Feature/add azure dev ops

Directory.Packages.props

@@ -191,6 +191,8 @@
         <PackageVersion Include="NSubstitute" Version="5.3.0"/>
         <PackageVersion Include="NuGet.Packaging" Version="7.0.1"/>
         <PackageVersion Include="NuGet.Protocol" Version="7.0.1"/>
+        <PackageVersion Include="Microsoft.TeamFoundationServer.Client" Version="19.225.2"/>
+        <PackageVersion Include="Microsoft.VisualStudio.Services.Client" Version="19.225.2"/>
         <PackageVersion Include="Octokit" Version="14.0.0"/>
         <PackageVersion Include="Open.Linq.AsyncExtensions" Version="1.2.0"/>
         <PackageVersion Include="Polly" Version="8.6.5"/>

Elsa.Extensions.sln

@@ -1,7 +1,6 @@
-
 Microsoft Visual Studio Solution File, Format Version 12.00
-# Visual Studio Version 17
-VisualStudioVersion = 17.12.35527.113
+# Visual Studio Version 18
+VisualStudioVersion = 18.1.11312.151 d18.0
 MinimumVisualStudioVersion = 10.0.40219.1
 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "src", "src", "{527248D6-B851-4C8D-8667-E2FB0A91DABF}"
 EndProject
@@ -24,9 +23,9 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "github", "github", "{D02123
 EndProject
 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "workflows", "workflows", "{3948BAF0-023F-4B43-8E77-56C3B00C6EFD}"
 	ProjectSection(SolutionItems) = preProject
+		.github\workflows\copilot-setup-steps.yml.yml = .github\workflows\copilot-setup-steps.yml.yml
 		.github\workflows\packages.yml = .github\workflows\packages.yml
 		.github\workflows\pr.yml = .github\workflows\pr.yml
-		.github\workflows\copilot-setup-steps.yml.yml = .github\workflows\copilot-setup-steps.yml.yml
 	EndProjectSection
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "_build", "build\_build.csproj", "{4D16DD17-0BC9-476D-9B38-0A8644DD92FE}"
@@ -204,6 +203,8 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "devops", "devops", "{9B6DFC
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Elsa.DevOps.GitHub", "src\modules\devops\Elsa.DevOps.GitHub\Elsa.DevOps.GitHub.csproj", "{4E8D5DEA-6FB5-8878-0029-584C8F0D2D68}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Elsa.DevOps.AzureDevOps", "src\modules\devops\Elsa.DevOps.AzureDevOps\Elsa.DevOps.AzureDevOps.csproj", "{A1B2C3D4-E5F6-7890-ABCD-EF1234567890}"
+EndProject
 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "workbench", "workbench", "{F4CD4668-A0D0-4CD7-91C1-09EE80A03C26}"
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Elsa.Server.Web", "src\workbench\Elsa.Server.Web\Elsa.Server.Web.csproj", "{76E6A59C-4F67-40D7-9354-1370893F16A9}"
@@ -1091,6 +1092,18 @@ Global
 		{4E8D5DEA-6FB5-8878-0029-584C8F0D2D68}.Release|x64.Build.0 = Release|Any CPU
 		{4E8D5DEA-6FB5-8878-0029-584C8F0D2D68}.Release|x86.ActiveCfg = Release|Any CPU
 		{4E8D5DEA-6FB5-8878-0029-584C8F0D2D68}.Release|x86.Build.0 = Release|Any CPU
+		{A1B2C3D4-E5F6-7890-ABCD-EF1234567890}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{A1B2C3D4-E5F6-7890-ABCD-EF1234567890}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{A1B2C3D4-E5F6-7890-ABCD-EF1234567890}.Debug|x64.ActiveCfg = Debug|Any CPU
+		{A1B2C3D4-E5F6-7890-ABCD-EF1234567890}.Debug|x64.Build.0 = Debug|Any CPU
+		{A1B2C3D4-E5F6-7890-ABCD-EF1234567890}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{A1B2C3D4-E5F6-7890-ABCD-EF1234567890}.Debug|x86.Build.0 = Debug|Any CPU
+		{A1B2C3D4-E5F6-7890-ABCD-EF1234567890}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{A1B2C3D4-E5F6-7890-ABCD-EF1234567890}.Release|Any CPU.Build.0 = Release|Any CPU
+		{A1B2C3D4-E5F6-7890-ABCD-EF1234567890}.Release|x64.ActiveCfg = Release|Any CPU
+		{A1B2C3D4-E5F6-7890-ABCD-EF1234567890}.Release|x64.Build.0 = Release|Any CPU
+		{A1B2C3D4-E5F6-7890-ABCD-EF1234567890}.Release|x86.ActiveCfg = Release|Any CPU
+		{A1B2C3D4-E5F6-7890-ABCD-EF1234567890}.Release|x86.Build.0 = Release|Any CPU
 		{76E6A59C-4F67-40D7-9354-1370893F16A9}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
 		{76E6A59C-4F67-40D7-9354-1370893F16A9}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{76E6A59C-4F67-40D7-9354-1370893F16A9}.Debug|x64.ActiveCfg = Debug|Any CPU
@@ -1375,62 +1388,22 @@ Global
 		{7055576E-1144-4726-BA88-DF89F2A13FA8}.Debug|x86.Build.0 = Debug|Any CPU
 		{7055576E-1144-4726-BA88-DF89F2A13FA8}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{7055576E-1144-4726-BA88-DF89F2A13FA8}.Release|Any CPU.Build.0 = Release|Any CPU
-		{E9388ADF-B222-44CC-83AF-64BF6F07C808}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
-		{E9388ADF-B222-44CC-83AF-64BF6F07C808}.Debug|Any CPU.Build.0 = Debug|Any CPU
-		{E9388ADF-B222-44CC-83AF-64BF6F07C808}.Release|Any CPU.ActiveCfg = Release|Any CPU
-		{E9388ADF-B222-44CC-83AF-64BF6F07C808}.Release|Any CPU.Build.0 = Release|Any CPU
 		{7055576E-1144-4726-BA88-DF89F2A13FA8}.Release|x64.ActiveCfg = Release|Any CPU
 		{7055576E-1144-4726-BA88-DF89F2A13FA8}.Release|x64.Build.0 = Release|Any CPU
 		{7055576E-1144-4726-BA88-DF89F2A13FA8}.Release|x86.ActiveCfg = Release|Any CPU
 		{7055576E-1144-4726-BA88-DF89F2A13FA8}.Release|x86.Build.0 = Release|Any CPU
-		{A904A0FC-9D73-4349-90A3-498053B43CD6}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
-		{A904A0FC-9D73-4349-90A3-498053B43CD6}.Debug|Any CPU.Build.0 = Debug|Any CPU
-		{A904A0FC-9D73-4349-90A3-498053B43CD6}.Debug|x64.ActiveCfg = Debug|Any CPU
-		{A904A0FC-9D73-4349-90A3-498053B43CD6}.Debug|x64.Build.0 = Debug|Any CPU
-		{A904A0FC-9D73-4349-90A3-498053B43CD6}.Debug|x86.ActiveCfg = Debug|Any CPU
-		{A904A0FC-9D73-4349-90A3-498053B43CD6}.Debug|x86.Build.0 = Debug|Any CPU
-		{A904A0FC-9D73-4349-90A3-498053B43CD6}.Release|Any CPU.ActiveCfg = Release|Any CPU
-		{A904A0FC-9D73-4349-90A3-498053B43CD6}.Release|Any CPU.Build.0 = Release|Any CPU
-		{A904A0FC-9D73-4349-90A3-498053B43CD6}.Release|x64.ActiveCfg = Release|Any CPU
-		{A904A0FC-9D73-4349-90A3-498053B43CD6}.Release|x64.Build.0 = Release|Any CPU
-		{A904A0FC-9D73-4349-90A3-498053B43CD6}.Release|x86.ActiveCfg = Release|Any CPU
-		{A904A0FC-9D73-4349-90A3-498053B43CD6}.Release|x86.Build.0 = Release|Any CPU
-		{E87F26AD-1F6B-4723-A3B8-4EC761B08382}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
-		{E87F26AD-1F6B-4723-A3B8-4EC761B08382}.Debug|Any CPU.Build.0 = Debug|Any CPU
-		{E87F26AD-1F6B-4723-A3B8-4EC761B08382}.Debug|x64.ActiveCfg = Debug|Any CPU
-		{E87F26AD-1F6B-4723-A3B8-4EC761B08382}.Debug|x64.Build.0 = Debug|Any CPU
-		{E87F26AD-1F6B-4723-A3B8-4EC761B08382}.Debug|x86.ActiveCfg = Debug|Any CPU
-		{E87F26AD-1F6B-4723-A3B8-4EC761B08382}.Debug|x86.Build.0 = Debug|Any CPU
-		{E87F26AD-1F6B-4723-A3B8-4EC761B08382}.Release|Any CPU.ActiveCfg = Release|Any CPU
-		{E87F26AD-1F6B-4723-A3B8-4EC761B08382}.Release|Any CPU.Build.0 = Release|Any CPU
-		{E87F26AD-1F6B-4723-A3B8-4EC761B08382}.Release|x64.ActiveCfg = Release|Any CPU
-		{E87F26AD-1F6B-4723-A3B8-4EC761B08382}.Release|x64.Build.0 = Release|Any CPU
-		{E87F26AD-1F6B-4723-A3B8-4EC761B08382}.Release|x86.ActiveCfg = Release|Any CPU
-		{E87F26AD-1F6B-4723-A3B8-4EC761B08382}.Release|x86.Build.0 = Release|Any CPU
-		{C3D4E5F6-7890-1234-5678-90ABCDEF1234}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
-		{C3D4E5F6-7890-1234-5678-90ABCDEF1234}.Debug|Any CPU.Build.0 = Debug|Any CPU
-		{C3D4E5F6-7890-1234-5678-90ABCDEF1234}.Debug|x64.ActiveCfg = Debug|Any CPU
-		{C3D4E5F6-7890-1234-5678-90ABCDEF1234}.Debug|x64.Build.0 = Debug|Any CPU
-		{C3D4E5F6-7890-1234-5678-90ABCDEF1234}.Debug|x86.ActiveCfg = Debug|Any CPU
-		{C3D4E5F6-7890-1234-5678-90ABCDEF1234}.Debug|x86.Build.0 = Debug|Any CPU
-		{C3D4E5F6-7890-1234-5678-90ABCDEF1234}.Release|Any CPU.ActiveCfg = Release|Any CPU
-		{C3D4E5F6-7890-1234-5678-90ABCDEF1234}.Release|Any CPU.Build.0 = Release|Any CPU
-		{C3D4E5F6-7890-1234-5678-90ABCDEF1234}.Release|x64.ActiveCfg = Release|Any CPU
-		{C3D4E5F6-7890-1234-5678-90ABCDEF1234}.Release|x64.Build.0 = Release|Any CPU
-		{C3D4E5F6-7890-1234-5678-90ABCDEF1234}.Release|x86.ActiveCfg = Release|Any CPU
-		{C3D4E5F6-7890-1234-5678-90ABCDEF1234}.Release|x86.Build.0 = Release|Any CPU
-		{AF9D6B51-19A5-451F-8225-2F1348835A3A}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
-		{AF9D6B51-19A5-451F-8225-2F1348835A3A}.Debug|Any CPU.Build.0 = Debug|Any CPU
-		{AF9D6B51-19A5-451F-8225-2F1348835A3A}.Debug|x64.ActiveCfg = Debug|Any CPU
-		{AF9D6B51-19A5-451F-8225-2F1348835A3A}.Debug|x64.Build.0 = Debug|Any CPU
-		{AF9D6B51-19A5-451F-8225-2F1348835A3A}.Debug|x86.ActiveCfg = Debug|Any CPU
-		{AF9D6B51-19A5-451F-8225-2F1348835A3A}.Debug|x86.Build.0 = Debug|Any CPU
-		{AF9D6B51-19A5-451F-8225-2F1348835A3A}.Release|Any CPU.ActiveCfg = Release|Any CPU
-		{AF9D6B51-19A5-451F-8225-2F1348835A3A}.Release|Any CPU.Build.0 = Release|Any CPU
-		{AF9D6B51-19A5-451F-8225-2F1348835A3A}.Release|x64.ActiveCfg = Release|Any CPU
-		{AF9D6B51-19A5-451F-8225-2F1348835A3A}.Release|x64.Build.0 = Release|Any CPU
-		{AF9D6B51-19A5-451F-8225-2F1348835A3A}.Release|x86.ActiveCfg = Release|Any CPU
-		{AF9D6B51-19A5-451F-8225-2F1348835A3A}.Release|x86.Build.0 = Release|Any CPU
+		{E9388ADF-B222-44CC-83AF-64BF6F07C808}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{E9388ADF-B222-44CC-83AF-64BF6F07C808}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{E9388ADF-B222-44CC-83AF-64BF6F07C808}.Debug|x64.ActiveCfg = Debug|Any CPU
+		{E9388ADF-B222-44CC-83AF-64BF6F07C808}.Debug|x64.Build.0 = Debug|Any CPU
+		{E9388ADF-B222-44CC-83AF-64BF6F07C808}.Debug|x86.ActiveCfg = Debug|Any CPU
+		{E9388ADF-B222-44CC-83AF-64BF6F07C808}.Debug|x86.Build.0 = Debug|Any CPU
+		{E9388ADF-B222-44CC-83AF-64BF6F07C808}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{E9388ADF-B222-44CC-83AF-64BF6F07C808}.Release|Any CPU.Build.0 = Release|Any CPU
+		{E9388ADF-B222-44CC-83AF-64BF6F07C808}.Release|x64.ActiveCfg = Release|Any CPU
+		{E9388ADF-B222-44CC-83AF-64BF6F07C808}.Release|x64.Build.0 = Release|Any CPU
+		{E9388ADF-B222-44CC-83AF-64BF6F07C808}.Release|x86.ActiveCfg = Release|Any CPU
+		{E9388ADF-B222-44CC-83AF-64BF6F07C808}.Release|x86.Build.0 = Release|Any CPU
 		{65B9F528-568B-4E0E-894E-F22E0B7C64BB}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
 		{65B9F528-568B-4E0E-894E-F22E0B7C64BB}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{65B9F528-568B-4E0E-894E-F22E0B7C64BB}.Debug|x64.ActiveCfg = Debug|Any CPU
@@ -1546,6 +1519,7 @@ Global
 		{159E73C1-60F9-0D39-9CA1-79EC99187FDC} = {7D32914F-1D75-4E01-A0D1-BBF67789A0E5}
 		{9B6DFC6C-2514-4784-9952-9B0B913434F9} = {30CF0330-4B09-4784-B499-46BED303810B}
 		{4E8D5DEA-6FB5-8878-0029-584C8F0D2D68} = {9B6DFC6C-2514-4784-9952-9B0B913434F9}
+		{A1B2C3D4-E5F6-7890-ABCD-EF1234567890} = {9B6DFC6C-2514-4784-9952-9B0B913434F9}
 		{F4CD4668-A0D0-4CD7-91C1-09EE80A03C26} = {527248D6-B851-4C8D-8667-E2FB0A91DABF}
 		{76E6A59C-4F67-40D7-9354-1370893F16A9} = {F4CD4668-A0D0-4CD7-91C1-09EE80A03C26}
 		{37F3C251-9ADC-4BE8-81A5-C86C563901FF} = {F4CD4668-A0D0-4CD7-91C1-09EE80A03C26}

README.md

@@ -49,7 +49,7 @@ Below is the current status of each extension. Icons indicate implementation pro
 ### 🛠 DevOps & Monitoring
 | Status | Extension | Description | Module Name | Issue |
 |--------|------------|-------------|-------------|-------|
-| 🔲 | **Azure DevOps** | Pipelines, repositories, work items | `Elsa.AzureDevOps` | [Open Issue](https://github.com/elsa-workflows/elsa-extensions/issues/new) |
+| [🚧](https://github.com/elsa-workflows/elsa-extensions/tree/main/src/modules/devops/Elsa.DevOps.AzureDevOps/README.md) | **Azure DevOps** | Pipelines, repositories, work items | `Elsa.DevOps.AzureDevOps` | [View Issue](https://github.com/elsa-workflows/elsa-extensions/issues/124) |
 | [✅](https://github.com/elsa-workflows/elsa-extensions/tree/main/src/devops/Elsa.DevOps.GitHub/README.md) | **GitHub** | PR automation, repo events | `Elsa.DevOps.GitHub` | [Fixed Issue](https://github.com/elsa-workflows/elsa-extensions/issues/6) |
 | 🔲 | **GitLab** | CI/CD triggers and repo management | `Elsa.GitLab` | [Open Issue](https://github.com/elsa-workflows/elsa-extensions/issues/new) |
 | 🔲 | **Jenkins** | Pipeline automation and job execution | `Elsa.Jenkins` | [Open Issue](https://github.com/elsa-workflows/elsa-extensions/issues/new) |

src/modules/devops/Elsa.DevOps.AzureDevOps/Activities/ActivityInputValidation.cs

@@ -0,0 +1,62 @@
+namespace Elsa.DevOps.AzureDevOps.Activities;
+
+/// <summary>
+/// Helpers for validating activity inputs. Use Try* in CanExecuteAsync; use Throw* in ExecuteAsync/GetConnection as a safety net.
+/// </summary>
+internal static class ActivityInputValidation
+{
+    public static (bool Valid, string? Error) TryValidateRequired(string? value, string parameterName)
+    {
+        if (string.IsNullOrWhiteSpace(value))
+            return (false, $"'{parameterName}' must be specified and non-empty.");
+        return (true, null);
+    }
+
+    public static (bool Valid, string? Error) TryValidateUri(string? value, string parameterName)
+    {
+        var (requiredOk, requiredErr) = TryValidateRequired(value, parameterName);
+        if (!requiredOk) return (false, requiredErr);
+        if (!Uri.TryCreate(value!.Trim(), UriKind.Absolute, out var uri) || !uri.IsAbsoluteUri || (uri.Scheme != "http" && uri.Scheme != "https"))
+            return (false, $"'{parameterName}' must be a valid HTTP or HTTPS URL.");
+        return (true, null);
+    }
+
+    public static (bool Valid, string? Error) TryValidateNonNegative(int value, string parameterName)
+    {
+        if (value < 0)
+            return (false, $"'{parameterName}' must be non-negative.");
+        return (true, null);
+    }
+
+    public static (bool Valid, string? Error) TryValidatePositive(int value, string parameterName)
+    {
+        if (value <= 0)
+            return (false, $"'{parameterName}' must be greater than zero.");
+        return (true, null);
+    }
+
+    public static void ThrowIfNullOrEmpty(string? value, string parameterName)
+    {
+        if (string.IsNullOrWhiteSpace(value))
+            throw new ArgumentException($"'{parameterName}' must be specified and non-empty.", parameterName);
+    }
+
+    public static void ThrowIfInvalidUri(string? value, string parameterName)
+    {
+        ThrowIfNullOrEmpty(value, parameterName);
+        if (!Uri.TryCreate(value!.Trim(), UriKind.Absolute, out var uri) || !uri.IsAbsoluteUri || (uri.Scheme != "http" && uri.Scheme != "https"))
+            throw new ArgumentException($"'{parameterName}' must be a valid HTTP or HTTPS URL.", parameterName);
+    }
+
+    public static void ThrowIfNegative(int value, string parameterName)
+    {
+        if (value < 0)
+            throw new ArgumentOutOfRangeException(parameterName, value, $"'{parameterName}' must be non-negative.");
+    }
+
+    public static void ThrowIfNegativeOrZero(int value, string parameterName)
+    {
+        if (value <= 0)
+            throw new ArgumentOutOfRangeException(parameterName, value, $"'{parameterName}' must be greater than zero.");
+    }
+}

src/modules/devops/Elsa.DevOps.AzureDevOps/Activities/AzureDevOpsActivity.cs

@@ -0,0 +1,58 @@
+using Elsa.DevOps.AzureDevOps.Services;
+using Elsa.Workflows;
+using Elsa.Workflows.Attributes;
+using Elsa.Workflows.Models;
+using Microsoft.VisualStudio.Services.WebApi;
+
+namespace Elsa.DevOps.AzureDevOps.Activities;
+
+/// <summary>
+/// Generic base class inherited by all Azure DevOps activities.
+/// </summary>
+public abstract class AzureDevOpsActivity : Workflows.Activity
+{
+    /// <summary>
+    /// The Azure DevOps organization URL (e.g. https://dev.azure.com/myorg).
+    /// </summary>
+    [Input(Description = "The Azure DevOps organization URL (e.g. https://dev.azure.com/myorg).")]
+    public Input<string> OrganizationUrl { get; set; } = null!;
+
+    /// <summary>
+    /// The personal access token (PAT) for authentication.
+    /// </summary>
+    [Input(Description = "The personal access token (PAT) for authentication.")]
+    public Input<string> Token { get; set; } = null!;
+
+    /// <inheritdoc />
+    protected override ValueTask<bool> CanExecuteAsync(ActivityExecutionContext context)
+    {
+        var organizationUrl = context.Get(OrganizationUrl);
+        var token = context.Get(Token);
+        var (urlOk, urlError) = ActivityInputValidation.TryValidateUri(organizationUrl, nameof(OrganizationUrl));
+        if (!urlOk)
+        {
+            context.AddExecutionLogEntry("Precondition Failed", urlError);
+            return new ValueTask<bool>(false);
+        }
+        var (tokenOk, tokenError) = ActivityInputValidation.TryValidateRequired(token, nameof(Token));
+        if (!tokenOk)
+        {
+            context.AddExecutionLogEntry("Precondition Failed", tokenError);
+            return new ValueTask<bool>(false);
+        }
+        return base.CanExecuteAsync(context);
+    }
+
+    /// <summary>
+    /// Gets the Azure DevOps connection.
+    /// </summary>
+    protected VssConnection GetConnection(ActivityExecutionContext context)
+    {
+        var organizationUrl = context.Get(OrganizationUrl);
+        var token = context.Get(Token);
+        ActivityInputValidation.ThrowIfInvalidUri(organizationUrl, nameof(OrganizationUrl));
+        ActivityInputValidation.ThrowIfNullOrEmpty(token, nameof(Token));
+        var factory = context.GetRequiredService<AzureDevOpsConnectionFactory>();
+        return factory.GetConnection(organizationUrl!.Trim(), token!);
+    }
+}

src/modules/devops/Elsa.DevOps.AzureDevOps/Activities/AzureDevOpsTriggerActivity.cs

@@ -0,0 +1,19 @@
+using Elsa.Workflows;
+using Elsa.Workflows.Models;
+
+namespace Elsa.DevOps.AzureDevOps.Activities;
+
+/// <summary>
+/// Generic base class inherited by all Azure DevOps trigger activities.
+/// </summary>
+public abstract class AzureDevOpsTriggerActivity : AzureDevOpsActivity
+{
+    /// <summary>
+    /// Executes the activity.
+    /// </summary>
+    protected override ValueTask ExecuteAsync(ActivityExecutionContext context)
+    {
+        // Implementation depends on Azure DevOps Service Hooks / WebHook support
+        throw new NotImplementedException("Event subscription requires WebHook implementation.");
+    }
+}

src/modules/devops/Elsa.DevOps.AzureDevOps/Activities/Builds/GetBuild.cs

@@ -0,0 +1,61 @@
+using Elsa.DevOps.AzureDevOps.Activities;
+using Elsa.Workflows;
+using Elsa.Workflows.Attributes;
+using Elsa.Workflows.Models;
+using JetBrains.Annotations;
+using Microsoft.TeamFoundation.Build.WebApi;
+
+namespace Elsa.DevOps.AzureDevOps.Activities.Builds;
+
+/// <summary>
+/// Retrieves a build from Azure DevOps.
+/// </summary>
+[Activity(
+    "Elsa.AzureDevOps.Builds",
+    "Azure DevOps Builds",
+    "Retrieves a build from Azure DevOps.",
+    DisplayName = "Get Build")]
+[UsedImplicitly]
+public class GetBuild : AzureDevOpsActivity
+{
+    /// <summary>
+    /// The project name or ID.
+    /// </summary>
+    [Input(Description = "The project name or ID.")]
+    public Input<string> Project { get; set; } = null!;
+
+    /// <summary>
+    /// The build ID.
+    /// </summary>
+    [Input(Description = "The build ID.")]
+    public Input<int> BuildId { get; set; } = null!;
+
+    /// <summary>
+    /// The retrieved build.
+    /// </summary>
+    [Output(Description = "The retrieved build.")]
+    public Output<Build> RetrievedBuild { get; set; } = null!;
+
+    /// <inheritdoc />
+    protected override ValueTask<bool> CanExecuteAsync(ActivityExecutionContext context)
+    {
+        var project = context.Get(Project);
+        var buildId = context.Get(BuildId);
+        var (projectOk, projectErr) = ActivityInputValidation.TryValidateRequired(project, nameof(Project));
+        if (!projectOk) { context.AddExecutionLogEntry("Precondition Failed", projectErr); return new ValueTask<bool>(false); }
+        var (idOk, idErr) = ActivityInputValidation.TryValidatePositive(buildId, nameof(BuildId));
+        if (!idOk) { context.AddExecutionLogEntry("Precondition Failed", idErr); return new ValueTask<bool>(false); }
+        return base.CanExecuteAsync(context);
+    }
+
+    /// <inheritdoc />
+    protected override async ValueTask ExecuteAsync(ActivityExecutionContext context)
+    {
+        var project = context.Get(Project)!;
+        var buildId = context.Get(BuildId);
+        var connection = GetConnection(context);
+        var buildClient = connection.GetClient<BuildHttpClient>();
+        var build = await buildClient.GetBuildAsync(project, buildId, null, null, context.CancellationToken);
+        context.Set(RetrievedBuild, build);
+    }
+}