ondocs

Open-source Ask AI for your docs. Cited answers on your own model key, and an MCP server for coding agents, from one index built with your Starlight, Docusaurus or VitePress site. No vendor, no vector database.

For teams that run their own developer docs, at product, API and platform companies, who want Ask AI without a hosted assistant.

Answers with

Ask these docs from your editor, over this site's MCP server:

Website: ondocs.vercel.app, whose docs answer with OpenAI and serve agents at /api/mcp. Formerly ask-my-site (what changed).

ondocs.mp4

_{The live demo: a streamed answer with citations, one opening the section it came from, then the one-line setups.}

What you get

One index, ask-index.json, built with your site, feeds three things:

• An Ask box for people. A ⌘I dialog that streams a short answer from your model, with numbered citations to the exact section. Most off-topic questions get "I don't know" before the model is called. A page loads only the button; the dialog loads on first use.
• An MCP server for agents. search, fetch and list_pages over the same index, for coding agents and ChatGPT. Agents bring their own model, and keyword search, the default, calls no model at all.
• llms.txt, llms-full.txt and a .md copy of every page, written with the build.

Search runs in memory inside one function you deploy: BM25 and vectors, merged with reciprocal rank fusion.

Pick your setup

Your site	What you add	Guide
Starlight, or any Astro site	A plugin, or an integration	Astro and Starlight
Docusaurus 3	A plugin	Docusaurus
VitePress	One wrapper in its config	VitePress
Next.js or another React app	A route and a component	Next.js and React
Fumadocs	A route and a component	Fumadocs
Nextra	A route and a component	Nextra
Hugo, Jekyll, MkDocs or plain HTML	One script tag; for plain HTML, init --out <dir>	Script tag

Each answers from an endpoint you deploy as one function next to the site, rate-limited by default. npx ondocs init writes it for Vercel, Netlify, Cloudflare or GitHub Pages (as a Worker answering with Workers AI, no API key), and an Astro site with an SSR adapter needs none: see Deploying.

Live demos: Starlight, Docusaurus, VitePress.

Starlight. npm i ondocs ai @ai-sdk/openai react react-dom @radix-ui/react-dialog cmdk, then:

// astro.config.mjs
import starlight from '@astrojs/starlight';
import ondocs from 'ondocs/starlight';
import { defineConfig } from 'astro/config';

export default defineConfig({
  integrations: [starlight({ title: 'Acme Docs', plugins: [ondocs()] })],
});

After astro build, it indexes the pages into dist/ask-index.json, writes llms.txt and the .md pages, and adds an "Ask AI" button with ⌘I.

Docusaurus. npm i ondocs ai @ai-sdk/openai @radix-ui/react-dialog cmdk, then:

// docusaurus.config.ts
export default { plugins: ['ondocs/docusaurus'] };

It does the same after docusaurus build, into build/.

Next.js. With OPENAI_API_KEY set, index your content with npx ondocs index ./content --base-url /docs --llms-txt public, then:

// app/api/ask/route.ts
import { openai } from '@ai-sdk/openai';
import { createAskHandler } from 'ondocs/server';
import index from '../../../ask-index.json';

export const POST = createAskHandler({
  index,
  model: openai('gpt-5.4-mini'),
  embeddingModel: openai.embedding('text-embedding-3-small'),
});

and render the dialog in your layout, with its two stylesheets:

// app/layout.tsx
import { AskDialog } from 'ondocs/react';
import 'ondocs/react/styles.css';
import 'ondocs/embed/launcher.css';
// …then <AskDialog launcher /> in the body

Any other site. Index the HTML it builds, write the endpoint with npx ondocs init, and add the script tag:

npx ondocs index public -o public/ask-index.json -e none   # keyword-only; leave out -e none to embed with OPENAI_API_KEY
npx ondocs init --out public                               # plain HTML needs --out; Hugo, Jekyll, MkDocs and Eleventy are detected

On a GitHub Pages project site, at https://user.github.io/repo, add --base-url /repo to the index command.

<script src="https://cdn.jsdelivr.net/npm/ondocs@0.10/dist/embed.global.js" defer></script>

Try it without a key. npx ondocs index ./docs -e mock, then npx ondocs dev, serves the ask endpoint and MCP server on localhost, with a mock model that quotes your docs. See Try it locally.

For agents

The same index, served to agents with createMcpHandler:

// app/api/mcp/route.ts
import { createMcpHandler } from 'ondocs/server';
import index from '../../../ask-index.json';

const handler = createMcpHandler({ index, siteName: 'the Acme docs' });
export { handler as POST, handler as GET, handler as DELETE, handler as OPTIONS };

claude mcp add --transport http acme-docs https://docs.acme.dev/api/mcp

• Protocol. MCP 2026-07-28, and 2025-11-25 back to 2024-11-05 for clients that start with initialize, tested with the official TypeScript client.
• Tools. search returns ranked sections with a snippet and an anchor URL, and fetch a page or section as Markdown, as ChatGPT's connectors expect.
• Quality. On docusaurus.io's docs, keyword search puts the right page in the top three for 22 of 22 agent-style queries we wrote in the docs' terms, and 20 of 22 asked as a person asks: a best case, checked in CI (the queries). A reader's own words find it less often.
• On your docs. With the plugins' mcp option, a page can show an "Add to Cursor / VS Code / Claude" block.
• llms.txt. The plugins write it by default, and the CLI with --llms-txt <dir>.

See MCP server and llms.txt and Markdown pages.

Cost and safety defaults

• A question costs one embedding call and one model call, with at most 8,000 characters of sources in and 800 tokens out, and a follow-up one more short call to rewrite it. Most questions your docs don't cover stop before the model; one that shares enough words with your pages, such as a general programming question, can still reach it.
• An agent's search costs no model call, or one embedding call with an embeddingModel.
• Rate limits are on by default: 10 questions and 60 tool calls a minute per client IP, per server instance. Name your platform's client IP header outside Vercel.
• budget caps questions and model tokens per UTC day for the whole endpoint, answerCache answers repeated questions without a model call, and challenge adds an optional Turnstile bot check.
• Requests must be JSON and bodies are capped; model errors are masked, and answers render as text, never HTML, with links allow-listed.
• Set a spend limit with your model provider. It is the only hard cap. See Rate limits and security.

How it compares

• Kapa.ai and Inkeep are hosted, take more sources than your docs (forums, issues, chat) and have analytics dashboards; several hosted assistants now serve an MCP endpoint for agents as well. ondocs has ondocs eval, readers' ratings and a log of unanswered questions to wire yourself.
• Algolia DocSearch Ask AI adds answers to DocSearch's search box, with your own LLM provider and key, from the index Algolia's crawler builds on its platform, under an Algolia account. Choose it if you already use DocSearch.
• Context7, DeepWiki and DocSearch MCP serve many projects' docs to agents from one server; if one indexes yours, keep it. Your own endpoint is the first-party copy: your docs as last deployed, at your site's URLs, and onToolCall shows what agents search for.
• Fumadocs has first-party AI chat and an MCP route, native to its framework.
• docusaurus-plugin-mcp-server builds a similar index for an MCP endpoint, more widely used today, with no Ask box.
• The llms.txt plugins (docusaurus-plugin-llms, starlight-llms-txt, vitepress-plugin-llms and others) have more output options. ondocs writes the basics, and steps aside when one is installed.

What ondocs adds: open source you host. The index is a file in your build, the endpoint a function on your host, the model key yours, with no vendor account. See Limits and trade-offs for where it is the wrong tool.

Links

• Getting started, Deploying, API, CLI, Benchmarks and FAQ
• Changelog, Contributing, Security

Requires Node.js 22.12 or later and AI SDK 7 (ai@^7.0.95); AI SDK 6 is not supported. MIT © Diogo Esteves