Onto

Name: Onto
Author: ravixalgorithm

by ravixalgorithmversion 1.5.2i★ –iComputer or cloud

Registry nameio.github.ravixalgorithm/onto

Install

Overview

Description from the maker (original English)

Clean Markdown and AI-readability scoring for any URL. Built for AI agents.

PopNx MCP’s three pillars

These three are never merged into one score: opinions, measurements and popularity are different things.

User voiceiNo reviews yetReviews open together with accounts in a later step
Our basic checksi1 of 1 passedChecked from public information; code not scanned yet
UsageiNot measured yet★ –

What you can do with it

We have not written a plain-language summary for this one yet. Below are the facts we read from the registry.

Connection: Computer or cloud
Transport: stdio, Streamable HTTP
Category: Other
You need to fill in: ONTO_API_KEY

Install

Pick the AI app you use, then copy the settings.

Before you install

Basic checks: 1 of 1 passed
Runs on the maker’s server: what you ask it goes through their server.
You fill in yourself: ONTO_API_KEY, ONTO_API_BASE

Values marked secret are keys to your account. Never share them or paste them into a chat.

You need

Runs in the cloudNothing to install; it connects over the internet
npmNode.js installed (for the npx command)

Which app do you use?

ClaudeClaude CodeCursorVS CodeChatGPT

Pick your app above. We remember it, so next time the button says “Install in …”.

Works in Claude on the web, desktop and mobile:

Open Settings → Connectors
Press Add custom connector
Paste the address below and press Add
If it asks you to sign in, sign in with the maker

https://api.buildonto.dev/mcp

Or run it on your computer

Open Claude Desktop → Settings → Developer → Edit Config, and paste this into claude_desktop_config.json

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

Run this in your terminal

claude mcp add --transport http onto https://api.buildonto.dev/mcp

Or run it on your computer

claude mcp add onto --env ONTO_API_KEY=your-value --env ONTO_API_BASE=your-value -- npx -y @ontosdk/mcp

Fill in the empty values before running it.

Open in Cursor

Or copy the settings yourself

Paste into .cursor/mcp.json in your project, or ~/.cursor/mcp.json

{
  "mcpServers": {
    "onto": {
      "url": "https://api.buildonto.dev/mcp"
    }
  }
}

Or run it on your computer

Open in Cursor

Or copy the settings yourself

Paste into .cursor/mcp.json in your project, or ~/.cursor/mcp.json

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

Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.

Open in VS Code

Or copy the settings yourself

Paste into .vscode/mcp.json in your project

{
  "servers": {
    "onto": {
      "type": "http",
      "url": "https://api.buildonto.dev/mcp"
    }
  }
}

Or run it on your computer

Open in VS Code

Or copy the settings yourself

Paste into .vscode/mcp.json in your project

{
  "servers": {
    "onto": {
      "type": "stdio",
      "command": "npx",
      "args": [
        "-y",
        "@ontosdk/mcp"
      ],
      "env": {
        "ONTO_API_KEY": "your-value",
        "ONTO_API_BASE": "your-value"
      }
    }
  }
}

Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.

ChatGPT connects only to servers on the internet:

Open ChatGPT on the web → Settings → Connectors (Apps)
Press Create or Add (some plans need Developer mode under Advanced first)
Paste the address below, give it a name and save
If it asks you to sign in, sign in with the maker

https://api.buildonto.dev/mcp

Menu names can differ slightly by plan and over time.

Your choice stays on this device in a cookie; no account needed.

Values you fill in

ONTO_API_KEY secret required env
Your Onto API key (get one at https://app.buildonto.dev/read/keys — free tier includes 1,000 credits/month).
ONTO_API_BASE env
Optional override for the Onto API base URL. Defaults to https://api.buildonto.dev.

These settings are generated from the maker’s registry entry. If the README says otherwise, follow the README.

What it can do

We have not read this server’s tool list yet; we check endpoints in rotation.

Basic checksi

We check information anyone can see; we have not read the code. Checks that do not apply are left out of the count. · Checked Nov 7, 2026

✓ Pass
Maker matches the repo
The registry name was verified with the GitHub account ravixalgorithm, which owns the repo
… Not checked yet
Still maintained
We have not read this repo from GitHub yet
… Not checked yet
Has a licence
We have not read this repo from GitHub yet
… Not checked yet
Endpoint responds
Not checked yet; we check endpoints in rotation
… Not checked yet
Sign-in with OAuth
Not checked yet; we check endpoints in rotation
… Not checked yet
No hidden instructions in tool descriptions
Not checked yet; we read the tool list when we check the endpoint

Compared with others in Otheri

More stars than 0% of the other 32655 servers in this category
Published to the registry more recently than 33% of the other 32655 servers in this category
Basic checks equal to or better than 100% of the other 32655 servers in this category

Compared with every active server in this category in the registry. Stars count only when the publisher owns the repo.

Common questions

Is Onto safe?

It passed 1 of 1 applicable basic checks. We have not read the code. Before adding a key or token, see what access the server asks for and use a key with only the permissions you need.

What keys or codes does it need?

You need to fill in: ONTO_API_KEY

Does it run on my computer or in the cloud?

Either way works: install it on your computer or connect to the cloud version.

Is it still maintained?

The GitHub repo last changed –, and the latest version (1.5.2) reached the registry 2 months ago.

Which apps can use it?

Apps that support MCP, such as Claude Desktop, Claude Code, Cursor and VS Code. It connects by URL, so apps that accept remote MCP servers work too, such as ChatGPT in developer mode.

What can I use instead?

In the same category: Spec Driven Development, Remote Desktop Commander, SuperCollider

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README from the maker

Open the README

Copied from the maker’s repo as written. PopNx MCP has not reviewed or endorsed it. HTML, images and scripts are removed. Links lead off this site.

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 credits / 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 the Onto server to ~/.cursor/mcp.json (all projects) or .cursor/mcp.json (this repo). Or use the UI: Customize (sidebar) → MCPs → add a custom server, same JSON.

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

Fully quit Cursor (Cmd+Q / Ctrl+Q) and reopen.

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. N credits — one per URL in the list after the list is known. Failed URLs (ok: false) are refunded. Default mode read-and-score is still N, not 2N. 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. 1 credit per call (not per discovered URL) — 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 credits	Price
Free	1,000	$0
Starter	10,000	$9
Growth	100,000	$49
Scale	500,000	$250
Enterprise	Custom	Contact sales

MCP tool credits match the live API meter:

Tool	Credits
`read_url`	1
`read_and_score`	1
`score_url`	0 (free)
`extract_data`	1
`map_site`	1 per call (not per discovered URL)
`batch`	N — one per URL in the list after the list is known; failed URLs (`ok: false`) are refunded. Default mode `read-and-score` is still N, not 2N

Connect / OAuth is not a debit.

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.

Tool doesn't appear in Claude Code / Cursor

Verify the config file is valid JSON
Restart the MCP host (Claude Code, Cursor, etc.)
Check the host's MCP logs for connection errors
Make sure npx is on your PATH

"Request timed out"

The target site may be slow or unreachable. Onto's request timeout is 15 seconds. Retry, or try a different URL.

About Onto

Onto is the compatibility layer for the agent web. Three products on one engine:

Read (this MCP server + API) — AI developers read any URL cleanly
Serve (Next.js SDK) — Site owners serve clean Markdown to AI crawlers
Act (coming Q3 2026) — Agents act on websites through semantic intent

Built for AI agents reading the web. Built so they read it correctly.

License

MIT

Onto

Overview

PopNx MCP’s three pillars

What you can do with it

Install

Before you install

Or run it on your computer

Or run it on your computer

Or run it on your computer

Or run it on your computer

Values you fill in

What it can do

Basic checksi

Maker matches the repo

Still maintained

Has a licence

Endpoint responds

Sign-in with OAuth

No hidden instructions in tool descriptions

Compared with others in Otheri

Common questions

Alternatives

Spec Driven Development

Remote Desktop Commander

SuperCollider

README from the maker

Onto MCP Server

What this does

Why use this?

Quick start

1. Get an Onto API key

2. Install in Claude Code

3. Install in Cursor

4. Use it

Tools

read_url

score_url

read_and_score

batch

map_site

extract_data

Pricing

Configuration

Troubleshooting

"Invalid Onto API key"

"Monthly quota exceeded"

Tool doesn't appear in Claude Code / Cursor

"Request timed out"

Links

About Onto

License

`read_url`

`score_url`

`read_and_score`

`batch`

`map_site`

`extract_data`