`lookup_dns`

Looks up the DNS records of one type for a domain. It supports the same eight record types as the DNS tool on namebeta.com.

Read-only · Open world

Ask your assistant

Paste this into a chat with NameBeta connected:

Which mail servers does github.com use?

Your assistant calls lookup_dns with type MX.

Field	Type	Required	Constraints
`domain`	`string`	Yes	1–253 characters; Matches `\.`
`type`	`string`	No	One of `A`, `AAAA`, `CNAME`, `MX`, `TXT`, `NS`, `SRV`, `SOA`; Default `A`

Returned as structuredContent, and repeated as JSON in a text content block.

Field	Type	Required	Constraints
`domain`	`string`	Yes
`type`	`string`	Yes	One of `A`, `AAAA`, `CNAME`, `MX`, `TXT`, `NS`, `SRV`, `SOA`
`records`	`object[]`	Yes
`records[].type`	`string`	Yes	One of `A`, `AAAA`, `CNAME`, `MX`, `TXT`, `NS`, `SRV`, `SOA`
`records[].data`	`string`	Yes

domain must contain a dot. It can be a registered domain such as example.com or a host name under it such as www.github.com.
type defaults to A. Only records of the requested type are returned: a host that is an alias answers an A query with its addresses, and its CNAME record appears only when you ask for CNAME.
data is the record's value as text: an address for A and AAAA, a host name for CNAME and NS, and the preference followed by the host for MX, such as 10 mail.example.com.
A name with no records of that type returns an empty records array; that is not an error.
A domain that accepts no email may publish a null MX (RFC 7505), which comes back as 0 .. example.com is one.

Arguments:

{ "domain": "github.com", "type": "MX" }

Result of a call on 2026-09-29:

{
    "domain": "github.com",
    "type": "MX",
    "records": [
        { "type": "MX", "data": "0 github-com.mail.protection.outlook.com" }
    ]
}

dig MX github.com returns the same record: GitHub receives its mail through Microsoft 365.

Tool	Bucket	Free (hour / day)	Pro (hour / day)	Business (hour / day)	Enterprise (hour / day)
`lookup_dns`	`dns`	20 / 50	200 / 400	500 / 1,000	Unlimited

Errors specific to this tool. Errors covers the rest, including how each kind reaches your client.

Situation	Result
`domain` has no dot	Tool error `MCP error -32602: Input validation error: …` (`A full domain name is required`)
`domain` is not a valid domain	Tool error `Invalid domain format`
`type` is not one of the eight	Tool error `MCP error -32602: Input validation error: …`
The TLD's nameservers are unknown	Tool error `Zone missing`
The lookup fails or times out	Tool error with the reason