domain_lookupGet full registration details for a domain. Returns registrar, registrant, registration/expiration dates, nameservers, DNSSEC status, and domain status flags. Works for any TLD.
| Name | Required | Description | Default |
|---|---|---|---|
| domain | Yes | Domain name to look up (e.g., "google.com", "bbc.co.uk") |
| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
Changes observed during successful MCP inspections.
Output schema / (root)Previous value: -nullNew value: +{
+ "oneOf": [
+ {
+ "properties": {
+ "domain": {
+ "description": "Domain name queried",
+ "type": "string"
+ },
+ "error": {
+ "description": "Error message when domain not found",
+ "type": "string"
+ },
+ "registered": {
+ "description": "Domain registration status",
+ "enum": [
+ false
+ ],
+ "type": "boolean"
+ }
+ },
+ "required": [
+ "domain",
+ "registered",
+ "error"
+ ],
+ "type": "object"
+ },
+ {
+ "properties": {
+ "dnssec": {
+ "description": "DNSSEC delegation signed status",
+ "type": "boolean"
+ },
+ "domain": {
+ "description": "Domain name (LDH form)",
+ "type": "string"
+ },
+ "expiration_date": {
+ "description": "ISO 8601 expiration date",
+ "type": [
+ "string",
+ "null"
+ ]
+ },
+ "last_changed": {
+ "description": "ISO 8601 last change/update date",
+ "type": [
+ "string",
+ "null"
+ ]
+ },
+ "nameservers": {
+ "description": "Authoritative nameserver hostnames",
+ "items": {
+ "type": "string"
+ },
+ "type": "array"
+ },
+ "registered": {
+ "description": "Domain is registered",
+ "enum": [
+ true
+ ],
+ "type": "boolean"
+ },
+ "registrant": {
+ "description": "Registrant name or organization",
+ "type": [
+ "string",
+ "null"
+ ]
+ },
+ "registrar": {
+ "description": "Registrar name or organization",
+ "type": [
+ "string",
+ "null"
+ ]
+ },
+ "registration_date": {
+ "description": "ISO 8601 registration date",
+ "type": [
+ "string",
+ "null"
+ ]
+ },
+ "status": {
+ "description": "Domain status flags (e.g., active, clientHold)",
+ "items": {
+ "type": "string"
+ },
+ "type": "array"
+ },
+ "unicode_name": {
+ "description": "Unicode/IDN representation of domain",
+ "type": [
+ "string",
+ "null"
+ ]
+ }
+ },
+ "required": [
+ "domain",
+ "unicode_name",
+ "registered",
+ "status",
+ "registrar",
+ "registrant",
+ "registration_date",
+ "expiration_date",
+ "last_changed",
+ "nameservers",
+ "dnssec"
+ ],
+ "type": "object"
+ }
+ ],
+ "type": "object"
+}Input schema / examplesAdded value: +[
+ {
+ "domain": "google.com"
+ },
+ {
+ "domain": "bbc.co.uk"
+ }
+]Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The description adds context beyond annotations by specifying the return fields and the universal TLD support. However, it does not disclose potential caveats like privacy redaction of registrant data, and 'full registration details' could be slightly overpromising. Overall, it adds useful behavioral context consistent with the readOnlyHint.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is two sentences, front-loaded with the main action, and every sentence adds value. It is concise without sacrificing necessary detail.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given the tool's simplicity, one parameter, and annotations covering safety, the description is largely complete. It could benefit from mentioning alternatives or when to prefer this over domain_status, but the output schema likely covers return details. Overall adequate.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is 100% with a clear description and examples for the domain parameter. The tool description does not add additional parameter semantics beyond what the schema already provides, so baseline 3 is appropriate.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description uses a specific verb ('Get') and clearly identifies the resource ('full registration details for a domain') and lists specific return fields, making the tool's function unambiguous. It implicitly distinguishes from siblings like domain_status by covering comprehensive registration data.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description provides some usage context ('Works for any TLD') but does not explicitly state when to use this tool over alternatives or when not to use it. No mention of sibling tools or exclusions.
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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