Eleventy Plugin: Generator for llms.txt and llms-full.txt

A plugin for 11ty to automatically generate llms.txt and llms-full.txt files specifically formatted for Large Language Models (LLMs):

1. llms.txt: A master index of your site's content with titles and absolute URLs, perfect for providing LLMs with a sitemap.
2. llms-full.txt: A concatenated corpus of all your eligible Markdown content (frontmatter stripped), ideal for fine-tuning, retrieval-augmented generation (RAG), or creating a knowledge base.

More info at llmstxt.org.

Features

• Automatic llms.txt Generation: Creates a Markdown-formatted list of all your live documents with links (like a Sitemap).
• Automatic llms-full.txt Generation: Concatenates the content of all eligible Markdown files into a single text file.
• Configurable Header: Add a custom header to both generated files.
• Draft Exclusion: Automatically excludes draft posts (or those with eleventyExcludeFromCollections: true).
• Content Exclusion: Fine-grained control to exclude specific pages using frontmatter (robots: noindex or excludeFromLlms: true).
• Absolute URLs: Generates full, absolute URLs for llms.txt using your site's base URL.
• Source Comments (Optional): Include comments in llms-full.txt indicating the source file for each content block.

Installation

npm install eleventy-plugin-llms --save-dev

Usage

Open your Eleventy config file (usually .eleventy.js) and add the plugin:

const eleventyPluginLlms = require('eleventy-plugin-llms');

module.exports = (eleventyConfig) => {
	eleventyConfig.addPlugin(eleventyPluginLlms, {
    	siteUrl: "https://www.example.com", // REQUIRED for absolute URLs
    	headerText: `# My Static Site - LLM Corpus

This document contains content from My Static Site, prepared for LLM consumption.

## Documents Index`,
    // See more options below!
	});

  	// Your other Eleventy configurations...
};

The plugin will then generate llms.txt and llms-full.txt in your output directory (e.g., _site/) after each Eleventy build.

Configuration Options

You can pass an options object as the second argument to addPlugin. Here are the available options:

Option	Type	Description
siteUrl	String	Default: "" REQUIRED for absolute URLs. Your site's full base URL (e.g., "https://www.example.com"). A warning is issued if not set, and links in llms.txt will be relative.
headerText	String	Default: "# My Site LLM Data\n\nThis file contains information about the site's content, formatted for Large Language Models.\n\n## Documents" The header content prepended to both generated files. Supports Markdown.
llmsFilename	String	Default: "llms.txt" The filename for the document index file.
llmsFullFilename	String	Default: "llms-full.txt" The filename for the concatenated full content file.
includeDrafts	Boolean	Default: false Set to true to include documents marked as drafts (e.g., draft: true or eleventyExcludeFromCollections: true in frontmatter).
markdownOnly	Boolean	Default: true If true, only processes files with a .md extension.
includeSourceComment	Boolean	Default: true If true, adds an HTML comment <!-- Source: path/to/file.md --> before each document's content in llms-full.txt.
defaultTitleFormatter	Function	Default: A function that takes inputPath, extracts the filename, replaces hyphens/underscores with spaces, and title-cases it. A function (inputPath) => string to generate a title if one isn't found in the document's frontmatter.

Excluding Content from LLM Files

Drafts are automatically excluded unless you set includeDrafts to true. Furthermore, you can specify in the front matter of every Markdown file whether to exclude it.

A document will be excluded if its frontmatter contains robots: noindex or excludeFromLlms: true

This allows you to easily omit pages like 404 error pages, private drafts, or any other content you don't want to feed to LLMs.

Example: Excluding a 404 Page

Let's say you have a 404.md page:

---
title: Page Not Found
permalink: /404.html
layout: layouts/base.njk
eleventyExcludeFromCollections: true # Already excluded from sitemaps, etc.
robots: noindex # Add this to exclude from LLM files
excludeFromLlms: true # This would also work
---
# 404 Page Not Found

The page you were looking for doesn't exist.
You might have mistyped the address, or the page may have moved.

By adding robots: noindex (or excludeFromLlms: true), this 404 page will not appear in llms.txt or have its content included in llms-full.txt.

Enjoy!