MCP Server with ArcGIS Pro Add-In (C# .NET 8)

This repository demonstrates how to integrate a Model Context Protocol (MCP) server with an ArcGIS Pro Add-In. The goal is to expose ArcGIS Pro functionality as MCP tools so that GitHub Copilot (in Agent mode) or any MCP client can interact with your GIS environment.

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Overview

• ArcGIS Pro Add-In (C# with ArcGIS Pro SDK): runs in-process with ArcGIS Pro and exposes GIS operations through a local IPC channel (Named Pipes).
• MCP Server (.NET 8 console app): defines MCP tools, communicates with the Add-In via Named Pipes, and is configured as an MCP server in Visual Studio through .mcp.json.

This can allow Copilot (Agent Mode) to query maps, list layers, count features, zoom to layers, and more — directly in ArcGIS Pro.

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Prerequisites

• Visual Studio 2022 17.14 or later (for MCP Agent Mode support)
• ArcGIS Pro SDK for .NET
• ArcGIS Pro installed (same machine)
• .NET 8 SDK

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Solution Structure

ArcGisProMcpSample/
+- ArcGisProBridgeAddIn/           # ArcGIS Pro Add-In project (in-process)
¦  +- Config.daml
¦  +- Module.cs
¦  +- ProBridgeService.cs          # Named Pipe server + command handler
¦  +- IpcModels.cs                 # IPC request/response DTOs
+- ArcGisMcpServer/                # MCP server project (.NET 8)
¦  +- Program.cs
¦  +- Tools/ProTools.cs            # MCP tool definitions (bridge client)
¦  +- Ipc/BridgeClient.cs          # Named Pipe client
¦  +- Ipc/IpcModels.cs             # Shared IPC DTOs
+- .mcp.json                       # MCP server manifest for VS Copilot

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ArcGIS Pro Add-In

The Add-In starts a Named Pipe server on ArcGIS Pro launch. It handles operations like:

• pro.getActiveMapName
• pro.listLayers
• pro.countFeatures
• pro.zoomToLayer

Example: Module.cs (in sample is in a button)

protected override bool Initialize()
{
    _service = new ProBridgeService("ArcGisProBridgePipe");
    _service.Start();
    return true; // initialization successful
}

protected override bool CanUnload()
{
    _service?.Dispose();
    return true;
}

Example: ProBridgeService handler

case "pro.countFeatures":
{
    if (req.Args == null ||
        !req.Args.TryGetValue("layer", out string? layerName) ||
        string.IsNullOrWhiteSpace(layerName))
        return new(false, "arg 'layer' required", null);

    int count = await QueuedTask.Run(() =>
    {
        var fl = MapView.Active?.Map?.Layers
            .OfType<FeatureLayer>()
            .FirstOrDefault(l => l.Name.Equals(layerName, StringComparison.OrdinalIgnoreCase));
        if (fl == null) return 0;
        using var fc = fl.GetFeatureClass();
        return (int)fc.GetCount();
    });

    return new(true, null, new { count });
}

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MCP Server (.NET 8)

The MCP server uses the official ModelContextProtocol NuGet package.

Program.cs

await Host.CreateDefaultBuilder(args)
    .ConfigureServices(services =>
    {
        services.AddSingleton(new BridgeClient("ArcGisProBridgePipe"));
        services.AddMcpServer()
            .WithStdioServerTransport()
            .WithToolsFromAssembly(typeof(ProTools).Assembly);
    })
    .RunConsoleAsync();

Example tool

[McpServerToolType]
public static class ProTools
{
    private static BridgeClient _client;
    public static void Configure(BridgeClient client) => _client = client;

    [McpServerTool(Title = "Count features in a layer", Name = "pro.countFeatures")]
    public static async Task<object> CountFeatures(string layer)
    {
        var r = await _client.OpAsync("pro.countFeatures", new() { ["layer"] = layer });
        if (!r.Ok) throw new Exception(r.Error);
        var count = ((System.Text.Json.JsonElement)r.Data).GetProperty("count").GetInt32();
        return new { layer, count };
    }
}

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.mcp.json Manifest

Place in solution root (.mcp.json):

{
  "servers": {
    "arcgis": {
      "type": "stdio",
      "command": "dotnet",
      "args": [
        "run",
        "--project",
        "McpServer/ArcGisMcpServer/ArcGisMcpServer.csproj"
      ]
    }
  }
}

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Running in Visual Studio

1. Open the solution in Visual Studio 2022 (=17.14).
2. Ensure ArcGIS Pro is running with the Add-In loaded (so the Named Pipe exists).
3. In VS, open Copilot Chat Agent Mode.
4. Copilot reads .mcp.json and starts the MCP server.
5. Type in chat:
   • pro.listLayers ? returns the layers in the active map
   • pro.countFeatures layer=Buildings ? returns the feature count

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Next Steps

• Extend tools with operations like pro.selectByAttribute, pro.getCurrentExtent, pro.exportLayer.
• Add retry/timeout logic for IPC communication.
• Containerize the MCP server for deployment. ...

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