Subdomain API
REMOTE · API.SUBDOMAIN.APP · SCANNED AUG 3
Find known subdomains of a domain. Passive data; may include historic entries. List or count.
Available components
How this component scores in each security and reliability category. Every signal is checked automatically against the live server, and we only credit what we can confirm. How we score →
Endpoint Security60
- The endpoint's TLS certificate is valid, in date, and uses a strong key. View diagnostics → Pass
- Authorisation not fully verified: no authorisation is required to call this server, and 2 tool(s) never declared a destructiveHint. The MCP spec treats an absent hint as destructive by default, so we cannot call this surface safe. See how to fix → View diagnostics → Unverified
- HTTPS is enforced; there's no plaintext access path. View diagnostics → Pass
- HSTS check failed: the Strict-Transport-Security header is absent. See how to fix → View diagnostics → Fail
- DNSSEC is configured correctly; the domain's records validate against the full chain to the root. View diagnostics → Pass
Transport & Reachability100
- Verified streamable-http transport via a live MCP handshake. View diagnostics → Pass
Schema Quality & AI Usability79
- AI-judged instruction clarity (excellent).Pass
- Context-footprint check failed: tool/resource definitions use about 344 tokens (~172/item across 2 items; 2 tools + 0 resources), over budget; trim descriptions and params. See how to fix → Fail
- Usage-examples check failed: none of the tools include examples. See how to fix → Fail
Stability & Change Management27
- Stability observed for 8 of 30 days with no destabilising changes; credit accrues until the full window elapses.Partial
Tool Coverage100
- 100% of tools have a non-trivial description (not blank, and not just the tool's name).Pass
- 100% of tool parameters carry a description.Pass
- Structured output schemas are declared (100% of tools); any adoption earns full credit.Pass
Capabilities100
- Implements a supported MCP spec version (2025-11-25); the latest is 2026-07-28.Pass
Add this component to your MCP client. Where a client-specific snippet is available, pick your client below and copy it straight into your config; otherwise use the connection detail shown.
remote · api.subdomain.app
claude mcp add --transport http app-subdomain-subdomains https://api.subdomain.app/mcp
[mcp_servers.app-subdomain-subdomains] url = "https://api.subdomain.app/mcp"
{
"$schema": "https://opencode.ai/config.json",
"mcp": {
"app-subdomain-subdomains": {
"type": "remote",
"url": "https://api.subdomain.app/mcp",
"enabled": true
}
}
} openclaw mcp add app-subdomain-subdomains --url https://api.subdomain.app/mcp --transport streamable-http
mcp_servers:
app-subdomain-subdomains:
url: "https://api.subdomain.app/mcp" {
"mcpServers": {
"app-subdomain-subdomains": {
"type": "http",
"url": "https://api.subdomain.app/mcp"
}
}
} The mcpServers block is a cross-client convention. Remote transports vary, so check your client's docs.
Every change we have recorded for this component, newest first. Security-relevant changes are always shown. ▲ marks a change for the better, ▼ a change for the worse; unmarked changes are neutral.
- 3 Aug 26 +1
No change was recorded against any check on this day. Stability & Change Management went from 23 to 27. That category is still filling its 30-day observation window: 7 days of observed history at the previous scan, 8 at this one. The score rises as the window fills, whether or not the server changes.
- 1 Aug 26 +1
No change was recorded against any check on this day. Stability & Change Management went from 17 to 20. That category is still filling its 30-day observation window: 5 days of observed history at the previous scan, 6 at this one. The score rises as the window fills, whether or not the server changes.
- 31 Jul 26 0
- We updated how we score, so this day's move reflects our rubric, not a change to the server See what changed → functional
- 30 Jul 26 0
- We updated how we score, so this day's move reflects our rubric, not a change to the server See what changed → functional
- 29 Jul 26 +1
No change was recorded against any check on this day. Stability & Change Management went from 7 to 10. That category is still filling its 30-day observation window: 2 days of observed history at the previous scan, 3 at this one. The score rises as the window fills, whether or not the server changes.
- 28 Jul 26 +1
No change was recorded against any check on this day. Stability & Change Management went from 3 to 7. That category is still filling its 30-day observation window: 1 days of observed history at the previous scan, 2 at this one. The score rises as the window fills, whether or not the server changes.
- 27 Jul 26 0
- We updated how we score, so this day's move reflects our rubric, not a change to the server See what changed → functional
- 26 Jul 26 65
First indexed and scored.
Diagnostic detail from the automated scan of this channel: what the scanner observed at each step, so you can see exactly where a check passed or failed. It is informational only and never changes the trust score.
Captured 3 Aug 2026 · Probed https://api.subdomain.app/mcp
TLS valid
Negotiated TLS 1.3 with TLS_AES_128_GCM_SHA256 .
| Subject | Issuer | Valid from | Valid until | Key | Signature | Serial |
|---|---|---|---|---|---|---|
| CN=subdomain.app | CN=WE1,O=Google Trust Services,C=US | 17 Jun 2026 | 15 Sept 2026 | ECDSA 256 | ECDSA-SHA256 | 858821ed28811b40edb60d5bfc46ccf |
| SANs: subdomain.app, api.subdomain.app, *.api.subdomain.app | ||||||
| CN=WE1,O=Google Trust Services,C=US (CA) | CN=GTS Root R4,O=Google Trust Services LLC,C=US | 13 Dec 2023 | 20 Feb 2029 | ECDSA 256 | ECDSA-SHA384 | 7ff31977972c224a76155d13b6d685e3 |
| CN=GTS Root R4,O=Google Trust Services LLC,C=US (CA) | CN=GlobalSign Root CA,OU=Root CA,O=GlobalSign nv-sa,C=BE | 15 Nov 2023 | 28 Jan 2028 | ECDSA 384 | SHA256-RSA | 7fe530bf331343bedd821610493d8a1b |
DNSSEC secure
Validation of api.subdomain.app. — Secure
| Zone | DS | Keys | Algorithms | Outcome |
|---|---|---|---|---|
| . | trust_anchor | 20326, 38696 | 8, 8 | Verified |
| app. | present | 23684 | 8 | Verified |
| subdomain.app. | present | 2371 | 13 | Verified |
| api.subdomain.app. | Verified address RRset verified with the apex keys |
Authentication No authorisation required
The endpoint answered without asking for a token. Anyone who knows the URL can reach it.
| Result | No authorisation required |
|---|---|
| HTTP status | 200 |
Transports 2 probes
| Transport | URL | Outcome | Status | Location |
|---|---|---|---|---|
| streamable-http | https://api.subdomain.app/mcp | Verified | 200 | |
| http (plaintext) | http://api.subdomain.app/mcp | HTTPS enforced | 301 | https://api.subdomain.app/mcp |
The tools this component advertises to a client, with an estimated token cost for each. Expand a tool to see its parameters and schema. The per-tool counts are indicative and are not scored directly; the schema's total context footprint is one signal in Schema Quality & AI Usability.
count_subdomains Count subdomains ~132
Return only the total number of distinct subdomains known for a domain — no list. Cheap and low-token. Use when the user asks "how many subdomains" or you only need the size of the attack surface. Count includes historic subdomains that may no longer be live. It is a point-in-time figure that changes over time, so treat it as current-as-of-query, not a fixed value.
| Name | Type | Req | Description |
|---|---|---|---|
| domain | string | yes | Root (registrable) domain as a bare hostname, e.g. "example.com". No scheme, path, port, or leading "www." — these are stripped. |
| Name | Type | Req | Description |
|---|---|---|---|
| domain | string | yes | — |
| total | integer | yes | Total distinct subdomains known. |
No examples provided.
find_subdomains Find subdomains ~212
List known subdomains (hostnames) of a root domain. Data is passive (not active scanning): results are historic observations and may include subdomains that no longer resolve or are no longer live. Results are a point-in-time snapshot that changes over time as new subdomains are observed — re-query rather than caching the result. Use for attack-surface mapping, security recon, asset inventory, or SEO host discovery. Hostnames are returned most-recently-seen first. The response always reports `total` (full distinct count known) and a `truncated` flag, so you can tell when more exist beyond `limit`.
| Name | Type | Req | Description |
|---|---|---|---|
| domain | string | yes | Root (registrable) domain as a bare hostname, e.g. "example.com". No scheme, path, port, or leading "www." — these are stripped. |
| limit | integer | — | Max subdomains to return (1-1000, default 200). `total` always reports the full count regardless of this cap. |
| Name | Type | Req | Description |
|---|---|---|---|
| domain | string | yes | — |
| returned | integer | yes | Number in `subdomains`. |
| subdomains | array | yes | — |
| total | integer | yes | Total distinct subdomains known. |
| truncated | boolean | yes | True if more exist beyond `limit`. |
No examples provided.