essentials

name	essentials
description	Critical rules that must always be followed

Source Cursor rule: .cursor/rules/essentials.mdc. Original file scope: **/*.{ts,tsx}. Original Cursor alwaysApply: true.

Essentials

Package Manager

Use bun, never npm/yarn/pnpm.

bun install          # Install deps
bun add <pkg>        # Add package
bun run <script>     # Run script
bunx <cmd>           # Execute binary

Components

Use @trycompai/design-system first, @trycompai/ui only as fallback.

// ✅ Design system
import { Button, Card, Input, Select } from '@trycompai/design-system';
import { Add, Close } from '@trycompai/design-system/icons';

// ❌ Don't use when DS has the component
import { Button } from '@trycompai/ui/button';
import { Plus } from 'lucide-react';

No className on DS components - use variants and props only.

// ✅ Use variants
<Button variant="destructive" size="sm">Delete</Button>

// ❌ No className overrides
<Button className="bg-red-500">Delete</Button>

TypeScript

No any. No unsafe type assertions.

// ✅ Validate external data with zod
const TaskSchema = z.object({ id: z.string(), title: z.string() });
const task = TaskSchema.parse(response.data);

// ❌ Never
const data: any = fetchData();
const task = response as Task;

Data Fetching

Get organizationId from URL params, not session.

// ✅ From params
export default async function Page({ params }: { params: Promise<{ orgId: string }> }) {
  const { orgId } = await params;
}

// ❌ Not from session
const session = await auth.api.getSession();
const orgId = session?.session?.activeOrganizationId;

Server components fetch, pass to client with SWR fallbackData.

// Server page
const data = await fetchData(orgId);
return <ClientComponent initialData={data} />;

// Client component
const { data } = useSWR(key, fetcher, { fallbackData: initialData });

State Management

No nuqs - use React useState for UI state, Next.js for URL state.

// ✅ React state for UI
const [isOpen, setIsOpen] = useState(false);

// ❌ No nuqs
import { useQueryState } from 'nuqs';

After Changes

Always run checks after code changes:

bun run typecheck
bun run lint

Fix all errors before committing.