Frontmatter Fields

2026-01-20 1 min read (146 words)

Frontmatter is the YAML block between --- fences at the top of a Markdown file. It is where a document declares the metadata that the rest of the pipeline consumes — and every feature reads only the fields it owns.

The fields this site uses

yaml
---
title: Frontmatter Fields   # shown in <title>, lists, and the feed
date: 2026-01-20            # ordering, archives, scheduling
tags: [reference]           # tag archives and related-post scoring
draft: true                 # hides a post unless --drafts is passed
layout: index               # which template renders the document
---

What happens to it

• The parser validates that the block is a YAML mapping and that date is a real date; anything else is left alone for features to check.
• tags must be a list of non-empty strings — an empty tag fails the build with a message naming the file.
• layout chooses the template; when it is absent, posts render through the default post layout.

Defaults you rarely touch

Directory names (content/, templates/, public/, dist/) live in kiln.config.ts and stay at their defaults here, so the whole site resolves relative to its own folder.

reference