diff --git a/packages/stage-pages/src/pages/settings/providers/chat/[providerId].vue b/packages/stage-pages/src/pages/settings/providers/chat/[providerId].vue
index 271b3478b..705f6d20c 100644
--- a/packages/stage-pages/src/pages/settings/providers/chat/[providerId].vue
+++ b/packages/stage-pages/src/pages/settings/providers/chat/[providerId].vue
@@ -14,6 +14,7 @@ import { useProviderValidation } from '@proj-airi/stage-ui/composables/use-provi
 import { getDefinedProvider } from '@proj-airi/stage-ui/libs'
 import { useConsciousnessStore } from '@proj-airi/stage-ui/stores/modules/consciousness'
 import { useProviderConfigStore } from '@proj-airi/stage-ui/stores/providers/config'
+import { useProviderStore } from '@proj-airi/stage-ui/stores/providers/provider'
 import { FieldCombobox } from '@proj-airi/ui'
 import { storeToRefs } from 'pinia'
 import { computed } from 'vue'
@@ -21,10 +22,12 @@ import { useRoute } from 'vue-router'
 
 const route = useRoute()
 const providerId = route.params.providerId as string
-const providerStore = useProviderConfigStore()
+const providerConfigStore = useProviderConfigStore()
+const providersStore = useProviderStore()
 const consciousnessStore = useConsciousnessStore()
-const { configs: providers } = storeToRefs(providerStore) as { configs: RemovableRef<Record<string, any>> }
+const { configs: providers } = storeToRefs(providerConfigStore) as { configs: RemovableRef<Record<string, any>> }
 const { activeProvider } = storeToRefs(consciousnessStore)
+const providerDefinition = computed(() => providersStore.findProviderDefinition(providerId))
 
 // Define computed properties for credentials
 const apiKey = computed({
@@ -54,7 +57,7 @@ const thinkingMode = computed({
   },
 })
 
-const supportsDeepSeekThinkingMode = computed(() => providerId === 'deepseek')
+const supportsDeepSeekThinkingMode = computed(() => providerDefinition.value?.id === 'deepseek')
 
 // Use the composable to get validation logic and state
 const {
@@ -74,7 +77,7 @@ const {
 } = useProviderValidation(providerId)
 
 const apiKeyPlaceholder = computed(() => {
-  const definition = getDefinedProvider(providerId)
+  const definition = providerDefinition.value ?? getDefinedProvider(providerId)
   if (!definition?.createProviderConfig)
     return 'sk-...'
 
diff --git a/packages/stage-ui/src/stores/providers/config-defaults.test.ts b/packages/stage-ui/src/stores/providers/config-defaults.test.ts
new file mode 100644
index 000000000..0a7d9d9fd
--- /dev/null
+++ b/packages/stage-ui/src/stores/providers/config-defaults.test.ts
@@ -0,0 +1,25 @@
+import { describe, expect, it } from 'vitest'
+
+import { normalizeProviderConfigDefaults } from './config-defaults'
+
+describe('normalizeProviderConfigDefaults', () => {
+  it('treats omitted schema defaults as unchanged provider config', () => {
+    expect(normalizeProviderConfigDefaults(
+      { baseUrl: 'https://api.deepseek.com/' },
+      { baseUrl: 'https://api.deepseek.com/', thinkingMode: 'auto' },
+    )).toEqual({
+      baseUrl: 'https://api.deepseek.com/',
+      thinkingMode: 'auto',
+    })
+  })
+
+  it('keeps explicit non-default values dirty', () => {
+    expect(normalizeProviderConfigDefaults(
+      { baseUrl: 'https://api.deepseek.com/', thinkingMode: 'disable' },
+      { baseUrl: 'https://api.deepseek.com/', thinkingMode: 'auto' },
+    )).toEqual({
+      baseUrl: 'https://api.deepseek.com/',
+      thinkingMode: 'disable',
+    })
+  })
+})
diff --git a/packages/stage-ui/src/stores/providers/config-defaults.ts b/packages/stage-ui/src/stores/providers/config-defaults.ts
new file mode 100644
index 000000000..04a21f9de
--- /dev/null
+++ b/packages/stage-ui/src/stores/providers/config-defaults.ts
@@ -0,0 +1,9 @@
+export function normalizeProviderConfigDefaults(config: Record<string, unknown>, defaultOptions: Record<string, unknown>) {
+  const keys = [...new Set([...Object.keys(defaultOptions), ...Object.keys(config)])]
+  return Object.fromEntries(keys.map((key) => {
+    if (Object.hasOwn(config, key))
+      return [key, config[key]]
+
+    return [key, defaultOptions[key]]
+  }))
+}
diff --git a/packages/stage-ui/src/stores/providers/provider.ts b/packages/stage-ui/src/stores/providers/provider.ts
index 3284f4309..778b7bc71 100644
--- a/packages/stage-ui/src/stores/providers/provider.ts
+++ b/packages/stage-ui/src/stores/providers/provider.ts
@@ -32,6 +32,7 @@ import {
 } from '../../libs/providers'
 import { selectProviderMetadata, selectProvidersMetadata } from '../../libs/providers/metadata'
 import { useProviderConfigStore } from './config'
+import { normalizeProviderConfigDefaults } from './config-defaults'
 
 export type { ModelInfo, VoiceInfo } from '../../libs/providers/types'
 
@@ -836,7 +837,7 @@ export const useProviderStore = defineStore('provider', () => {
       return false
 
     const defaultOptions = getDefaultProviderConfig(providerId)
-    return JSON.stringify(config) !== JSON.stringify(defaultOptions)
+    return JSON.stringify(normalizeProviderConfigDefaults(config, defaultOptions)) !== JSON.stringify(defaultOptions)
   }
 
   function shouldListProvider(providerId: string) {