If your sqlnet connectivity has been setup for LDAP in the sqlneet.ora file, then it should be as simple as:
SQL> show tns
Available TNS Entries
to get sqlcl to query the ldap server, like it does for tnsnames.ora files when TNSNAMES connectivity is in use. I haven't tried this myself with LDAP connectivity though.
If that doesn't do it then you could try using "ldapsearch" tool to query the repository. Something like:
$ ldapsearch -h ldaphost -p 389 -D "cn=orcladmin" -w password -b "cn=OracleContext,dc=company,dc=com" -s base "objectclass=*" orclnetdescstring
perhaps, using the values from your sqlnet.ora for the connection details, host and port.