Currently, the QSL service allows for square bracket filtering for attrs such as @name, @resourceid, etc. But though the attr always exists, @uid is not supported.
Here is an example query:
https://dev-devx-cmdb-api-prd.paas-prod-west2.a.intuit.com/v1.1/qsl/application[@uid=%220x8a%22$$limit=25,offset=0]%7B*%7D.deployment%7B*%7D.cluster%7B@name%7D