CitedBy

Check a page, AI-crawler access, llms.txt and backlinks of any site. Free, read-only, no account. 40 calls per hour per IP.

GitHub

Hosted MCP Server

npx add-mcp 'https://citedby.eu/mcp'

Installs into Claude Code, Codex, Cursor and more

Documentation

CitedBy MCP server

Ask your AI tool to check whether a website can be found and cited by AI assistants and search engines. Free, no account, read-only.

Server address: https://citedby.eu/mcp (MCP Streamable HTTP, no sign-in). Page with the same instructions: https://citedby.eu/mcp-server

Tools

ToolWhat you get
check_pageOne page, fetched as CitedBot (robots.txt respected): what is wrong for AI answers and search, each finding with why it matters and the exact fix. Deterministic checks only.
check_ai_crawler_accessFor GPTBot, OAI-SearchBot, ChatGPT-User, PerplexityBot, ClaudeBot, Google-Extended, Bingbot and Googlebot: allowed by robots.txt, and answered by the server, or not.
check_llms_txtWhether /llms.txt exists, whether its links work, whether /llms-full.txt exists.
backlinksHow many domains link to a domain, and the strongest ones, from the Common Crawl web graph. Says when a domain is not in the data.

When a site refuses the crawler or does not answer, the tool says so. It does not score what it could not read.

Install

Claude Code

claude mcp add --transport http citedby https://citedby.eu/mcp

or install the plugin, which also adds a skill that picks the right tool for the question:

/plugin marketplace add resaleiq/citedby-mcp
/plugin install citedby@citedby

Claude on the web and desktop: Settings, Connectors, Add custom connector, paste https://citedby.eu/mcp.

Cursor: add CitedBy to Cursor, or add to ~/.cursor/mcp.json:

{ "mcpServers": { "citedby": { "url": "https://citedby.eu/mcp" } } }

Codex

codex mcp add citedby --url https://citedby.eu/mcp

Any other MCP client: add a remote server with the address above.

Ask it like this

  • "Check https://example.com/pricing with CitedBy and tell me what to fix first."
  • "Can GPTBot and PerplexityBot read example.com?"
  • "Does example.com have a working llms.txt?"
  • "Which domains link to example.com?"

Limits

40 checks an hour from one address; a result is reused for up to 6 hours (1 hour for a page check). check_page is one page. A whole-site audit, with every page up to your plan's limit and the exact fix for each, is at https://citedby.eu/plans.

Also from CitedBy: citedby-check, the same AI-crawler check as a command-line tool and GitHub Action.

Questions: hello@citedby.eu. MIT licence.