MCP 服务器

Onto MCP Server

Enables AI agents to read clean Markdown from any URL and assess source quality with AI-readability scores.

README

Onto MCP Server

The official Onto Model Context Protocol server. Add clean web content reading and AI-readability scoring to Claude Code, Cursor, Cline, Zed, or any MCP-compatible AI client.

What this does

Onto's MCP server exposes these tools to any AI agent:

read_url — Read any URL and get back clean, agent-ready Markdown (typically 10× smaller than raw HTML)
score_url — Get the AIO (AI-readability) score for any URL with a breakdown of what helps and what hurts AI consumption
read_and_score — Both at once: clean content plus quality assessment so the agent knows how much to trust the source
batch — Read, score, or extract many URLs (an explicit list or a whole site) in one call
map_site — Discover a site's URLs via its sitemap, without reading them
extract_data — Return the structured data a page already declares (JSON-LD, OpenGraph, meta)

Every tool response ends with a one-line ⚡ Onto report — reduction, tokens saved, and AIO score — so the value is visible on every call.

This is the official MCP wrapper for the Onto Read API. It's a thin, deterministic layer: Onto cleans and scores with a rule-based engine (no LLM in the loop), so your agent's own model never has to parse raw HTML.

Why use this?

When AI agents read websites today, they parse hundreds of KB of React noise to find a few KB of actual content. This burns tokens and causes hallucinations.

Onto strips the noise server-side, returns the agent-ready format, and reports a confidence score for the source. One tool call, one accurate answer.

Quick start

1. Get an Onto API key

Free tier: 1,000 requests / month. No credit card.

2. Install in Claude Code

Add to your Claude Code MCP config:

{
  "mcpServers": {
    "onto": {
      "command": "npx",
      "args": ["-y", "@ontosdk/mcp@latest"],
      "env": {
        "ONTO_API_KEY": "onto_sk_live_your_key_here"
      }
    }
  }
}

Restart Claude Code. The Onto tools (read_url, score_url, read_and_score, batch, map_site, extract_data) will appear in the available tools list.

3. Install in Cursor

Add to Cursor's MCP configuration (Settings → Features → MCP):

{
  "mcpServers": {
    "onto": {
      "command": "npx",
      "args": ["-y", "@ontosdk/mcp@latest"],
      "env": {
        "ONTO_API_KEY": "onto_sk_live_your_key_here"
      }
    }
  }
}

See examples/ for Cline, Zed, and Continue configs.

4. Use it

In Claude Code or Cursor, try:

Read https://stripe.com/pricing using Onto and summarize the pricing tiers.

The agent calls read_url, gets clean Markdown, and returns an accurate summary without parsing hundreds of KB of layout HTML.

Tools

`read_url`

Returns clean Markdown for a URL with metadata about the extraction (sizes, reduction %, cache state).

Input:

Field	Type	Required	Description
`url`	string	yes	Publicly accessible HTTP(S) URL
`fresh`	boolean	no	If true, bypass cache (default: false)

`score_url`

Returns the AIO (AI-readability) score for a URL — 0-100 with a letter grade, hallucination risk, and a structured list of penalties / benefits / recommendations.

Input:

Field	Type	Required	Description
`url`	string	yes	URL to score

`read_and_score`

Returns clean Markdown plus the AIO score in one call. Recommended default for agentic workflows.

Input: same as read_url.

`batch`

Process many URLs in one call — billed as a single request, so you don't spend a credit per URL. Give an explicit list or a base URL whose pages are auto-discovered.

Input:

Field	Type	Required	Description
`urls`	string[]	one of	Explicit list of URLs (max 50). Use this or `site`.
`site`	string	one of	Base URL whose pages are auto-discovered via sitemap. Use this or `urls`.
`mode`	`"read"` \| `"read-and-score"` \| `"extract"`	no	What to do per URL (default `"read-and-score"`)
`limit`	number	no	Site mode only: max pages to discover (default 25, max 50)

`map_site`

Discover a site's URLs (sitemap → on-page links) without reading them. Cheap — use it to plan which pages to read or batch next.

Input:

Field	Type	Required	Description
`url`	string	yes	Base URL of the site to map
`limit`	number	no	Max URLs to return (default 100, max 1000)

`extract_data`

Return the structured data a page already declares — JSON-LD, OpenGraph, and meta tags — plus the AIO score. Deterministic; no fields are inferred by a model.

Input:

Field	Type	Required	Description
`url`	string	yes	URL to extract structured data from

Pricing

Tier	Monthly requests	Price
Free	1,000	$0
Starter	10,000	$9
Growth	100,000	$49
Scale	500,000	$250
Enterprise	Custom	Contact sales

Manage your subscription at app.buildonto.dev/read/billing. Credit packs ($5–$200) are available for overflow once you're on a paid tier.

Configuration

Environment variables:

ONTO_API_KEY (required) — Your Onto API key from app.buildonto.dev/read/keys
ONTO_API_BASE (optional) — Override the API base URL (default: https://api.buildonto.dev)

Troubleshooting

"Invalid Onto API key"

Verify your key at app.buildonto.dev/read/keys. If you recently rotated keys, your MCP config may have a stale value.

"Monthly quota exceeded"

You've used your monthly allotment. Upgrade at app.buildonto.dev/read/billing or wait for the monthly reset. Paid tiers can also top up with credit packs.