In Astro, the Astro.props object contains any values that have been passed as component attributes. For .md and .mdx files, layout components receive frontmatter values as props (source (https://docs.astro.build/en/reference/api-reference/#astroprops)).
In your case, you are trying to destructure title and description from Astro.props. However, in your frontmatter, you have defined title, href, and snippet, but not description. This is why description is undefined.
To fix this, you should either add a description field to your frontmatter, like this:
---
layout: /src/layouts/Layout.astro
title: "John Solly's Resume"
description: "Your description here"
href: /resume/
snippet: "A two-page resume for John Solly, a lead software engineer with a focus on cloud computing and geospatial technologies."
---
Or, if you meant to use snippet as the description, you should destructure snippet from Astro.props instead of description, like this:
const { title, snippet } = Astro.props;
Remember, the names of the variables you are destructuring need to match the names of the properties in the Astro.props object.
Note: you can ask me a follow up question by @ mentioning me again :speech_balloon: