diff --git a/ui/desktop/frontend/src/components/agents/AgentList.tsx b/ui/desktop/frontend/src/components/agents/AgentList.tsx
index f4698397..08080604 100644
--- a/ui/desktop/frontend/src/components/agents/AgentList.tsx
+++ b/ui/desktop/frontend/src/components/agents/AgentList.tsx
@@ -11,7 +11,7 @@ import type { AgentData, AgentInput } from '../../types/agent'
 
 export function AgentList() {
   const { t } = useTranslation(['agents', 'common'])
-  const { agents, loading, atLimit, createAgent, updateAgent, deleteAgent, resummonAgent, fetchAgents } = useAgentCrud()
+  const { agents, loading, atLimit, createAgent, updateAgent, deleteAgent, resummonAgent, cancelSummonAgent, fetchAgents } = useAgentCrud()
   const setStoreAgents = useAgentStore((s) => s.setAgents)
 
   const [formOpen, setFormOpen] = useState(false)
@@ -140,6 +140,7 @@ export function AgentList() {
           agentId={summoningAgent.id}
           agentName={summoningAgent.name}
           onContinue={handleSummoningComplete}
+          onCancel={cancelSummonAgent}
         />
       )}
     </>
diff --git a/ui/desktop/frontend/src/components/onboarding/AgentStep.tsx b/ui/desktop/frontend/src/components/onboarding/AgentStep.tsx
index 08b74afb..bb11b974 100644
--- a/ui/desktop/frontend/src/components/onboarding/AgentStep.tsx
+++ b/ui/desktop/frontend/src/components/onboarding/AgentStep.tsx
@@ -1,6 +1,7 @@
 import { useState, useMemo, useEffect } from 'react'
 import { useTranslation } from 'react-i18next'
 import { getApiClient } from '../../lib/api'
+import { agentService } from '../../services/agent-service'
 
 import { SummoningModal } from './SummoningModal'
 import type { ProviderData } from '../../types/provider'
@@ -109,6 +110,7 @@ export function AgentStep({ provider, model, onBack, onComplete }: AgentStepProp
         agentId={createdAgent.id}
         agentName={createdAgent.name}
         onContinue={onComplete}
+        onCancel={(id) => agentService.cancelSummon(id)}
       />
     )
   }
diff --git a/ui/desktop/frontend/src/components/onboarding/SummoningModal.tsx b/ui/desktop/frontend/src/components/onboarding/SummoningModal.tsx
index 2f19b430..a0eeb01d 100644
--- a/ui/desktop/frontend/src/components/onboarding/SummoningModal.tsx
+++ b/ui/desktop/frontend/src/components/onboarding/SummoningModal.tsx
@@ -11,14 +11,18 @@ interface SummoningModalProps {
   agentId: string
   agentName: string
   onContinue: () => void
+  onCancel?: (agentId: string) => Promise<void>
 }
 
-export function SummoningModal({ agentId, agentName, onContinue }: SummoningModalProps) {
+const CANCEL_THRESHOLD_SEC = 60
+
+export function SummoningModal({ agentId, agentName, onContinue, onCancel }: SummoningModalProps) {
   const { t } = useTranslation(['desktop', 'common'])
   const [generatedFiles, setGeneratedFiles] = useState<string[]>([])
   const [status, setStatus] = useState<'summoning' | 'completed' | 'failed'>('summoning')
   const [errorMsg, setErrorMsg] = useState('')
   const [retrying, setRetrying] = useState(false)
+  const [cancelling, setCancelling] = useState(false)
   const [elapsed, setElapsed] = useState(0)
   const timerRef = useRef<ReturnType<typeof setInterval> | null>(null)
 
@@ -84,6 +88,19 @@ export function SummoningModal({ agentId, agentName, onContinue }: SummoningModa
     }
   }
 
+  const handleCancel = async () => {
+    if (!onCancel) return
+    setCancelling(true)
+    try {
+      await onCancel(agentId)
+      // BE emits WS type=failed → listener above switches to failed state
+    } catch {
+      // keep modal open
+    } finally {
+      setCancelling(false)
+    }
+  }
+
   return (
     <div className="fixed inset-0 z-[70] flex items-center justify-center bg-black/50 backdrop-blur-sm">
       <div className="bg-surface-secondary border border-border rounded-2xl shadow-xl max-w-md w-full mx-4">
@@ -164,6 +181,19 @@ export function SummoningModal({ agentId, agentName, onContinue }: SummoningModa
             </p>
           )}
 
+          {status === 'summoning' && elapsed >= CANCEL_THRESHOLD_SEC && onCancel && (
+            <div className="flex flex-col items-center gap-1">
+              <p className="text-xs text-text-muted">{t('desktop:summoning.takingTooLong')}</p>
+              <button
+                onClick={handleCancel}
+                disabled={cancelling}
+                className="px-3 py-1.5 text-sm text-text-secondary hover:bg-surface-tertiary rounded-md transition-colors disabled:opacity-50"
+              >
+                {cancelling ? t('desktop:summoning.cancelling') : t('desktop:summoning.cancel')}
+              </button>
+            </div>
+          )}
+
           {status === 'completed' && (
             <button
               onClick={onContinue}
diff --git a/ui/desktop/frontend/src/hooks/use-agent-crud.ts b/ui/desktop/frontend/src/hooks/use-agent-crud.ts
index 05461a24..c629e884 100644
--- a/ui/desktop/frontend/src/hooks/use-agent-crud.ts
+++ b/ui/desktop/frontend/src/hooks/use-agent-crud.ts
@@ -63,7 +63,11 @@ export function useAgentCrud() {
     setAgents((prev) => prev.map((a) => a.id === id ? { ...a, status: 'summoning' } : a))
   }, [])
 
+  const cancelSummonAgent = useCallback(async (id: string) => {
+    await agentService.cancelSummon(id)
+  }, [])
+
   const atLimit = agents.length >= MAX_AGENTS_LITE
 
-  return { agents, loading, atLimit, fetchAgents, createAgent, updateAgent, deleteAgent, resummonAgent }
+  return { agents, loading, atLimit, fetchAgents, createAgent, updateAgent, deleteAgent, resummonAgent, cancelSummonAgent }
 }
diff --git a/ui/desktop/frontend/src/i18n/locales/en/desktop.json b/ui/desktop/frontend/src/i18n/locales/en/desktop.json
index 986bb691..8cef045f 100644
--- a/ui/desktop/frontend/src/i18n/locales/en/desktop.json
+++ b/ui/desktop/frontend/src/i18n/locales/en/desktop.json
@@ -26,7 +26,10 @@
     "fileLabelSOUL": "Core personality",
     "fileLabelIDENTITY": "Identity & knowledge",
     "agentReady": "{{name}} is ready!",
-    "retrying": "Retrying..."
+    "retrying": "Retrying...",
+    "takingTooLong": "Taking too long?",
+    "cancel": "Cancel",
+    "cancelling": "Cancelling..."
   },
   "settings": {
     "title": "Settings",
diff --git a/ui/desktop/frontend/src/i18n/locales/vi/desktop.json b/ui/desktop/frontend/src/i18n/locales/vi/desktop.json
index f93bce38..fcc6322f 100644
--- a/ui/desktop/frontend/src/i18n/locales/vi/desktop.json
+++ b/ui/desktop/frontend/src/i18n/locales/vi/desktop.json
@@ -26,7 +26,10 @@
     "fileLabelSOUL": "Tính cách cốt lõi",
     "fileLabelIDENTITY": "Danh tính & kiến thức",
     "agentReady": "{{name}} đã sẵn sàng!",
-    "retrying": "Đang thử lại..."
+    "retrying": "Đang thử lại...",
+    "takingTooLong": "Mất quá nhiều thời gian?",
+    "cancel": "Huỷ",
+    "cancelling": "Đang huỷ..."
   },
   "settings": {
     "title": "Settings",
diff --git a/ui/desktop/frontend/src/i18n/locales/zh/desktop.json b/ui/desktop/frontend/src/i18n/locales/zh/desktop.json
index 6ff7f706..bafc3678 100644
--- a/ui/desktop/frontend/src/i18n/locales/zh/desktop.json
+++ b/ui/desktop/frontend/src/i18n/locales/zh/desktop.json
@@ -26,7 +26,10 @@
     "fileLabelSOUL": "核心个性",
     "fileLabelIDENTITY": "身份与知识",
     "agentReady": "{{name}} 已就绪！",
-    "retrying": "重试中..."
+    "retrying": "重试中...",
+    "takingTooLong": "耗时过长？",
+    "cancel": "取消",
+    "cancelling": "正在取消..."
   },
   "settings": {
     "title": "Settings",
diff --git a/ui/desktop/frontend/src/services/agent-service.ts b/ui/desktop/frontend/src/services/agent-service.ts
index 7abc2805..a3ba4f3f 100644
--- a/ui/desktop/frontend/src/services/agent-service.ts
+++ b/ui/desktop/frontend/src/services/agent-service.ts
@@ -38,6 +38,10 @@ export const agentService = {
     return getApiClient().post<void>(`/v1/agents/${id}/resummon`, {})
   },
 
+  cancelSummon(id: string): Promise<void> {
+    return getApiClient().post<void>(`/v1/agents/${id}/cancel-summon`, {})
+  },
+
   resummonWs(agentId: string): Promise<unknown> {
     return getWsClient().call('agents.resummon', { agentId })
   },