hook llms:generate only runs on build time once but not called for every request to /llms.txt?

[AronLEEdev]

I am trying to implement a server plugin of a nuxt project to change the domain of llms.txt dynamically.
I have set the domain in the nuxt.config.ts to be {DOMAIN} and i intend to replace them using hook llms:generate, here is my code:

// server/plugins/llms.ts
export default defineNitroPlugin(nitroApp => {
	nitroApp.hooks.hook('llms:generate', (event, options) => {
        const host = getRequestHeader(event, 'x-real-host') || getRequestHeader(event, 'x-forwarded-host') || getRequestHeader(event, 'host');
        const proto = getRequestHeader(event, 'x-forwarded-proto') || getRequestHeader(event, 'cloudfront-forwarded-proto') || 'https';
        let fullDomain = ''
        if (host) {
            fullDomain = `${proto}://${host}`;
        }
        console.log('generating llms: fullDomain is ', fullDomain);
        options.sections.forEach(section => {
            const links = section.links;
            links?.forEach(link => {
                link.href = link.href.replace('{DOMAIN}', fullDomain + '/md') + '.md'
            })
        })
        setHeader(event, 'Content-Type', 'text/plain; charset=utf-8');
	});
});

// nuxt.config.ts
llms: {
		// change dynamically afterwards
		domain: '{DOMAIN}',
		title: 'meta-title',
	},

but when i preview it locally after build or deploy on server, neither of them works as expected.
I also notice that the console.log that i have inside the plugin is print out during build process, and a static llms.txt is generated under .output folder.
So my question is according to the docs, this hook should be called on every request:

But this is not as expected as the hook is only called once during build time, or is there something i am doing wrong?

[jianbin-lim]

I encountered the same problem.