How do we use "Follow" to support Google Scripts?

[Karlstens]

I'm struggling to get the REST Client extension working with Google Scripts. Details of my adventure below.

Using the Postman app, I'm able to:

POST https://script.google.com/macros/s/{{GUID}}/exec
Content-Type: application/json

{
  "message": "Hello World"
}

Postman exports cURL as;

curl --location 'https://script.google.com/macros/s/{{GUID}}/exec' \
--header 'Content-Type: application/json' \
--data '{
  "message": "Hello World Again"
}'

And Postman executes as I'd hope, giving the expected return from my deployed Google Script.

When I craft up a similar .rest file for REST Client VS Code extension, I get follow errors upon execution... either as native .rest or using the supported cURL method.

POST https://script.google.com/macros/s/{(GUID}}/exec
Content-Type: application/json

{
  "message": "Hello World"
}

###
curl 'https://script.google.com/macros/s/{(GUID}}/exec' -L
--header 'Content-Type: application/json' 
--data '{
  "message": "Hello World"
}'

Google Script returns:

HTTP/1.1 302 Moved Temporarily
Content-Type: text/html; charset=UTF-8
Access-Control-Allow-Origin: *
Cache-Control: no-cache, no-store, max-age=0, must-revalidate
Pragma: no-cache
Expires: Mon, 01 Jan 1990 00:00:00 GMT
Date: Fri, 21 Mar 2025 20:52:33 GMT
Location: https://script.googleusercontent.com/macros/echo?user_content_key=ABC...XYZ&lib=ABC...XYZ
Content-Encoding: gzip
X-Content-Type-Options: nosniff
X-Frame-Options: SAMEORIGIN
Content-Security-Policy: frame-ancestors 'self'
X-XSS-Protection: 1; mode=block
Server: GSE
Alt-Svc: h3=":443"; ma=2592000,h3-29=":443"; ma=2592000
Connection: close
Transfer-Encoding: chunked

And if I manually follow the location, google then returns.

HTTP/1.1 404 Not Found
Cache-Control: no-cache, no-store, max-age=0, must-revalidate
Pragma: no-cache
Expires: Mon, 01 Jan 1990 00:00:00 GMT
Date: Fri, 21 Mar 2025 20:53:37 GMT
Content-Type: text/html; charset=utf-8
Content-Encoding: gzip
X-Content-Type-Options: nosniff
X-XSS-Protection: 1; mode=block
Server: GSE
Alt-Svc: h3=":443"; ma=2592000,h3-29=":443"; ma=2592000
Connection: close
Transfer-Encoding: chunked

In further testing, I have the following .mjs file executing successfully in node.js, and Google Script returns as expected without error.

// googleAPI.mjs
const url = "https://script.google.com/macros/s/{{GUID}}/exec";

const response = await fetch(url, {
  method: "POST",
  headers: {
    "Content-Type": "application/json",
  },
  body: JSON.stringify({ message: "Hello World" }),
  redirect: "follow", // Automatically follow redirects (default behavior)
});

const data = await response.json();
console.log("Response:", data);

Is this a limitation of the "REST Client" api extension, or have I simply got a malformed query?