microsoft/semantic-kernel · error · ArgumentException

The option key '{bindingType}.storage_service_endpoint' is r

Error message

The option key '{bindingType}.storage_service_endpoint' is required.

What it means

Thrown while constructing an AzureFunctionBinding via GetAzureFunctionBinding. After fetching the required option dict for the given bindingType, it must contain a 'storage_service_endpoint' key whose value is a string. If the key is missing or the value is not a string, ArgumentException is thrown. The endpoint identifies the Azure Storage account backing the function queue.

Source

Thrown at dotnet/src/Agents/AzureAI/Extensions/AgentToolDefinitionExtensions.cs:181

                {
                    throw new ArgumentException("The option keys 'store_name' and 'data_sources' are required for a vector store configuration.");
                }

                configurations.Add(new VectorStoreConfigurations(storeName, new VectorStoreConfiguration(dataSources)));
            }
        }

        return configurations;
    }

    private static AzureFunctionBinding GetAzureFunctionBinding(this AgentToolDefinition agentToolDefinition, string bindingType)
    {
        Verify.NotNull(agentToolDefinition.Options);

        var binding = agentToolDefinition.GetRequiredOption<Dictionary<object, object>>(bindingType);
        if (!binding.TryGetValue("storage_service_endpoint", out var endpointValue) || endpointValue is not string storageServiceEndpoint)
        {
            throw new ArgumentException($"The option key '{bindingType}.storage_service_endpoint' is required.");
        }
        if (!binding.TryGetValue("queue_name", out var nameValue) || nameValue is not string queueName)
        {
            throw new ArgumentException($"The option key '{bindingType}.queue_name' is required.");
        }

        return new AzureFunctionBinding(new AzureFunctionStorageQueue(storageServiceEndpoint, queueName));
    }

    internal static int? GetTopK(this AgentToolDefinition agentToolDefinition)
    {
        return agentToolDefinition.Options?.TryGetValue("top_k", out var topKValue) ?? false
            ? int.Parse((string)topKValue!)
            : null;
    }

    internal static string? GetFilter(this AgentToolDefinition agentToolDefinition)
    {

View on GitHub (pinned to c028a0c7dc)

Solutions

1. Add 'storage_service_endpoint' (string) under the binding-type key in the tool options.
2. Ensure the value is the full Azure Storage queue service endpoint URL.

Example fix

// before
storage_queue:
  queue_name: myqueue
  # storage_service_endpoint missing -> throws 165

// after
storage_queue:
  storage_service_endpoint: https://mystorage.queue.core.windows.net
  queue_name: myqueue

var binding = tool.GetRequiredOption<Dictionary<object, object>>(bindingType);
if (!binding.TryGetValue("storage_service_endpoint", out var e) || e is not string)
    throw new ArgumentException($"{bindingType}.storage_service_endpoint (string) is required.");

static bool HasStorageEndpoint(Dictionary<object, object> b) =>
    b.TryGetValue("storage_service_endpoint", out var e) && e is string s && !string.IsNullOrEmpty(s);

When it happens

Trigger: An Azure Function tool binding (e.g., 'storage_queue') option dictionary lacks 'storage_service_endpoint', or its value is a non-string type.

Common situations: Agent definition YAML missing the storage endpoint for an Azure Function tool; endpoint set to a null or numeric value; bindingType key itself misnamed.

Related errors

• The option key '{bindingType}.queue_name' is required.
• Azure AI Search tool definition must have both 'index_connec
• The option keys 'asset_identifiers' and 'asset_type' are req
• The option keys 'store_name' and 'data_sources' are required
• Invalid kernel selection. {selectedKernelName} is not a vali

AI-assisted analysis of microsoft/semantic-kernel@c028a0c7dc (2026-08-13). Data as JSON: /api/errors/526305b4149fab3f. Report an issue: GitHub.