Folder sidecar (`_meta.yml`)
Per-folder YAML sidecar that overrides a folder's display title, sort order in its parent, and llms.txt subtree opt-in.
A _meta.yml file dropped in any content folder declares folder-level metadata: an alternative display title, an explicit position in the parent navigation level, and (optionally) opt-in to a dedicated llms.txt subtree split. All fields are optional.
Without a sidecar, a folder's sort position is the min-of-children value: the smallest order: found on any page inside it. The order key below overrides that emergent value.
Schema
title: "Reference"
order: 5
llms:
description: "API surface, host extensions, front-matter keys, ..."
| Key | Type | Default | Effect |
|---|---|---|---|
title |
string | null |
Overrides both FormatSectionTitle (auto-generated from the folder slug) and the title from a sibling index.md. |
order |
int | null |
Sets the folder's position among its parent's children. Overrides the emergent min-of-children rule and any order: set on a sibling index.md. |
llms.description |
string | null |
When present, opts the folder into llms.txt subtree generation. Requires title to also be set; without it the description is silently ignored (no subtree, no warning, no error). |
Resolution rules
- A field that's set wins over every other source for that folder.
- A field that's omitted falls through to the original behavior:
FormatSectionTitle(folderSlug)for the title, min-of-children for the order, and "not an llms subtree" for the llms split. - Folders without
_meta.ymlare unaffected — adoption is folder-by-folder.
Discovery
MarkdownContentService discovers _meta.yml files under its content path, but it is not the only source. FolderMetadataRegistry aggregates rows from every registered IContentService that implements IFolderMetadataProvider, keyed by the folder's canonical URL prefix. A custom content service that surfaces its own folder metadata through that interface contributes sidecars on equal footing. Hot-reload refreshes the registry on file change.
Example
# docs/Pennington.Docs/Content/reference/_meta.yml
title: Reference
llms:
description: "API surface, host extensions, front-matter keys, Markdig extensions, UI components, diagnostics codes."
The Reference folder appears in the sidebar with that title, and /reference/llms.txt is generated as a subtree split of the main llms.txt.
See also
- Background: Navigation-tree construction — how
_meta.ymlinteracts withHierarchyPartsand per-pageorder:. - Related reference: Front-matter keys — per-page YAML keys including
order:.