diff --git a/frontend/src/contracts/index.ts b/frontend/src/contracts/index.ts
index cf1a1be..2a3d973 100644
--- a/frontend/src/contracts/index.ts
+++ b/frontend/src/contracts/index.ts
@@ -295,6 +295,7 @@ export interface ProviderPreset {
   name: string
   provider_type: ProviderType
   base_url: string
+  default_credential_id?: string | null
   requires_credential: boolean
 }
 
@@ -523,6 +524,7 @@ export interface ApiProviderPreset {
   name: string
   provider_type: ApiProviderType
   base_url: string
+  default_credential_id?: string | null
   requires_credential: boolean
 }
 
diff --git a/frontend/src/features/settings/SettingsView.vue b/frontend/src/features/settings/SettingsView.vue
index 62503f8..cf81403 100644
--- a/frontend/src/features/settings/SettingsView.vue
+++ b/frontend/src/features/settings/SettingsView.vue
@@ -35,7 +35,9 @@ function presetIdFor(provider?: ProviderConfig) {
 
 function openProvider(provider?: ProviderConfig) {
   editingProviderId.value = provider?.provider_id ?? null
-  Object.assign(providerForm, { preset_id: presetIdFor(provider), provider_type: provider?.provider_type ?? 'openai_compatible', name: provider?.name ?? '', base_url: provider?.base_url ?? '', default_model: provider?.default_model ?? '', credential_id: provider?.credential_id ?? '', enabled: provider?.enabled ?? true })
+  const presetId = presetIdFor(provider)
+  const preset = providerStore.presets.find((item) => item.preset_id === presetId)
+  Object.assign(providerForm, { preset_id: presetId, provider_type: provider?.provider_type ?? 'openai_compatible', name: provider?.name ?? '', base_url: provider?.base_url ?? '', default_model: provider?.default_model ?? '', credential_id: provider?.credential_id ?? preset?.default_credential_id ?? '', enabled: provider?.enabled ?? true })
   showProviderForm.value = true
   if (provider) void providerStore.loadModels(provider.provider_id).catch(() => undefined)
 }
@@ -47,6 +49,7 @@ function applyProviderPreset() {
     provider_type: preset.provider_type,
     name: preset.name,
     base_url: preset.base_url,
+    credential_id: preset.default_credential_id ?? '',
   })
 }
 
@@ -141,7 +144,7 @@ async function chooseDefaultModel(provider: ProviderConfig, event: Event) {
             <input v-model="providerForm.default_model" class="input" :list="editingProviderId ? 'provider-model-options' : undefined" placeholder="保存后自动获取，也可以手动输入" />
             <datalist id="provider-model-options"><option v-for="model in formModels" :key="model.model_id" :value="model.model_id">{{ model.name }}</option></datalist>
           </div>
-          <div class="field"><label>Credential ID</label><input v-model="providerForm.credential_id" class="input" placeholder="由桌面 Host 注入的凭据标识" /><small class="subtle">此处不输入或回显 API Key，密钥明文由 Stronghold 保存。</small></div>
+          <div class="field"><label>Credential ID</label><input v-model="providerForm.credential_id" class="input" placeholder="例如 deepseek" /><small class="subtle">这里填写凭据标识，不是 API Key。DeepSeek 开发环境默认读取 DEEPSEEK_API_KEY，密钥明文不会保存到 Provider。</small></div>
           <label class="inline-actions"><input v-model="providerForm.enabled" type="checkbox" /> 启用</label>
           <div class="inline-actions"><button class="button-primary">保存并获取模型</button><button type="button" class="button-secondary" @click="showProviderForm = false">取消</button></div>
         </form>
diff --git a/frontend/src/stores/provider.spec.ts b/frontend/src/stores/provider.spec.ts
index 95cb3ad..a2798d5 100644
--- a/frontend/src/stores/provider.spec.ts
+++ b/frontend/src/stores/provider.spec.ts
@@ -17,6 +17,7 @@ vi.mock('@/services/providerService', () => ({
 
 import { useProviderStore } from './provider'
 import { listModels, listProviderPresets, listProviders } from '@/services/providerService'
+import { ApiErrorClass } from '@/services/apiClient'
 
 const providers: ProviderConfig[] = [
   {
@@ -27,6 +28,7 @@ const providers: ProviderConfig[] = [
     default_model: '',
     enabled: true,
     capabilities: { chat: true },
+    credential_id: 'deepseek',
     has_credential: true,
   },
 ]
@@ -37,6 +39,7 @@ const presets: ProviderPreset[] = [
     name: 'DeepSeek',
     provider_type: 'openai_compatible',
     base_url: 'https://api.deepseek.com',
+    default_credential_id: 'deepseek',
     requires_credential: true,
   },
 ]
@@ -76,4 +79,16 @@ describe('provider store model discovery', () => {
     expect(store.modelLoadingByProvider.openai).toBe(false)
     expect(store.modelErrorsByProvider.openai).toBe('认证失败')
   })
+
+  it('explains how to inject a missing DeepSeek credential', async () => {
+    vi.mocked(listModels).mockRejectedValue(
+      new ApiErrorClass('PROVIDER_CREDENTIAL_MISSING', 'Credential is unavailable')
+    )
+    const store = useProviderStore()
+    await store.loadProviders()
+
+    await expect(store.loadModels('openai')).rejects.toThrow('Credential is unavailable')
+
+    expect(store.modelErrorsByProvider.openai).toContain('DEEPSEEK_API_KEY')
+  })
 })
diff --git a/frontend/src/stores/provider.ts b/frontend/src/stores/provider.ts
index 999920c..ca12557 100644
--- a/frontend/src/stores/provider.ts
+++ b/frontend/src/stores/provider.ts
@@ -2,6 +2,7 @@ import { defineStore } from 'pinia'
 import { ref, computed } from 'vue'
 import type { ProviderConfig, ModelInfo, ProviderPreset } from '@/contracts'
 import { createProvider, deleteProvider as deleteProviderRequest, listModels, listProviderPresets, listProviders, mockProviders, mockModels, testProvider as testProviderRequest, updateProvider as updateProviderRequest } from '@/services/providerService'
+import { ApiErrorClass } from '@/services/apiClient'
 
 export const useProviderStore = defineStore('provider', () => {
   const providers = ref<ProviderConfig[]>(mockProviders)
@@ -48,7 +49,17 @@ export const useProviderStore = defineStore('provider', () => {
       modelsByProvider.value[providerId] = uniqueModels
       return uniqueModels
     } catch (reason) {
-      const message = reason instanceof Error ? reason.message : '模型列表获取失败'
+      const provider = providers.value.find((item) => item.provider_id === providerId)
+      const credentialId = provider?.credential_id
+      let message = reason instanceof Error ? reason.message : '模型列表获取失败'
+      if (reason instanceof ApiErrorClass && reason.code === 'PROVIDER_CREDENTIAL_MISSING') {
+        const environmentName = credentialId === 'deepseek'
+          ? 'DEEPSEEK_API_KEY'
+          : `AINOTE_CREDENTIAL_${credentialId?.replace(/[^A-Za-z0-9]/g, '_').toUpperCase() || '<ID>'}`
+        message = `未找到凭据“${credentialId || '未设置'}”，请在启动 AI Core 前设置 ${environmentName}。`
+      } else if (reason instanceof ApiErrorClass && reason.code === 'PROVIDER_AUTH_FAILED') {
+        message = `鉴权失败，请检查凭据“${credentialId || '未设置'}”对应的 API Key 是否有效。`
+      }
       modelErrorsByProvider.value[providerId] = message
       throw reason
     } finally {