.NET: Add shell support to the HarnessAgent (#6005)

* Add shell support to the HarnessAgent

* Address PR comments

* Address PR comments

dotnet/src/Microsoft.Agents.AI.Harness/HarnessAgent.cs

@@ -6,6 +6,9 @@ using System.Diagnostics.CodeAnalysis;
 using System.IO;
 using System.Linq;
 using Microsoft.Agents.AI.Compaction;
+#if NET
+using Microsoft.Agents.AI.Tools.Shell;
+#endif
 using Microsoft.Extensions.AI;
 using Microsoft.Shared.DiagnosticIds;
 using Microsoft.Shared.Diagnostics;
@@ -201,6 +204,14 @@ public sealed class HarnessAgent : DelegatingAIAgent
             result.Tools.Add(new HostedWebSearchTool());
         }
 
+#if NET
+        if (options?.ShellExecutor is ShellExecutor shellExecutor)
+        {
+            result.Tools ??= [];
+            result.Tools.Add(shellExecutor.AsAIFunction());
+        }
+#endif
+
         return result;
     }
 
@@ -259,6 +270,13 @@ public sealed class HarnessAgent : DelegatingAIAgent
             }
         }
 
+#if NET
+        if (options?.ShellExecutor is ShellExecutor shellExecutor)
+        {
+            providers.Add(new ShellEnvironmentProvider(shellExecutor, options.ShellEnvironmentProviderOptions));
+        }
+#endif
+
         if (options?.AIContextProviders is IEnumerable<AIContextProvider> userProviders)
         {
             providers.AddRange(userProviders);

dotnet/src/Microsoft.Agents.AI.Harness/HarnessAgentOptions.cs

@@ -2,6 +2,9 @@
 
 using System.Collections.Generic;
 using System.Diagnostics.CodeAnalysis;
+#if NET
+using Microsoft.Agents.AI.Tools.Shell;
+#endif
 using Microsoft.Extensions.AI;
 using Microsoft.Shared.DiagnosticIds;
 
@@ -240,4 +243,27 @@ public sealed class HarnessAgentOptions
     /// This property is ignored when <see cref="BackgroundAgents"/> is <see langword="null"/> or empty.
     /// </remarks>
     public BackgroundAgentsProviderOptions? BackgroundAgentsProviderOptions { get; set; }
+
+#if NET
+    /// <summary>
+    /// Gets or sets the shell executor used to enable shell tool and environment probing via <see cref="ShellEnvironmentProvider"/>.
+    /// </summary>
+    /// <remarks>
+    /// When non-null, a <see cref="ShellEnvironmentProvider"/> is automatically included in the agent's context
+    /// providers (injecting OS/shell/CWD information into the system prompt), and the executor's
+    /// <see cref="ShellExecutor.AsAIFunction"/> is registered as a callable tool.
+    /// When <see langword="null"/> (the default), no shell features are enabled.
+    /// </remarks>
+    public ShellExecutor? ShellExecutor { get; set; }
+
+    /// <summary>
+    /// Gets or sets optional configuration for the <see cref="ShellEnvironmentProvider"/>.
+    /// </summary>
+    /// <remarks>
+    /// Use this to customize which tools are probed, the probe timeout, shell family override,
+    /// or the instructions formatter.
+    /// This property is ignored when <see cref="ShellExecutor"/> is <see langword="null"/>.
+    /// </remarks>
+    public ShellEnvironmentProviderOptions? ShellEnvironmentProviderOptions { get; set; }
+#endif
 }

dotnet/src/Microsoft.Agents.AI.Harness/Microsoft.Agents.AI.Harness.csproj

@@ -15,6 +15,10 @@
     <ProjectReference Include="..\Microsoft.Agents.AI\Microsoft.Agents.AI.csproj" />
   </ItemGroup>
 
+  <ItemGroup Condition="$([MSBuild]::IsTargetFrameworkCompatible('$(TargetFramework)', 'net8.0'))">
+    <ProjectReference Include="..\Microsoft.Agents.AI.Tools.Shell\Microsoft.Agents.AI.Tools.Shell.csproj" />
+  </ItemGroup>
+
   <PropertyGroup>
     <!-- NuGet Package Settings -->
     <Title>Microsoft Agent Framework Harness</Title>