Built-in plugins

Fibel assembles its default behavior from normal plugins. Projects can use that set as-is, append their own plugins, or replace individual responsibilities.

Default set

import { defaultPlugins } from "@k2b/fibel";

const plugins = defaultPlugins();

The default set includes:

• markdownPlugin: renders Markdown to HTML, processes code blocks, and creates heading anchors.
• themePlugin: reads the theme cookie and provides the selected theme to the layout. See Theme.
• i18nPlugin: checks whether translated pages exist in the configured locales.
• seoPlugin: serves SEO files such as favicon, sitemap, and robots output, and adds language alternates and social card metadata to every page.
• llmsPlugin: serves llms.txt and llms-full.txt so language models can discover and read the documentation. See SEO.
• assetsPlugin: serves files from the configured assets folder.
• searchPlugin: builds the search index and exposes the search endpoint. See Search.
• poweredByPlugin: adds the Powered by fibel.dev attribution to the footer.
• layoutPlugin: renders navigation, page layout, page actions, footer, search dialog, and client script. layoutPlugin({ header: false }) removes only the built-in header.

Optional plugins

Fibel ships plugins that are not part of the default set because they need configuration.

assistantPlugin adds a bounded documentation chat powered by @k2b/nessi. It uses in-memory rate limits by default and keeps provider credentials on the server. See Documentation assistant.

mcpPlugin exposes visible documentation to coding agents through a public, read-only Streamable HTTP endpoint. By itself it adds an MCP setup item to the footer. See MCP for coding agents.

agentSkillsPlugin publishes self-contained Agent Skills from a configured directory at the origin-level well-known endpoint and adds an Agents setup item for the Vercel Skills CLI. When MCP is active, one Agents dialog contains both setup methods. See Agent Skills discovery.

blogPlugin({ collection: "blog" }) turns one Markdown collection into a date-sorted editorial feed with year navigation. Posts remain normal Fibel pages and therefore stay available to search, Assistant, MCP, raw Markdown, and llms.txt. See Blog collections.

imprintPlugin adds a footer link to legal information hosted somewhere else. Use it when the imprint belongs to the company or person behind several sites and should not be maintained as a documentation page.

import { defineFibel, defaultPlugins } from "@k2b/fibel";
import { imprintPlugin } from "@k2b/fibel/plugins";

export default defineFibel({
  title: "Product Docs",
  plugins: [...defaultPlugins(), imprintPlugin({ url: "https://example.com/imprint", label: "Imprint" })],
});

The URL is used as written, so it can point at any external page. label defaults to Imprint.

Extend the defaults

Append project plugins to the default set when the built-in behavior should remain active.

import { defineFibel, defaultPlugins } from "@k2b/fibel";
import { projectLinksPlugin } from "./plugins/project-links";

export default defineFibel({
  title: "Product Docs",
  plugins: [...defaultPlugins(), projectLinksPlugin()],
});

This is the right starting point for most projects. The Plugin API describes the available hooks.

Replace the defaults

Replace the plugin list when a project owns rendering, layout, search, or routes itself.

import { defineFibel } from "@k2b/fibel";
import { searchPlugin, themePlugin } from "@k2b/fibel/plugins";

export default defineFibel({
  title: "Product Docs",
  plugins: [
    customMarkdownPlugin(),
    themePlugin(),
    searchPlugin(),
    customLayoutPlugin(),
  ],
});

Fibel does not add omitted plugins automatically. A custom list should include every capability the website needs.

To remove the default footer attribution, use a plugin list without poweredByPlugin.

Routes and ownership

Several built-in plugins own routes. The search plugin owns the search endpoint. The layout plugin serves the client script. The SEO plugin serves SEO files. The assets plugin serves public files.

Custom plugins should choose route paths explicitly. This prevents collisions and keeps documentation predictable under a base path.