How to fix "untitled" document name in Sanity schema type?

The issue you're seeing is because your schema doesn't have a preview configuration set up! When Sanity doesn't know which field to use as the document title, it defaults to showing "untitled" everywhere.

Here's how to fix it - you need to add a preview configuration to your 'content' schema type. This tells Sanity which field to display as the title:

export default {
  name: 'content',
  type: 'document',
  fields: [
    {
      name: 'title',
      type: 'string',
      title: 'Title'
    },
    // your other fields...
  ],
  preview: {
    select: {
      title: 'title'  // This tells Sanity to use the 'title' field
    }
  }
}

The preview configuration uses two parts:

• select: Specifies which fields to pull from your document
• prepare (optional): Lets you transform the data before display

If you want to get fancier, you can add subtitles and media too:

preview: {
  select: {
    title: 'title',
    subtitle: 'description',
    media: 'coverImage'
  }
}

Or use the prepare function for custom formatting:

preview: {
  select: {
    title: 'title',
    publishedAt: 'publishedAt'
  },
  prepare({title, publishedAt}) {
    return {
      title: title,
      subtitle: publishedAt ? `Published: ${publishedAt}` : 'Draft'
    }
  }
}

Once you add this to your schema and save, your documents should show their actual title instead of "untitled" in lists, references, and search results!