Public MCP server

Three read-only tools, no account and no key, ten requests a minute per IP.

A second MCP server with no account, no key and no sign-up.

Endpoint POST https://domduck.com/api/mcp/public
Authentication none
Rate limit 10 requests a minute, per IP
Server name domduck-public, so a client with both connected can tell them apart

claude mcp add --transport http domduck-public https://domduck.com/api/mcp/public

{
  "mcpServers": {
    "domduck-public": {
      "type": "http",
      "url": "https://domduck.com/api/mcp/public"
    }
  }
}

What it reads, and what it will not do

This server answers from what Domduck has already collected. It never fetches a domain on demand. A domain nobody has ever looked up returns hasReading: false, and that is a real answer rather than an error: it says nobody has looked, not that the domain does not exist.

That single rule is why the tier can exist. It also means:

One domain per call. There is no bulk argument and no bulk tool.
No history. The dated series is the product and it cannot be backfilled by anyone who did not collect it.
No list tool, no search tool, no ranking. You have to know the name already.

A free Domduck account adds the history, unlimited tracked domains with a daily re-read of every source, tags, alerts, the write tools, and 240 requests a minute instead of 10.

Tools

Tool	Writes	What it does
[`lookup_domain`](#lookup-domain)	no	Public reputation snapshot for one domain from Domduck's store: Domain Rating, Tranco rank, OpenPageRank, registration date, TLS certificate state and AI crawler policy.
[`get_ai_crawler_policy`](#get-ai-crawler-policy)	no	Which of the eight tracked AI crawlers a domain's robots.txt admits, and whether it publishes an llms.txt.
[`list_sources`](#list-sources)	no	What Domduck reads and what each source means, including the eight AI crawlers whose robots.txt policy is tracked.

A worked call

curl -s https://domduck.com/api/mcp/public \
  -H "content-type: application/json" \
  -d '{"jsonrpc":"2.0","id":1,"method":"tools/call",
       "params":{"name":"get_ai_crawler_policy","arguments":{"domain":"stripe.com"}}}'

lookup_domain

Public reputation snapshot for one domain from Domduck's store: Domain Rating, Tranco rank, OpenPageRank, registration date, TLS certificate state and AI crawler policy. Returns hasReading false for a domain nobody has looked up yet, which is a real answer and not an error. One domain per call, and no history: the dated series is what a Domduck account is for.

Argument	Type	Required	Notes
`domain`	`string`	yes	A domain name. Scheme, www and trailing dots are stripped.

get_ai_crawler_policy

Which of the eight tracked AI crawlers a domain's robots.txt admits, and whether it publishes an llms.txt. Three states per agent: allowed, disallowed, unspecified. Unspecified is NOT allowed, because a catch-all Disallow blocks an agent the file never names, so read effective for what is in force. Reads the last stored reading; it does not fetch the file.

Argument	Type	Required	Notes
`domain`	`string`	yes	A domain name. Scheme, www and trailing dots are stripped.

list_sources

What Domduck reads and what each source means, including the eight AI crawlers whose robots.txt policy is tracked. A constant. Read it first: it is what lets a model interpret lookup_domain without guessing at field names or at which direction is better. Takes no arguments.