Who using WithListToolsHandler and WithCallToolHandler plz help

[jason-lee-x]

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• I have checked that this question would not be more appropriate as an issue in a specific repository
• I have searched existing discussions and documentation for answers

Question Category

• Protocol Specification
• SDK Usage
• Server Implementation
• General Implementation
• Documentation
• Other

Your Question

Thanks for taking the time to read this.

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Question:

1. Load different tool lists based on user permissions
2. Require secondary authorization for sensitive operations

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What I’ve tried:

I attempted to use WithListToolsHandler and WithCallToolHandler for interception.

According to the official example, in WithListToolsHandler, I need to add each tool individually using new Tool(). For each tool’s InputSchema, I have to repeatedly define the parameters and their descriptions, which is quite cumbersome.

Is there a way to simplify this process? If so, could you share a demo?

[kaniosm]

Hi @jason-lee-x ,

Below what I tried so far....
Since if you use the .WithTools(...) or WithToolsFromAssembly extension methods, tools are added to the dependency container, listing will always read them, therefore I had to skip the extensions are replicate the discovery in a new method.

public static IEnumerable<McpServerTool> GetTools()
{
    var toolAssembly = Assembly.GetEntryAssembly();// .GetCallingAssembly(); (in my case the correct was the entry assembly)
    var tools = (from t in toolAssembly.GetTypes()
                 where t.GetCustomAttribute<McpServerToolTypeAttribute>() != null
                 select new { t, Methods = t.GetMethods(BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Static | BindingFlags.Instance) });

    foreach (var tool in tools)
    {
        foreach (var toolMethod in tool.Methods)
        {
            if (toolMethod.GetCustomAttribute<McpServerToolAttribute>() is not null)
            {
                yield return toolMethod.IsStatic ?
                    McpServerTool.Create(toolMethod) : McpServerTool.Create(toolMethod, tool.t);
            }
        }
    }
}

and in startup:

builder.Services.AddMcpServer()
    .WithHttpTransport()
    .WithListToolsHandler(async (ctx, ct) =>
    {
       //Some logic here to get the "Mcp-Session-Id" which I intent to use to filter my tools
        var accessor = ctx.Services.GetService<IHttpContextAccessor>();
        if (accessor.HttpContext!.Request.Headers.TryGetValue("Mcp-Session-Id", out var sessionId))
        {
            //requestContext.SessionId = sessionId;
        }
        var tools = ToolParser.GetTools().ToList();
        return new ModelContextProtocol.Protocol.Types.ListToolsResult
        {
            Tools = tools.Select(t => t.ProtocolTool).ToList()
        };
    })

I hope this adds a small brick to your puzzle!

[jason-lee-x]

It really helped a lot,THANKS!!!

I hope you have a nice day Sir.