From db23533adf6b0e5db34443085228551184b72d05 Mon Sep 17 00:00:00 2001
From: YeonGyu-Kim <code.yeon.gyu@gmail.com>
Date: Wed, 1 Apr 2026 18:18:32 -0700
Subject: [PATCH] fix(tmux): properly cleanup isolated container pane on first
 subagent deletion

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>
---
 src/features/tmux-subagent/manager.test.ts | 69 ++++++++++++++++++++++
 src/features/tmux-subagent/manager.ts      | 54 +++++++++++++++++
 2 files changed, 123 insertions(+)

diff --git a/src/features/tmux-subagent/manager.test.ts b/src/features/tmux-subagent/manager.test.ts
index 6853349a3..40179fe79 100644
--- a/src/features/tmux-subagent/manager.test.ts
+++ b/src/features/tmux-subagent/manager.test.ts
@@ -1025,6 +1025,75 @@ describe('TmuxSessionManager', () => {
       })
     })
 
+    test('#given session isolation with a spawned container #when the first isolated subagent is deleted #then it cleans up the isolated container and clears the anchor pane id', async () => {
+      // given
+      mockIsInsideTmux.mockReturnValue(true)
+
+      let stateCallCount = 0
+      mockQueryWindowState.mockImplementation(async (paneId) => {
+        stateCallCount++
+
+        if (paneId === '%isolated-session-ses_first') {
+          return createWindowState({
+            mainPane: {
+              paneId,
+              width: 110,
+              height: 44,
+              left: 0,
+              top: 0,
+              title: 'isolated',
+              isActive: true,
+            },
+          })
+        }
+
+        if (stateCallCount === 1) {
+          return createWindowState()
+        }
+
+        return createWindowState({
+          mainPane: {
+            paneId: '%isolated-session-ses_first',
+            width: 110,
+            height: 44,
+            left: 0,
+            top: 0,
+            title: 'isolated',
+            isActive: true,
+          },
+        })
+      })
+
+      const { TmuxSessionManager } = await import('./manager')
+      const ctx = createMockContext()
+      const config: TmuxConfig = {
+        enabled: true,
+        isolation: 'session',
+        layout: 'main-vertical',
+        main_pane_size: 60,
+        main_pane_min_width: 80,
+        agent_pane_min_width: 40,
+      }
+      const manager = new TmuxSessionManager(ctx, config, mockTmuxDeps)
+
+      await manager.onSessionCreated(
+        createSessionCreatedEvent('ses_first', 'ses_parent', 'First Task')
+      )
+      mockExecuteAction.mockClear()
+
+      // when
+      await manager.onSessionDeleted({ sessionID: 'ses_first' })
+
+      // then
+      expect(mockExecuteAction).toHaveBeenCalledTimes(1)
+      expect(mockExecuteAction.mock.calls[0]?.[0]).toEqual({
+        type: 'close',
+        paneId: '%isolated-session-ses_first',
+        sessionId: 'ses_first',
+      })
+      expect(Reflect.get(manager, 'isolatedWindowPaneId')).toBeUndefined()
+    })
+
     test('does nothing when untracked session is deleted', async () => {
       // given
       mockIsInsideTmux.mockReturnValue(true)
diff --git a/src/features/tmux-subagent/manager.ts b/src/features/tmux-subagent/manager.ts
index a61b1433d..2a985223d 100644
--- a/src/features/tmux-subagent/manager.ts
+++ b/src/features/tmux-subagent/manager.ts
@@ -172,6 +172,51 @@ export class TmuxSessionManager {
     }
   }
 
+  private async cleanupIsolatedContainerAfterSessionDeletion(
+    tracked: TrackedSession,
+    isolatedPaneAlreadyClosed: boolean,
+    state: WindowState,
+  ): Promise<void> {
+    if (tracked.paneId !== this.isolatedWindowPaneId) {
+      return
+    }
+
+    if (this.sessions.size > 0) {
+      return
+    }
+
+    this.isolatedWindowPaneId = undefined
+
+    if (isolatedPaneAlreadyClosed) {
+      return
+    }
+
+    try {
+      const result = await executeAction(
+        { type: "close", paneId: tracked.paneId, sessionId: tracked.sessionId },
+        {
+          config: this.tmuxConfig,
+          serverUrl: this.serverUrl,
+          windowState: state,
+          sourcePaneId: this.sourcePaneId ?? tracked.paneId,
+        },
+      )
+
+      if (!result.success) {
+        log("[tmux-session-manager] failed to close isolated container pane after anchor session deletion", {
+          sessionId: tracked.sessionId,
+          paneId: tracked.paneId,
+        })
+      }
+    } catch (error) {
+      log("[tmux-session-manager] failed to cleanup isolated container pane after anchor session deletion", {
+        sessionId: tracked.sessionId,
+        paneId: tracked.paneId,
+        error: String(error),
+      })
+    }
+  }
+
   private markSessionClosePending(sessionId: string): void {
     const tracked = this.sessions.get(sessionId)
     if (!tracked) return
@@ -698,9 +743,13 @@ export class TmuxSessionManager {
     const closeAction = decideCloseAction(state, event.sessionID, this.getSessionMappings())
     if (!closeAction) {
       this.removeTrackedSession(event.sessionID)
+      await this.cleanupIsolatedContainerAfterSessionDeletion(tracked, false, state)
       return
     }
 
+    const isolatedPaneAlreadyClosed =
+      closeAction.type === "close" && closeAction.paneId === tracked.paneId
+
     try {
       const result = await executeAction(closeAction, {
         config: this.tmuxConfig,
@@ -723,6 +772,11 @@ export class TmuxSessionManager {
     }
 
     this.removeTrackedSession(event.sessionID)
+    await this.cleanupIsolatedContainerAfterSessionDeletion(
+      tracked,
+      isolatedPaneAlreadyClosed,
+      state,
+    )
   }