diff --git a/src/shared/agent-hook-listener.ts b/src/shared/agent-hook-listener.ts
index f77a4ebae3c..1e3728eaef7 100644
--- a/src/shared/agent-hook-listener.ts
+++ b/src/shared/agent-hook-listener.ts
@@ -2412,7 +2412,14 @@ function normalizeClaudeSubagentLifecycleEvent(
         Date.now()
       )
     } else {
-      finishClaudeSubagent(roster, agentId)
+      // Why: SubagentStop carries the session's task inventory; a stopping
+      // agent listed id-exact as a subagent task is a workflow/named one-shot
+      // (teammate lifecycle ids never appear there), not a resumable teammate.
+      const stopTasks = readClaudeBackgroundAgentTasks(hookPayload)
+      finishClaudeSubagent(roster, agentId, {
+        listedAsSubagentTask:
+          stopTasks.present && stopTasks.tasks.some((task) => !task.teammate && task.id === agentId)
+      })
       // Why: a blocked child that dies (killed, errored) without another tool
       // event would otherwise pin its permission/question wait on the pane
       // forever — nothing else references that agent again.
diff --git a/src/shared/claude-subagent-roster.test.ts b/src/shared/claude-subagent-roster.test.ts
index 5e226ca38ab..99cd9bbb8dc 100644
--- a/src/shared/claude-subagent-roster.test.ts
+++ b/src/shared/claude-subagent-roster.test.ts
@@ -32,6 +32,83 @@ describe('claude-subagent-roster', () => {
     expect(roster.get('aprobe1-6d3cb5b5')).toMatchObject({ state: 'idle', teammate: true })
   })
 
+  it('removes a finished workflow lane despite its teammate-shaped id when task-listed', () => {
+    const roster: ClaudeSubagentRoster = new Map()
+    // Why: workflow lanes get name-embedding ids (afinder-C-<hex>) like
+    // teammates, but their SubagentStop payload lists them id-exact as a
+    // subagent task — real teammate lifecycle ids never appear there.
+    upsertWorkingClaudeSubagent(
+      roster,
+      'afinder-C-5d713c0781b7f8d2',
+      { agentType: 'finder-C' },
+      100
+    )
+    finishClaudeSubagent(roster, 'afinder-C-5d713c0781b7f8d2', { listedAsSubagentTask: true })
+    expect(roster.size).toBe(0)
+  })
+
+  it('reclassifies a task-listed teammate-shaped entry as a one-shot', () => {
+    const roster: ClaudeSubagentRoster = new Map()
+    upsertWorkingClaudeSubagent(
+      roster,
+      'av1-streaming-0b1c2d3e',
+      { agentType: 'v1-streaming' },
+      100
+    )
+    foldClaudeBackgroundTasksIntoRoster(
+      roster,
+      [
+        {
+          id: 'av1-streaming-0b1c2d3e',
+          agentType: 'v1-streaming',
+          description: undefined,
+          running: true,
+          teammate: false
+        },
+        {
+          id: 'tteam1',
+          agentType: undefined,
+          description: undefined,
+          running: true,
+          teammate: true
+        }
+      ],
+      200
+    )
+    // A later stop without its own inventory still removes it: the fold
+    // already proved the id is a task id, not a teammate.
+    finishClaudeSubagent(roster, 'av1-streaming-0b1c2d3e')
+    expect(roster.has('av1-streaming-0b1c2d3e')).toBe(false)
+  })
+
+  it('removes teammate-shaped leftovers when a complete inventory lists no teammates', () => {
+    const roster: ClaudeSubagentRoster = new Map()
+    upsertWorkingClaudeSubagent(roster, 'acr-triage-1-c5a0588e', { agentType: 'cr-triage-1' }, 100)
+    finishClaudeSubagent(roster, 'acr-triage-1-c5a0588e')
+    expect(roster.get('acr-triage-1-c5a0588e')).toMatchObject({ state: 'idle' })
+    upsertWorkingClaudeSubagent(roster, 'afix-main-11223344', { agentType: 'fix-main' }, 150)
+
+    // Why: a teams session lists its teammates (even idle) as teammate-typed
+    // tasks; an inventory with none proves these name-shaped rows are dead
+    // workflow lanes, not resumable teammates.
+    foldClaudeBackgroundTasksIntoRoster(
+      roster,
+      [
+        {
+          id: 'aunrelated0000001',
+          agentType: 'general-purpose',
+          description: undefined,
+          running: true,
+          teammate: false
+        }
+      ],
+      200
+    )
+    expect(roster.has('acr-triage-1-c5a0588e')).toBe(false)
+    expect(roster.has('afix-main-11223344')).toBe(false)
+    expect(roster.has('aunrelated0000001')).toBe(true)
+  })
+
   it('re-marks an idle teammate working without resetting startedAt', () => {
     const roster: ClaudeSubagentRoster = new Map()
     upsertWorkingClaudeSubagent(roster, 'aprobe1-6d3cb5b5', { agentType: 'probe1' }, 100)
diff --git a/src/shared/claude-subagent-roster.ts b/src/shared/claude-subagent-roster.ts
index f4fb1bc6429..b0b945a76e2 100644
--- a/src/shared/claude-subagent-roster.ts
+++ b/src/shared/claude-subagent-roster.ts
@@ -105,13 +105,24 @@ function evictOldestIdleClaudeSubagent(roster: ClaudeSubagentRoster): boolean {
 /** SubagentStop: a finished one-shot subagent leaves the sidebar immediately —
  *  retaining it as an idle row made long workflow/ultracode sessions pile up
  *  dozens of dead rows. Teammates only idle (alive + resumable): SubagentStop
- *  fires each time a teammate finishes a task, not just at shutdown. */
-export function finishClaudeSubagent(roster: ClaudeSubagentRoster, id: string): void {
+ *  fires each time a teammate finishes a task, not just at shutdown.
+ *
+ *  Workflow/named one-shots share the teammate id shape (`a<label>-<hex>`),
+ *  but unlike real teammates they ARE listed id-exact as `type: "subagent"`
+ *  background tasks — including inside their own SubagentStop payload
+ *  (verified against live hook captures). `listedAsSubagentTask` carries that
+ *  corroboration so a finished workflow lane is removed instead of squatting
+ *  as a phantom idle teammate. */
+export function finishClaudeSubagent(
+  roster: ClaudeSubagentRoster,
+  id: string,
+  options?: { listedAsSubagentTask?: boolean }
+): void {
   const existing = roster.get(id)
   if (!existing) {
     return
   }
-  if (existing.teammate) {
+  if (existing.teammate && options?.listedAsSubagentTask !== true) {
     existing.state = 'idle'
     return
   }
@@ -178,7 +189,12 @@ export function readClaudeBackgroundAgentTasks(hookPayload: Record<string, unkno
  *  - teammates are exempt: their task ids never match lifecycle agent_ids, so
  *    omission proves nothing — except a snapshot-seeded phantom
  *    (backgroundTasksAuthoritative), which demotes to idle so it cannot gate
- *    the pane while teams sessions never send an empty list. */
+ *    the pane while teams sessions never send an empty list;
+ *  - teammate-SHAPED entries are reclassified as one-shots when a subagent-
+ *    typed task lists their lifecycle id, and are removed on omission when a
+ *    complete inventory lists no teammate-typed task at all (a teams session
+ *    always lists its teammates, even idle ones) — workflow/named one-shot
+ *    lanes share the id shape and must not squat as phantom teammates. */
 export function foldClaudeBackgroundTasksIntoRoster(
   roster: ClaudeSubagentRoster,
   tasks: ClaudeBackgroundAgentTask[],
@@ -192,6 +208,7 @@ export function foldClaudeBackgroundTasksIntoRoster(
     return
   }
   const listedIds = new Set<string>()
+  const hasTeammateTypedTask = tasks.some((task) => task.teammate)
   for (const task of tasks) {
     listedIds.add(task.id)
     const existing = roster.get(task.id)
@@ -203,6 +220,12 @@ export function foldClaudeBackgroundTasksIntoRoster(
       existing.state = 'working'
       existing.agentType = task.agentType ?? existing.agentType
       existing.description = task.description ?? existing.description
+      // Why: real teammate lifecycle ids never appear as task ids, so an
+      // id-exact subagent-typed listing proves this teammate-SHAPED entry is
+      // a workflow/named one-shot; unflag it so its stop/omission removes it.
+      if (!task.teammate) {
+        existing.teammate = undefined
+      }
       continue
     }
     if (task.teammate || !task.running) {
@@ -227,6 +250,14 @@ export function foldClaudeBackgroundTasksIntoRoster(
       continue
     }
     if (tracked.teammate) {
+      // Why: a teams session lists its teammates as teammate-typed tasks even
+      // while they idle. A complete inventory with NONE proves no teammate is
+      // alive — so teammate-SHAPED leftovers are dead workflow/named one-shots
+      // (e.g. killed lanes whose SubagentStop was lost) and must go.
+      if (!hasTeammateTypedTask) {
+        roster.delete(id)
+        continue
+      }
       if (tracked.backgroundTasksAuthoritative && tracked.state === 'working') {
         tracked.state = 'idle'
       }
diff --git a/src/shared/claude-subagent-row-lifecycle.test.ts b/src/shared/claude-subagent-row-lifecycle.test.ts
index b724e3a3b8d..8e9531b523c 100644
--- a/src/shared/claude-subagent-row-lifecycle.test.ts
+++ b/src/shared/claude-subagent-row-lifecycle.test.ts
@@ -149,6 +149,65 @@ describe('claude subagent sidebar row lifecycle', () => {
     ])
   })
 
+  it('drops named workflow lanes instead of retaining them as phantom idle teammates', () => {
+    // Regression for the live-observed 32-row pile: workflow lanes report
+    // name-embedding ids (afinder-C-<hex>, agent_type = the label), which
+    // share the teammate id shape but are one-shots.
+    claudeEvent({ hook_event_name: 'UserPromptSubmit', prompt: 'native chat review (ultracode)' })
+    claudeEvent({
+      hook_event_name: 'SubagentStart',
+      agent_id: 'afinder-C-5d713c0781b7f8d2',
+      agent_type: 'finder-C'
+    })
+    claudeEvent({
+      hook_event_name: 'SubagentStart',
+      agent_id: 'acr-triage-1-c5a0588e7a2e4151',
+      agent_type: 'cr-triage-1'
+    })
+
+    // finder-C finishes; its SubagentStop carries the task inventory that
+    // lists it id-exact as a subagent — proof it is not a teammate.
+    const stopped = claudeEvent({
+      hook_event_name: 'SubagentStop',
+      agent_id: 'afinder-C-5d713c0781b7f8d2',
+      agent_type: 'finder-C',
+      background_tasks: [
+        {
+          id: 'afinder-C-5d713c0781b7f8d2',
+          type: 'subagent',
+          status: 'running',
+          agent_type: 'finder-C'
+        },
+        {
+          id: 'acr-triage-1-c5a0588e7a2e4151',
+          type: 'subagent',
+          status: 'running',
+          agent_type: 'cr-triage-1'
+        }
+      ]
+    })
+    expect(stopped?.payload.subagents).toEqual([
+      expect.objectContaining({ id: 'acr-triage-1-c5a0588e7a2e4151', state: 'working' })
+    ])
+
+    // cr-triage-1 is killed (SubagentStop lost). The lead Stop's complete
+    // inventory lists no teammate-typed task, so the leftover is removed.
+    const stop = claudeEvent({
+      hook_event_name: 'Stop',
+      background_tasks: [
+        {
+          id: 'awf0000000000000zz',
+          type: 'subagent',
+          status: 'running',
+          agent_type: 'general-purpose'
+        }
+      ]
+    })
+    expect(stop?.payload.subagents).toEqual([
+      expect.objectContaining({ id: 'awf0000000000000zz', state: 'working' })
+    ])
+  })
+
   it('removes aborted subagents on the interrupt Stop so the pane can resolve', () => {
     claudeEvent({ hook_event_name: 'UserPromptSubmit', prompt: 'long batch' })
     claudeEvent({