diff --git a/apps/desktop/src/renderer/src/App.test.tsx b/apps/desktop/src/renderer/src/App.test.tsx
index 3b5c45e1..40e9d6aa 100644
--- a/apps/desktop/src/renderer/src/App.test.tsx
+++ b/apps/desktop/src/renderer/src/App.test.tsx
@@ -419,6 +419,60 @@ describe('Shell split panes', () => {
     expect(screen.getByRole('region', { name: 'Beta' })).toHaveClass('border-accent/40')
   })
 
+  it('prefixes each pane header with the session\'s project title', async () => {
+    invokeMock.mockImplementation(async (method) => {
+      switch (method) {
+        case 'ping':
+          return 'pong'
+        case 'app.info':
+          return { homeDir: 'C:\\Users\\tester' }
+        case 'session.list':
+          return [
+            {
+              id: 'sess-alpha',
+              projectId: 'proj-ari',
+              title: 'New session',
+              updatedAt: NOW - 60_000,
+              messageCount: 1,
+            },
+            {
+              id: 'sess-beta',
+              projectId: 'proj-docs',
+              title: 'Draft notes',
+              updatedAt: NOW - 120_000,
+              messageCount: 1,
+            },
+          ]
+        case 'project.list':
+          return [
+            { id: 'proj-ari', name: 'Ari', path: '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/projects/ari', status: 'ok', open: true },
+            { id: 'proj-docs', name: 'Docs', path: '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/projects/docs', status: 'ok', open: true },
+          ]
+        case 'providers.detect':
+          return []
+        case 'providers.models':
+          return []
+        case 'files.index':
+          return { paths: [] }
+        case 'endpoints.list':
+          return []
+        case 'session.load':
+          return { session: null, activeTurnId: null }
+        default:
+          throw new Error(`unexpected method: ${String(method)}`)
+      }
+    })
+
+    openTwoPanes()
+    render(<App />)
+
+    expect(
+      await screen.findByRole('region', { name: 'Ari - New session' }, { timeout: 10_000 }),
+    ).toBeInTheDocument()
+    expect(screen.getByRole('region', { name: 'Docs - Draft notes' })).toBeInTheDocument()
+    expect(screen.getByRole('button', { name: 'Close Ari - New session' })).toBeInTheDocument()
+  })
+
   it('keeps the newest session list when an older one answers last', async () => {
     // Lists overlap at boot and on the event feed, so answers can arrive out of
     // order. A stale one — started before Beta existed — would prune Beta's pane.
diff --git a/apps/desktop/src/renderer/src/App.tsx b/apps/desktop/src/renderer/src/App.tsx
index 3c8385da..d721cb1e 100644
--- a/apps/desktop/src/renderer/src/App.tsx
+++ b/apps/desktop/src/renderer/src/App.tsx
@@ -15,6 +15,7 @@ import { Titlebar } from './shell/Titlebar'
 import { GalleryView } from './views'
 import { SessionView } from './features/session/SessionView'
 import {
+  UNFILED_GROUP_ID,
   moveProjectInList,
   projectMoveForDelta,
   shellRootFor,
@@ -39,6 +40,7 @@ import { useCommands } from './features/palette/useCommands'
 import { ContentSearchOverlay } from './features/search'
 import { AwakenSplash, AWAKEN_MAX_MS } from './features/moment'
 import { useSessionActivity } from './features/session/use-session-activity'
+import { formatPaneTitle } from './features/split/pane-title'
 import { SplitView } from './features/split/SplitView'
 import { splitLayoutActions, useSplitLayout } from './features/split/use-split-layout'
 import { focusNeighbour } from './features/split/split-geometry'
@@ -981,7 +983,15 @@ function Shell() {
                   <ErrorBoundary label="Session">
                     <SplitView
                       layout={layout}
-                      titleOf={(id) => sessions.find((s) => s.id === id)?.title ?? null}
+                      titleOf={(id) => {
+                        const session = sessions.find((s) => s.id === id)
+                        if (session === undefined) return null
+                        const projectName =
+                          session.projectId === UNFILED_GROUP_ID
+                            ? null
+                            : (projects.find((p) => p.id === session.projectId)?.name ?? null)
+                        return formatPaneTitle(session.title, projectName)
+                      }}
                       onFocus={splitLayoutActions.focus}
                       onClose={splitLayoutActions.close}
                       onSplit={splitLayoutActions.split}
diff --git a/apps/desktop/src/renderer/src/features/split/PaneFrame.tsx b/apps/desktop/src/renderer/src/features/split/PaneFrame.tsx
index 253c8384..281acd42 100644
--- a/apps/desktop/src/renderer/src/features/split/PaneFrame.tsx
+++ b/apps/desktop/src/renderer/src/features/split/PaneFrame.tsx
@@ -89,6 +89,7 @@ export function PaneFrame({
       >
         <GripVertical size={10} aria-hidden className="shrink-0 text-fg-subtle/60" />
         <span
+          title={label}
           className={`min-w-0 flex-1 truncate text-2xs ${
             focused ? 'font-medium text-fg' : 'text-fg-subtle'
           }`}
diff --git a/apps/desktop/src/renderer/src/features/split/pane-title.test.ts b/apps/desktop/src/renderer/src/features/split/pane-title.test.ts
new file mode 100644
index 00000000..56c42d3c
--- /dev/null
+++ b/apps/desktop/src/renderer/src/features/split/pane-title.test.ts
@@ -0,0 +1,20 @@
+import { describe, expect, it } from 'vitest'
+import { formatPaneTitle } from './pane-title'
+
+describe('formatPaneTitle', () => {
+  it('joins a project name and session title with a hyphen', () => {
+    expect(formatPaneTitle('New session', 'Ari')).toBe('Ari - New session')
+  })
+
+  it('falls back to the session title when there is no project', () => {
+    expect(formatPaneTitle('Alpha', null)).toBe('Alpha')
+    expect(formatPaneTitle('Alpha', undefined)).toBe('Alpha')
+    expect(formatPaneTitle('Alpha', '')).toBe('Alpha')
+  })
+
+  it('stays null while the session itself has no name yet', () => {
+    expect(formatPaneTitle(null, 'Ari')).toBe(null)
+    expect(formatPaneTitle(undefined, 'Ari')).toBe(null)
+    expect(formatPaneTitle('', 'Ari')).toBe(null)
+  })
+})
diff --git a/apps/desktop/src/renderer/src/features/split/pane-title.ts b/apps/desktop/src/renderer/src/features/split/pane-title.ts
new file mode 100644
index 00000000..2f68e5a0
--- /dev/null
+++ b/apps/desktop/src/renderer/src/features/split/pane-title.ts
@@ -0,0 +1,12 @@
+/**
+ * The pane header's on-screen name: the session, prefixed with its project
+ * when one is known. Ad-hoc / unfiled sessions keep the session title alone.
+ */
+export function formatPaneTitle(
+  sessionTitle: string | null | undefined,
+  projectName: string | null | undefined,
+): string | null {
+  if (sessionTitle == null || sessionTitle === '') return null
+  if (projectName == null || projectName === '') return sessionTitle
+  return `${projectName} - ${sessionTitle}`
+}