Authoring a Digital Garden plugin

A garden plugin is a directory that extends a Digital Garden site: markup injected into named layout slots, site-wide styles/scripts, and build-time Eleventy/markdown-it hooks. Plugins are distributed as public GitHub repos with a garden-plugin.json manifest at the repo root, and installed into src/plugins/<id>/ of a garden repo. Follow this skill end to end; do not invent extension points that are not listed here.

Where to work

• Inside a garden or template checkout (a repo with .eleventy.js and src/site/): create your plugin directly at src/plugins/<id>/ and it runs immediately.
• Standalone plugin repo: develop the plugin as its own directory, and for testing clone https://github.com/oleeskild/digitalgarden, run npm install, and symlink or copy your plugin into src/plugins/<id>/.

The plugin id must match ^[a-z0-9][a-z0-9-]*$, must equal the directory name, and must NOT start with dg- (reserved for first-party plugins).

Minimal viable plugin

src/plugins/reading-time/
  garden-plugin.json
  templates/badge.njk

{
  "id": "reading-time",
  "name": "Reading Time",
  "version": "1.0.0",
  "description": "Shows an estimated reading time under the note title.",
  "author": "Your Name",
  "slots": { "notes.header": "templates/badge.njk" },
  "noteSettings": ["dgReadingTime"]
}

{% if settings.dgReadingTime === true %}
<div class="reading-time">{{ ((content | striptags).split(" ").length / 200) | round }} min read</div>
{% endif %}

id, name, version, description, author are required. Everything else is optional. All declared paths must be relative, use /, and contain no .. — a violation makes the loader (and installers) reject the plugin.

Slots

Slot templates are plain Nunjucks fragments (no front matter). They are rendered with the full Eleventy data cascade — meta, settings, title, tags, created, updated, content, collections, graph, filetree, page — plus pluginSettings (this plugin's resolved settings). Always self-gate on your own setting: every enabled plugin's slots render unconditionally.

Manifest form: "slots": { "<slot>": "file.njk" } or a list of files. Use common.footer for anything with a <script> or overlay markup.

Render order within a slot is the site owner's call, not the plugin's: plugins render by the order number on their entry in src/plugins/plugins.json (lower first, default 0), then by id. In floating.bottomRight a lower order sits nearer the corner. Example: {"plugins": {"theme-switcher": {"order": 10}, "random-note": {"order": 20}}}.

Regions (exclusive replacement)

A region replaces a core UI area instead of adding to it — at most one enabled plugin provides each region (first by id wins; conflicts warn). Currently: navigation (default: the core navbar; the shipped dg-filetree plugin claims it to render the folder-tree sidebar).

"regions": { "navigation": "templates/my-nav.njk" }

A custom navigation plugin gets the full data cascade, including the core-computed filetree data structure, and may include core components (e.g. fall back to {% include "components/navbar.njk" %}) and render sub-slots via components/pluginSlot.njk. Users switch navigations by disabling dg-filetree and enabling yours. Read src/plugins/dg-filetree/ in the template as the reference.

A navigation plugin MUST render the surfaces other extensions rely on, in its own markup: the navbar.actions and filetree.actions plugin slots (the search button lives there), and the site owner's custom filetree components — {% for imp in dynamics.filetree.beforeTitle %}{% include imp %}{% endfor %} plus the same for dynamics.filetree.afterTitle. dg-filetree does both; copy its template as the starting point.

Build hooks ("hooks": "index.js")

module.exports = {
  // Both optional. context = { settings, manifest, pluginDir }
  setupMarkdown(md, context) { md.use(require("markdown-it-footnote")); },
  setupEleventy(eleventyConfig, context) {
    eleventyConfig.addFilter("myFilter", (v) => v);
    // To emit a page (needs collections), register a virtual template:
    // eleventyConfig.addTemplate("my-page.njk",
    //   require("fs").readFileSync(require("path").join(context.pluginDir, "templates/page.njk"), "utf8"),
    //   { permalink: "/my-page.json", eleventyExcludeFromCollections: true });
  },
};

Rules: hooks run at config time in Node; they may only require packages the template already ships (check the template's package.json) or pure JS files vendored inside the plugin dir — plugins cannot add npm dependencies. Hook changes need a dev-server restart. Thrown errors are caught and the hook is skipped with a [plugins] warning.

Settings and per-note flags

"settings": [
  { "key": "label", "name": "Label", "description": "…",
    "type": "text",              // text | boolean | number | select
    "default": "Hello",
    "options": ["a", "b"],       // select only
    "env": "MY_ENV_VAR" }        // optional env fallback
],
"noteSettings": ["dgMyFlag"]

• Setting resolution: stored value in src/plugins/plugins.json → env var (env or the key) from the garden's .env → default. Read them as pluginSettings.<key> in templates, context.settings.<key> in hooks.
• noteSettings keys (camelCase, dg-prefixed by convention) resolve like core note settings: env var of the same name is the global default, a note's frontmatter dg-my-flag: true/false overrides per note. Read as settings.<key> in templates.

Styles, scripts, assets

• "styles": ["styles/x.scss"] — .scss compiled per file (_partials skipped) to /plugins/<id>/styles/x.css and linked in <head>; plain .css copied and linked as-is. Prefer the garden's --dg-* CSS variables for colors/spacing so themes keep working.
• "scripts": ["assets/client.js"] — copied and loaded via <script defer> in <head>.
• "assets": ["assets/"] — copied to /plugins/<id>/…, referenced only by your own code.

Test before publishing

From the template/garden checkout:

1. npm install once, then npm run dev — slot template, style, and plugins.json edits hot-reload; restart after hook or manifest changes.
2. Watch for [plugins] … warnings in the build log — each one is a manifest or runtime problem in your plugin.
3. Build once with the plugin disabled (src/plugins/plugins.json → {"plugins": {"<id>": {"enabled": false}}}) and confirm the site is unchanged.
4. If the template has a test suite, npm test must stay green.

Publish

1. Put the plugin at the root of a public GitHub repo (garden-plugin.json at top level). Suggested repo name: garden-plugin-<id>.
2. Add a README (what it does, a screenshot, settings) and a screenshot file — the community directory shows it.
3. Tag a release matching the manifest version: git tag v1.0.0 && git push --tags. Installers fetch the latest release tag, falling back to the default branch only when no release exists. Every future change: bump version, tag again.
4. Users can now install it by pasting the repo URL, or manually by copying the directory into src/plugins/<id>/.
5. To list it in the community directory, open a PR against oleeskild/digitalgarden-plugins adding one entry to community-plugins.json: { "id": "<id>", "name": "…", "author": "…", "description": "…", "repo": "you/garden-plugin-<id>", "screenshot": "screenshot.png" }.

Hard rules

• Never require install-time execution: no postinstall steps, no "run this script to finish setup". Installation is file copying only.
• A plugin must never break the build when misconfigured — the loader warns and skips, but keep your own code defensive too.
• Don't touch files outside your plugin directory or claim another plugin's id. Don't use the dg- prefix.
• Plugin code runs in the site build and in visitors' browsers — keep it small, readable, and dependency-light so users can audit it.

For deeper reference, read the first-party plugins under src/plugins/ in the template repo — dg-link-preview is the smallest, dg-search the most complete, and dg-filetree the navigation reference.