Add IoT Hub device list command

.vscode/mcp.json

@@ -0,0 +1,16 @@
+{
+  "servers": {
+    "iris-local-mcp": {
+      "type": "stdio",
+      "command": "dotnet",
+      "args": [
+        "servers/Azure.Mcp.Server/src/bin/Release/net9.0/azmcp.dll",
+        "server",
+        "start",
+        "--namespace",
+        "iothub"
+      ]
+    }
+  },
+  "inputs": []
+}

.vscode/settings.json

@@ -0,0 +1,7 @@
+{
+    "chat.mcp.serverSampling": {
+        ".vscode/mcp.json: iris-local-mcp": {
+            "allowedDuringChat": true
+        }
+    }
+}

Directory.Packages.props

@@ -34,6 +34,7 @@
     <PackageVersion Include="Azure.ResourceManager.ContainerService" Version="1.2.5" />
     <PackageVersion Include="Azure.ResourceManager.EventGrid" Version="1.2.0-beta.2" />
     <PackageVersion Include="Azure.ResourceManager.EventHubs" Version="1.2.1" />
+    <PackageVersion Include="Azure.ResourceManager.IotHub" Version="1.2.0-beta.2" />
     <PackageVersion Include="Azure.ResourceManager.CognitiveServices" Version="1.5.1" />
     <PackageVersion Include="Azure.ResourceManager.Monitor" Version="1.4.0-beta.4" />
     <PackageVersion Include="Azure.ResourceManager.MySql" Version="1.1.2" />

dotnet-tools.json

@@ -0,0 +1,13 @@
+{
+  "version": 1,
+  "isRoot": true,
+  "tools": {
+    "azure.mcp": {
+      "version": "2.0.4",
+      "commands": [
+        "azmcp"
+      ],
+      "rollForward": false
+    }
+  }
+}

package.json

@@ -0,0 +1,5 @@
+{
+  "dependencies": {
+    "@azure/mcp": "^3.0.0-beta.19"
+  }
+}

servers/Azure.Mcp.Server/CHANGELOG.md

@@ -6,6 +6,7 @@ The Azure MCP Server updates automatically by default whenever a new release com
 
 ### Features Added
 
+- Added `azmcp iothub device list` to list device identities in an Azure IoT Hub device registry. The command returns device metadata without authentication keys, applies a default page size of 100 and a maximum of 100 to `--max-count`, returns a validation error when `--max-count` is less than 1, and flags `truncated` (with an explanatory message) when the hub contains more devices than were returned.
 - Added Azure IoT Hub integration updates including command docs, e2e prompts, README service coverage, consolidated tool mapping, and CODEOWNERS ownership. [[#3005](https://github.com/microsoft/mcp/pull/3005)]
 
 ### Breaking Changes

servers/Azure.Mcp.Server/docs/azmcp-commands.md

@@ -2939,6 +2939,20 @@ azmcp loadtesting testrun createorupdate --subscription <subscription> \
 azmcp grafana list --subscription <subscription> \
                   [--resource-group <resource-group>]
 ```
+### Azure IoT Hub Operations
+
+#### Device Registry Operations
+
+```bash
+# List devices in an IoT Hub
+# Returns one page of device identities. --max-count sets the page size (default 100, maximum 100).
+# When the hub has more devices than were returned, the response sets truncated=true with an explanatory message.
+# ❌ Destructive | ✅ Idempotent | ❌ OpenWorld | ✅ ReadOnly | ❌ Secret | ❌ LocalRequired
+azmcp iothub device list --subscription <subscription> \
+                         --resource-group <resource-group> \
+                         --name <iothub-name> \
+                         [--max-count <max-count>]
+```
 
 ### Azure Marketplace Operations
 

servers/Azure.Mcp.Server/src/Program.cs

@@ -69,6 +69,8 @@ private static async Task<int> Main(string[] args)
 
             services.AddLogging(builder =>
             {
+                // Send console logs to stderr so stdout carries only the command's JSON
+                // response. Keeps CLI output parseable and avoids corrupting stdio MCP output.
                 builder.AddConsole(options => options.LogToStandardErrorThreshold = LogLevel.Trace);
                 builder.SetMinimumLevel(LogLevel.Information);
             });

servers/Azure.Mcp.Server/src/Resources/consolidated-tools.json

@@ -2128,7 +2128,7 @@
     },
     {
       "name": "get_azure_iot_hub",
-      "description": "Get details about an Azure IoT Hub.",
+      "description": "Get details about an Azure IoT Hub and list devices registered in its device registry.",
       "toolMetadata": {
         "destructive": {
           "value": false,
@@ -2156,7 +2156,8 @@
         }
       },
       "mappedToolList": [
-        "iothub_hub_get"
+        "iothub_hub_get",
+        "iothub_device_list"
       ]
     },
     {

tools/Azure.Mcp.Tools.IoTHub/src/AssemblyInfo.cs

@@ -4,3 +4,4 @@
 using System.Runtime.CompilerServices;
 
 [assembly: InternalsVisibleTo("Azure.Mcp.Tools.IoTHub.UnitTests")]
+[assembly: InternalsVisibleTo("Azure.Mcp.Tools.IoTHub.LiveTests")]

tools/Azure.Mcp.Tools.IoTHub/src/Azure.Mcp.Tools.IoTHub.csproj

@@ -11,6 +11,8 @@
   </ItemGroup>
   <ItemGroup />
   <ItemGroup>
+    <PackageReference Include="Azure.ResourceManager" />
+    <PackageReference Include="Azure.ResourceManager.IotHub" />
     <PackageReference Include="Microsoft.Extensions.DependencyInjection" />
     <PackageReference Include="ModelContextProtocol" />
   </ItemGroup>

tools/Azure.Mcp.Tools.IoTHub/src/Commands/Device/IoTHubDeviceListCommand.cs

@@ -0,0 +1,93 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+using System.CommandLine;
+using Azure.Mcp.Core.Commands.Subscription;
+using Azure.Mcp.Core.Services.Azure.Subscription;
+using Azure.Mcp.Tools.IoTHub.Models;
+using Azure.Mcp.Tools.IoTHub.Options.Device;
+using Azure.Mcp.Tools.IoTHub.Services;
+using Microsoft.Extensions.Logging;
+using Microsoft.Mcp.Core.Commands;
+using Microsoft.Mcp.Core.Models.Command;
+
+namespace Azure.Mcp.Tools.IoTHub.Commands.Device;
+
+[CommandMetadata(
+    Id = "426028ac-ac9b-4348-b549-74c0b53ad3e7",
+    Name = "list",
+    Title = "List IoT Hub Devices",
+    Description = """
+        List devices in an IoT Hub device registry. Returns device identity metadata without authentication keys.
+        Use --max-count to limit results (default 100, maximum 100). Values greater than 100 are capped at 100; if more devices exist, truncated=true is set.
+        Hub names/IDs are case-sensitive and must match exactly.
+        """,
+    Destructive = false,
+    Idempotent = true,
+    OpenWorld = false,
+    ReadOnly = true,
+    Secret = false,
+    LocalRequired = false)]
+public sealed class IoTHubDeviceListCommand(
+    ILogger<IoTHubDeviceListCommand> logger,
+    IIoTHubDeviceService service,
+    ISubscriptionResolver subscriptionResolver)
+    : SubscriptionCommand<IoTHubDeviceListOptions, DeviceListResult>(subscriptionResolver)
+{
+    private const int DefaultMaxCount = 100;
+    private const int MinMaxCount = 1;
+    private const int MaxMaxCount = DefaultMaxCount;
+
+    private readonly ILogger<IoTHubDeviceListCommand> _logger = logger;
+    private readonly IIoTHubDeviceService _service = service;
+
+    public override void ValidateOptions(IoTHubDeviceListOptions options, ValidationResult validationResult)
+    {
+        base.ValidateOptions(options, validationResult);
+
+        if (options.MaxCount is < MinMaxCount)
+        {
+            validationResult.Errors.Add(
+                $"The entered max-count '{options.MaxCount}' is less than 1 device. Please specify a value of at least 1.");
+        }
+    }
+
+    public override async Task<CommandResponse> ExecuteAsync(
+        CommandContext context,
+        IoTHubDeviceListOptions options,
+        CancellationToken cancellationToken)
+    {
+        try
+        {
+            var maxCount = options.MaxCount switch
+            {
+                null => DefaultMaxCount,
+                > MaxMaxCount => MaxMaxCount,
+                _ => options.MaxCount.Value
+            };
+
+            var result = await _service.ListDevices(
+                options.Name,
+                options.ResourceGroup,
+                options.Subscription!,
+                maxCount,
+                options.RetryPolicy,
+                cancellationToken);
+
+            context.Response.Results = ResponseResult.Create(result, IoTHubJsonContext.Default.DeviceListResult);
+
+            if (result.Truncated)
+            {
+                context.Response.Message =
+                    $"Showing the first {maxCount} devices. The hub contains more devices, but the results were truncated because the maximum is {maxCount}.";
+            }
+        }
+        catch (Exception ex)
+        {
+            _logger.LogError(ex, "Error listing devices in IoT Hub '{HubName}'.", options.Name);
+            HandleException(context, ex);
+        }
+
+        return context.Response;
+    }
+}

tools/Azure.Mcp.Tools.IoTHub/src/Commands/IoTHub/IoTHubGetCommand.cs

@@ -1,6 +1,7 @@
 // Copyright (c) Microsoft Corporation.
 // Licensed under the MIT License.
 
+using System.Text.Json.Serialization;
 using Azure.Mcp.Core.Commands.Subscription;
 using Azure.Mcp.Core.Services.Azure.Subscription;
 using Azure.Mcp.Tools.IoTHub.Models;
@@ -77,7 +78,9 @@ public override async Task<CommandResponse> ExecuteAsync(
         return context.Response;
     }
 
-    public record IoTHubGetCommandResult(IoTHubDescription IoTHub, bool AreResultsTruncated);
+    public record IoTHubGetCommandResult(
+        [property: JsonPropertyName("iotHub")] IoTHubDescription IoTHub,
+        bool AreResultsTruncated);
 
     private static bool IsValidIoTHubName(string value)
     {