diff --git a/src/shared/agent-hook-listener.test.ts b/src/shared/agent-hook-listener.test.ts
index 1ee2bb1bd00..efafcaa5b06 100644
--- a/src/shared/agent-hook-listener.test.ts
+++ b/src/shared/agent-hook-listener.test.ts
@@ -26,6 +26,7 @@ import {
   clearGrokSessionPathLookupCacheForTests,
   findGrokChatHistoryBySessionId
 } from './grok-session-paths'
+import { AGENT_STATUS_MAX_SUBAGENTS } from './agent-status-types'
 import { makePaneKey } from './stable-pane-id'
 
 const LEAF_ID = '11111111-1111-4111-8111-111111111111'
@@ -2408,6 +2409,35 @@ describe('shared agent-hook-listener', () => {
       ])
     })
 
+    it('keeps a teammate whose name differs from its configured agent type', () => {
+      claudeEvent({ hook_event_name: 'UserPromptSubmit', prompt: 'spawn reviewer' })
+      claudeEvent({
+        hook_event_name: 'SubagentStart',
+        agent_id: 'areviewer-6d3cb5b52120b7bf',
+        agent_type: 'security-reviewer'
+      })
+
+      // Why: teammate name and agent type are separate Agent-tool inputs; the
+      // lifecycle id embeds the former while the hook reports the latter.
+      claudeEvent({
+        hook_event_name: 'SubagentStop',
+        agent_id: 'areviewer-6d3cb5b52120b7bf',
+        agent_type: 'security-reviewer'
+      })
+      const idled = claudeEvent({
+        hook_event_name: 'TeammateIdle',
+        teammate_name: 'reviewer',
+        team_name: 'session-x'
+      })
+      expect(idled?.payload.subagents).toEqual([
+        expect.objectContaining({
+          id: 'areviewer-6d3cb5b52120b7bf',
+          agentType: 'security-reviewer',
+          state: 'idle'
+        })
+      ])
+    })
+
     it('scopes subagent rosters per pane', () => {
       claudeEvent(
         { hook_event_name: 'SubagentStart', agent_id: 'a1', agent_type: 'general-purpose' },
@@ -2587,6 +2617,29 @@ describe('shared agent-hook-listener', () => {
       ])
     })
 
+    it('keeps a live child omitted by the background task snapshot cap', () => {
+      claudeEvent({
+        hook_event_name: 'SubagentStart',
+        agent_id: 'alive-after-cap',
+        agent_type: 'general-purpose'
+      })
+      const stop = claudeEvent({
+        hook_event_name: 'Stop',
+        background_tasks: Array.from({ length: AGENT_STATUS_MAX_SUBAGENTS + 1 }, (_, index) => ({
+          id: index === AGENT_STATUS_MAX_SUBAGENTS ? 'alive-after-cap' : `a${index}`,
+          type: 'subagent',
+          status: 'running'
+        }))
+      })
+
+      // Why: the inventory was capped before this id, so omission cannot
+      // prove the lifecycle-tracked child finished or was killed.
+      expect(stop?.payload.subagents).toContainEqual(
+        expect.objectContaining({ id: 'alive-after-cap', state: 'working' })
+      )
+      expect(stop?.payload.state).toBe('working')
+    })
+
     it('does not adopt a known child turn-boundary event as the lead state', () => {
       claudeEvent({ hook_event_name: 'UserPromptSubmit', prompt: 'go' })
       claudeEvent({
@@ -2652,7 +2705,12 @@ describe('shared agent-hook-listener', () => {
 
     it('seeds the roster from persisted snapshots so a teammate-bearing Stop keeps child rows', () => {
       seedClaudeSubagentRosterFromSnapshots(state, PANE_KEY, [
-        { id: 'aprobe2-abc', state: 'idle', startedAt: 1000, agentType: 'probe2' }
+        {
+          id: 'aprobe2-6d3cb5b52120b7bf',
+          state: 'idle',
+          startedAt: 1000,
+          agentType: 'security-reviewer'
+        }
       ])
       claudeEvent({ hook_event_name: 'UserPromptSubmit', prompt: 'after restart' })
       const stop = claudeEvent({
@@ -2663,7 +2721,11 @@ describe('shared agent-hook-listener', () => {
       })
       expect(stop?.payload.state).toBe('done')
       expect(stop?.payload.subagents).toEqual([
-        expect.objectContaining({ id: 'aprobe2-abc', state: 'idle' })
+        expect.objectContaining({
+          id: 'aprobe2-6d3cb5b52120b7bf',
+          agentType: 'security-reviewer',
+          state: 'idle'
+        })
       ])
     })
 
diff --git a/src/shared/agent-hook-listener.ts b/src/shared/agent-hook-listener.ts
index b016e23d1ac..f77a4ebae3c 100644
--- a/src/shared/agent-hook-listener.ts
+++ b/src/shared/agent-hook-listener.ts
@@ -40,6 +40,7 @@ import {
   claudeTeammateIdMatchesName,
   finishClaudeSubagent,
   foldClaudeBackgroundTasksIntoRoster,
+  isClaudeTeammateLifecycleId,
   markClaudeTeammateIdleByName,
   readClaudeBackgroundAgentTasks,
   upsertWorkingClaudeSubagent,
@@ -2449,12 +2450,9 @@ export function seedClaudeSubagentRosterFromSnapshots(
       startedAt: snapshot.startedAt,
       agentType: snapshot.agentType,
       description: snapshot.description,
-      // Why: re-derive teammate-ness from the persisted id/agentType so a
-      // seeded teammate keeps its idle row instead of being removed as a
-      // finished one-shot by the next fold.
-      ...(snapshot.agentType && claudeTeammateIdMatchesName(snapshot.id, snapshot.agentType)
-        ? { teammate: true as const }
-        : {}),
+      // Why: teammate name and agent type can differ, but the provider id
+      // shape survives persistence and keeps the row across restart folds.
+      ...(isClaudeTeammateLifecycleId(snapshot.id) ? { teammate: true as const } : {}),
       // Why: the seed can be a phantom (child finished while Orca was down,
       // its SubagentStop lost). Let a PRESENT background_tasks list that
       // omits the id remove it (or demote a teammate) instead of gating the
@@ -2616,7 +2614,8 @@ function normalizeClaudeEvent(
       foldClaudeBackgroundTasksIntoRoster(
         getOrCreateClaudeSubagentRoster(state, paneKey),
         backgroundTasks.tasks,
-        Date.now()
+        Date.now(),
+        { inventoryComplete: !backgroundTasks.truncated }
       )
     }
   }
diff --git a/src/shared/claude-subagent-roster.test.ts b/src/shared/claude-subagent-roster.test.ts
index de0a2870a76..5e226ca38ab 100644
--- a/src/shared/claude-subagent-roster.test.ts
+++ b/src/shared/claude-subagent-roster.test.ts
@@ -109,10 +109,21 @@ describe('claude-subagent-roster', () => {
     expect(readClaudeBackgroundAgentTasks({ background_tasks: 'nope' }).present).toBe(false)
   })
 
+  it('marks a background task inventory truncated after the snapshot cap', () => {
+    const tasks = Array.from({ length: AGENT_STATUS_MAX_SUBAGENTS + 1 }, (_, index) => ({
+      id: `a${index}`,
+      type: 'subagent',
+      status: 'running'
+    }))
+    const result = readClaudeBackgroundAgentTasks({ background_tasks: tasks })
+    expect(result.tasks).toHaveLength(AGENT_STATUS_MAX_SUBAGENTS)
+    expect(result.truncated).toBe(true)
+  })
+
   it('folds background_tasks in without trusting ambiguous entries', () => {
     const roster: ClaudeSubagentRoster = new Map()
     upsertWorkingClaudeSubagent(roster, 'a1', {}, 100)
-    upsertWorkingClaudeSubagent(roster, 'ateam-xyz', { agentType: 'team' }, 150)
+    upsertWorkingClaudeSubagent(roster, 'ateam-6d3cb5b5', { agentType: 'security-reviewer' }, 150)
 
     foldClaudeBackgroundTasksIntoRoster(
       roster,
@@ -142,7 +153,10 @@ describe('claude-subagent-roster', () => {
     expect(roster.get('a1')).toMatchObject({ state: 'working', description: 'review loop' })
     // Why: the working lifecycle-tracked teammate is not listed by id, but
     // omission proves nothing for teammates — it must survive the fold.
-    expect(roster.get('ateam-xyz')).toMatchObject({ state: 'working', agentType: 'team' })
+    expect(roster.get('ateam-6d3cb5b5')).toMatchObject({
+      state: 'working',
+      agentType: 'security-reviewer'
+    })
   })
 
   it('removes an id-matched task reported not running', () => {
@@ -172,6 +186,23 @@ describe('claude-subagent-roster', () => {
     expect(roster.size).toBe(0)
   })
 
+  it('retains an unlisted live child when the background task inventory was truncated', () => {
+    const roster: ClaudeSubagentRoster = new Map()
+    upsertWorkingClaudeSubagent(roster, 'alive-after-cap', {}, 100)
+    const parsed = readClaudeBackgroundAgentTasks({
+      background_tasks: Array.from({ length: AGENT_STATUS_MAX_SUBAGENTS + 1 }, (_, index) => ({
+        id: index === AGENT_STATUS_MAX_SUBAGENTS ? 'alive-after-cap' : `a${index}`,
+        type: 'subagent',
+        status: 'running'
+      }))
+    })
+
+    foldClaudeBackgroundTasksIntoRoster(roster, parsed.tasks, 200, {
+      inventoryComplete: !parsed.truncated
+    })
+    expect(roster.has('alive-after-cap')).toBe(true)
+  })
+
   it('recreates unmatched running one-shot subagents after a listener restart', () => {
     const roster: ClaudeSubagentRoster = new Map()
     foldClaudeBackgroundTasksIntoRoster(
@@ -213,7 +244,7 @@ describe('claude-subagent-roster', () => {
       startedAt: 100,
       backgroundTasksAuthoritative: true
     })
-    upsertWorkingClaudeSubagent(roster, 'ateam-xyz', { agentType: 'team' }, 150)
+    upsertWorkingClaudeSubagent(roster, 'ateam-6d3cb5b5', { agentType: 'security-reviewer' }, 150)
 
     foldClaudeBackgroundTasksIntoRoster(
       roster,
@@ -223,7 +254,7 @@ describe('claude-subagent-roster', () => {
       200
     )
     expect(roster.has('a-phantom')).toBe(false)
-    expect(roster.get('ateam-xyz')).toMatchObject({ state: 'working' })
+    expect(roster.get('ateam-6d3cb5b5')).toMatchObject({ state: 'working' })
   })
 
   it('demotes a seeded teammate phantom missing from a present list to idle', () => {
diff --git a/src/shared/claude-subagent-roster.ts b/src/shared/claude-subagent-roster.ts
index d312721d246..f4fb1bc6429 100644
--- a/src/shared/claude-subagent-roster.ts
+++ b/src/shared/claude-subagent-roster.ts
@@ -42,6 +42,14 @@ export type ClaudeBackgroundAgentTask = {
   teammate: boolean
 }
 
+/** Agent-team lifecycle ids are `a<teammate-name>-<hex>`. The teammate name
+ *  and agent type are independent spawn fields, so the id shape is the only
+ *  reliable discriminator available on SubagentStart/SubagentStop hooks. */
+export function isClaudeTeammateLifecycleId(id: string): boolean {
+  const separator = id.lastIndexOf('-')
+  return separator > 1 && id.startsWith('a') && /^[0-9a-f]+$/i.test(id.slice(separator + 1))
+}
+
 export function upsertWorkingClaudeSubagent(
   roster: ClaudeSubagentRoster,
   id: string,
@@ -51,10 +59,7 @@ export function upsertWorkingClaudeSubagent(
   if (id.length === 0 || id.length > CLAUDE_SUBAGENT_ID_MAX_LENGTH) {
     return
   }
-  // Why: teammate SubagentStart carries agent_type = teammate name and the id
-  // embeds it; one-shot ids are hyphen-free hex so they can never match.
-  const teammate =
-    fields.agentType !== undefined && claudeTeammateIdMatchesName(id, fields.agentType)
+  const teammate = isClaudeTeammateLifecycleId(id)
   const existing = roster.get(id)
   if (existing) {
     existing.state = 'working'
@@ -119,12 +124,14 @@ export function finishClaudeSubagent(roster: ClaudeSubagentRoster, id: string):
 export function readClaudeBackgroundAgentTasks(hookPayload: Record<string, unknown>): {
   present: boolean
   tasks: ClaudeBackgroundAgentTask[]
+  truncated: boolean
 } {
   const raw = hookPayload['background_tasks']
   if (!Array.isArray(raw)) {
-    return { present: false, tasks: [] }
+    return { present: false, tasks: [], truncated: false }
   }
   const tasks: ClaudeBackgroundAgentTask[] = []
+  let truncated = false
   for (const item of raw) {
     if (typeof item !== 'object' || item === null) {
       continue
@@ -136,6 +143,12 @@ export function readClaudeBackgroundAgentTasks(hookPayload: Record<string, unkno
     if (typeof obj.id !== 'string' || obj.id.trim().length === 0) {
       continue
     }
+    if (tasks.length >= AGENT_STATUS_MAX_SUBAGENTS) {
+      // Why: a capped inventory cannot prove a tracked id is absent; callers
+      // must retain unlisted rows rather than deleting live overflow tasks.
+      truncated = true
+      break
+    }
     tasks.push({
       id: obj.id,
       agentType: typeof obj.agent_type === 'string' ? obj.agent_type : undefined,
@@ -143,11 +156,8 @@ export function readClaudeBackgroundAgentTasks(hookPayload: Record<string, unkno
       running: obj.status === 'running',
       teammate: obj.type === 'teammate'
     })
-    if (tasks.length >= AGENT_STATUS_MAX_SUBAGENTS) {
-      break
-    }
   }
-  return { present: true, tasks }
+  return { present: true, tasks, truncated }
 }
 
 /** Fold a lead Stop's `background_tasks` into the lifecycle-tracked roster.
@@ -172,10 +182,13 @@ export function readClaudeBackgroundAgentTasks(hookPayload: Record<string, unkno
 export function foldClaudeBackgroundTasksIntoRoster(
   roster: ClaudeSubagentRoster,
   tasks: ClaudeBackgroundAgentTask[],
-  now: number
+  now: number,
+  options?: { inventoryComplete?: boolean }
 ): void {
   if (tasks.length === 0) {
-    roster.clear()
+    if (options?.inventoryComplete !== false) {
+      roster.clear()
+    }
     return
   }
   const listedIds = new Set<string>()
@@ -206,6 +219,9 @@ export function foldClaudeBackgroundTasksIntoRoster(
       created.backgroundTasksAuthoritative = true
     }
   }
+  if (options?.inventoryComplete === false) {
+    return
+  }
   for (const [id, tracked] of roster) {
     if (listedIds.has(id)) {
       continue
diff --git a/src/shared/claude-subagent-row-lifecycle.test.ts b/src/shared/claude-subagent-row-lifecycle.test.ts
index d4a82e23c0c..b724e3a3b8d 100644
--- a/src/shared/claude-subagent-row-lifecycle.test.ts
+++ b/src/shared/claude-subagent-row-lifecycle.test.ts
@@ -113,7 +113,7 @@ describe('claude subagent sidebar row lifecycle', () => {
     claudeEvent({
       hook_event_name: 'SubagentStart',
       agent_id: 'areviewer-6d3cb5b52120b7bf',
-      agent_type: 'reviewer'
+      agent_type: 'security-reviewer'
     })
     claudeEvent({
       hook_event_name: 'SubagentStart',
@@ -125,7 +125,7 @@ describe('claude subagent sidebar row lifecycle', () => {
     claudeEvent({
       hook_event_name: 'SubagentStop',
       agent_id: 'areviewer-6d3cb5b52120b7bf',
-      agent_type: 'reviewer'
+      agent_type: 'security-reviewer'
     })
     const idled = claudeEvent({
       hook_event_name: 'TeammateIdle',