docs: note BrowseChildren in gateway overview and client READMEs

clients/dotnet/README.md

@@ -196,6 +196,28 @@ dotnet run --project clients/dotnet/ZB.MOM.WW.MxGateway.Client.Cli -- galaxy-las
 dotnet run --project clients/dotnet/ZB.MOM.WW.MxGateway.Client.Cli -- galaxy-discover --endpoint http://localhost:5000 --api-key-env MXGATEWAY_API_KEY
 ```
 
+### Browsing lazily
+
+For UI trees or OPC UA bridges, use `BrowseChildrenAsync` to walk one level at a
+time instead of paging the full hierarchy. Pass an empty request for root objects;
+subsequent calls supply `ParentGobjectId`, `ParentTagName`, or
+`ParentContainedPath`. Each child's `ChildHasChildren[i]` tells you whether to
+draw an expand triangle. Filter fields match `DiscoverHierarchy`. See
+[Galaxy Repository](../../docs/GalaxyRepository.md#browsechildren) for full
+request and filter semantics.
+
+```csharp
+BrowseChildrenReply roots = await repository.BrowseChildrenAsync(
+    new BrowseChildrenRequest());
+
+for (int i = 0; i < roots.Children.Count; i++)
+{
+    GalaxyObject child = roots.Children[i];
+    bool hasChildren = roots.ChildHasChildren[i];
+    Console.WriteLine($"{child.TagName} expand={hasChildren}");
+}
+```
+
 ### Watching deploy events
 
 `WatchDeployEventsAsync` opens the `WatchDeployEvents` server-streaming RPC. The

clients/go/README.md

@@ -121,6 +121,28 @@ reports `present=false` (no deploy recorded). `DiscoverHierarchy` returns
 the generated `*GalaxyObject` slice with each object's dynamic attributes
 populated for direct contract access.
 
+### Browsing lazily
+
+For UI trees or OPC UA bridges, use `BrowseChildren` to walk one level at a
+time instead of loading the full hierarchy. Pass an empty request for root
+objects; subsequent calls set `ParentGobjectId`, `ParentTagName`, or
+`ParentContainedPath`. Filter fields match `DiscoverHierarchy`. Each response
+pairs `Children` with `ChildHasChildren` so you know which nodes to expand. See
+[Galaxy Repository](../../docs/GalaxyRepository.md#browsechildren) for full
+request and filter semantics.
+
+```go
+import pb "gitea.dohertylan.com/dohertj2/mxaccessgw/clients/go/internal/generated/galaxy_repository/v1"
+
+reply, err := galaxy.BrowseChildren(ctx, &pb.BrowseChildrenRequest{})
+if err != nil {
+    return err
+}
+for i, child := range reply.GetChildren() {
+    fmt.Printf("%s expand=%v\n", child.GetTagName(), reply.GetChildHasChildren()[i])
+}
+```
+
 ### Watching deploy events
 
 `WatchDeployEvents` opens a server-streaming subscription. The server emits a

clients/java/README.md

@@ -116,6 +116,29 @@ gradle :zb-mom-ww-mxgateway-cli:run --args="galaxy-deploy-time --endpoint localh
 gradle :zb-mom-ww-mxgateway-cli:run --args="galaxy-discover --endpoint localhost:5000 --api-key-env MXGATEWAY_API_KEY --plaintext --json"
 ```
 
+### Browsing lazily
+
+For UI trees or OPC UA bridges, use `browseChildren` to walk one level at a
+time instead of loading the full hierarchy with `discoverHierarchy`. Pass a
+default request for root objects; subsequent calls set `parentGobjectId`,
+`parentTagName`, or `parentContainedPath`. Filter fields match
+`DiscoverHierarchy`. Each response pairs `getChildrenList()` with
+`getChildHasChildrenList()` so you know which nodes to expand. See
+[Galaxy Repository](../../docs/GalaxyRepository.md#browsechildren) for full
+request and filter semantics. This snippet documents the API as it appears once
+the Java client is regenerated on the Windows host.
+
+```java
+BrowseChildrenReply reply = galaxy.browseChildren(
+        BrowseChildrenRequest.newBuilder().build());
+
+List<GalaxyObject> children = reply.getChildrenList();
+List<Boolean> hasChildren = reply.getChildHasChildrenList();
+for (int i = 0; i < children.size(); i++) {
+    System.out.printf("%s expand=%b%n", children.get(i).getTagName(), hasChildren.get(i));
+}
+```
+
 ### Watching deploy events
 
 `GalaxyRepository.WatchDeployEvents` is a server-streaming RPC: the gateway

clients/python/README.md

@@ -138,6 +138,25 @@ The methods return native Python types (`bool`, `datetime | None`, and a
 into the hierarchy without learning the underlying stub class. The
 service requires the `metadata:read` scope on the API key.
 
+### Browsing lazily
+
+For UI trees or OPC UA bridges, use `browse_children` to walk one level at a
+time instead of loading the full hierarchy with `discover_hierarchy`. Pass an
+empty request for root objects; subsequent calls set `parent_gobject_id`,
+`parent_tag_name`, or `parent_contained_path`. Filter fields match
+`DiscoverHierarchy`. Each response pairs `children` with `child_has_children` so
+you know which nodes to expand. See
+[Galaxy Repository](../../docs/GalaxyRepository.md#browsechildren) for full
+request and filter semantics.
+
+```python
+from zb_mom_ww_mxgateway.generated import galaxy_repository_pb2 as galaxy_pb2
+
+reply = await galaxy.browse_children(galaxy_pb2.BrowseChildrenRequest())
+for child, has_children in zip(reply.children, reply.child_has_children):
+    print(child.tag_name, "expand=" + str(has_children))
+```
+
 ### Watching deploy events
 
 `GalaxyRepositoryClient.watch_deploy_events` opens a server-streaming

clients/rust/README.md

@@ -138,6 +138,25 @@ cargo run -p mxgw-cli -- galaxy last-deploy-time --endpoint http://localhost:500
 cargo run -p mxgw-cli -- galaxy discover-hierarchy --endpoint http://localhost:5000 --api-key-env MXGATEWAY_API_KEY --json
 ```
 
+### Browsing lazily
+
+For UI trees or OPC UA bridges, use `browse_children` to walk one level at a
+time instead of paging the full hierarchy. Pass a default request for root
+objects; subsequent calls set `parent_gobject_id`, `parent_tag_name`, or
+`parent_contained_path`. Filter fields match `discover_hierarchy`. Each response
+pairs `children` with `child_has_children` so you know which nodes to expand. See
+[Galaxy Repository](../../docs/GalaxyRepository.md#browsechildren) for full
+request and filter semantics.
+
+```rust
+use zb_mom_ww_mxgateway_client::generated::galaxy_repository::v1::BrowseChildrenRequest;
+
+let reply = galaxy.browse_children(BrowseChildrenRequest::default()).await?.into_inner();
+for (child, has_children) in reply.children.iter().zip(reply.child_has_children.iter()) {
+    println!("{} expand={}", child.tag_name, has_children);
+}
+```
+
 ### Watching deploy events
 
 `watch_deploy_events` opens the `WatchDeployEvents` server stream. The

gateway.md

@@ -65,6 +65,9 @@ Detailed follow-up docs:
 - `docs/GalaxyRepository.md` covers the read-only Galaxy Repository browse
   RPCs that let clients enumerate the deployed object hierarchy and dynamic
   attributes before subscribing via the MXAccess gateway service.
+  `DiscoverHierarchy` returns paged flat results; `BrowseChildren` returns
+  the direct children of one parent for OPC UA-style lazy tree walks — see
+  [Galaxy Repository](docs/GalaxyRepository.md#browsechildren).
 
 Implementation style guides: