Reverse-lookup organization for one or more domains
ctscout_lookup_domainIdentify the organization behind one or more apex domains by querying a domain-attribution warehouse built from OV/EV TLS certificates.
Instructions
Reverse-lookup ctscout.dev's domain-attribution warehouse: given one or more apex domains, return the organization(s) attributed to each.
Args:
domains (string[], required): apex domains to look up. Each between 3 and 253 chars. Max 10 per call. Examples: ["gs.com"], ["coalition.com", "at-bay.com"].
response_format ('markdown' | 'json', default 'markdown'): output format.
Returns:
In markdown: a table of (domain, org, cert count, subdomain count). Only domains found in the warehouse appear; missing domains indicate no attribution.
In JSON: the same structure as ctscout_search_company. The 'domains' array contains one entry per (domain, org) pair found.
Examples:
Use when: "Who owns gs.com?" -> { domains: ["gs.com"] }
Use when: "Are coalition.com and at-bay.com owned by the same parent?" -> { domains: ["coalition.com", "at-bay.com"] }
Don't use when: You have a company name and want to enumerate its domains — use ctscout_search_company instead.
Coverage caveat:
Returns 0 results if domain isn't in the warehouse. Either the domain is not in our index, or no OV/EV certs have been issued for it. DV-only domains (Let's Encrypt etc.) are typically not indexed.
When a domain IS in the warehouse but ownership is via subsidiary (e.g. an Allianz brand domain), the 'org' field shows the cert-subject organization which may differ from the brand on the homepage.
Auth & limits: same as ctscout_search_company.
Input Schema
| Name | Required | Description | Default |
|---|---|---|---|
| domains | Yes | Apex domains to look up (e.g. ['gs.com', 'goldmansachs.com']). Returns the organization(s) that own each domain, plus any sibling domains in the warehouse owned by the same orgs. Max 10. | |
| response_format | No | Output format: 'markdown' for human-readable summary, 'json' for the raw API response. | markdown |