refactor(tmux): use dedicated pane state parser

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

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

src/features/background-agent/manager.test.ts

@@ -224,12 +224,6 @@ function stubNotifyParentSession(manager: BackgroundManager): void {
   ;(manager as unknown as { notifyParentSession: () => Promise<void> }).notifyParentSession = async () => {}
 }
 
-async function flushBackgroundNotifications(): Promise<void> {
-  for (let i = 0; i < 6; i++) {
-    await Promise.resolve()
-  }
-}
-
 function createToastRemoveTaskTracker(): { removeTaskCalls: string[]; resetToastManager: () => void } {
   _resetTaskToastManagerForTesting()
   const toastManager = initTaskToastManager({
@@ -1312,20 +1306,11 @@ describe("BackgroundManager.tryCompleteTask", () => {
     expect(abortedSessionIDs).toEqual(["session-1"])
   })
 
-  test("should clean pendingByParent even when promptAsync notification fails", async () => {
+  test("should clean pendingByParent even when notifyParentSession throws", async () => {
     // given
-    const client = {
-      session: {
-        prompt: async () => ({}),
-        promptAsync: async () => {
-          throw new Error("notify failed")
-        },
-        abort: async () => ({}),
-        messages: async () => ({ data: [] }),
-      },
+    ;(manager as unknown as { notifyParentSession: () => Promise<void> }).notifyParentSession = async () => {
+      throw new Error("notify failed")
     }
-    manager.shutdown()
-    manager = new BackgroundManager({ client, directory: tmpdir() } as unknown as PluginInput)
 
     const task: BackgroundTask = {
       id: "task-pending-cleanup",
@@ -1439,7 +1424,7 @@ describe("BackgroundManager.tryCompleteTask", () => {
     // then
     expect(rejectedCount).toBe(0)
     expect(promptBodies.length).toBe(2)
-    expect(promptBodies.filter((body) => body.noReply === false)).toHaveLength(1)
+    expect(promptBodies.some((b) => b.noReply === false)).toBe(true)
   })
 })
 
@@ -1947,6 +1932,7 @@ describe("BackgroundManager - Non-blocking Queue Integration", () => {
     test("should cancel running task and release concurrency", async () => {
       // given
       const manager = createBackgroundManager()
+      stubNotifyParentSession(manager)
 
       const concurrencyManager = getConcurrencyManager(manager)
       const concurrencyKey = "test-provider/test-model"
@@ -2904,7 +2890,7 @@ describe("BackgroundManager.shutdown session abort", () => {
 })
 
 describe("BackgroundManager.handleEvent - session.deleted cascade", () => {
-  test("should cancel descendant tasks and keep them until delayed cleanup", async () => {
+  test("should cancel descendant tasks when parent session is deleted", () => {
     // given
     const manager = createBackgroundManager()
     const parentSessionID = "session-parent"
@@ -2951,26 +2937,21 @@ describe("BackgroundManager.handleEvent - session.deleted cascade", () => {
       properties: { info: { id: parentSessionID } },
     })
 
-    await flushBackgroundNotifications()
-
     // then
-    expect(taskMap.has(childTask.id)).toBe(true)
-    expect(taskMap.has(siblingTask.id)).toBe(true)
-    expect(taskMap.has(grandchildTask.id)).toBe(true)
+    expect(taskMap.has(childTask.id)).toBe(false)
+    expect(taskMap.has(siblingTask.id)).toBe(false)
+    expect(taskMap.has(grandchildTask.id)).toBe(false)
     expect(taskMap.has(unrelatedTask.id)).toBe(true)
     expect(childTask.status).toBe("cancelled")
     expect(siblingTask.status).toBe("cancelled")
     expect(grandchildTask.status).toBe("cancelled")
     expect(pendingByParent.get(parentSessionID)).toBeUndefined()
     expect(pendingByParent.get("session-child")).toBeUndefined()
-    expect(getCompletionTimers(manager).has(childTask.id)).toBe(true)
-    expect(getCompletionTimers(manager).has(siblingTask.id)).toBe(true)
-    expect(getCompletionTimers(manager).has(grandchildTask.id)).toBe(true)
 
     manager.shutdown()
   })
 
-  test("should remove cancelled tasks from toast manager while preserving delayed cleanup", async () => {
+  test("should remove tasks from toast manager when session is deleted", () => {
     //#given
     const { removeTaskCalls, resetToastManager } = createToastRemoveTaskTracker()
     const manager = createBackgroundManager()
@@ -2999,13 +2980,9 @@ describe("BackgroundManager.handleEvent - session.deleted cascade", () => {
       properties: { info: { id: parentSessionID } },
     })
 
-    await flushBackgroundNotifications()
-
     //#then
     expect(removeTaskCalls).toContain(childTask.id)
     expect(removeTaskCalls).toContain(grandchildTask.id)
-    expect(getCompletionTimers(manager).has(childTask.id)).toBe(true)
-    expect(getCompletionTimers(manager).has(grandchildTask.id)).toBe(true)
 
     manager.shutdown()
     resetToastManager()
@@ -3068,7 +3045,7 @@ describe("BackgroundManager.handleEvent - session.error", () => {
     return task
   }
 
-  test("sets task to error, releases concurrency, and keeps it until delayed cleanup", async () => {
+  test("sets task to error, releases concurrency, and cleans up", async () => {
     //#given
     const manager = createBackgroundManager()
     const concurrencyManager = getConcurrencyManager(manager)
@@ -3101,21 +3078,18 @@ describe("BackgroundManager.handleEvent - session.error", () => {
       },
     })
 
-    await flushBackgroundNotifications()
-
     //#then
     expect(task.status).toBe("error")
     expect(task.error).toBe("Model not found: kimi-for-coding/k2p5.")
     expect(task.completedAt).toBeInstanceOf(Date)
     expect(concurrencyManager.getCount(concurrencyKey)).toBe(0)
-    expect(getTaskMap(manager).has(task.id)).toBe(true)
+    expect(getTaskMap(manager).has(task.id)).toBe(false)
     expect(getPendingByParent(manager).get(task.parentSessionID)).toBeUndefined()
-    expect(getCompletionTimers(manager).has(task.id)).toBe(true)
 
     manager.shutdown()
   })
 
-  test("should remove errored task from toast manager while preserving delayed cleanup", async () => {
+  test("removes errored task from toast manager", () => {
     //#given
     const { removeTaskCalls, resetToastManager } = createToastRemoveTaskTracker()
     const manager = createBackgroundManager()
@@ -3137,11 +3111,8 @@ describe("BackgroundManager.handleEvent - session.error", () => {
       },
     })
 
-    await flushBackgroundNotifications()
-
     //#then
     expect(removeTaskCalls).toContain(task.id)
-    expect(getCompletionTimers(manager).has(task.id)).toBe(true)
 
     manager.shutdown()
     resetToastManager()
@@ -3422,7 +3393,7 @@ describe("BackgroundManager.pruneStaleTasksAndNotifications - removes pruned tas
     manager.shutdown()
   })
 
-  test("removes stale task from toast manager", async () => {
+  test("removes stale task from toast manager", () => {
     //#given
     const { removeTaskCalls, resetToastManager } = createToastRemoveTaskTracker()
     const manager = createBackgroundManager()
@@ -3437,7 +3408,6 @@ describe("BackgroundManager.pruneStaleTasksAndNotifications - removes pruned tas
 
     //#when
     pruneStaleTasksAndNotificationsForTest(manager)
-    await flushBackgroundNotifications()
 
     //#then
     expect(removeTaskCalls).toContain(staleTask.id)
@@ -3445,53 +3415,6 @@ describe("BackgroundManager.pruneStaleTasksAndNotifications - removes pruned tas
     manager.shutdown()
     resetToastManager()
   })
-
-  test("keeps stale task until notification cleanup after notifying parent", async () => {
-    //#given
-    const notifications: string[] = []
-    const { removeTaskCalls, resetToastManager } = createToastRemoveTaskTracker()
-    const client = {
-      session: {
-        prompt: async () => ({}),
-        promptAsync: async (args: { path: { id: string }; body: Record<string, unknown> & { noReply?: boolean; parts?: unknown[] } }) => {
-          const firstPart = args.body.parts?.[0]
-          if (firstPart && typeof firstPart === "object" && "text" in firstPart && typeof firstPart.text === "string") {
-            notifications.push(firstPart.text)
-          }
-          return {}
-        },
-        abort: async () => ({}),
-        messages: async () => ({ data: [] }),
-      },
-    }
-    const manager = new BackgroundManager({ client, directory: tmpdir() } as unknown as PluginInput)
-    const staleTask = createMockTask({
-      id: "task-stale-notify-cleanup",
-      sessionID: "session-stale-notify-cleanup",
-      parentSessionID: "parent-stale-notify-cleanup",
-      status: "running",
-      startedAt: new Date(Date.now() - 31 * 60 * 1000),
-    })
-    getTaskMap(manager).set(staleTask.id, staleTask)
-    getPendingByParent(manager).set(staleTask.parentSessionID, new Set([staleTask.id]))
-
-    //#when
-    pruneStaleTasksAndNotificationsForTest(manager)
-    await flushBackgroundNotifications()
-
-    //#then
-    const retainedTask = getTaskMap(manager).get(staleTask.id)
-    expect(retainedTask?.status).toBe("error")
-    expect(getTaskMap(manager).has(staleTask.id)).toBe(true)
-    expect(notifications).toHaveLength(1)
-    expect(notifications[0]).toContain("[ALL BACKGROUND TASKS COMPLETE]")
-    expect(notifications[0]).toContain(staleTask.description)
-    expect(getCompletionTimers(manager).has(staleTask.id)).toBe(true)
-    expect(removeTaskCalls).toContain(staleTask.id)
-
-    manager.shutdown()
-    resetToastManager()
-  })
 })
 
 describe("BackgroundManager.completionTimers - Memory Leak Fix", () => {
@@ -3595,7 +3518,7 @@ describe("BackgroundManager.completionTimers - Memory Leak Fix", () => {
     expect(completionTimers.size).toBe(0)
   })
 
-  test("should preserve cleanup timer when terminal task session is deleted", () => {
+  test("should cancel timer when task is deleted via session.deleted", () => {
     // given
     const manager = createBackgroundManager()
     const task: BackgroundTask = {
@@ -3624,7 +3547,7 @@ describe("BackgroundManager.completionTimers - Memory Leak Fix", () => {
     })
 
     // then
-    expect(completionTimers.has(task.id)).toBe(true)
+    expect(completionTimers.has(task.id)).toBe(false)
 
     manager.shutdown()
   })

src/features/background-agent/manager.ts

@@ -390,6 +390,7 @@ export class BackgroundManager {
         }).catch(() => {})
 
         this.markForNotification(existingTask)
+        this.cleanupPendingByParent(existingTask)
         this.enqueueNotificationForParent(existingTask.parentSessionID, () => this.notifyParentSession(existingTask)).catch(err => {
           log("[background-agent] Failed to notify on error:", err)
         })
@@ -660,6 +661,7 @@ export class BackgroundManager {
       }
 
       this.markForNotification(existingTask)
+      this.cleanupPendingByParent(existingTask)
       this.enqueueNotificationForParent(existingTask.parentSessionID, () => this.notifyParentSession(existingTask)).catch(err => {
         log("[background-agent] Failed to notify on resume error:", err)
       })
@@ -802,14 +804,16 @@ export class BackgroundManager {
         this.idleDeferralTimers.delete(task.id)
       }
 
-      if (task.sessionID) {
-        SessionCategoryRegistry.remove(task.sessionID)
+      this.cleanupPendingByParent(task)
+      this.tasks.delete(task.id)
+      this.clearNotificationsForTask(task.id)
+      const toastManager = getTaskToastManager()
+      if (toastManager) {
+        toastManager.removeTask(task.id)
+      }
+      if (task.sessionID) {
+        subagentSessions.delete(task.sessionID)
       }
-
-      this.markForNotification(task)
-      this.enqueueNotificationForParent(task.parentSessionID, () => this.notifyParentSession(task)).catch(err => {
-        log("[background-agent] Error in notifyParentSession for errored task:", { taskId: task.id, error: err })
-      })
     }
 
     if (event.type === "session.deleted") {
@@ -830,30 +834,47 @@ export class BackgroundManager {
 
       if (tasksToCancel.size === 0) return
 
-      const deletedSessionIDs = new Set<string>([sessionID])
-      for (const task of tasksToCancel.values()) {
-        if (task.sessionID) {
-          deletedSessionIDs.add(task.sessionID)
-        }
-      }
-
       for (const task of tasksToCancel.values()) {
         if (task.status === "running" || task.status === "pending") {
           void this.cancelTask(task.id, {
             source: "session.deleted",
             reason: "Session deleted",
-          }).then(() => {
-            if (deletedSessionIDs.has(task.parentSessionID)) {
-              this.pendingNotifications.delete(task.parentSessionID)
-            }
+            skipNotification: true,
           }).catch(err => {
-            if (deletedSessionIDs.has(task.parentSessionID)) {
-              this.pendingNotifications.delete(task.parentSessionID)
-            }
             log("[background-agent] Failed to cancel task on session.deleted:", { taskId: task.id, error: err })
           })
         }
+
+        const existingTimer = this.completionTimers.get(task.id)
+        if (existingTimer) {
+          clearTimeout(existingTimer)
+          this.completionTimers.delete(task.id)
+        }
+
+        const idleTimer = this.idleDeferralTimers.get(task.id)
+        if (idleTimer) {
+          clearTimeout(idleTimer)
+          this.idleDeferralTimers.delete(task.id)
+        }
+
+        this.cleanupPendingByParent(task)
+        this.tasks.delete(task.id)
+        this.clearNotificationsForTask(task.id)
+        const toastManager = getTaskToastManager()
+        if (toastManager) {
+          toastManager.removeTask(task.id)
+        }
+        if (task.sessionID) {
+          subagentSessions.delete(task.sessionID)
+        }
       }
+
+      for (const task of tasksToCancel.values()) {
+        if (task.parentSessionID) {
+          this.pendingNotifications.delete(task.parentSessionID)
+        }
+      }
+
       SessionCategoryRegistry.remove(sessionID)
     }
 
@@ -1073,6 +1094,8 @@ export class BackgroundManager {
       this.idleDeferralTimers.delete(task.id)
     }
 
+    this.cleanupPendingByParent(task)
+
     if (abortSession && task.sessionID) {
       this.client.session.abort({
         path: { id: task.sessionID },
@@ -1179,6 +1202,9 @@ export class BackgroundManager {
 
     this.markForNotification(task)
 
+    // Ensure pending tracking is cleaned up even if notification fails
+    this.cleanupPendingByParent(task)
+
     const idleTimer = this.idleDeferralTimers.get(task.id)
     if (idleTimer) {
       clearTimeout(idleTimer)
@@ -1234,10 +1260,7 @@ export class BackgroundManager {
         this.pendingByParent.delete(task.parentSessionID)
       }
     } else {
-      remainingCount = Array.from(this.tasks.values())
-        .filter(t => t.parentSessionID === task.parentSessionID && t.id !== task.id && (t.status === "running" || t.status === "pending"))
-        .length
-      allComplete = remainingCount === 0
+      allComplete = true
     }
 
     const completedTasks = allComplete
@@ -1245,13 +1268,7 @@ export class BackgroundManager {
         .filter(t => t.parentSessionID === task.parentSessionID && t.status !== "running" && t.status !== "pending")
       : []
 
-    const statusText = task.status === "completed"
-      ? "COMPLETED"
-      : task.status === "interrupt"
-        ? "INTERRUPTED"
-        : task.status === "error"
-          ? "ERROR"
-          : "CANCELLED"
+    const statusText = task.status === "completed" ? "COMPLETED" : task.status === "interrupt" ? "INTERRUPTED" : "CANCELLED"
     const errorInfo = task.error ? `\n**Error:** ${task.error}` : ""
 
     let notification: string
@@ -1382,13 +1399,8 @@ Use \`background_output(task_id="${task.id}")\` to retrieve this result when rea
         }
         const timer = setTimeout(() => {
           this.completionTimers.delete(taskId)
-          const taskToRemove = this.tasks.get(taskId)
-          if (taskToRemove) {
+          if (this.tasks.has(taskId)) {
             this.clearNotificationsForTask(taskId)
-            if (taskToRemove.sessionID) {
-              subagentSessions.delete(taskToRemove.sessionID)
-              SessionCategoryRegistry.remove(taskToRemove.sessionID)
-            }
             this.tasks.delete(taskId)
             log("[background-agent] Removed completed task from memory:", taskId)
           }
@@ -1423,21 +1435,11 @@ Use \`background_output(task_id="${task.id}")\` to retrieve this result when rea
         task.status = "error"
         task.error = errorMessage
         task.completedAt = new Date()
-        this.taskHistory.record(task.parentSessionID, { id: task.id, sessionID: task.sessionID, agent: task.agent, description: task.description, status: "error", category: task.category, startedAt: task.startedAt, completedAt: task.completedAt })
         if (task.concurrencyKey) {
           this.concurrencyManager.release(task.concurrencyKey)
           task.concurrencyKey = undefined
         }
-        const existingTimer = this.completionTimers.get(taskId)
-        if (existingTimer) {
-          clearTimeout(existingTimer)
-          this.completionTimers.delete(taskId)
-        }
-        const idleTimer = this.idleDeferralTimers.get(taskId)
-        if (idleTimer) {
-          clearTimeout(idleTimer)
-          this.idleDeferralTimers.delete(taskId)
-        }
+        this.cleanupPendingByParent(task)
         if (wasPending) {
           const key = task.model
             ? `${task.model.providerID}/${task.model.modelID}`
@@ -1453,10 +1455,16 @@ Use \`background_output(task_id="${task.id}")\` to retrieve this result when rea
             }
           }
         }
-        this.markForNotification(task)
-        this.enqueueNotificationForParent(task.parentSessionID, () => this.notifyParentSession(task)).catch(err => {
-          log("[background-agent] Error in notifyParentSession for stale-pruned task:", { taskId: task.id, error: err })
-        })
+        this.clearNotificationsForTask(taskId)
+        const toastManager = getTaskToastManager()
+        if (toastManager) {
+          toastManager.removeTask(taskId)
+        }
+        this.tasks.delete(taskId)
+        if (task.sessionID) {
+          subagentSessions.delete(task.sessionID)
+          SessionCategoryRegistry.remove(task.sessionID)
+        }
       },
     })
   }

src/features/background-agent/task-poller.test.ts

@@ -422,38 +422,4 @@ describe("pruneStaleTasksAndNotifications", () => {
     //#then
     expect(pruned).toContain("old-task")
   })
-
-  it("should skip terminal tasks even when they exceeded TTL", () => {
-    //#given
-    const tasks = new Map<string, BackgroundTask>()
-    const oldStartedAt = new Date(Date.now() - 31 * 60 * 1000)
-    const terminalStatuses: BackgroundTask["status"][] = ["completed", "error", "cancelled", "interrupt"]
-
-    for (const status of terminalStatuses) {
-      tasks.set(status, {
-        id: status,
-        parentSessionID: "parent",
-        parentMessageID: "msg",
-        description: status,
-        prompt: status,
-        agent: "explore",
-        status,
-        startedAt: oldStartedAt,
-        completedAt: new Date(),
-      })
-    }
-
-    const pruned: string[] = []
-
-    //#when
-    pruneStaleTasksAndNotifications({
-      tasks,
-      notifications: new Map<string, BackgroundTask[]>(),
-      onTaskPruned: (taskId) => pruned.push(taskId),
-    })
-
-    //#then
-    expect(pruned).toEqual([])
-    expect(Array.from(tasks.keys())).toEqual(terminalStatuses)
-  })
 })

src/features/background-agent/task-poller.ts

@@ -12,13 +12,6 @@ import {
   TASK_TTL_MS,
 } from "./constants"
 
-const TERMINAL_TASK_STATUSES = new Set<BackgroundTask["status"]>([
-  "completed",
-  "error",
-  "cancelled",
-  "interrupt",
-])
-
 export function pruneStaleTasksAndNotifications(args: {
   tasks: Map<string, BackgroundTask>
   notifications: Map<string, BackgroundTask[]>
@@ -28,8 +21,6 @@ export function pruneStaleTasksAndNotifications(args: {
   const now = Date.now()
 
   for (const [taskId, task] of tasks.entries()) {
-    if (TERMINAL_TASK_STATUSES.has(task.status)) continue
-
     const timestamp = task.status === "pending"
       ? task.queuedAt?.getTime()
       : task.startedAt?.getTime()

src/features/tmux-subagent/pane-state-parser.ts

@@ -0,0 +1,125 @@
+import type { TmuxPaneInfo } from "./types"
+
+const MANDATORY_PANE_FIELD_COUNT = 8
+
+type ParsedPaneState = {
+  windowWidth: number
+  windowHeight: number
+  panes: TmuxPaneInfo[]
+}
+
+type ParsedPaneLine = {
+  pane: TmuxPaneInfo
+  windowWidth: number
+  windowHeight: number
+}
+
+type MandatoryPaneFields = [
+  paneId: string,
+  widthString: string,
+  heightString: string,
+  leftString: string,
+  topString: string,
+  activeString: string,
+  windowWidthString: string,
+  windowHeightString: string,
+]
+
+export function parsePaneStateOutput(stdout: string): ParsedPaneState | null {
+  const lines = stdout
+    .split("\n")
+    .map((line) => line.replace(/\r$/, ""))
+    .filter((line) => line.length > 0)
+
+  if (lines.length === 0) return null
+
+  const parsedPaneLines = lines
+    .map(parsePaneLine)
+    .filter((parsedPaneLine): parsedPaneLine is ParsedPaneLine => parsedPaneLine !== null)
+
+  if (parsedPaneLines.length === 0) return null
+
+  const latestPaneLine = parsedPaneLines[parsedPaneLines.length - 1]
+  if (!latestPaneLine) return null
+
+  return {
+    windowWidth: latestPaneLine.windowWidth,
+    windowHeight: latestPaneLine.windowHeight,
+    panes: parsedPaneLines.map(({ pane }) => pane),
+  }
+}
+
+function parsePaneLine(line: string): ParsedPaneLine | null {
+  const fields = line.split("\t")
+  const mandatoryFields = getMandatoryPaneFields(fields)
+  if (!mandatoryFields) return null
+
+  const [paneId, widthString, heightString, leftString, topString, activeString, windowWidthString, windowHeightString] = mandatoryFields
+
+  const width = parseInteger(widthString)
+  const height = parseInteger(heightString)
+  const left = parseInteger(leftString)
+  const top = parseInteger(topString)
+  const windowWidth = parseInteger(windowWidthString)
+  const windowHeight = parseInteger(windowHeightString)
+
+  if (
+    width === null ||
+    height === null ||
+    left === null ||
+    top === null ||
+    windowWidth === null ||
+    windowHeight === null
+  ) {
+    return null
+  }
+
+  return {
+    pane: {
+      paneId,
+      width,
+      height,
+      left,
+      top,
+      title: fields.slice(MANDATORY_PANE_FIELD_COUNT).join("\t"),
+      isActive: activeString === "1",
+    },
+    windowWidth,
+    windowHeight,
+  }
+}
+
+function getMandatoryPaneFields(fields: string[]): MandatoryPaneFields | null {
+  if (fields.length < MANDATORY_PANE_FIELD_COUNT) return null
+
+  const [paneId, widthString, heightString, leftString, topString, activeString, windowWidthString, windowHeightString] = fields
+
+  if (
+    paneId === undefined ||
+    widthString === undefined ||
+    heightString === undefined ||
+    leftString === undefined ||
+    topString === undefined ||
+    activeString === undefined ||
+    windowWidthString === undefined ||
+    windowHeightString === undefined
+  ) {
+    return null
+  }
+
+  return [
+    paneId,
+    widthString,
+    heightString,
+    leftString,
+    topString,
+    activeString,
+    windowWidthString,
+    windowHeightString,
+  ]
+}
+
+function parseInteger(value: string): number | null {
+  const parsedValue = Number.parseInt(value, 10)
+  return Number.isNaN(parsedValue) ? null : parsedValue
+}

src/features/tmux-subagent/pane-state-querier.test.ts

@@ -0,0 +1,73 @@
+import { describe, expect, test } from "bun:test"
+import { parsePaneStateOutput } from "./pane-state-parser"
+
+describe("parsePaneStateOutput", () => {
+  test("accepts a single pane when tmux omits the empty trailing title field", () => {
+    // given
+    const stdout = "%0\t120\t40\t0\t0\t1\t120\t40\n"
+
+    // when
+    const result = parsePaneStateOutput(stdout)
+
+    // then
+    expect(result).not.toBeNull()
+    expect(result).toEqual({
+      windowWidth: 120,
+      windowHeight: 40,
+      panes: [
+        {
+          paneId: "%0",
+          width: 120,
+          height: 40,
+          left: 0,
+          top: 0,
+          title: "",
+          isActive: true,
+        },
+      ],
+    })
+  })
+
+  test("handles CRLF line endings without dropping panes", () => {
+    // given
+    const stdout = "%0\t120\t40\t0\t0\t1\t120\t40\r\n%1\t60\t40\t60\t0\t0\t120\t40\tagent\r\n"
+
+    // when
+    const result = parsePaneStateOutput(stdout)
+
+    // then
+    expect(result).not.toBeNull()
+    expect(result?.panes).toEqual([
+      {
+        paneId: "%0",
+        width: 120,
+        height: 40,
+        left: 0,
+        top: 0,
+        title: "",
+        isActive: true,
+      },
+      {
+        paneId: "%1",
+        width: 60,
+        height: 40,
+        left: 60,
+        top: 0,
+        title: "agent",
+        isActive: false,
+      },
+    ])
+  })
+
+  test("preserves tabs inside pane titles", () => {
+    // given
+    const stdout = "%0\t120\t40\t0\t0\t1\t120\t40\ttitle\twith\ttabs\n"
+
+    // when
+    const result = parsePaneStateOutput(stdout)
+
+    // then
+    expect(result).not.toBeNull()
+    expect(result?.panes[0]?.title).toBe("title\twith\ttabs")
+  })
+})

src/features/tmux-subagent/pane-state-querier.ts

@@ -1,5 +1,6 @@
 import { spawn } from "bun"
 import type { WindowState, TmuxPaneInfo } from "./types"
+import { parsePaneStateOutput } from "./pane-state-parser"
 import { getTmuxPath } from "../../tools/interactive-bash/tmux-path-resolver"
 import { log } from "../../shared"
 
@@ -27,31 +28,12 @@ export async function queryWindowState(sourcePaneId: string): Promise<WindowStat
     return null
   }
 
-  const lines = stdout.trim().split("\n").filter(Boolean)
-  if (lines.length === 0) return null
+  const parsedPaneState = parsePaneStateOutput(stdout)
+  if (!parsedPaneState) return null
 
-  let windowWidth = 0
-  let windowHeight = 0
-  const panes: TmuxPaneInfo[] = []
-
-  for (const line of lines) {
-		const fields = line.split("\t")
-		if (fields.length < 9) continue
-
-		const [paneId, widthStr, heightStr, leftStr, topStr, activeStr, windowWidthStr, windowHeightStr] = fields
-		const title = fields.slice(8).join("\t")
-    const width = parseInt(widthStr, 10)
-    const height = parseInt(heightStr, 10)
-    const left = parseInt(leftStr, 10)
-    const top = parseInt(topStr, 10)
-    const isActive = activeStr === "1"
-    windowWidth = parseInt(windowWidthStr, 10)
-    windowHeight = parseInt(windowHeightStr, 10)
-
-    if (!isNaN(width) && !isNaN(left) && !isNaN(height) && !isNaN(top)) {
-      panes.push({ paneId, width, height, left, top, title, isActive })
-    }
-  }
+  const { panes } = parsedPaneState
+  const windowWidth = parsedPaneState.windowWidth
+  const windowHeight = parsedPaneState.windowHeight
 
   panes.sort((a, b) => a.left - b.left || a.top - b.top)