Not support string[]?

[realMJZ]

        [McpServerTool, Description("...")]
        [return: Description("...")]
        private static async Task<IEnumerable<string>> Abc(ViewModel vm,
            [Description("...")] string[] names)

schema

{
  "name": "abc",
  "description": "...\nReturns: ...",
  "parameters": {
    "type": "object",
    "properties": {}
  },
  "strict": false
}

[realMJZ]

Okay, it looks like this was my own issue.
After commenting out builder.Host.UseServiceProviderFactory(serviceProviderFactory);, everything works as expected.
I’ll investigate why this happens. If I make any progress, I’ll post it here and then close the issue.

[realMJZ]

This happens when using builder.Host.UseServiceProviderFactory(new DryIocServiceProviderFactory());, but I still don’t know why.

[stephentoub]

I don't know what DryIocServiceProviderFactory does, but the MCP code will query the IServiceProvider to see whether it implements IServiceProviderIsService, and if it does, for each parameter in the tool method it'll ask the IServiceProviderIsService whether that parameter's type (e.g. string[]) can be satisfied from the service provider. If it can, it'll get the parameter's value from IServiceProvider.GetService rather than getting it from the wire. Sounds like that DryIocServiceProviderFactory is causing that to treat the string[] as something that comes from DI.