Quickstart (C#) -- GetForecast needs to make two client api calls

[mikekidder]

Testing dotnet quickstart from changes merged in PR #221

-- C# version was missing getting the forecast URL for first request. Needed additional client request.
-- Added a little more description detail on functions. Now llm can infer passing two-letter state abbreviations.
-- Minor cleanup (whitespace) when I saved file.
-- Added Globalization into PR per #230

Motivation and Context

Docs source code updates for C#

How Has This Been Tested?

Test MCP functions with LLM

Breaking Changes

No

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation update

Checklist

• I have read the MCP Documentation
• My code follows the repository's style guidelines
• New and existing tests pass locally
• I have added appropriate error handling
• I have added or updated documentation as needed

Additional context

[DGuhr]

hey 👋 I just opened #230 and then saw this PR, which fixes one of the two problems mentioned there. It'd be nice if you could also fix the other one with the langitude/longitude formatting. see my example code in the ticket (and e.g. here for ref)

code:

[McpServerTool,
 Description(@"
      Get weather forecast for a location.
      Args:
      Latitude: Latitude of the location.
      Longitude: Longitude of the location.
")]
public static async Task<string> GetForecast(
    HttpClient client,
    [Description("Latitude of the location.")] double latitude,
    [Description("Longitude of the location.")] double longitude)
{
    var jsonElement = await client.GetFromJsonAsync<JsonElement>($"/points/{latitude.ToString(CultureInfo.InvariantCulture)},{longitude.ToString(CultureInfo.InvariantCulture)}");
    var forecastUrl = jsonElement.GetProperty("properties").GetProperty("forecast").GetString();

    jsonElement = await client.GetFromJsonAsync<JsonElement>(forecastUrl);
    var periods = jsonElement.GetProperty("properties").GetProperty("periods").EnumerateArray();

    return string.Join("\n---\n", periods.Select(period => $"""
                                                            {period.GetProperty("name").GetString()}
                                                            Temperature: {period.GetProperty("temperature").GetInt32()}°F
                                                            Wind: {period.GetProperty("windSpeed").GetString()} {period.GetProperty("windDirection").GetString()}
                                                            Forecast: {period.GetProperty("detailedForecast").GetString()}
                                                            """));
}

[DGuhr]

Worked for me, so LGTM 👌 hopefully someone from the team will approve quickly, it's a quite bad first impression honestly.

Solves #230

[mikekidder]

Hi @aaronpowell and @dsp-ant.

Just wanted to say that you have a couple of .Net enthusiasts here.
We both found MCP Quickstart (C# version) was not functional in its latest iteration.

Both @DGuhr (thanks for the collaboration) and I have tested updates to Aaron's PR #221.
Hope to see these changes to the MCP quickstart docs updated soon.

Thanks!

[aaronpowell]

Yep, my bad. Seems I'm quite bad at reading Python code. We have modelcontextprotocol/csharp-sdk#134 tracking it in the main repo, so once that's merged, we should align the docs.

[aaronpowell]

You shouldn't need to add args info here, it should be inferred from the parameters (and their description). If that info isn't getting surfaced correctly, we should look at improving the SDK rather than requiring a duplication of info.

[mikekidder]

Without the additional description, the model was attempting to pass the full state name to the weather api resulting in a 404. Ex. "Give me the current alerts in Kansas"

The addition replicates what the python sample did.. and it worked.

[puran1218]

Agree with @aaronpowell, this additional info can be added in the description of the state parameter. For example:
public static async Task<string> GetAlerts(HttpClient client, [Description("The US state to get alerts for. Use two-letter US state code (e.g. CA, NY).")] string state)

[aaronpowell]

I don't disagree that this is important information, more that it shouldn't be in the description of the tool, but as @puran1218 points out, it should be on the description of the argument.

With Python, the reason it is that was is because they don't have argument annotations, in fact they don't use annotations in the same way we use attributes (providing the description), instead they use the doc comments, which they regex at runtime to extract the description/args info from.