fix(sidebar): transfer launch provenance on pane detach

src/renderer/src/components/sidebar/worktree-title-derived-agent-rows.test.ts

@@ -323,6 +323,26 @@ describe('buildTitleDerivedAgentRows', () => {
     expect(rows[0]?.entry.terminalTitle).toBe('Rename the auth helper')
   })
 
+  it('keeps a live mirrored Cursor title that was also stamped as the tab default', () => {
+    const rows = buildWorktreeAgentRows({
+      tabs: [
+        makeTab('tab-1', {
+          launchAgent: 'cursor',
+          launchAgentLeafId: LEAF_ID_1,
+          defaultTitle: 'Cursor Agent'
+        })
+      ],
+      entries: [],
+      retained: [],
+      runtimePaneTitlesByTabId: { 'tab-1': { 1: 'Cursor Agent' } },
+      ptyIdsByTabId: { 'tab-1': ['pty-cursor'] },
+      terminalLayoutsByTabId: { 'tab-1': makeSingleLayout(LEAF_ID_1) },
+      now: 2000
+    })
+
+    expect(rows.map((row) => [row.agentType, row.state])).toEqual([['cursor', 'idle']])
+  })
+
   it('keeps a launched Codex pane visible under an arbitrary session title', () => {
     const rows = buildWorktreeAgentRows({
       tabs: [makeTab('tab-1', { launchAgent: 'codex', launchAgentLeafId: LEAF_ID_1 })],

src/renderer/src/store/slices/launch-agent-leaf-stamp.test.ts

@@ -3,7 +3,8 @@ import type { TerminalLayoutSnapshot, TerminalTab } from '../../../../shared/ter
 import { emptyLayoutSnapshot, singlePaneLayoutSnapshot } from './terminal-helpers'
 import {
   resolveLaunchAgentLeafId,
-  stampLaunchAgentLeafIdOnFirstLayout
+  stampLaunchAgentLeafIdOnFirstLayout,
+  transferLaunchAgentLeafStampOnDetach
 } from './launch-agent-leaf-stamp'
 
 const LEAF_A = '11111111-1111-4111-8111-111111111111'
@@ -116,3 +117,49 @@ describe('resolveLaunchAgentLeafId', () => {
     ).toBeUndefined()
   })
 })
+
+describe('transferLaunchAgentLeafStampOnDetach', () => {
+  it('moves launch provenance with the detached leaf', () => {
+    const tabs = transferLaunchAgentLeafStampOnDetach({
+      tabs: [
+        makeTab({ id: 'source', launchAgent: 'cursor', launchAgentLeafId: LEAF_A }),
+        makeTab({ id: 'target' })
+      ],
+      sourceTabId: 'source',
+      targetTabId: 'target',
+      detachedLeafId: LEAF_A
+    })
+
+    expect(tabs?.find((tab) => tab.id === 'source')).not.toHaveProperty('launchAgent')
+    expect(tabs?.find((tab) => tab.id === 'source')).not.toHaveProperty('launchAgentLeafId')
+    expect(tabs?.find((tab) => tab.id === 'target')).toMatchObject({
+      launchAgent: 'cursor',
+      launchAgentLeafId: LEAF_A
+    })
+  })
+
+  it('does not overwrite existing target launch provenance', () => {
+    expect(
+      transferLaunchAgentLeafStampOnDetach({
+        tabs: [
+          makeTab({ id: 'source', launchAgent: 'cursor', launchAgentLeafId: LEAF_A }),
+          makeTab({ id: 'target', launchAgent: 'codex', launchAgentLeafId: LEAF_B })
+        ],
+        sourceTabId: 'source',
+        targetTabId: 'target',
+        detachedLeafId: LEAF_A
+      })
+    ).toBeNull()
+  })
+
+  it('does not guess ownership for an unpinned launch', () => {
+    expect(
+      transferLaunchAgentLeafStampOnDetach({
+        tabs: [makeTab({ id: 'source', launchAgent: 'cursor' }), makeTab({ id: 'target' })],
+        sourceTabId: 'source',
+        targetTabId: 'target',
+        detachedLeafId: LEAF_A
+      })
+    ).toBeNull()
+  })
+})

src/renderer/src/store/slices/launch-agent-leaf-stamp.ts

@@ -48,6 +48,40 @@ export function stampLaunchAgentLeafIdOnFirstLayout(args: {
   return nextTabs
 }
 
+/** Moves launch provenance with a detached leaf without overwriting existing target ownership. */
+export function transferLaunchAgentLeafStampOnDetach(args: {
+  tabs: readonly TerminalTab[]
+  sourceTabId: string
+  targetTabId: string
+  detachedLeafId: string
+}): TerminalTab[] | null {
+  const sourceIndex = args.tabs.findIndex((tab) => tab.id === args.sourceTabId)
+  const targetIndex = args.tabs.findIndex((tab) => tab.id === args.targetTabId)
+  const source = args.tabs[sourceIndex]
+  const target = args.tabs[targetIndex]
+  if (
+    !source?.launchAgent ||
+    source.launchAgentLeafId !== args.detachedLeafId ||
+    !target ||
+    target.launchAgent ||
+    target.launchAgentLeafId
+  ) {
+    return null
+  }
+
+  const sourceWithoutLaunchProvenance = { ...source }
+  delete sourceWithoutLaunchProvenance.launchAgent
+  delete sourceWithoutLaunchProvenance.launchAgentLeafId
+  const nextTabs = [...args.tabs]
+  nextTabs[sourceIndex] = sourceWithoutLaunchProvenance
+  nextTabs[targetIndex] = {
+    ...target,
+    launchAgent: source.launchAgent,
+    launchAgentLeafId: args.detachedLeafId
+  }
+  return nextTabs
+}
+
 function soleLeafIdOnFirstLayout(
   previousLayout: TerminalLayoutSnapshot | undefined,
   nextLayout: TerminalLayoutSnapshot

src/renderer/src/store/slices/terminal-pane-detach-agent-identity.test.ts

@@ -20,7 +20,13 @@ describe('syncPaneDetachPtyOwnership agent identity', () => {
       },
       tabsByWorktree: {
         [worktreeId]: [
-          makeTab({ id: sourceTabId, worktreeId, ptyId: 'pty-droid' }),
+          makeTab({
+            id: sourceTabId,
+            worktreeId,
+            ptyId: 'pty-droid',
+            launchAgent: 'droid',
+            launchAgentLeafId: detachedLeafId
+          }),
           makeTab({ id: targetTabId, worktreeId, ptyId: null })
         ]
       },
@@ -113,6 +119,13 @@ describe('syncPaneDetachPtyOwnership agent identity', () => {
       agent: 'antigravity',
       shellForeground: false
     })
+    const tabs = state.tabsByWorktree[worktreeId] ?? []
+    expect(tabs.find((tab) => tab.id === sourceTabId)).not.toHaveProperty('launchAgent')
+    expect(tabs.find((tab) => tab.id === sourceTabId)).not.toHaveProperty('launchAgentLeafId')
+    expect(tabs.find((tab) => tab.id === targetTabId)).toMatchObject({
+      launchAgent: 'droid',
+      launchAgentLeafId: detachedLeafId
+    })
     expect(resolveWindowsShiftEnterEncodingForPane(state, targetPaneKey)).toBe('csi-u')
     expect(resolveWindowsShiftEnterEncodingForPane(state, siblingPaneKey)).toBe('alt-enter')
   })

src/renderer/src/store/slices/terminals.ts

@@ -51,7 +51,10 @@ import type { AiVaultSessionTitle } from '../../../../shared/ai-vault-session-ti
 import { scheduleRuntimeGraphSync } from '@/runtime/sync-runtime-graph'
 import { terminalLayoutEqual } from '@/lib/terminal-layout-equality'
 import { sweepRetiredTerminalTabState } from './retired-terminal-tab-state-sweep'
-import { stampLaunchAgentLeafIdOnFirstLayout } from './launch-agent-leaf-stamp'
+import {
+  stampLaunchAgentLeafIdOnFirstLayout,
+  transferLaunchAgentLeafStampOnDetach
+} from './launch-agent-leaf-stamp'
 import { clearTransientTerminalState, emptyLayoutSnapshot } from './terminal-helpers'
 import {
   collectReleasedLeafIds,
@@ -3663,6 +3666,24 @@ export const createTerminalSlice: StateCreator<AppState, [], [], TerminalSlice>
       const nextTabsByWorktree = detachedPtyId
         ? withTerminalTabPtyId(sourceTabsByWorktree, targetTabId, detachedPtyId)
         : sourceTabsByWorktree
+      const sourceWorktreeId = getTerminalTabOwnerWorktreeId(nextTabsByWorktree, sourceTabId)
+      const targetWorktreeId = getTerminalTabOwnerWorktreeId(nextTabsByWorktree, targetTabId)
+      const transferredTabs =
+        sourceWorktreeId !== null && sourceWorktreeId === targetWorktreeId
+          ? transferLaunchAgentLeafStampOnDetach({
+              tabs: nextTabsByWorktree[sourceWorktreeId] ?? [],
+              sourceTabId,
+              targetTabId,
+              detachedLeafId
+            })
+          : null
+      const tabsByWorktree =
+        transferredTabs && sourceWorktreeId !== null
+          ? { ...nextTabsByWorktree, [sourceWorktreeId]: transferredTabs }
+          : nextTabsByWorktree
+      if (transferredTabs) {
+        scheduleRuntimeGraphSync()
+      }
       const directSshLedger = transferDirectSshPaneDetachLedger(s, {
         detachedPtyId,
         sourcePtyId: sourcePrimaryPtyId,
@@ -3675,7 +3696,7 @@ export const createTerminalSlice: StateCreator<AppState, [], [], TerminalSlice>
         ptyIdsByTabId: nextPtyIdsByTabId,
         lastKnownRelayPtyIdByTabId: nextLastKnownRelayPtyIdByTabId,
         ...directSshLedger,
-        ...(nextTabsByWorktree !== s.tabsByWorktree ? { tabsByWorktree: nextTabsByWorktree } : {})
+        ...(tabsByWorktree !== s.tabsByWorktree ? { tabsByWorktree } : {})
       }
     })
     // Why: detach keeps the process and its pane key alive, so move resume/status authority to the new surface before the source closes.