Cursor rule

1---
2alwaysApply: false
3---
4 
5## Minimize Serialization at RSC Boundaries
6 
7The React Server/Client boundary serializes all object properties into strings and embeds them in the HTML response and subsequent RSC requests. This serialized data directly impacts page weight and load time, so **size matters a lot**. Only pass fields that the client actually uses.
8 
9**Incorrect (serializes all 50 fields):**
10 
11```tsx
12async function Page() {
13  const user = await fetchUser()  // 50 fields
14  return <Profile user={user} />
15}
16 
17'use client'
18function Profile({ user }: { user: User }) {
19  return <div>{user.name}</div>  // uses 1 field
20}
21```
22 
23**Correct (serializes only 1 field):**
24 
25```tsx
26async function Page() {
27  const user = await fetchUser()
28  return <Profile name={user.name} />
29}
30 
31'use client'
32function Profile({ name }: { name: string }) {
33  return <div>{name}</div>
34}
35```
36