Crawlora MCP

domain_subdomains

Read-only

Returns up to 5,000 indexed subdomain records and names for one registrable domain; use these for name discovery, then call domain_dns_resolve to check live DNS. Names may be historical. The anonymous source limits requests to 100 per source IP per day.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "domain": "<domain>"
    },
    "name": "domain_subdomains"
  }
}

Input Schema

Name	Required	Description	Default
`domain`	Yes	Bare public DNS hostname such as github.com; do not include a scheme, path, port, or IP address.

Output Schema

Name	Required	Description	Default
`data`	Yes	The tool result payload (shape varies per tool; see each tool's docs resource).

Schema Changelog

Changes observed during successful MCP inspections.

AddedNov 7, 2026

TDQS

A4.9/5.0

Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Goes well beyond the readOnly/openWorld annotations by disclosing the 5,000-record cap, that names may be historical (i.e. results can be stale), and the 100-requests-per-source-IP-per-day throttle on the anonymous source. These are exactly the operational facts an agent needs before planning calls.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Three short sentences, front-loaded with the core behavior, then the follow-up tool, then the data-quality and rate-limit caveats. No wasted clauses.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a single-parameter read tool with an output schema and annotations already covering safety and openness, the description supplies the remaining unknowns: result cap, staleness, and throttling. Nothing needed to call it correctly is missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100% and the param is already documented as a bare hostname, so the baseline is 3. The description adds the useful framing 'one registrable domain', clarifying that the input is the apex domain being enumerated rather than a subdomain to look up.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource ('Returns up to 5,000 indexed subdomain records and names for one registrable domain') with explicit scope. It is immediately distinguishable from sibling domain_dns_resolve, which it names as the live-check counterpart.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines5/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Gives an explicit workflow: use this for name discovery, then call domain_dns_resolve to check live DNS. The alternative and the condition that selects it are both spelled out, so nothing is left to inference.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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