diff --git a/docs/features/deepseek-harness/technical-design.md b/docs/features/deepseek-harness/technical-design.md
index 811569b0..76972f1c 100644
--- a/docs/features/deepseek-harness/technical-design.md
+++ b/docs/features/deepseek-harness/technical-design.md
@@ -433,6 +433,7 @@ DeepSeek Harness 首版只使用符合下列边界的 GoodBuddy 模型连接：
 - 图片能力只读取所选 GoodBuddy 模型连接的 `supportsImageInput`；Main、Utility 启动配置、ACP 能力和 Pi-AI 模型输入模态必须使用同一个布尔值。
 - API Key 继续保存在 GoodBuddy 加密设置中。
 - 启动环境提供的部署连接只由 Main 自动解析，不在 Renderer 中显示为可选来源。
+- 未显式指定 Harness 模型且没有可用的管理员预置连接时，Main 优先使用当前默认的兼容 GoodBuddy 模型连接；默认连接不兼容时使用首个兼容连接。只有不存在任何兼容连接时才提示用户前往模型或 Runtime 设置。
 
 不允许选择 Harness 自有的用户配置文件或自定义 Host。Runtime 始终使用随当前 GoodBuddy 版本发布的内置 Host，并通过完整内部能力握手。
 
diff --git a/src/main/runtime-settings-store.test.ts b/src/main/runtime-settings-store.test.ts
index 66168355..01360d3d 100644
--- a/src/main/runtime-settings-store.test.ts
+++ b/src/main/runtime-settings-store.test.ts
@@ -408,6 +408,78 @@ describe('RuntimeSettingsStore', () => {
     })
   })
 
+  it('uses a compatible GoodBuddy model for Harness when no platform model is configured', async () => {
+    const profileId = '00000000-0000-4000-8000-000000000044'
+    const { store } = await createStore()
+    await store.update(
+      settings({
+        modelProfiles: [
+          {
+            id: profileId,
+            name: 'OpenAI-compatible gateway',
+            baseUrl: 'https://gateway.example/openai/v1',
+            modelName: 'qwen-plus',
+            protocol: 'openai-chat-completions',
+            authentication: 'api-key',
+            imageGenerationQuality: 'auto',
+            apiKey: { action: 'replace', value: 'deepseek-secret' }
+          }
+        ],
+        defaultModelProfileId: profileId
+      })
+    )
+
+    await expect(store.getPublicSettings()).resolves.toMatchObject({
+      deepseekHarnessModelSource: { kind: 'profile', profileId },
+      configured: {
+        deepseekHarnessModelSource: { kind: 'platform' }
+      }
+    })
+    await expect(store.getResolvedSettings()).resolves.toMatchObject({
+      deepseekHarnessModelProfile: {
+        id: profileId,
+        apiKey: 'deepseek-secret'
+      }
+    })
+  })
+
+  it('uses the first compatible Harness model when the default model is incompatible', async () => {
+    const defaultId = '00000000-0000-4000-8000-000000000043'
+    const harnessId = '00000000-0000-4000-8000-000000000044'
+    const { store } = await createStore()
+    await store.update(
+      settings({
+        modelProfiles: [
+          {
+            id: defaultId,
+            name: 'Anthropic model',
+            baseUrl: 'https://anthropic.example',
+            modelName: 'claude',
+            protocol: 'anthropic-messages',
+            authentication: 'api-key',
+            imageGenerationQuality: 'auto',
+            apiKey: { action: 'replace', value: 'anthropic-secret' }
+          },
+          {
+            id: harnessId,
+            name: 'OpenAI-compatible gateway',
+            baseUrl: 'https://gateway.example/openai/v1',
+            modelName: 'qwen-plus',
+            protocol: 'openai-chat-completions',
+            authentication: 'api-key',
+            imageGenerationQuality: 'auto',
+            apiKey: { action: 'replace', value: 'deepseek-secret' }
+          }
+        ],
+        defaultModelProfileId: defaultId
+      })
+    )
+
+    await expect(store.getResolvedSettings()).resolves.toMatchObject({
+      deepseekHarnessModelProfile: { id: harnessId }
+    })
+  })
+
   it('migrates DeepSeek Harness to controlled platform mode and stores a compatible profile', async () => {
     const { filePath, store } = await createStore()
     await store.update(settings())
diff --git a/src/main/runtime-settings-store.ts b/src/main/runtime-settings-store.ts
index bae77a36..187e525c 100644
--- a/src/main/runtime-settings-store.ts
+++ b/src/main/runtime-settings-store.ts
@@ -1423,6 +1423,30 @@ export class RuntimeSettingsStore {
     }
   }
 
+  private resolveDeepSeekHarnessModelProfile(
+    settings: StoredSettings,
+    modelProfiles: readonly ResolvedModelProfile[]
+  ): ResolvedModelProfile | undefined {
+    const source = settings.deepseekHarnessModelSource
+    if (source.kind === 'profile') {
+      return modelProfiles.find(
+        (profile) => profile.id === source.profileId
+      )
+    }
+    const platformProfile = this.resolvePlatformHarnessProfile()
+    if (platformProfile) {
+      return platformProfile
+    }
+    return (
+      modelProfiles.find(
+        (profile) =>
+          profile.id === settings.defaultModelProfileId &&
+          isDeepSeekHarnessModelProfile(profile)
+      ) ??
+      modelProfiles.find(isDeepSeekHarnessModelProfile)
+    )
+  }
+
   private resolveModelCredentials(
     settings: StoredSettings
   ): Map<string, ResolvedModelCredential> {
@@ -1692,6 +1716,20 @@ export class RuntimeSettingsStore {
         credentialSource: credential.source
       }
     })
+    const deepseekHarnessModelProfile =
+      this.resolveDeepSeekHarnessModelProfile(
+        settings,
+        resolvedModelProfiles
+      )
+    const deepseekHarnessModelSource =
+      settings.deepseekHarnessModelSource.kind === 'platform' &&
+      deepseekHarnessModelProfile &&
+      resolvedProfilesById.has(deepseekHarnessModelProfile.id)
+        ? {
+            kind: 'profile' as const,
+            profileId: deepseekHarnessModelProfile.id
+          }
+        : settings.deepseekHarnessModelSource
     const embeddingEnvironmentApiKey =
       this.environment.GOODBUDDY_EMBEDDING_API_KEY?.trim()
     const embeddingStoredApiKey = embeddingEnvironmentApiKey
@@ -1797,8 +1835,7 @@ export class RuntimeSettingsStore {
         ? { kind: 'platform' }
         : settings.opencodeModelSource,
       continueModelSource: settings.continueModelSource,
-      deepseekHarnessModelSource:
-        settings.deepseekHarnessModelSource,
+      deepseekHarnessModelSource,
       secureStorageAvailable: this.cipher.isAvailable(),
       toolApproval: settings.toolApproval,
       configured: {
@@ -1892,11 +1929,7 @@ export class RuntimeSettingsStore {
         ? profilesById.get(settings.continueModelSource.profileId)
         : undefined
     const deepseekHarnessModelProfile =
-      settings.deepseekHarnessModelSource.kind === 'profile'
-        ? profilesById.get(
-            settings.deepseekHarnessModelSource.profileId
-          )
-        : this.resolvePlatformHarnessProfile()
+      this.resolveDeepSeekHarnessModelProfile(settings, modelProfiles)
     const embeddingConnections =
       this.resolveEmbeddingConnections(settings)
     const activeEmbeddingConnection =
diff --git a/src/renderer/src/SettingsPanel.test.tsx b/src/renderer/src/SettingsPanel.test.tsx
index 9c8b449d..e9675bcf 100644
--- a/src/renderer/src/SettingsPanel.test.tsx
+++ b/src/renderer/src/SettingsPanel.test.tsx
@@ -3057,7 +3057,9 @@ describe('SettingsPanel runtime files', () => {
     )
     expect(screen.queryByRole('radio')).not.toBeInTheDocument()
     expect(
-      screen.getByText('管理员预置的 OpenAI 兼容连接')
+      screen.getByText(
+        '自动选择：优先使用管理员预置连接，否则跟随当前兼容模型'
+      )
     ).toBeInTheDocument()
     const source = screen.getByLabelText(
       'DeepSeek Harness OpenAI 兼容模型连接'
diff --git a/src/renderer/src/i18n/locales/en-US/settings.ts b/src/renderer/src/i18n/locales/en-US/settings.ts
index e547e1d6..50774999 100644
--- a/src/renderer/src/i18n/locales/en-US/settings.ts
+++ b/src/renderer/src/i18n/locales/en-US/settings.ts
@@ -395,12 +395,12 @@ export const settings = {
       description:
         'GoodBuddy maintains the fixed Host and control protocol internally and uses pinned Harness libraries underneath. Ask can call native read/skill plus enabled Web Search/Fetch, while Execute can use every enabled tool and DSH plugin capability. Cancellation and workspace boundaries remain in place.',
       managedSource:
-        'Administrator-provided OpenAI-compatible connection',
+        'Automatic: prefer the administrator connection, otherwise follow a compatible current model',
       connection: 'OpenAI-compatible model connection',
       connectionPlaceholder:
-        'Select an OpenAI-compatible model connection',
+        'Automatically select a compatible model connection',
       connectionDescription:
-        'Choose a GoodBuddy model connection. It must use OpenAI Chat Completions with API-key authentication.',
+        'Optionally select a GoodBuddy model connection. Otherwise GoodBuddy uses the administrator connection, the compatible current default, or the first compatible connection. It must use OpenAI Chat Completions with API-key authentication.',
       advancedDescription:
         'This Runtime always uses GoodBuddy’s bundled, version-pinned Host and does not load user profiles or custom Hosts. GoodBuddy manages enabled marketplace plugins and loads them with the Host.',
       marketplace: {
diff --git a/src/renderer/src/i18n/locales/zh-CN/settings.ts b/src/renderer/src/i18n/locales/zh-CN/settings.ts
index d9c896ee..10d69a36 100644
--- a/src/renderer/src/i18n/locales/zh-CN/settings.ts
+++ b/src/renderer/src/i18n/locales/zh-CN/settings.ts
@@ -362,11 +362,12 @@ export const settings = {
       previewDescription: '开发者预览 · OpenAI 兼容',
       description:
         '由 GoodBuddy 内部维护固定 Host 与控制协议，复用锁定的 Harness 底层库；Ask 可调用 Harness 原生 read/skill 与已启用的网页搜索/抓取，Execute 可调用全部已启用工具及 DSH 插件能力，并保留取消和工作区边界。',
-      managedSource: '管理员预置的 OpenAI 兼容连接',
+      managedSource:
+        '自动选择：优先使用管理员预置连接，否则跟随当前兼容模型',
       connection: 'OpenAI 兼容模型连接',
-      connectionPlaceholder: '选择 OpenAI 兼容模型连接',
+      connectionPlaceholder: '自动选择兼容模型连接',
       connectionDescription:
-        '从 GoodBuddy 模型连接中选择；协议必须为 OpenAI Chat Completions，并使用 API Key。',
+        '可从 GoodBuddy 模型连接中显式指定；未指定时自动使用管理员预置连接、当前默认兼容连接或首个兼容连接。协议必须为 OpenAI Chat Completions，并使用 API Key。',
       advancedDescription:
         '该 Runtime 始终使用 GoodBuddy 内置并固定版本的 Host，不加载用户 profile 或自定义 Host；已启用的市场插件由 GoodBuddy 托管并随 Host 启动。',
       marketplace: {