diff --git a/ui/desktop/src/components/settings/providers/modal/ProviderConfiguationModal.tsx b/ui/desktop/src/components/settings/providers/modal/ProviderConfiguationModal.tsx
index 688d86cfc767..1244bac42053 100644
--- a/ui/desktop/src/components/settings/providers/modal/ProviderConfiguationModal.tsx
+++ b/ui/desktop/src/components/settings/providers/modal/ProviderConfiguationModal.tsx
@@ -104,9 +104,20 @@ export default function ProviderConfigurationModal({
     }
 
     const toSubmit = Object.fromEntries(
-      Object.entries(configValues)
-        .filter(([_k, entry]) => !!entry.value)
-        .map(([k, entry]) => [k, entry.value || ''])
+      parameters
+        .map((parameter) => {
+          const entry = configValues[parameter.name];
+          if (entry?.value) {
+            return [parameter.name, entry.value] as const;
+          }
+
+          if (!parameter.secret && typeof entry?.serverValue === 'string' && entry.serverValue) {
+            return [parameter.name, entry.serverValue] as const;
+          }
+
+          return null;
+        })
+        .filter((item): item is readonly [string, string] => item !== null)
     );
 
     try {
diff --git a/ui/desktop/src/components/settings/providers/modal/subcomponents/handlers/DefaultSubmitHandler.test.ts b/ui/desktop/src/components/settings/providers/modal/subcomponents/handlers/DefaultSubmitHandler.test.ts
new file mode 100644
index 000000000000..aa190e697934
--- /dev/null
+++ b/ui/desktop/src/components/settings/providers/modal/subcomponents/handlers/DefaultSubmitHandler.test.ts
@@ -0,0 +1,61 @@
+import { beforeEach, describe, expect, it, vi } from 'vitest';
+
+import { providerConfigSubmitHandler } from './DefaultSubmitHandler';
+import { getProviderModels, readConfig } from '../../../../../../api';
+
+vi.mock('../../../../../../api', () => ({
+  getProviderModels: vi.fn(),
+  readConfig: vi.fn(),
+}));
+
+describe('providerConfigSubmitHandler', () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+  });
+
+  it('keeps existing OPENAI_HOST when saving only another field', async () => {
+    const upsertFn = vi.fn().mockResolvedValue(undefined);
+    vi.mocked(getProviderModels).mockResolvedValue({} as never);
+
+    vi.mocked(readConfig).mockImplementation(async ({ body }) => {
+      if (body.key === 'OPENAI_HOST') {
+        return { data: 'https://proxy.example.com/v1' } as never;
+      }
+      if (body.key === 'OPENAI_BASE_PATH') {
+        return { data: 'v1/chat/completions' } as never;
+      }
+      return { data: null } as never;
+    });
+
+    await providerConfigSubmitHandler(
+      upsertFn,
+      {
+        name: 'openai',
+        metadata: {
+          config_keys: [
+            { name: 'OPENAI_API_KEY', required: false, secret: true },
+            {
+              name: 'OPENAI_HOST',
+              required: true,
+              secret: false,
+              default: 'https://api.openai.com',
+            },
+            {
+              name: 'OPENAI_BASE_PATH',
+              required: true,
+              secret: false,
+              default: 'v1/chat/completions',
+            },
+          ],
+        },
+      },
+      {
+        OPENAI_API_KEY: 'new-key',
+      }
+    );
+
+    expect(upsertFn).toHaveBeenCalledWith('OPENAI_API_KEY', 'new-key', true);
+    expect(upsertFn).toHaveBeenCalledWith('OPENAI_HOST', 'https://proxy.example.com/v1', false);
+    expect(upsertFn).not.toHaveBeenCalledWith('OPENAI_HOST', 'https://api.openai.com', false);
+  });
+});
diff --git a/ui/desktop/src/components/settings/providers/modal/subcomponents/handlers/DefaultSubmitHandler.tsx b/ui/desktop/src/components/settings/providers/modal/subcomponents/handlers/DefaultSubmitHandler.tsx
index 26a853f6031f..610f9fd2477b 100644
--- a/ui/desktop/src/components/settings/providers/modal/subcomponents/handlers/DefaultSubmitHandler.tsx
+++ b/ui/desktop/src/components/settings/providers/modal/subcomponents/handlers/DefaultSubmitHandler.tsx
@@ -80,7 +80,9 @@ export const providerConfigSubmitHandler = async (
       const value =
         configValues[parameter.name] !== undefined
           ? configValues[parameter.name]
-          : parameter.default;
+          : previousConfigValues[parameter.name]?.value !== undefined
+            ? previousConfigValues[parameter.name].value
+            : parameter.default;
 
       if (value === undefined || value === null) {
         return;