Problem: I'm working with Next.js 15 and trying to update a server component's UI after a client component triggers a server action.

Here's the simplified setup: Client Component

'use client';

import { updateText } from './parent_comp';

export default function ClientComp() {
 const handleClick = async () => {
  await updateText('devtz007'); // Sends new data to the server
};
return (
 <button
  onClick={handleClick}
  style={{ color: 'black', background: 'coral' }}
 >
  Send Text
 </button>
 );
}

Server Component + Action

'use server';

import ClientComp from './client_comp';
import { revalidatePath } from 'next/cache';

let text = 'initial text';

export async function updateText(newText: string): Promise<string> {
 text = newText;
  // revalidatePath('/example_page'); // This re-renders the page, but I want a 
 more targeted update!
  return text;
}

export default async function ParentComp() {
  return (
    <>
      <p style={{ color: 'green', backgroundColor: 'coral' }}>
         Received Text: {text}
        </p>
       <ClientComp />
     </>
    );
}

What I’ve Tried

• revalidatePath() works but refreshes the entire page. I updated my

• code to use revalidateTag() and added cache tags like textUpdate:

   // Server action with revalidateTag
   export async function updateText(
     newText: string,
     options: { next: { tags: string[] } },
   ) {
     if (options.next.tags.includes('textUpdate')) {
       text = newText;
       revalidateTag('textUpdate'); // Should trigger the related components
      }
    }
  

And the component:

export default async function ParentComp() {
   return (
     <>
      <p style={{ color: 'green', backgroundColor: 'coral' }}>{text}</p>
      <ClientComp />
     </>
    );

  }

Issue

1. Is revalidateTag() re-rendering just the related portion (e.g.,

   Received Text

   ) or the whole page?
2. If I use ClientComp on another page, clicking the button does not immediately update the ParentComp without a manual page refresh.
3. I don’t want to use router.refresh() because it refreshes the full page.
4. What's the intended pattern in Next.js 15 to partially refresh components after an action without reloading the whole page?