diff --git a/apis/linked.d.ts b/apis/linked.d.ts
index 8c4ed156..fbb78dfc 100644
--- a/apis/linked.d.ts
+++ b/apis/linked.d.ts
@@ -2,6 +2,7 @@ import * as csn from './csn'
 import { IterableMap } from './internal/util'
 import { Definitions, any_, entity, service_ } from './linked/classes'
 
+// TODO: the function usage for services is not documented and will be removed with cds^10
 export type ModelPart<T extends any_> = IterableMap<T> & ((namespace: string) => IterableMap<T>)
 type Visitor = (def: any_, name: string, parent: any_, defs: Definitions) => void
 type Filter = string | (<T extends any_ = any_>(def: T) => boolean)
diff --git a/test/typescript/apis/project/cds-services.ts b/test/typescript/apis/project/cds-services.ts
index 5442e069..e1054f08 100644
--- a/test/typescript/apis/project/cds-services.ts
+++ b/test/typescript/apis/project/cds-services.ts
@@ -24,10 +24,16 @@ cds.connect({kind: 'odata', model:'some/imported/model', service: 'BusinessPartn
 // basic properties
 srv.name.length
 srv.entities[0] = Books // same type
+srv.events[0] = ???
+srv.types[0] = ???
+srv.actions[0] = ???
+
+// TODO: function usage was never official, is now deprecated, and will be removed with cds^10
 srv.entities('namespace')
 srv.events('namespace')
 srv.types('namespace')
-srv.operations('namespace')
+srv.operations('namespace') //> should be .actions()
+srv.actions('namespace')
 
 await srv.init()
 
@@ -469,6 +475,14 @@ srv.entities('namespace');
 // @ts-expect-error
 srv.entities('namespace')('and again')
 
+// TODO: function usage was never official, is now deprecated, and will be removed with cds^10
+// @ts-expect-deprecated -> is there such a thing? :D
+srv.entities('namespace')
+srv.events('namespace')
+srv.types('namespace')
+srv.operations('namespace') //> should be .actions()
+srv.actions('namespace')
+
 type ActionType = HandlerFunction<typeof unboundAction>
 srv.on(unboundAction, externalActionHandler)
 function externalActionHandler(req: ActionType['parameters']['req']): ActionType['returns'] {
@@ -499,4 +513,4 @@ asrv.on('', (req) => {
   asrv.dispatch([req])
 })
 asrv.dispatch('foo')
-asrv.dispatch(['foo', 'bar'])
\ No newline at end of file
+asrv.dispatch(['foo', 'bar'])