diff --git a/packages/app/src/shell/titlebar/inbox-working.test.ts b/packages/app/src/shell/titlebar/inbox-working.test.ts
new file mode 100644
index 000000000000..dc30dd0aa8ce
--- /dev/null
+++ b/packages/app/src/shell/titlebar/inbox-working.test.ts
@@ -0,0 +1,26 @@
+import { expect, test } from "bun:test"
+import { compareWorking, workingSince } from "./inbox-working"
+
+test("uses the current run's start", () => {
+  expect(workingSince({ time: { busy: 20 } })).toBe(20)
+  expect(workingSince({ time: { busy: 20, idle: 10 } })).toBe(20)
+})
+
+test("has no start while only an earlier run's start is known", () => {
+  expect(workingSince({ time: { busy: 10, idle: 20 } })).toBeUndefined()
+  expect(workingSince({ time: { idle: 20 } })).toBeUndefined()
+  expect(workingSince({ time: {} })).toBeUndefined()
+})
+
+test("orders by run start, then puts runs with no known start last", () => {
+  const entry = (key: string, time: { busy?: number; idle?: number }) => ({ key, session: { time } })
+
+  const sorted = [
+    entry("d", {}),
+    entry("b", { busy: 30 }),
+    entry("c", { busy: 5, idle: 10 }),
+    entry("a", { busy: 20, idle: 10 }),
+  ].toSorted(compareWorking)
+
+  expect(sorted.map((item) => item.key)).toEqual(["a", "b", "c", "d"])
+})
diff --git a/packages/app/src/shell/titlebar/inbox-working.ts b/packages/app/src/shell/titlebar/inbox-working.ts
new file mode 100644
index 000000000000..db62002b592f
--- /dev/null
+++ b/packages/app/src/shell/titlebar/inbox-working.ts
@@ -0,0 +1,22 @@
+type SessionTime = { time: { busy?: number; idle?: number } }
+
+/**
+ * When the session's current run started. Undefined while the client still holds an earlier run's start (it ended at
+ * `time.idle`, after `time.busy`) or the server does not record `time.busy`.
+ */
+export function workingSince(session: SessionTime) {
+  const { busy, idle } = session.time
+
+  if (busy === undefined || (idle !== undefined && idle > busy)) return undefined
+
+  return busy
+}
+
+/** Earliest run start first, so a session that starts working joins the end. Runs with no known start go last. */
+export function compareWorking(a: { key: string; session: SessionTime }, b: { key: string; session: SessionTime }) {
+  const start = (workingSince(a.session) ?? Infinity) - (workingSince(b.session) ?? Infinity)
+
+  if (start) return start
+
+  return a.key < b.key ? -1 : a.key > b.key ? 1 : 0
+}
diff --git a/packages/app/src/shell/titlebar/inbox.tsx b/packages/app/src/shell/titlebar/inbox.tsx
index 7c97331778f9..a67e6dbf3843 100644
--- a/packages/app/src/shell/titlebar/inbox.tsx
+++ b/packages/app/src/shell/titlebar/inbox.tsx
@@ -16,6 +16,7 @@ import { SessionTabAvatarView } from "@/shell/layout/session-tab-avatar"
 import { sessionTabTitle } from "./tab-title"
 import { sessionTitle } from "@/session/title"
 import { createSessionInbox, inboxArchived, inboxBusy, type InboxEntry, type InboxStatus } from "./inbox-model"
+import { compareWorking, workingSince } from "./inbox-working"
 
 // `since` is when the inbox was first used; Recent only lists sessions that finished a run after it.
 const InboxState = Persistence.struct({
@@ -35,6 +36,7 @@ export function SidebarInbox() {
 
   const sections = createMemo(() => {
     const list = inbox.entries()
+
     // The most recently finished session comes first.
     const finished = list
       .filter((entry) => {
@@ -48,7 +50,8 @@ export function SidebarInbox() {
       needs: list.filter((entry) => entry.status === "approval" || entry.status === "input"),
       inbox: finished.filter((entry) => !inboxArchived(entry)),
       archived: finished.filter(inboxArchived),
-      working: list.filter((entry) => entry.status === "working"),
+      // `time.updated` moves with every message of a run, so order by when each run started to keep rows in place.
+      working: list.filter((entry) => entry.status === "working").toSorted(compareWorking),
     }
   })
 
@@ -77,6 +80,7 @@ export function SidebarInbox() {
       await inbox.remove(props.entry)
       dialog.close()
     }
+
     return (
       <Dialog fit>
         <DialogHeader hideClose>
@@ -251,13 +255,22 @@ function InboxRow(props: {
     return language.plural("sidebar.inbox.elapsed.days", Math.floor(seconds / 86_400))
   }
 
-  const elapsed = () => {
-    // `time.updated` moves when a prompt is enqueued, so it marks when the current run was requested.
-    const seconds = Math.max(0, Math.floor((props.now - props.entry.session.time.updated) / 1000))
+  // Without the current run's start yet, say only that the session is working.
+  const working = () => {
+    const since = workingSince(props.entry.session)
+
+    if (since === undefined) return language.t("sidebar.inbox.status.working")
 
-    return seconds < 60 ? language.plural("sidebar.inbox.elapsed.seconds", seconds) : compact(seconds)
+    const seconds = Math.max(0, Math.floor((props.now - since) / 1000))
+    const duration = seconds < 60 ? language.plural("sidebar.inbox.elapsed.seconds", seconds) : compact(seconds)
+
+    return language.t("sidebar.inbox.status.workingFor", { duration })
   }
 
+  // Ready rows show their age instead of a status.
+  const statusLabel = (value: InboxStatus) =>
+    value === "ready" ? undefined : language.t(`sidebar.inbox.status.${value}`)
+
   const age = () => {
     const seconds = Math.max(
       0,
@@ -304,10 +317,7 @@ function InboxRow(props: {
                   "text-v2-state-fg-success": status() === "done",
                 }}
               >
-                <Show
-                  when={status() === "working"}
-                  fallback={language.t(`sidebar.inbox.status.${status() as Exclude<InboxStatus, "ready">}`)}
-                >
+                <Show when={status() === "working"} fallback={statusLabel(status())}>
                   {/* Announce only the status: the ticking duration would be re-read every second. */}
                   <span class="sr-only">{language.t("sidebar.inbox.status.working")}</span>
                   {/* Keep the status colour under the sweep. */}
@@ -315,7 +325,7 @@ function InboxRow(props: {
                     aria-hidden="true"
                     class="[&_[data-component=text-shimmer]]:[--text-shimmer-base-color:var(--v2-state-fg-info)]"
                   >
-                    <TextShimmer text={language.t("sidebar.inbox.status.workingFor", { duration: elapsed() })} active />
+                    <TextShimmer text={working()} active />
                   </span>
                 </Show>
               </span>