How to use hooks to augment md content in v3?

[AloisSeckar]

In Nuxt Content v2 I had Nitro plugin like this:

export default defineNitroPlugin((nitroApp) => {
  nitroApp.hooks.hook('content:file:beforeParse', (file) => {
    if (file._id.endsWith('.md')) {
      file.body = // do stuff
    }
  })
})

How can I use this in v3?

IDE says: "Argument of type '"content:file:beforeParse"' is not assignable to parameter of type 'HookKeys'." and the augmentation is not happening.

Based on (very brief) documentation page I tried to add following into defineNuxtConfig but it doesnt seem to work the way I am trying it:

hooks: {
  'content:file:beforeParse'(ctx: { file: { path: string, body: string } }) {
    const file = ctx.file
    if (file.path.endsWith('.md')) {
      file.body = // do stuff
    }
  },
},

Did I figured out the ctx object structure incorrectly or is there something else I am doing wrong?