diff --git a/apps/desktop/src/renderer/locales/settings-provider-copy.ts b/apps/desktop/src/renderer/locales/settings-provider-copy.ts
index e5e6ff39e3..1aa4b06e6b 100644
--- a/apps/desktop/src/renderer/locales/settings-provider-copy.ts
+++ b/apps/desktop/src/renderer/locales/settings-provider-copy.ts
@@ -79,7 +79,7 @@ const zhCopy = {
     tabs: { recommended: '推荐', accounts: '账号', plans: '模型计划', api: 'API', aggregators: '聚合服务', local: '本地' },
     loadFailed: '载入模型连接失败', loadingAria: '正在加载模型供应商', connections: '模型连接',
     retry: '点击重试。', empty: '还没有模型连接',
-    emptyHelp: '从下方选择一种连接方式开始。', default: '默认', addHelp: '选择账号登录、模型计划、API、聚合服务或本地运行时。',
+    emptyHelp: '从下方选择一种连接方式开始。', default: '默认', setDefault: '设为默认', setDefaultTitle: '让新对话默认使用这个连接', setDefaultPending: '设置中…', setDefaultFailed: '设为默认失败', addHelp: '选择账号登录、模型计划、API、聚合服务或本地运行时。',
     categoriesAria: '模型供应商分类', searchPlaceholder: '搜索服务商', searchAria: '搜索模型服务商', noMatch: '没有匹配的服务商',
     createSubtitle: '完成必要配置后，连接会出现在模型页上方。', connection: '模型连接',
     count: (value: number) => `· ${value}`, connectTitle: (name: string) => `连接 ${name}`,
@@ -220,7 +220,7 @@ const enCopy: ProviderSettingsCopy = {
     tabs: { recommended: 'Recommended', accounts: 'Accounts', plans: 'Model plans', api: 'API', aggregators: 'Aggregators', local: 'Local' },
     loadFailed: 'Failed to load model connections', loadingAria: 'Loading model providers', connections: 'Connections',
     retry: 'Select to retry.', empty: 'No model connections yet',
-    emptyHelp: 'Choose a connection method below to begin.', default: 'Default', addHelp: 'Choose account sign-in, a model plan, API, aggregator, or local runtime.',
+    emptyHelp: 'Choose a connection method below to begin.', default: 'Default', setDefault: 'Set as default', setDefaultTitle: 'New chats will use this connection', setDefaultPending: 'Setting…', setDefaultFailed: 'Could not set as default', addHelp: 'Choose account sign-in, a model plan, API, aggregator, or local runtime.',
     categoriesAria: 'Model provider categories', searchPlaceholder: 'Search providers', searchAria: 'Search model providers', noMatch: 'No matching providers',
     createSubtitle: 'After required setup, the connection appears above on the Models page.', connection: 'Model connection',
     count: (value: number) => `· ${value}`, connectTitle: (name: string) => `Connect ${name}`,
diff --git a/apps/desktop/src/renderer/settings/ProvidersPanel.tsx b/apps/desktop/src/renderer/settings/ProvidersPanel.tsx
index 7364ca5e14..87c6815a6e 100644
--- a/apps/desktop/src/renderer/settings/ProvidersPanel.tsx
+++ b/apps/desktop/src/renderer/settings/ProvidersPanel.tsx
@@ -19,6 +19,7 @@ import {
   type ProviderType,
 } from '@maka/core';
 import { useMountedRef, useUiLocale, useToast , dotForStatus } from '@maka/ui';
+import { settingsActionErrorMessage } from './settings-error-copy';
 import { connectionChipStatus } from './provider-connection-status';
 import {
   CATALOG_INITIAL_FILTER,
@@ -249,7 +250,43 @@ export function ProvidersPanel({ bridge, initialPage = 'connections', initialCon
             logo={<ProviderLogo type={selected.providerType} compact />}
             titleId={detailTitleId}
             title={selected.name}
-            badge={selected.slug === defaultSlug ? <Badge variant="neutral" label={copy.default} /> : null}
+            /* The control sits in the slot that shows the state. Setting the
+               default connection was reachable only from the command palette,
+               while this page displayed a 默认 Badge and offered no way to
+               change it — so a user who came here to change it (the obvious
+               place, since it is where the answer is shown) found a read-only
+               label and gave up. Whichever of the two a connection is, this
+               slot now tells the truth AND is the way to change it.
+
+               `secondary`, not ghost: this button sits alone beside a title,
+               where a ghost's bare text reads as a subtitle rather than
+               something you can press — which would recreate the very problem
+               it exists to solve. 测试连接 below is secondary sm, and that is
+               this page's dialect for "quiet but unmistakably a control".
+
+               `clickAction` rather than onClick: it opens no confirm, so there
+               is no state-driven UI to await inside the transition, and the
+               button gets its own pending affordance for free. */
+            badge={selected.slug === defaultSlug
+              ? <Badge variant="neutral" label={copy.default} />
+              : (
+                <Button
+                  variant="secondary"
+                  size="sm"
+                  label={copy.setDefault}
+                  tooltip={copy.setDefaultTitle}
+                  clickAction={async () => {
+                    try {
+                      await window.maka.connections.setDefault(selected.slug);
+                      await reload();
+                    } catch (error) {
+                      // The state is unchanged on failure, so the Badge stays
+                      // where it was and the button remains the way to retry.
+                      toast.error(copy.setDefaultFailed, settingsActionErrorMessage(error, locale));
+                    }
+                  }}
+                />
+              )}
             subtitle={connectionSubtitle(selected, locale)}
           />
           <ConnectionDetail