SPF Validator Skill

Overview

This tool performs a DNS lookup to retrieve the SPF record for the domain and validates its syntax, structure, and IP ranges. When an IP address is provided, the API tests whether it is permitted under the domain’s SPF rules for sending mail.

The tool

Once your client is connected to the VerveKit server, this appears in its tool list as SPFValidatorSkill. It is read-only and open-world — it fetches and never mutates anything on your side — so most clients call it without asking you to confirm.

Tool call

{
  "name": "SPFValidatorSkill",
  "arguments": {
    "domain": "myspace.com"
  }
}

You do not name the tool yourself; the model picks it. Asking about myspace.com in the terms this skill covers is enough for it to reach for SPFValidatorSkill on its own — naming it explicitly also works, and is the way to force the call.

Connecting

One server URL covers every skill in the catalog, including this one. Authorization is OAuth: the client opens a browser once, and there is no key to paste into a config file.

{
  "mcpServers": {
    "vervekit": {
      "url": "https://api.vervekit.com/v1/mcp"
    }
  }
}

Per-client setup — Claude, Cursor, VS Code, ChatGPT — is on the MCP setup page.

Arguments

These are the properties on the tool's inputSchema, so a well-behaved client validates them before the call is made. Premium arguments are accepted on every plan but only take effect on plans that include them.

Argument	Type	Description
`domain`Required	string	The domain to validate the SPF record for domain

What the model gets back

The result carries a structuredContent object matching the tool's declared outputSchema, so a client reads fields without parsing prose. status is "ok" and error is null on success; a null field means the value was not available for that input, not that the call failed.

Result

{
  "status": "ok",
  "error": null,
  "data": {
    "host": "myspace.com",
    "has_spf_record": true,
    "dns_lookups_num": 9,
    "spf_record": "v=spf1 mx ip4:63.208.226.34 ip4:204.16.32.0/22 ip4:67.134.143.0/24 ip4:216.205.243.0/24 ip4:34.85.156.5/32 ip4:35.245.108.108/32 ip4:34.86.129.193/32 ip4:34.86.134.94/32 ip4:34.85.222.234/32 ip4:34.86.176.234/32 ip4:34.86.125.212/32 ip4:34.85.224.60/32 ip4:34.86.160.49/32 ip4:35.245.64.166/32 ip4:35.188.226.11/32 ip4:34.86.208.228/32 ip4:34.85.216.144/32 ip4:35.221.22.153/32 ip4:34.86.137.108/32 ip4:34.86.51.35/32 ip4:34.150.221.40/32 ip4:34.85.216.70/32 ip4:34.86.37.191/32 ip4:34.85.214.215/32 ip4:35.236.234.82/32 ip4:34.86.161.241/32 ip4:216.32.181.16 ip4:216.178.32.0/20 ip4:168.235.224.0/24 include:_netblocks.mimecast.com -all",
    "spf_records_list": [
      {
        "origin": "myspace.com",
        "record": "v=spf1 mx ip4:63.208.226.34 ip4:204.16.32.0/22 ip4:67.134.143.0/24 ip4:216.205.243.0/24 ip4:34.85.156.5/32 ip4:35.245.108.108/32 ip4:34.86.129.193/32 ip4:34.86.134.94/32 ip4:34.85.222.234/32 ip4:34.86.176.234/32 ip4:34.86.125.212/32 ip4:34.85.224.60/32 ip4:34.86.160.49/32 ip4:35.245.64.166/32 ip4:35.188.226.11/32 ip4:34.86.208.228/32 ip4:34.85.216.144/32 ip4:35.221.22.153/32 ip4:34.86.137.108/32 ip4:34.86.51.35/32 ip4:34.150.221.40/32 ip4:34.85.216.70/32 ip4:34.86.37.191/32 ip4:34.85.214.215/32 ip4:35.236.234.82/32 ip4:34.86.161.241/32 ip4:216.32.181.16 ip4:216.178.32.0/20 ip4:168.235.224.0/24 include:_netblocks.mimecast.com -all",
        "chars_num": 637,
        "use_macro": false,
        "domains": [
          "_netblocks.mimecast.com"
        ],
        "authorized_ips": {
          "ipv4": [
            "63.208.226.34",
            "204.16.32.0/22",
            "67.134.143.0/24",
            "216.205.243.0/24",
            "34.85.156.5/32",
            "35.245.108.108/32",
            "34.86.129.193/32",
            "34.86.134.94/32",
            "34.85.222.234/32",
            "34.86.176.234/32",
            "34.86.125.212/32",
            "34.85.224.60/32",
            "34.86.160.49/32",
            "35.245.64.166/32",
            "35.188.226.11/32",
            "34.86.208.228/32",
            "34.85.216.144/32",
            "35.221.22.153/32",
            "34.86.137.108/32",
            "34.86.51.35/32",
            "34.150.221.40/32",
            "34.85.216.70/32",
            "34.86.37.191/32",
            "34.85.214.215/32",
            "35.236.234.82/32",
            "34.86.161.241/32",
            "216.32.181.16",
            "216.178.32.0/20",
            "168.235.224.0/24"
          ]
        }
      },
      {
        "origin": "_netblocks.mimecast.com",
        "record": "v=spf1 include:eu._netblocks.mimecast.com include:us._netblocks.mimecast.com include:za._netblocks.mimecast.com include:de._netblocks.mimecast.com include:au._netblocks.mimecast.com include:ca._netblocks.mimecast.com include:usb._netblocks.mimecast.com ~all",
        "chars_num": 257,
        "use_macro": false,
        "domains": [
          "eu._netblocks.mimecast.com",
          "us._netblocks.mimecast.com",
          "za._netblocks.mimecast.com",
          "de._netblocks.mimecast.com",
          "au._netblocks.mimecast.com",
          "ca._netblocks.mimecast.com",
          "usb._netblocks.mimecast.com"
        ]
      },
      {
        "origin": "eu._netblocks.mimecast.com",
        "record": "v=spf1 ip4:195.130.217.0/24 ip4:91.220.42.0/24 ip4:146.101.78.0/24 ip4:207.82.80.0/24 ip4:213.167.81.0/25 ip4:193.7.207.0/25 ip4:213.167.75.0/25 ip4:185.58.85.0/24 ip4:185.58.86.0/24 ip4:193.7.206.0/25 ip4:147.28.36.0/24 ~all",
        "chars_num": 225,
        "use_macro": false,
        "authorized_ips": {
          "ipv4": [
            "195.130.217.0/24",
            "91.220.42.0/24",
            "146.101.78.0/24",
            "207.82.80.0/24",
            "213.167.81.0/25",
            "193.7.207.0/25",
            "213.167.75.0/25",
            "185.58.85.0/24",
            "185.58.86.0/24",
            "193.7.206.0/25",
            "147.28.36.0/24"
          ]
        }
      },
      {
        "origin": "us._netblocks.mimecast.com",
        "record": "v=spf1 ip4:207.211.31.0/25 ip4:205.139.110.0/24 ip4:216.205.24.0/24 ip4:170.10.129.0/24 ip4:63.128.21.0/24 ip4:170.10.133.0/24 ip4:185.58.84.93/32 ip4:207.211.41.113/32 ip4:207.211.30.64/26 ip4:207.211.30.128/25 ip4:216.145.221.0/24 ip4:170.10.128.0/24 ip4:170.10.132.56/29 ip4:170.10.132.64/29 ~all",
        "chars_num": 299,
        "use_macro": false,
        "authorized_ips": {
          "ipv4": [
            "207.211.31.0/25",
            "205.139.110.0/24",
            "216.205.24.0/24",
            "170.10.129.0/24",
            "63.128.21.0/24",
            "170.10.133.0/24",
            "185.58.84.93/32",
            "207.211.41.113/32",
            "207.211.30.64/26",
            "207.211.30.128/25",
            "216.145.221.0/24",
            "170.10.128.0/24",
            "170.10.132.56/29",
            "170.10.132.64/29"
          ]
        }
      },
      {
        "origin": "za._netblocks.mimecast.com",
        "record": "v=spf1 ip4:41.74.192.0/22 ip4:41.74.200.0/23 ip4:41.74.196.0/22 ip4:41.74.204.0/23 ip4:41.74.206.0/24 ~all",
        "chars_num": 106,
        "use_macro": false,
        "authorized_ips": {
          "ipv4": [
            "41.74.192.0/22",
            "41.74.200.0/23",
            "41.74.196.0/22",
            "41.74.204.0/23",
            "41.74.206.0/24"
          ]
        }
      },
      {
        "origin": "de._netblocks.mimecast.com",
        "record": "v=spf1 ip4:51.163.158.0/24 ip4:194.104.109.0/24 ip4:194.104.111.0/24 ip4:194.104.110.21/32 ip4:194.104.110.240/28 ip4:62.140.10.21/32 ip4:62.140.7.0/24 ip4:194.104.108.240/29 ip4:194.104.108.21/32 ip4:51.163.159.0/24 ~all",
        "chars_num": 221,
        "use_macro": false,
        "authorized_ips": {
          "ipv4": [
            "51.163.158.0/24",
            "194.104.109.0/24",
            "194.104.111.0/24",
            "194.104.110.21/32",
            "194.104.110.240/28",
            "62.140.10.21/32",
            "62.140.7.0/24",
            "194.104.108.240/29",
            "194.104.108.21/32",
            "51.163.159.0/24"
          ]
        }
      },
      {
        "origin": "au._netblocks.mimecast.com",
        "record": "v=spf1 ip4:103.13.69.0/24 ip4:124.47.150.0/24 ip4:124.47.189.0/24 ip4:103.96.23.0/24 ip4:103.96.21.0/24 ip4:180.189.28.0/24 ip4:216.145.217.0/24 ip4:103.96.22.96/28 ip4:103.96.22.22/32 ip4:103.96.20.22/32 ip4:103.96.20.96/28 ~all",
        "chars_num": 229,
        "use_macro": false,
        "authorized_ips": {
          "ipv4": [
            "103.13.69.0/24",
            "124.47.150.0/24",
            "124.47.189.0/24",
            "103.96.23.0/24",
            "103.96.21.0/24",
            "180.189.28.0/24",
            "216.145.217.0/24",
            "103.96.22.96/28",
            "103.96.22.22/32",
            "103.96.20.22/32",
            "103.96.20.96/28"
          ]
        }
      },
      {
        "origin": "ca._netblocks.mimecast.com",
        "record": "v=spf1 ip4:170.10.145.0/24 ip4:170.10.147.0/24 ip4:170.10.144.126/32 ip4:170.10.146.126/32 ip4:170.10.144.240/29 ip4:170.10.146.240/29 ip4:216.145.216.0/24 ~all",
        "chars_num": 160,
        "use_macro": false,
        "authorized_ips": {
          "ipv4": [
            "170.10.145.0/24",
            "170.10.147.0/24",
            "170.10.144.126/32",
            "170.10.146.126/32",
            "170.10.144.240/29",
            "170.10.146.240/29",
            "216.145.216.0/24"
          ]
        }
      },
      {
        "origin": "usb._netblocks.mimecast.com",
        "record": "v=spf1 ip4:170.10.151.0/24 ip4:170.10.153.0/24 ip4:170.10.150.240/29 ip4:170.10.152.240/29 ip4:170.10.156.0/24 ip4:170.10.157.0/24 ~all",
        "chars_num": 135,
        "use_macro": false,
        "authorized_ips": {
          "ipv4": [
            "170.10.151.0/24",
            "170.10.153.0/24",
            "170.10.150.240/29",
            "170.10.152.240/29",
            "170.10.156.0/24",
            "170.10.157.0/24"
          ]
        }
      }
    ],
    "domains_extracted": [
      "myspace.com",
      "_netblocks.mimecast.com",
      "eu._netblocks.mimecast.com",
      "us._netblocks.mimecast.com",
      "za._netblocks.mimecast.com",
      "de._netblocks.mimecast.com",
      "au._netblocks.mimecast.com",
      "ca._netblocks.mimecast.com",
      "usb._netblocks.mimecast.com"
    ],
    "authorized_ips": {
      "ipv4": [
        "63.208.226.34",
        "204.16.32.0/22",
        "67.134.143.0/24",
        "216.205.243.0/24",
        "34.85.156.5/32",
        "35.245.108.108/32",
        "34.86.129.193/32",
        "34.86.134.94/32",
        "34.85.222.234/32",
        "34.86.176.234/32",
        "34.86.125.212/32",
        "34.85.224.60/32",
        "34.86.160.49/32",
        "35.245.64.166/32",
        "35.188.226.11/32",
        "34.86.208.228/32",
        "34.85.216.144/32",
        "35.221.22.153/32",
        "34.86.137.108/32",
        "34.86.51.35/32",
        "34.150.221.40/32",
        "34.85.216.70/32",
        "34.86.37.191/32",
        "34.85.214.215/32",
        "35.236.234.82/32",
        "34.86.161.241/32",
        "216.32.181.16",
        "216.178.32.0/20",
        "168.235.224.0/24",
        "195.130.217.0/24",
        "91.220.42.0/24",
        "146.101.78.0/24",
        "207.82.80.0/24",
        "213.167.81.0/25",
        "193.7.207.0/25",
        "213.167.75.0/25",
        "185.58.85.0/24",
        "185.58.86.0/24",
        "193.7.206.0/25",
        "147.28.36.0/24",
        "207.211.31.0/25",
        "205.139.110.0/24",
        "216.205.24.0/24",
        "170.10.129.0/24",
        "63.128.21.0/24",
        "170.10.133.0/24",
        "185.58.84.93/32",
        "207.211.41.113/32",
        "207.211.30.64/26",
        "207.211.30.128/25",
        "216.145.221.0/24",
        "170.10.128.0/24",
        "170.10.132.56/29",
        "170.10.132.64/29",
        "41.74.192.0/22",
        "41.74.200.0/23",
        "41.74.196.0/22",
        "41.74.204.0/23",
        "41.74.206.0/24",
        "51.163.158.0/24",
        "194.104.109.0/24",
        "194.104.111.0/24",
        "194.104.110.21/32",
        "194.104.110.240/28",
        "62.140.10.21/32",
        "62.140.7.0/24",
        "194.104.108.240/29",
        "194.104.108.21/32",
        "51.163.159.0/24",
        "103.13.69.0/24",
        "124.47.150.0/24",
        "124.47.189.0/24",
        "103.96.23.0/24",
        "103.96.21.0/24",
        "180.189.28.0/24",
        "216.145.217.0/24",
        "103.96.22.96/28",
        "103.96.22.22/32",
        "103.96.20.22/32",
        "103.96.20.96/28",
        "170.10.145.0/24",
        "170.10.147.0/24",
        "170.10.144.126/32",
        "170.10.146.126/32",
        "170.10.144.240/29",
        "170.10.146.240/29",
        "216.145.216.0/24",
        "170.10.151.0/24",
        "170.10.153.0/24",
        "170.10.150.240/29",
        "170.10.152.240/29",
        "170.10.156.0/24",
        "170.10.157.0/24"
      ],
      "ipv6": []
    },
    "issues_found": [],
    "spf_valid": true,
    "has_issues": false,
    "macros_found": false,
    "ip_pass": false,
    "elapsed_ms": 431,
    "all_qualifier": "fail",
    "risk_score": 5,
    "risk_level": "low"
  }
}

Response fields

Paths are relative to data. Premium fields are absent rather than zeroed on plans that do not include them, so check for presence instead of comparing to 0.

Field	Type	Example	Description
`host`	string	`myspace.com`	The domain name being validated
`has_spf_record`	boolean	`true`	Whether the domain has SPF record
`dns_lookups_num`Premium	number	`9`	Total number of DNS lookups performed
`spf_record`	string	v=spf1 mx ip4:63.208.226.34 ip4:204.16.32.0/22 ip4:67.134.143.0/24 ip4:216.205.243.0/24 ip4:34.85.156.5/32 ip4:35.245.108.108/32 ip4:34.86.129.193/32 ip4:34.86.134.94/32 ip4:34.85.222.234/32 ip4:34.86.176.234/32 ip4:34.86.125.212/32 ip4:34.85.224.60/32 ip4:34.86.160.49/32 ip4:35.245.64.166/32 ip4:35.188.226.11/32 ip4:34.86.208.228/32 ip4:34.85.216.144/32 ip4:35.221.22.153/32 ip4:34.86.137.108/32 ip4:34.86.51.35/32 ip4:34.150.221.40/32 ip4:34.85.216.70/32 ip4:34.86.37.191/32 ip4:34.85.214.215/32 ip4:35.236.234.82/32 ip4:34.86.161.241/32 ip4:216.32.181.16 ip4:216.178.32.0/20 ip4:168.235.224.0/24 include:_netblocks.mimecast.com -all	The complete SPF record string
`spf_records_list`Premium	array[9]		List of SPF records with detailed parsing
`spf_records_list.0.origin`Premium	string	`myspace.com`	Domain origin of SPF record
`spf_records_list.0.record`Premium	string	v=spf1 mx ip4:63.208.226.34 ip4:204.16.32.0/22 ip4:67.134.143.0/24 ip4:216.205.243.0/24 ip4:34.85.156.5/32 ip4:35.245.108.108/32 ip4:34.86.129.193/32 ip4:34.86.134.94/32 ip4:34.85.222.234/32 ip4:34.86.176.234/32 ip4:34.86.125.212/32 ip4:34.85.224.60/32 ip4:34.86.160.49/32 ip4:35.245.64.166/32 ip4:35.188.226.11/32 ip4:34.86.208.228/32 ip4:34.85.216.144/32 ip4:35.221.22.153/32 ip4:34.86.137.108/32 ip4:34.86.51.35/32 ip4:34.150.221.40/32 ip4:34.85.216.70/32 ip4:34.86.37.191/32 ip4:34.85.214.215/32 ip4:35.236.234.82/32 ip4:34.86.161.241/32 ip4:216.32.181.16 ip4:216.178.32.0/20 ip4:168.235.224.0/24 include:_netblocks.mimecast.com -all	Full SPF record content
`spf_records_list.0.chars_num`Premium	number	`637`	Character count of SPF record
`spf_records_list.0.use_macro`Premium	boolean	`false`	Whether record uses macros
`spf_records_list.0.domains`Premium	array	`["_netblocks.mimecast.com"]`	Domains referenced in SPF record
`spf_records_list.0.authorized_ips`Premium	object	`{…}`	All IP addresses authorized by SPF
`spf_records_list.0.authorized_ips.ipv4`Premium	array	`["63.208.226.34","204.16.32.0/22","67.134.143.0/24"]`	IPv4 addresses authorized to send mail
`domains_extracted`Premium	array	`["myspace.com","_netblocks.mimecast.com","eu._netblocks.mimecast.com"]`	All domains found in SPF chain
`authorized_ips`Premium	object	`{…}`	All IP addresses authorized by SPF
`authorized_ips.ipv4`Premium	array	`["63.208.226.34","204.16.32.0/22","67.134.143.0/24"]`	All IPv4 addresses authorized by SPF
`authorized_ips.ipv6`Premium	array	`[]`	All IPv6 addresses authorized by SPF
`issues_found`Premium	array	`[]`	List of SPF validation issues
`spf_valid`	boolean	`true`	Whether SPF record is valid
`has_issues`	boolean	`false`	Whether validation found issues
`macros_found`Premium	boolean	`false`	Whether SPF record uses macros
`ip_pass`	boolean	`false`	Whether IP passes SPF check
`elapsed_ms`Premium	number	`431`	Validation processing time in milliseconds
`all_qualifier`	string	`fail`	The qualifier on the SPF 'all' mechanism: fail (-all, strict), softfail (~all), neutral (?all) or pass (+all, authorizes any sender). Null when the record has no all mechanism (e.g. defers via redirect)
`risk_score`Premium	number	`5`	Composite 0-100 email-spoofing risk based on the SPF enforcement qualifier and DNS-lookup limit — higher means the domain is more easily spoofed (no SPF or +all scores high; -all scores low)
`risk_level`Premium	string	`low`	Risk band derived from the score: low, medium or high

Failure modes

Errors come back as tool errors carrying a sentence the model can act on, not a bare status code. Error handling covers the full list.

Status	What it means
`400` / `422`	The arguments did not validate. The message names the offending one.
`401`	The OAuth session is invalid or expired — reconnect the server.
`403`	Blocked by a key restriction or an IP allow-list. Never a bad identity.
`404`	This skill is not part of VerveKit. Check the catalog.
`429`	Out of credits, or a brief rate limit. The message tells them apart.

A call costs 10 credits each time the tool actually runs; a model that reasons about the tool without calling it costs nothing.

Other ways to use SPF Validator Skill

Set up SPF Validator Skill on VerveKit, or reach the same source a different way. Your VerveKit account and credits work on all of them — one key, one balance.

Call it as a REST APIOne HTTPS endpoint and an x-api-key header, with SDKs for Node, Python and .NET.APIVerve →Reference →

Google Sheets or ExcelA =VERVE() formula fills a column — no script, no export, recalculates in place.VerveSheets →Reference →

Ground an agent on itA cited, machine-checkable fact your model can't produce on its own.VerveContext →Reference →