Bug Description

When adding, editing, or importing MCP servers, success toasts and auto-tests execute before syncSettingsToServer() completes. This causes "Server not found" errors during auto-test because the server hasn't been persisted to disk yet.

Impact

• Severity: High - Breaks the "add server and test immediately" user flow
• User Experience: Users see success toast, then immediately see "Server not found" error
• Affected Operations: Add server, Edit server, Import servers, Toggle enabled, Delete server
• Data Integrity: UI state and disk state temporarily out of sync

Affected Code

File: apps/ui/src/components/views/settings-view/mcp-servers/hooks/use-mcp-servers.ts

Affected Functions:

• Lines 276-290: handleSave (edit flow)
• Lines 307-343: handleSecurityWarningConfirm (add/import flows)
• Lines 345-356: handleToggleEnabled
• Lines 358-370: handleDelete

Current Behavior (Incorrect)

const handleSecurityWarningConfirm = async () => {
  if (pendingServerData.type === 'add' && pendingServerData.serverData) {
    addMCPServer(pendingServerData.serverData); // Updates UI state only
    toast.success('MCP server added'); // ❌ Shows before sync completes
    await syncSettingsToServer(); // Still writing to disk...
    handleCloseDialog();
  }
};

Sequence of Events:

1. User adds MCP server
2. addMCPServer() updates Zustand store (UI state)
3. ❌ Success toast appears immediately
4. ❌ Auto-test fires (if enabled)
5. Auto-test calls backend → "Server not found" (not on disk yet)
6. syncSettingsToServer() completes (finally written to disk)

Expected Behavior

Wait for syncSettingsToServer() to complete before showing success feedback or triggering dependent operations.

Proposed Solution

Pattern: Await sync completion and handle errors before success notifications

const handleSecurityWarningConfirm = async () => {
  if (pendingServerData.type === 'add' && pendingServerData.serverData) {
    addMCPServer(pendingServerData.serverData);

    // ✅ Wait for sync to complete
    const syncSuccess = await syncSettingsToServer();

    if (!syncSuccess) {
      toast.error('Failed to save MCP server to disk');
      return;
    }

    toast.success('MCP server added'); // ✅ Only after sync succeeds
    handleCloseDialog();
  }
};

Apply to all 4 affected functions:

1. handleSave (edit existing server)
2. handleSecurityWarningConfirm (add new / import multiple)
3. handleToggleEnabled (enable/disable toggle)
4. handleDelete (remove server)

Testing

Before Fix:

1. Add new MCP server with auto-test enabled
2. See success toast immediately
3. See "Server not found" error from auto-test
4. Refresh → Server appears (sync completed in background)

After Fix:

1. Add new MCP server with auto-test enabled
2. Brief wait while sync completes
3. Success toast appears
4. Auto-test runs successfully (server already on disk)

Dependencies

• Requires: HTTP error handling fix (see related issue) for proper error visibility
• Enables: Correct JSON format persistence (see related issue about array format)

Additional Context

• syncSettingsToServer() is async and takes 50-200ms depending on disk I/O
• This is a timing bug, not a logic bug - the operations were correct but out of order
• No breaking changes - only improves operation sequencing
• Performance impact: User sees ~100ms delay before success toast (acceptable trade-off)