feat: header metadata support

[Hsienz]

Pull Request Checklist

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• Target branch: Please verify that the pull request targets the dev branch.
• Description: Provide a concise description of the changes made in this pull request.
• Changelog: Ensure a changelog entry following the format of Keep a Changelog is added at the bottom of the PR description.
• Dependencies: Are there any new dependencies? Have you updated the dependency versions in the documentation?
• Testing: Have you written and run sufficient tests to validate the changes?
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  • BREAKING CHANGE: Significant changes that may affect compatibility
  • build: Changes that affect the build system or external dependencies
  • ci: Changes to our continuous integration processes or workflows
  • chore: Refactor, cleanup, or other non-functional code changes
  • docs: Documentation update or addition
  • feat: Introduces a new feature or enhancement to the codebase
  • fix: Bug fix or error correction
  • i18n: Internationalization or localization changes
  • perf: Performance improvement
  • refactor: Code restructuring for better maintainability, readability, or scalability
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  • test: Adding missing tests or correcting existing tests
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Changelog Entry

Description

Update mcp package so that ClientSession.tool_call() function support meta parameter.

So we can pass unused meta to tool call from exist client-header-forwarding functionality.

Also, implementing the client-header-forwarding to cli command ONLY for streamable-http because I rarely use other type and not able to testing

Added

• Send unused meta from client-header-forwarding functionality to tool_call

• Add client-header-forwarding to cli command for streamable-http type

  usage:

  mcpo --port 8001 --type streamable-http --client-header-forwarding '{"enabled":true,"whitelist":["*"]}' -- http://localhost:8000/mcp

  mcpo --port 8001 --config config.json

  See here for format of config.json

Changed

• Update mcp package from 0.17.0 to 0.28.0 for meta suporting

---

Additional Information

You need to add something like middleware to get meta field
e.g.

// in Programs.cs
builder
    .Services.AddMcpServer()
    .WithHttpTransport(options =>
    {
        options.Stateless = true;
    })
    .WithToolsFromAssembly();

builder.Services.AddHttpContextAccessor();

var app = builder.Build();
app.Use(
    async (ctx, next) =>
    {
        ctx.Request.EnableBuffering();

        using var reader = new StreamReader(ctx.Request.Body, leaveOpen: true);

        var body = await reader.ReadToEndAsync();
        var bodyObject = JObject.Parse(body);

        var auth = bodyObject?["params"]?["_meta"]?["headers"]?["authorization"]?.ToString();
        if (auth != null)
        {
            Console.WriteLine(body);
            ctx.Request.Headers.TryAdd("Authorization", auth);
        }

        ctx.Request.Body.Position = 0;

        await next();
    }
);
app.MapMcp("/mcp");

// in Tool.cs
[McpServerToolType]
internal class HeaderTest
{
    [McpServerTool, Description("this function is use for test, if header is sent to server")]
    public static async Task<string> HeaderTesting(IHttpContextAccessor accessor)
    {
        var request = accessor.HttpContext?.Request;


        foreach (var header in accessor.HttpContext!.Request.Headers)
        {
            Console.WriteLine($"{header.Key}: {header.Value}");
        }
        return "OK";
    }
}

Screenshots or Videos

Left panel is mcpo log
Right panel is MCP server log
You can see Authorization appear in the MCP server log