Subdomain Finder Skill
The tool
Let your agent map a domain's attack surface. Call it as an MCP tool to enumerate live subdomains and their DNS records in real time.
Once your client is connected to the VerveKit MCP server, this appears in its tool list as SubdomainFinderSkill. It is read-only and open-world: it fetches, it never mutates anything on your side, so most clients will call it without asking you to confirm.
{
"name": "SubdomainFinderSkill",
"arguments": {
"domain": "google.com"
}
}What that looks like in a conversation
You don't name the tool — the model picks it. Asking about google.com in the terms this source covers is enough for it to reach for SubdomainFinderSkill on its own.
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"
}
}
}https://api.vervekit.com/v1/mcpPer-client setup — Claude Desktop, 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.
| Argument | Type | Example | Description |
|---|---|---|---|
domainRequired | string | google.com | The domain you want to find all the available subdomains for (e.g. google.com) |
limitPremium | integer | 5 | Limit the number of subdomains to detect |
deepScanPremium | boolean | true | Search the full wordlist instead of only certificate transparency and common names. Slower, and may still report complete: false when the time limit is reached |
What the model gets back
The result carries a structuredContent object matching the tool's declared outputSchema, so a client can read fields without parsing prose. status is "ok" on success and error is null; a null field means the value wasn't available for that input, not that the call failed.
{
"status": "ok",
"error": null,
"data": {
"rootDomain": {
"domain": "paypal.com",
"records": [
"151.101.3.1",
"151.101.195.1",
"162.159.141.96"
]
},
"subDomains": [
{
"host": "api.paypal.com",
"records": [
"66.211.168.123"
]
},
{
"host": "mail.paypal.com",
"records": [
"159.127.187.12"
]
},
{
"host": "admin.paypal.com",
"records": [
"173.0.88.10"
]
},
{
"host": "smtp.paypal.com",
"records": [
"64.4.244.68"
]
},
{
"host": "ns2.paypal.com",
"records": [
"64.4.244.71"
]
},
{
"host": "test.paypal.com",
"records": [
"156.59.125.88"
]
},
{
"host": "ns1.paypal.com",
"records": [
"64.4.244.70"
]
},
{
"host": "mx.paypal.com",
"records": [
"10.190.3.55"
]Fields
| Field | Type | Example | Description |
|---|---|---|---|
rootDomain | object | {…} | |
rootDomain.domain | string | paypal.com | The primary domain name for the scan |
rootDomain.records | array | ["151.101.3.1","151.101.195.1","162.159.141.96"] | IP addresses associated with the root domain |
subDomains | array[47] | list of rows | List of discovered subdomains with their DNS records |
subDomains.0.host | string | api.paypal.com | |
subDomains.0.records | array | ["66.211.168.123"] | |
count | number | 47 | Total number of subdomains discovered in this scan |
totalFound | number | 47 | Total number of subdomains found for the domain. Reads as "N+ (limit reached)" or "N+ (scan time limit reached)" when the scan stopped before exhausting the wordlist |
Failure modes
Errors come back as tool errors with a sentence the model can act on, not a bare status code.
| Status | What it means |
|---|---|
400 / 422 | The arguments didn't validate. The message names the offending one. |
401 | The OAuth session is invalid or expired — reconnect the server. |
403 | Out of credits. Not a bad key — the month's allowance is spent. |
404 | This skill isn't part of VerveKit. Check the catalog. |
429 | Brief rate limit. Retrying after a moment succeeds. |
Other ways to use Subdomain Finder Skill
Set up Subdomain Finder 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.
Frequently asked questions
Do I have to tell the agent to use SubdomainFinderSkill?
No. The tool's name and description are in the model's context once the server is connected, so it selects the tool when the question calls for it. Naming it explicitly works too and is useful when you want to force the call.
Does connecting the server expose every tool at once?
Yes — one connection lists the whole VerveKit catalog. Clients with a tool budget can usually filter the list; the credit cost is per call, so an unused tool costs nothing.
What does a call cost?
500 credits each time the tool actually runs. A model that reasons about the tool without calling it costs nothing.
Is there a REST version of this?
Yes — the same source is available as a plain HTTPS endpoint on APIVerve, linked above. Same data, same credits, same account.