Fix shared context backup runtime config

Author: IM.codes

shared/shared-context-runtime-config.ts

@@ -90,20 +90,20 @@ export function normalizeSharedContextRuntimeConfig(
     ? rawPrimaryContextModel
     : getDefaultSharedContextModelForBackend(normalizedPrimaryBackend);
   const normalizedBackupBackendCandidate = normalizeSharedContextRuntimeBackend(input?.backupContextBackend)
-    ?? inferSharedContextRuntimeBackend(input?.backupContextModel)
-    ?? normalizedPrimaryBackend;
+    ?? inferSharedContextRuntimeBackend(input?.backupContextModel);
   const rawBackupContextModel = trimModelValue(input?.backupContextModel);
-  const backupContextModel = rawBackupContextModel
-    ? (isKnownSharedContextModelForBackend(normalizedBackupBackendCandidate, rawBackupContextModel)
-      ? rawBackupContextModel
-      : getDefaultSharedContextModelForBackend(normalizedBackupBackendCandidate))
+  const backupContextBackend = normalizedBackupBackendCandidate;
+  const backupContextModel = backupContextBackend
+    ? (rawBackupContextModel
+      ? (isKnownSharedContextModelForBackend(backupContextBackend, rawBackupContextModel)
+        ? rawBackupContextModel
+        : getDefaultSharedContextModelForBackend(backupContextBackend))
+      : getDefaultSharedContextModelForBackend(backupContextBackend))
     : undefined;
   return {
     primaryContextBackend: normalizedPrimaryBackend,
     primaryContextModel,
-    backupContextBackend: backupContextModel
-      ? normalizedBackupBackendCandidate
-      : undefined,
+    backupContextBackend,
     backupContextModel,
   };
 }

src/daemon/command-handler.ts

@@ -60,6 +60,7 @@ import {
 } from '../../shared/effort-levels.js';
 import { getSavedP2pConfig, upsertSavedP2pConfig } from '../store/p2p-config-store.js';
 import {
+  normalizeSharedContextRuntimeConfig,
   normalizeSharedContextRuntimeBackend,
   SHARED_CONTEXT_RUNTIME_CONFIG_MSG,
 } from '../../shared/shared-context-runtime-config.js';
@@ -3842,23 +3843,20 @@ async function handleCcPresetsSave(cmd: Record<string, unknown>, serverLink: Ser
 
 async function handleSharedContextRuntimeConfigApply(cmd: Record<string, unknown>): Promise<void> {
   const config = cmd.config as Record<string, unknown> | undefined;
-  const primaryContextBackend = normalizeSharedContextRuntimeBackend(
-    typeof config?.primaryContextBackend === 'string' ? config.primaryContextBackend : undefined,
-  );
-  const primaryContextModel = typeof config?.primaryContextModel === 'string' ? config.primaryContextModel.trim() : '';
-  const backupContextBackend = normalizeSharedContextRuntimeBackend(
-    typeof config?.backupContextBackend === 'string' ? config.backupContextBackend : undefined,
-  );
-  const backupContextModel = typeof config?.backupContextModel === 'string' ? config.backupContextModel.trim() : '';
-  if (!primaryContextBackend || !primaryContextModel) {
+  const normalized = normalizeSharedContextRuntimeConfig({
+    primaryContextBackend: normalizeSharedContextRuntimeBackend(
+      typeof config?.primaryContextBackend === 'string' ? config.primaryContextBackend : undefined,
+    ),
+    primaryContextModel: typeof config?.primaryContextModel === 'string' ? config.primaryContextModel : undefined,
+    backupContextBackend: normalizeSharedContextRuntimeBackend(
+      typeof config?.backupContextBackend === 'string' ? config.backupContextBackend : undefined,
+    ),
+    backupContextModel: typeof config?.backupContextModel === 'string' ? config.backupContextModel : undefined,
+  });
+  if (!normalized.primaryContextBackend || !normalized.primaryContextModel) {
     logger.warn({ cmd }, 'invalid shared-context runtime config apply command');
     return;
   }
   const { setContextModelRuntimeConfig } = await import('../context/context-model-config.js');
-  setContextModelRuntimeConfig({
-    primaryContextBackend,
-    primaryContextModel,
-    backupContextBackend: backupContextModel ? (backupContextBackend ?? primaryContextBackend) : undefined,
-    backupContextModel: backupContextModel || undefined,
-  });
+  setContextModelRuntimeConfig(normalized);
 }

test/daemon/context-model-config.test.ts

@@ -31,4 +31,18 @@ describe('context-model-config', () => {
     expect(getContextModelConfig().primaryContextModel).toBe('gpt-5.4-mini');
     expect(getContextModelConfig().primaryContextBackend).toBe('codex-sdk');
   });
+
+  it('fills the backup model from the selected backup backend when runtime config omits it', () => {
+    setContextModelRuntimeConfig({
+      primaryContextBackend: 'claude-code-sdk',
+      primaryContextModel: 'sonnet',
+      backupContextBackend: 'qwen',
+    });
+    expect(getContextModelConfig()).toEqual({
+      primaryContextBackend: 'claude-code-sdk',
+      primaryContextModel: 'sonnet',
+      backupContextBackend: 'qwen',
+      backupContextModel: 'qwen3-coder-plus',
+    });
+  });
 });

test/shared-context-runtime-config.test.ts

@@ -29,4 +29,17 @@ describe('shared-context-runtime-config', () => {
       backupContextModel: getDefaultSharedContextModelForBackend('codex-sdk'),
     });
   });
+
+  it('keeps a configured backup backend by filling its default model when the model is omitted', () => {
+    expect(normalizeSharedContextRuntimeConfig({
+      primaryContextBackend: 'claude-code-sdk',
+      primaryContextModel: 'sonnet',
+      backupContextBackend: 'qwen',
+    })).toEqual({
+      primaryContextBackend: 'claude-code-sdk',
+      primaryContextModel: 'sonnet',
+      backupContextBackend: 'qwen',
+      backupContextModel: getDefaultSharedContextModelForBackend('qwen'),
+    });
+  });
 });

web/src/components/SharedContextManagementPanel.tsx

@@ -688,10 +688,7 @@ export function SharedContextManagementPanel({ enterpriseId: initialEnterpriseId
 
   const handleProcessingBackupBackendChange = useCallback((nextBackend: SharedContextRuntimeBackend) => {
     setProcessingBackupBackend((prevBackend) => {
-      setProcessingBackupModel((prevModel) => {
-        if (!prevModel.trim()) return '';
-        return resolveProcessingModelForBackend(nextBackend, prevModel, prevBackend);
-      });
+      setProcessingBackupModel((prevModel) => resolveProcessingModelForBackend(nextBackend, prevModel, prevBackend));
       return nextBackend;
     });
   }, []);

web/test/components/SharedContextManagementPanel.test.tsx

@@ -313,23 +313,24 @@ describe('SharedContextManagementPanel', () => {
 
     const primaryBackend = screen.getByLabelText('sharedContext.management.processingPrimaryBackend: codex-sdk');
     const primaryInput = screen.getByLabelText('sharedContext.management.processingPrimaryModel') as HTMLInputElement;
-    const backupBackend = screen.getByLabelText('sharedContext.management.processingBackupBackend: claude-code-sdk');
+    const backupBackend = screen.getByLabelText('sharedContext.management.processingBackupBackend: qwen');
     const backupInput = screen.getByLabelText('sharedContext.management.processingBackupModel') as HTMLInputElement;
     fireEvent.click(primaryBackend);
     fireEvent.input(primaryInput, { target: { value: 'gpt-5.4' } });
     fireEvent.click(backupBackend);
-    fireEvent.input(backupInput, { target: { value: 'haiku' } });
     await flush();
 
+    expect(backupInput.value).toBe('qwen3-coder-plus');
+
     await act(async () => {
       fireEvent.click(screen.getByText('sharedContext.management.processingSave'));
     });
 
     await waitFor(() => expect(updateSharedContextRuntimeConfigMock).toHaveBeenCalledWith('srv-1', {
       primaryContextBackend: 'codex-sdk',
       primaryContextModel: 'gpt-5.4',
-      backupContextBackend: 'claude-code-sdk',
-      backupContextModel: 'haiku',
+      backupContextBackend: 'qwen',
+      backupContextModel: 'qwen3-coder-plus',
     }));
     expect((screen.getByLabelText('sharedContext.management.processingPrimaryModel') as HTMLInputElement).value).toBe('gpt-5.4');
     expect(await screen.findByText('sharedContext.management.processingSavedPrimaryBackend')).toBeDefined();
@@ -386,4 +387,22 @@ describe('SharedContextManagementPanel', () => {
 
     expect(backupInput.value).toBe('qwen3-coder-plus');
   });
+
+  it('preloads a backend-appropriate backup model as soon as the backup backend changes', async () => {
+    render(<SharedContextManagementPanel serverId="srv-1" />);
+    await flush();
+
+    await act(async () => {
+      fireEvent.click(screen.getByText('sharedContext.management.tabs.processing'));
+    });
+
+    const backupInput = await screen.findByLabelText('sharedContext.management.processingBackupModel') as HTMLInputElement;
+    expect(backupInput.value).toBe('');
+
+    await act(async () => {
+      fireEvent.click(screen.getByLabelText('sharedContext.management.processingBackupBackend: qwen'));
+    });
+
+    expect(backupInput.value).toBe('qwen3-coder-plus');
+  });
 });