refactor(session): centralize fallback title policy (#39890)

packages/app/src/components/titlebar-tab-nav.tsx

@@ -4,6 +4,7 @@ import { createResizeObserver } from "@solid-primitives/resize-observer"
 import { createMutation } from "@tanstack/solid-query"
 import { IconButtonV2 } from "@opencode-ai/ui/v2/icon-button-v2"
 import { Icon as IconV2 } from "@opencode-ai/ui/v2/icon"
+import { displayLabel } from "@opencode-ai/util/session-title-fallback"
 import { useGlobal } from "@/context/global"
 import { ServerConnection, serverName } from "@/context/server"
 import { displayName, projectForSession } from "@/pages/layout/helpers"
@@ -11,7 +12,6 @@ import { SessionTabAvatar } from "@/pages/layout/session-tab-avatar"
 import type { Session } from "@opencode-ai/sdk/v2"
 import { canOpenTabRename, forwardTabRef } from "./titlebar-tab-gesture"
 import { TabPreviewPopover } from "./titlebar-tab-popover"
-import { sessionTitle } from "@/utils/session-title"
 import "./titlebar-tab-nav.css"
 
 // MouseEvent.button uses 1 for the middle/wheel button.
@@ -57,7 +57,7 @@ export function TabNavItem(props: {
   })
   const title = createMemo(() => {
     const session = props.session()
-    return session ? sessionTitle(session.title, session.parentID) : props.fallbackTitle
+    return session ? displayLabel(session) : props.fallbackTitle
   })
 
   const projectName = createMemo(() => {

packages/app/src/pages/home/home-session-search-controller.ts

@@ -3,11 +3,11 @@ import { useLanguage } from "@/context/language"
 import { serverName } from "@/context/server"
 import { displayName } from "@/pages/layout/helpers"
 import { makeEventListener } from "@solid-primitives/event-listener"
+import { displayLabel } from "@opencode-ai/util/session-title-fallback"
 import { createMemo, onCleanup } from "solid-js"
 import { createStore } from "solid-js/store"
 import type { HomeController } from "./home-controller"
 import { homeSessionSearchKey, type HomeSessionRecord, type HomeSessionsController } from "./home-sessions-controller"
-import { sessionTitle } from "@/utils/session-title"
 
 type HomeSessionSearchSource = Pick<HomeSessionsController, "data" | "session">
 
@@ -24,7 +24,7 @@ export function createHomeSessionSearchController(home: HomeController, sessions
     if (!value) return []
     return sessions.data
       .searchRecords()
-      .filter((record) => `${sessionTitle(record.session.title)} ${record.projectName}`.toLowerCase().includes(value))
+      .filter((record) => `${displayLabel(record.session)} ${record.projectName}`.toLowerCase().includes(value))
   })
   const active = createMemo(() => {
     const records = results()

packages/app/src/pages/home/home-sessions-view.tsx

@@ -6,10 +6,10 @@ import { ButtonV2 } from "@opencode-ai/ui/v2/button-v2"
 import { Icon as IconV2 } from "@opencode-ai/ui/v2/icon"
 import { IconButtonV2 } from "@opencode-ai/ui/v2/icon-button-v2"
 import { TooltipV2 } from "@opencode-ai/ui/v2/tooltip-v2"
+import { displayLabel } from "@opencode-ai/util/session-title-fallback"
 import { useLanguage } from "@/context/language"
 import { ServerConnection } from "@/context/server"
 import { SessionTabAvatarView } from "@/pages/layout/session-tab-avatar"
-import { sessionTitle } from "@/utils/session-title"
 import { shouldOpenSessionInBackground } from "../home-session-open"
 import {
   HomeSessionStatusController,
@@ -344,7 +344,7 @@ function HomeSessionSearchResultRow(
     selected: boolean
   },
 ) {
-  const title = createMemo(() => sessionTitle(props.record.session.title) || props.record.session.id)
+  const title = createMemo(() => displayLabel(props.record.session))
   const showProjectName = () => props.showProjectName() && props.record.projectName
   const key = () => homeSessionSearchKey(props.record)
 
@@ -415,7 +415,7 @@ function HomeSessionGroupHeader(props: {
 }
 
 function HomeSessionRow(props: HomeSessionsViewProps & { record: HomeSessionRecord }) {
-  const title = createMemo(() => sessionTitle(props.record.session.title) || props.record.session.id)
+  const title = createMemo(() => displayLabel(props.record.session))
   const showProjectName = () => props.showProjectName() && props.record.projectName
 
   return (

packages/app/src/pages/layout/sidebar-items.tsx

@@ -5,6 +5,7 @@ import { Icon as IconV2 } from "@opencode-ai/ui/v2/icon"
 import { IconButton } from "@opencode-ai/ui/icon-button"
 import { Spinner } from "@opencode-ai/ui/spinner"
 import { Tooltip } from "@opencode-ai/ui/tooltip"
+import { displayLabel } from "@opencode-ai/util/session-title-fallback"
 import { getFilename } from "@opencode-ai/core/util/path"
 import { A, useParams } from "@solidjs/router"
 import { type Accessor, createMemo, For, type JSX, Match, Show, Switch } from "solid-js"
@@ -14,7 +15,6 @@ import { getAvatarColors, type LocalProject, useLayout } from "@/context/layout"
 import { useNotification } from "@/context/notification"
 import { usePermission } from "@/context/permission"
 import { messageAgentColor } from "@/utils/agent"
-import { sessionTitle } from "@/utils/session-title"
 import { sessionPermissionRequest } from "../session/composer/session-request-tree"
 import { childSessionOnPath, getProjectAvatarSource, hasProjectPermissions } from "./helpers"
 
@@ -104,7 +104,7 @@ const SessionRow = (props: {
   warmPress: () => void
   warmFocus: () => void
 }): JSX.Element => {
-  const title = () => sessionTitle(props.session.title, props.session.parentID)
+  const title = () => displayLabel(props.session)
 
   return (
     <A
@@ -229,7 +229,7 @@ export const SessionItem = (props: SessionItemProps): JSX.Element => {
               fallback={
                 <Tooltip
                   placement={props.mobile ? "bottom" : "right"}
-                  value={sessionTitle(props.session.title, props.session.parentID)}
+                  value={displayLabel(props.session)}
                   gutter={10}
                   class="min-w-0 w-full"
                 >

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

@@ -70,7 +70,7 @@ import { legacySessionHref, requireServerKey, sessionHref } from "@/utils/sessio
 import { useSDK } from "@/context/sdk"
 import { useSync } from "@/context/sync"
 import { notifySessionTabsRemoved } from "@/components/titlebar-session-events"
-import { sessionTitle } from "@/utils/session-title"
+import { displayLabel } from "@opencode-ai/util/session-title-fallback"
 import { scheduleConnectedMeasure } from "./measure"
 import { observeElementOffsetReconnectAware } from "./observe-element-offset"
 import { createTimelineProjection } from "./projection"
@@ -296,11 +296,10 @@ export function MessageTimeline(props: {
     if (!id) return
     return sync().session.get(id)
   })
-  const titleValue = createMemo(() => info()?.title)
   const titleLabel = createMemo(() => {
     const session = info()
     if (!session) return
-    return sessionTitle(titleValue(), session.parentID)
+    return displayLabel(session)
   })
   const shareUrl = createMemo(() => info()?.share?.url)
   const shareEnabled = createMemo(() => sync().data.config.share !== "disabled")
@@ -317,7 +316,7 @@ export function MessageTimeline(props: {
   })
   const parentTitle = createMemo(() => {
     const session = parent()
-    return session ? sessionTitle(session.title, session.parentID) : language.t("command.session.new")
+    return session ? displayLabel(session) : language.t("command.session.new")
   })
   const getMsgParts = (msgId: string) => sync().data.part[msgId] ?? emptyParts
   const getMsgPart = (messageID: string, partID: string) => getMsgParts(messageID).find((part) => part.id === partID)
@@ -921,7 +920,7 @@ export function MessageTimeline(props: {
   function DialogDeleteSession(props: { sessionID: string }) {
     const name = createMemo(() => {
       const session = sync().session.get(props.sessionID)
-      return session ? sessionTitle(session.title, session.parentID) : language.t("command.session.new")
+      return session ? displayLabel(session) : language.t("command.session.new")
     })
     const handleDelete = async () => {
       await deleteSession(props.sessionID)

packages/app/src/utils/session-title.test.ts

@@ -1,11 +0,0 @@
-import { describe, expect, test } from "bun:test"
-import { sessionTitle } from "./session-title"
-
-describe("sessionTitle", () => {
-  test("uses a display fallback without persisting it", () => {
-    expect(sessionTitle(undefined)).toBe("New session")
-    expect(sessionTitle(undefined, "ses_parent")).toBe("Child session")
-    expect(sessionTitle("New session - 2026-07-30T18:45:03.662Z")).toBe("New session")
-    expect(sessionTitle("Generated title")).toBe("Generated title")
-  })
-})

packages/app/src/utils/session-title.ts

@@ -1,7 +0,0 @@
-const pattern = /^(New session|Child session) - \d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}\.\d{3}Z$/
-
-export function sessionTitle(title?: string, parentID?: string) {
-  if (!title) return parentID ? "Child session" : "New session"
-  const match = title.match(pattern)
-  return match?.[1] ?? title
-}

packages/app/src/utils/session.ts

@@ -1,5 +1,6 @@
 import type { SessionApi, SessionInfo, SessionListInput } from "@opencode-ai/client/promise"
 import type { Session } from "@opencode-ai/sdk/v2/client"
+import { withTimestampedFallback } from "@opencode-ai/util/session-title-fallback"
 
 export function normalizeSessionInfo(input: SessionInfo | Session): Session {
   if (!("location" in input)) return input
@@ -13,7 +14,7 @@ export function normalizeSessionInfo(input: SessionInfo | Session): Session {
     parentID: input.parentID,
     cost: input.cost,
     tokens: input.tokens,
-    title: input.title ?? `${input.parentID ? "Child" : "New"} session - ${new Date(input.time.created).toISOString()}`,
+    title: withTimestampedFallback(input),
     agent: input.agent,
     model: input.model,
     version: "",