keyChainServiceName null exception on macOS - tool crashes on startup

Environment

macOS 15 (Sequoia), Apple Silicon (arm64)
Tool version: microsoft.powerplatform.dataverse.mcp 0.2.310025
.NET runtimes installed: 8.0.24 and 10.0.2/10.0.3
MCP client: Claude AI (claude-ai 0.1.0)

Description
The Dataverse MCP tool crashes immediately on startup on macOS with the following unhandled exception:
Unhandled exception. System.ArgumentNullException: Value cannot be null. (Parameter 'keyChainServiceName')
at Microsoft.Identity.Client.Extensions.Msal.MacKeychainAccessor..ctor(String cacheFilePath, String keyChainServiceName, String keyChainAccountName, TraceSourceLogger logger)
at Microsoft.Identity.Client.Extensions.Msal.Storage.Create(StorageCreationProperties creationProperties, TraceSource logger)
at Microsoft.Identity.Client.Extensions.Msal.MsalCacheHelper.CreateAsync(StorageCreationProperties storageCreationProperties, TraceSource logger)
at PowerPlatformMCPProxy.Auth.AuthenticationService.GetMsalClient()
at PowerPlatformMCPProxy.Auth.AuthenticationService..ctor(...)
at PowerPlatformMCPProxy.Runtime.MCPServerProxy.RunAsync()

Steps to reproduce
Install the tool: dotnet tool install --global microsoft.powerplatform.dataverse.mcp
Configure MCP client with the following args:

json{
"command": "/Users/sami/.dotnet/tools/Microsoft.PowerPlatform.Dataverse.MCP",
"args": [
"--ConnectionUrl", "https://make.powerautomate.com/environments//connections?apiName=shared_commondataserviceforapps&connectionName=",
"--MCPServerName", "DataverseMCPServer",
"--TenantId", "",
"--EnableHttpLogging", "true",
"--EnableMsalLogging", "false",
"--Debug", "false",
"--BackendProtocol", "HTTP"
]
}

Connect — tool crashes immediately after receiving the initialize message from the client.

Attempted workarounds

Added --KeychainServiceName DataverseMCPServer as an extra arg — the value appears in the args list at runtime but the crash still occurs, meaning the parameter is not being passed through to the MSAL StorageCreationProperties internally.
Reinstalled the tool — same result.
Verified .NET 8 runtime is installed — same result.

Expected behavior
Tool should use the provided MCPServerName (or a separate KeychainServiceName arg) as the keyChainServiceName when initializing MacKeychainAccessor on macOS.
Actual behavior
Tool passes null as keyChainServiceName to MacKeychainAccessor, causing an immediate crash. The tool is completely non-functional on macOS.

Start at PowerPlatformMCPProxy.Auth.AuthenticationService.GetMsalClient and trace how StorageCreationProperties is built before Microsoft.Identity.Client.Extensions.Msal.Storage.Create. Reproduce startup on macOS with the provided arguments, then verify that a keychain service name reaches MacKeychainAccessor and the MCP tool completes initialization without the null exception.