +439,33 @@ async function deleteMessagePart(instanceId: string, sessionId: string, messageI
   updateSessionInfo(instanceId, sessionId)
 }
 
+async function deleteMessage(instanceId: string, sessionId: string, messageId: string): Promise<void> {
+  if (!instanceId || !sessionId || !messageId) return
+  const instance = instances().get(instanceId)
+  if (!instance || !instance.client) {
+    throw new Error("Instance not ready")
+  }
+
+  const worktreeSlug = getWorktreeSlugForSession(instanceId, sessionId)
+  const client = getOrCreateWorktreeClient(instanceId, worktreeSlug)
+
+  // The SDK generator does not currently expose a typed method for deleting a message,
+  // but the API is available at DELETE /session/:sessionID/message/:messageID.
+  await requestData(
+    (client as any).client.delete({
+      url: `/session/${encodeURIComponent(sessionId)}/message/${encodeURIComponent(messageId)}`,
+    }),
+    "session.message.delete",
+  )
+
+  // Optimistic removal; SSE will also broadcast a message-removed event.
+  removeMessageV2(instanceId, messageId)
+  updateSessionInfo(instanceId, sessionId)
+}
+
 export {
   abortSession,
+  deleteMessage,
   deleteMessagePart,
   executeCustomCommand,
   renameSession,

packages/ui/src/styles/messaging.css

@@ -2,6 +2,8 @@
 @import "./messaging/prompt-input.css";
 @import "./messaging/message-section.css";
 @import "./messaging/message-block-list.css";
+@import "./messaging/message-selection.css";
+@import "./messaging/delete-overlays.css";
 @import "./messaging/message-timeline.css";
 @import "./messaging/tool-call.css";
 @import "./messaging/log-view.css";
@@ -110,4 +112,3 @@
 .reasoning-label {
   font-weight: var(--font-weight-medium);
 }
-

packages/ui/src/styles/messaging/delete-overlays.css

@@ -0,0 +1,35 @@
+/* Hover overlays for destructive actions (delete part / delete message). */
+
+.message-stream-block[data-delete-message-hover="true"] {
+  position: relative;
+}
+
+.message-stream-block[data-delete-message-hover="true"]::before {
+  content: "";
+  position: absolute;
+  inset: -2px;
+  background: var(--status-error-bg);
+  border-radius: 0;
+  pointer-events: none;
+  /* Overlay must sit above the message cards (they have opaque backgrounds). */
+  z-index: 10;
+}
+
+.message-part-shell {
+  display: block;
+}
+
+.delete-hover-scope[data-delete-part-hover="true"] {
+  position: relative;
+}
+
+.delete-hover-scope[data-delete-part-hover="true"]::before {
+  content: "";
+  position: absolute;
+  inset: -2px;
+  background: var(--status-error-bg);
+  border-radius: 0;
+  pointer-events: none;
+  /* Overlay must sit above the part card background. */
+  z-index: 10;
+}

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

@@ -8,7 +8,8 @@
 }
 
 .message-item-header {
-  @apply flex flex-col gap-0.5;
+  @apply flex flex-col;
+  gap: 0.25rem;
 }
 
 .message-item-header-row {
@@ -19,12 +20,58 @@
   @apply flex justify-between items-start gap-2.5;
 }
 
+.message-item-header-row--meta {
+  @apply w-full;
+}
+
+.message-header-left {
+  display: flex;
+  align-items: center;
+  gap: 0.5rem;
+  flex: 1 1 auto;
+  min-width: 0;
+}
+
 .message-item-header-row--bottom {
   @apply flex items-start;
 }
 
 .message-speaker {
-  @apply flex flex-col gap-0.5 text-xs;
+  /* Allow agent meta to wrap to a second row with comfortable spacing. */
+  @apply flex flex-wrap items-center gap-x-2 gap-y-0.5 text-xs;
+  flex: 1 1 auto;
+  min-width: 0;
+}
+
+.message-speaker-primary {
+  @apply inline-flex items-center;
+  white-space: nowrap;
+  flex: 0 0 auto;
+}
+
+.message-agent-meta-inline {
+  @apply text-[11px] font-medium;
+  color: var(--message-assistant-border);
+  white-space: nowrap;
+  flex: 0 0 auto;
+  line-height: 1.1;
+}
+
+.message-agent-meta-inline--measure {
+  position: fixed;
+  left: -9999px;
+  top: -9999px;
+  visibility: hidden;
+  pointer-events: none;
+  white-space: nowrap;
+}
+
+.message-agent-meta-block {
+  @apply text-[11px] font-medium;
+  color: var(--message-assistant-border);
+  overflow-wrap: anywhere;
+  word-break: break-word;
+  line-height: 1.15;
 }
 
 .message-speaker-label {
@@ -46,19 +93,19 @@
 
 .message-item-actions {
   @apply flex items-center gap-2;
+  flex: 0 0 auto;
 }
 
 .message-action-group {
-  @apply flex items-center gap-2;
+  @apply flex items-center gap-0;
 }
 
 .message-action-button {
-  @apply bg-transparent border border-[var(--border-base)] text-[var(--text-muted)] cursor-pointer px-3 py-0.5 rounded text-xs font-semibold leading-none transition-all duration-200 flex items-center justify-center h-6;
+  @apply bg-transparent border-0 text-[var(--text-muted)] cursor-pointer px-2 py-0.5 rounded text-xs font-semibold leading-none transition-all duration-200 flex items-center justify-center h-6;
 }
 
 .message-action-button:hover {
   background-color: var(--surface-hover);
-  border-color: var(--accent-primary);
   color: var(--accent-primary);
 }
 
@@ -296,6 +343,12 @@
   color: var(--message-assistant-border);
 }
 
+/* Keep reasoning meta as a single unit so it drops to the next line when needed. */
+.message-reasoning-label .message-step-meta-inline {
+  flex-wrap: nowrap;
+  white-space: nowrap;
+}
+
 
 .message-step-reason {
   @apply text-[11px] font-medium;
@@ -320,7 +373,7 @@
 
 .message-reasoning-header {
   display: flex;
-  align-items: stretch;
+  align-items: flex-start;
   justify-content: space-between;
   gap: 0.5rem;
   transition: background-color 0.2s ease, box-shadow 0.2s ease;
@@ -365,11 +418,36 @@
 }
 
 .message-reasoning-label {
+  display: flex;
+  flex-wrap: nowrap;
+  align-items: center;
+  gap: 0.5rem;
   font-size: 0.75rem;
   font-weight: var(--font-weight-medium);
   color: var(--message-assistant-border);
 }
 
+.message-reasoning-label-primary {
+  display: inline-flex;
+  align-items: center;
+  gap: 0.5rem;
+  white-space: nowrap;
+  flex: 0 0 auto;
+}
+
+.message-step-meta-inline--measure {
+  position: fixed;
+  left: -9999px;
+  top: -9999px;
+  visibility: hidden;
+  pointer-events: none;
+  white-space: nowrap;
+}
+
+.message-reasoning-meta-row {
+  padding: 0 0.6rem 0.15rem 0.6rem;
+}
+
 .message-reasoning-meta {
   display: inline-flex;
   align-items: center;

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

@@ -0,0 +1,84 @@
+/* Message multi-select delete mode UI. */
+
+.message-select-checkbox {
+  width: 14px;
+  height: 14px;
+  margin-right: 0.5rem;
+  cursor: pointer;
+  accent-color: var(--status-error);
+  flex: 0 0 auto;
+}
+
+.message-delete-mode-toolbar {
+  position: absolute;
+  right: 12px;
+  bottom: 12px;
+  display: flex;
+  align-items: center;
+  gap: 8px;
+  padding: 6px;
+  background: color-mix(in oklab, var(--surface-secondary) 92%, var(--status-error-bg));
+  border: 1px solid var(--border-base);
+  border-radius: 12px;
+  z-index: 50;
+  box-shadow: 0 8px 22px rgba(0, 0, 0, 0.18);
+}
+
+/* Avoid covering the scroll-to-top/bottom floating buttons. */
+.message-layout[data-scroll-buttons="1"] .message-delete-mode-toolbar {
+  bottom: 4.25rem;
+}
+
+.message-layout[data-scroll-buttons="2"] .message-delete-mode-toolbar {
+  bottom: 7.5rem;
+}
+
+/* When timeline is visible, pin the toolbar to the stream edge. */
+.message-layout--with-timeline .message-delete-mode-toolbar {
+  right: calc(64px + 12px);
+}
+
+@media (max-width: 720px) {
+  .message-layout--with-timeline .message-delete-mode-toolbar {
+    right: calc(40px + 12px);
+  }
+}
+
+.message-delete-mode-count {
+  min-width: 28px;
+  height: 28px;
+  display: inline-flex;
+  align-items: center;
+  justify-content: center;
+  padding: 0 8px;
+  border-radius: 999px;
+  font-size: 12px;
+  font-weight: 700;
+  color: var(--text-primary);
+  background: var(--surface-secondary);
+  border: 1px solid var(--border-base);
+}
+
+.message-delete-mode-button {
+  width: 32px;
+  height: 32px;
+  display: inline-flex;
+  align-items: center;
+  justify-content: center;
+  background: transparent;
+  border: 1px solid var(--border-base);
+  border-radius: 10px;
+  color: var(--text-muted);
+  transition: background-color 0.2s ease, color 0.2s ease, border-color 0.2s ease;
+}
+
+.message-delete-mode-button:hover {
+  background-color: var(--surface-hover);
+  border-color: var(--status-error);
+  color: var(--status-error);
+}
+
+.message-delete-mode-button:focus-visible {
+  outline: none;
+  box-shadow: 0 0 0 2px color-mix(in oklab, var(--accent-primary) 45%, transparent);
+}

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

@@ -87,6 +87,7 @@
   border-radius: 0;
   border: 1px solid var(--border-base);
   background-color: var(--surface-secondary);
+  position: relative;
   display: flex;
   align-items: center;
   justify-content: center;
@@ -98,6 +99,35 @@
   transition: transform 0.15s ease, background-color 0.2s ease, color 0.2s ease, border-color 0.2s ease, box-shadow 0.2s ease;
 }
 
+.message-timeline-segment[data-delete-hover="true"]::before {
+  content: "";
+  position: absolute;
+  inset: 0;
+  background: var(--status-error-bg);
+  border-radius: 0;
+  pointer-events: none;
+  z-index: 2;
+}
+
+/* Ensure delete hover is visible even on the active segment styling. */
+.message-timeline-segment[data-delete-hover="true"],
+.message-timeline-segment[data-delete-hover="true"]:hover,
+.message-timeline-segment[data-delete-hover="true"]:focus-visible,
+.message-timeline-segment-active[data-delete-hover="true"],
+.message-timeline-segment-active[data-delete-hover="true"]:hover,
+.message-timeline-segment-active[data-delete-hover="true"]:focus-visible {
+  /* Let the ::before overlay provide the highlight (matches stream behavior). */
+  background-color: transparent !important;
+  border-color: transparent !important;
+  box-shadow: none !important;
+  transform: none !important;
+}
+
+.message-timeline-label {
+  position: relative;
+  z-index: 3;
+}
+
 .message-timeline-segment.message-timeline-segment-hidden {
   display: none !important;
 }

packages/ui/src/styles/messaging/tool-call.css

@@ -21,9 +21,9 @@
 
 .tool-call-header-button {
   background-color: transparent;
-  border: 1px solid var(--tool-call-border-color, var(--border-base));
   color: var(--text-secondary);
-  padding: 0.15rem 0.75rem;
+  border: 0;
+  padding: 0.1rem 0.35rem;
   border-radius: 0.375rem;
   font-size: 0.75rem;
   font-weight: var(--font-weight-semibold);
@@ -37,7 +37,6 @@
 
 .tool-call-header-button:hover:not(:disabled) {
   background-color: var(--surface-hover);
-  border-color: var(--accent-primary);
   color: var(--accent-primary);
 }
 

packages/ui/src/types/delete-hover.ts

@@ -0,0 +1,4 @@
+export type DeleteHoverState =
+  | { kind: "none" }
+  | { kind: "message"; messageId: string }
+  | { kind: "deleteUpTo"; messageId: string }

packages/ui/src/types/message.ts

@@ -1,4 +1,4 @@
-// SDK types
+// SDK v2 types
 import type {
   EventMessageUpdated as MessageUpdateEvent,
   EventMessageRemoved as MessageRemovedEvent,
@@ -6,7 +6,8 @@ import type {
   EventMessagePartRemoved as MessagePartRemovedEvent,
   Part as SDKPart,
   Message as SDKMessage,
-} from "@opencode-ai/sdk"
+  AssistantMessage as SDKAssistantMessageV2,
+} from "@opencode-ai/sdk/v2"
 
 import type { PermissionRequestLike } from "./permission"
 
@@ -17,7 +18,8 @@ export type {
   MessagePartUpdatedEvent,
   MessagePartRemovedEvent,
   SDKPart,
-  SDKMessage
+  SDKMessage,
+  SDKAssistantMessageV2,
 }
 
 // Server streaming event: append-only delta updates.