diff --git a/src/features/background-agent/manager.ts b/src/features/background-agent/manager.ts
index 0ecc68e3b..eb48a9bdd 100644
--- a/src/features/background-agent/manager.ts
+++ b/src/features/background-agent/manager.ts
@@ -121,6 +121,7 @@ export class BackgroundManager {
   private queuesByKey: Map<string, QueueItem[]> = new Map()
   private processingKeys: Set<string> = new Set()
   private completionTimers: Map<string, ReturnType<typeof setTimeout>> = new Map()
+  private completedTaskSummaries: Map<string, Array<{id: string, description: string}>> = new Map()
   private idleDeferralTimers: Map<string, ReturnType<typeof setTimeout>> = new Map()
   private notificationQueueByParent: Map<string, Promise<void>> = new Map()
   private rootDescendantCounts: Map<string, number>
@@ -1379,6 +1380,14 @@ export class BackgroundManager {
       })
     }
 
+    if (!this.completedTaskSummaries.has(task.parentSessionID)) {
+      this.completedTaskSummaries.set(task.parentSessionID, [])
+    }
+    this.completedTaskSummaries.get(task.parentSessionID)!.push({
+      id: task.id,
+      description: task.description,
+    })
+
     // Update pending tracking and check if all tasks complete
     const pendingSet = this.pendingByParent.get(task.parentSessionID)
     let allComplete = false
@@ -1398,10 +1407,13 @@ export class BackgroundManager {
     }
 
     const completedTasks = allComplete
-      ? Array.from(this.tasks.values())
-        .filter(t => t.parentSessionID === task.parentSessionID && t.status !== "running" && t.status !== "pending")
+      ? (this.completedTaskSummaries.get(task.parentSessionID) ?? [{ id: task.id, description: task.description }])
       : []
 
+    if (allComplete) {
+      this.completedTaskSummaries.delete(task.parentSessionID)
+    }
+
     const statusText = task.status === "completed"
       ? "COMPLETED"
       : task.status === "interrupt"
@@ -1740,6 +1752,7 @@ Use \`background_output(task_id="${task.id}")\` to retrieve this result when rea
     this.queuesByKey.clear()
     this.processingKeys.clear()
     this.taskHistory.clearAll()
+    this.completedTaskSummaries.clear()
     this.unregisterProcessCleanup()
     log("[background-agent] Shutdown complete")
 
diff --git a/src/features/skill-mcp-manager/cleanup.ts b/src/features/skill-mcp-manager/cleanup.ts
index bbfe68baf..bd34c693a 100644
--- a/src/features/skill-mcp-manager/cleanup.ts
+++ b/src/features/skill-mcp-manager/cleanup.ts
@@ -87,7 +87,16 @@ async function cleanupIdleClients(state: SkillMcpManagerState): Promise<void> {
 }
 
 export async function disconnectSession(state: SkillMcpManagerState, sessionID: string): Promise<void> {
-  state.disconnectedSessions.add(sessionID)
+  let hasPendingForSession = false
+  for (const key of state.pendingConnections.keys()) {
+    if (key.startsWith(`${sessionID}:`)) {
+      hasPendingForSession = true
+      break
+    }
+  }
+  if (hasPendingForSession) {
+    state.disconnectedSessions.add(sessionID)
+  }
   const keysToRemove: string[] = []
 
   for (const [key, managed] of state.clients.entries()) {
diff --git a/src/features/skill-mcp-manager/connection-race.test.ts b/src/features/skill-mcp-manager/connection-race.test.ts
index f08750c27..70cf650a7 100644
--- a/src/features/skill-mcp-manager/connection-race.test.ts
+++ b/src/features/skill-mcp-manager/connection-race.test.ts
@@ -154,11 +154,11 @@ describe("getOrCreateClient disconnect race", () => {
     expect(createdClients[0]?.close).not.toHaveBeenCalled()
   })
 
-  it("#given no pending connections #when disconnectSession is called #then no errors occur and the session is added to disconnectedSessions", async () => {
+  it("#given no pending connections #when disconnectSession is called #then no errors occur and session is not added to disconnectedSessions", async () => {
     const state = createState()
 
     await expect(disconnectSession(state, "session-a")).resolves.toBeUndefined()
-    expect(state.disconnectedSessions.has("session-a")).toBe(true)
+    expect(state.disconnectedSessions.has("session-a")).toBe(false)
     expect(state.pendingConnections.size).toBe(0)
     expect(state.clients.size).toBe(0)
   })
diff --git a/src/features/skill-mcp-manager/connection.ts b/src/features/skill-mcp-manager/connection.ts
index e35215706..3ffe2e5f1 100644
--- a/src/features/skill-mcp-manager/connection.ts
+++ b/src/features/skill-mcp-manager/connection.ts
@@ -29,9 +29,16 @@ export async function getOrCreateClient(params: {
   }
 
   const expandedConfig = expandEnvVarsInObject(config)
-  const connectionPromise = (async () => {
+  let currentConnectionPromise!: Promise<Client>
+  currentConnectionPromise = (async () => {
     const client = await createClient({ state, clientKey, info, config: expandedConfig })
 
+    const isStale = state.pendingConnections.has(clientKey) && state.pendingConnections.get(clientKey) !== currentConnectionPromise
+    if (isStale) {
+      try { await client.close() } catch {}
+      throw new Error(`Connection for "${info.sessionID}" was superseded by a newer connection attempt.`)
+    }
+
     if (state.disconnectedSessions.has(info.sessionID)) {
       await forceReconnect(state, clientKey)
       throw new Error(`Session "${info.sessionID}" disconnected during MCP connection setup.`)
@@ -40,13 +47,13 @@ export async function getOrCreateClient(params: {
     return client
   })()
 
-  state.pendingConnections.set(clientKey, connectionPromise)
+  state.pendingConnections.set(clientKey, currentConnectionPromise)
 
   try {
-    const client = await connectionPromise
+    const client = await currentConnectionPromise
     return client
   } finally {
-    if (state.pendingConnections.get(clientKey) === connectionPromise) {
+    if (state.pendingConnections.get(clientKey) === currentConnectionPromise) {
       state.pendingConnections.delete(clientKey)
     }
   }
diff --git a/src/features/tmux-subagent/tracked-session-state.ts b/src/features/tmux-subagent/tracked-session-state.ts
index e18f6a827..87ba19f51 100644
--- a/src/features/tmux-subagent/tracked-session-state.ts
+++ b/src/features/tmux-subagent/tracked-session-state.ts
@@ -23,5 +23,6 @@ export function markTrackedSessionClosePending(tracked: TrackedSession): Tracked
   return {
     ...tracked,
     closePending: true,
+    closeRetryCount: tracked.closePending ? tracked.closeRetryCount + 1 : tracked.closeRetryCount,
   }
 }
diff --git a/src/hooks/auto-slash-command/hook.ts b/src/hooks/auto-slash-command/hook.ts
index 8438dcf36..715b67481 100644
--- a/src/hooks/auto-slash-command/hook.ts
+++ b/src/hooks/auto-slash-command/hook.ts
@@ -125,7 +125,7 @@ export function createAutoSlashCommandHook(options?: AutoSlashCommandHookOptions
       input: CommandExecuteBeforeInput,
       output: CommandExecuteBeforeOutput
     ): Promise<void> => {
-      const commandKey = `${input.sessionID}:${input.command.toLowerCase()}`
+      const commandKey = `${input.sessionID}:${input.command.toLowerCase()}:${input.arguments || ""}`
       if (sessionProcessedCommandExecutions.has(commandKey)) {
         return
       }
diff --git a/src/index.ts b/src/index.ts
index 70156f109..1b80d8c79 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -74,6 +74,7 @@ const OhMyOpenCodePlugin: Plugin = async (ctx) => {
   const dispose = createPluginDispose({
     backgroundManager: managers.backgroundManager,
     skillMcpManager: managers.skillMcpManager,
+    tmuxSessionManager: managers.tmuxSessionManager,
     disposeHooks: hooks.disposeHooks,
   })
 
diff --git a/src/plugin-dispose.test.ts b/src/plugin-dispose.test.ts
index 17ca88fe3..b3739c6c0 100644
--- a/src/plugin-dispose.test.ts
+++ b/src/plugin-dispose.test.ts
@@ -16,6 +16,7 @@ describe("createPluginDispose", () => {
     const dispose = createPluginDispose({
       backgroundManager,
       skillMcpManager,
+      tmuxSessionManager: { cleanup: async (): Promise<void> => {} },
       disposeHooks: (): void => {},
     })
 
@@ -38,6 +39,7 @@ describe("createPluginDispose", () => {
     const dispose = createPluginDispose({
       backgroundManager,
       skillMcpManager,
+      tmuxSessionManager: { cleanup: async (): Promise<void> => {} },
       disposeHooks: (): void => {},
     })
 
@@ -69,6 +71,7 @@ describe("createPluginDispose", () => {
       skillMcpManager: {
         disconnectAll: async (): Promise<void> => {},
       },
+      tmuxSessionManager: { cleanup: async (): Promise<void> => {} },
       disposeHooks: (): void => {
         disposeCreatedHooks({
           runtimeFallback,
@@ -104,6 +107,7 @@ describe("createPluginDispose", () => {
     const dispose = createPluginDispose({
       backgroundManager,
       skillMcpManager,
+      tmuxSessionManager: { cleanup: async (): Promise<void> => {} },
       disposeHooks: disposeHooks.run,
     })
 
diff --git a/src/plugin-dispose.ts b/src/plugin-dispose.ts
index 7b718bbe4..c813fa411 100644
--- a/src/plugin-dispose.ts
+++ b/src/plugin-dispose.ts
@@ -7,9 +7,12 @@ export function createPluginDispose(args: {
   skillMcpManager: {
     disconnectAll: () => Promise<void>
   }
+  tmuxSessionManager: {
+    cleanup: () => Promise<void>
+  }
   disposeHooks: () => void
 }): PluginDispose {
-  const { backgroundManager, skillMcpManager, disposeHooks } = args
+  const { backgroundManager, skillMcpManager, tmuxSessionManager, disposeHooks } = args
   let disposePromise: Promise<void> | null = null
 
   return async (): Promise<void> => {
@@ -20,7 +23,10 @@ export function createPluginDispose(args: {
 
     disposePromise = (async (): Promise<void> => {
       backgroundManager.shutdown()
-      await skillMcpManager.disconnectAll()
+      await Promise.all([
+        skillMcpManager.disconnectAll(),
+        tmuxSessionManager.cleanup(),
+      ])
       disposeHooks()
     })()