Fix doc references, stale comment, polling resilience and URI path join

Author: Shreya Sangwa

tools/Azure.Mcp.Tools.ManagedCleanroom/docs/architecture.md

@@ -30,7 +30,6 @@ Azure.Mcp.Tools.ManagedCleanroom/
 │   │   └── Collaborations/CollaborationsListOptions.cs
 │   └── Services/
 │       ├── IManagedCleanroomService.cs
-│       ├── ManagedCleanroomSerializerContext.cs
 │       └── ManagedCleanroomService.cs
 └── tests/
     └── Azure.Mcp.Tools.ManagedCleanroom.Tests/

tools/Azure.Mcp.Tools.ManagedCleanroom/src/Commands/ManagedCleanroomJsonContext.cs

@@ -6,10 +6,9 @@
 
 namespace Azure.Mcp.Tools.ManagedCleanroom.Commands;
 
-// Only JsonElement is registered here — no typed *CommandResult models — because
-// CollaborationClient is a protocol-method-only generated client that returns raw
-// Azure.Response with no typed deserialization. Commands pass the raw JsonElement
-// response directly to ResponseResult.Create without wrapping it in a result record.
+// Only JsonElement is registered here because the current Managed Cleanroom
+// commands pass through raw JSON payloads from HTTP/ARM responses directly to
+// ResponseResult.Create without wrapping them in typed result models.
 [JsonSerializable(typeof(JsonElement))]
 [JsonSourceGenerationOptions(PropertyNamingPolicy = JsonKnownNamingPolicy.CamelCase, WriteIndented = true, DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull)]
 internal partial class ManagedCleanroomJsonContext : JsonSerializerContext;

tools/Azure.Mcp.Tools.ManagedCleanroom/src/Services/ManagedCleanroomService.cs

@@ -154,7 +154,19 @@ await armClient.GetGenericResources()
 
             await Task.Delay(ProvisioningPollInterval, cancellationToken).ConfigureAwait(false);
 
-            var getResponse = await resource.GetAsync(cancellationToken: cancellationToken).ConfigureAwait(false);
+            Response<GenericResource> getResponse;
+
+            try
+            {
+                getResponse = await resource.GetAsync(cancellationToken: cancellationToken).ConfigureAwait(false);
+            }
+            catch (RequestFailedException ex) when (ex.Status == (int)HttpStatusCode.NotFound)
+            {
+                // ARM can briefly return 404 after the initial create starts but before the
+                // resource has fully materialized. Keep polling until the timeout or a terminal state.
+                continue;
+            }
+
             var propsBytes = getResponse.Value.Data.Properties?.ToArray() ?? [];
 
             if (propsBytes.Length > 0)
@@ -187,7 +199,15 @@ private HttpClient CreateHttpClient(bool allowUntrustedCert)
     private static Uri BuildCollaborationsListUri(Uri endpointUri, bool? activeOnly)
     {
         // The current frontend route for listing collaborations is /gets.
-        var builder = new UriBuilder(new Uri(endpointUri, CollaborationsListPath));
+        var basePath = endpointUri.AbsolutePath.TrimEnd('/');
+        var path = string.IsNullOrEmpty(basePath) || basePath == "/"
+            ? $"/{CollaborationsListPath}"
+            : $"{basePath}/{CollaborationsListPath}";
+
+        var builder = new UriBuilder(endpointUri)
+        {
+            Path = path
+        };
 
         if (activeOnly.HasValue)
         {