.NET: Harness code act skill sample

dotnet/Directory.Packages.props

@@ -112,6 +112,7 @@
     <PackageVersion Include="ModelContextProtocol" Version="1.1.0" />
     <!-- Hyperlight -->
     <PackageVersion Include="Hyperlight.HyperlightSandbox.Api" Version="0.4.0" />
+    <PackageVersion Include="Hyperlight.HyperlightSandbox.Guest.Python" Version="0.4.0" />
     <!-- Inference SDKs -->
     <PackageVersion Include="Microsoft.ML.OnnxRuntimeGenAI" Version="0.10.0" />
     <PackageVersion Include="Microsoft.ML.Tokenizers" Version="2.0.0" />

dotnet/agent-framework-dotnet.slnx

@@ -124,6 +124,7 @@
     <Project Path="samples/02-agents/Harness/Harness_Step01_Research/Harness_Step01_Research.csproj" />
     <Project Path="samples/02-agents/Harness/Harness_Step02_Research_WithBackgroundAgents/Harness_Step02_Research_WithBackgroundAgents.csproj" />
     <Project Path="samples/02-agents/Harness/Harness_Step03_DataProcessing/Harness_Step03_DataProcessing.csproj" />
+    <Project Path="samples/02-agents/Harness/Harness_Step04_CodeExecution/Harness_Step04_CodeExecution.csproj" />
     <Project Path="samples/02-agents/Harness/ConsoleReactiveFramework/ConsoleReactiveFramework.csproj" />
     <Project Path="samples/02-agents/Harness/ConsoleReactiveComponents/ConsoleReactiveComponents.csproj" />
   </Folder>

dotnet/samples/02-agents/Harness/ConsoleReactiveComponents/AnsiEscapes.cs

@@ -24,6 +24,11 @@ public static class AnsiEscapes
     /// </summary>
     public static string MoveCursor(int row, int column) => $"\x1b[{row};{column}H";
 
+    /// <summary>
+    /// Erases the current line from the cursor position to the end of the line (EL 0).
+    /// </summary>
+    public static string EraseToEndOfLine => "\x1b[0K";
+
     /// <summary>
     /// Erases the entire current line (EL 2).
     /// </summary>

dotnet/samples/02-agents/Harness/Harness_Shared_Console/Components/AgentStatus.cs

@@ -35,6 +35,7 @@ public class AgentStatus : ConsoleReactiveComponent<AgentStatusProps, AgentStatu
     ];
 
     private readonly Timer _timer;
+    private AgentStatusProps? _previousProps;
 
     /// <summary>
     /// Initializes a new instance of the <see cref="AgentStatus"/> class.
@@ -85,7 +86,12 @@ public override void RenderCore(AgentStatusProps props, AgentStatusState state)
         }
 
         System.Console.Write(AnsiEscapes.SaveCursor);
-        System.Console.Write(AnsiEscapes.MoveAndEraseLine(this.Y));
+        System.Console.Write(AnsiEscapes.MoveCursor(this.Y, this.X));
+        if (props != this._previousProps)
+        {
+            System.Console.Write(AnsiEscapes.EraseToEndOfLine);
+            this._previousProps = props;
+        }
 
         if (props.ShowSpinner)
         {

dotnet/samples/02-agents/Harness/Harness_Shared_Console/HarnessConsole.cs

@@ -1,5 +1,6 @@
 // Copyright (c) Microsoft. All rights reserved.
 
+using System.Text;
 using Harness.ConsoleReactiveComponents;
 using Microsoft.Agents.AI;
 
@@ -24,6 +25,8 @@ public static async Task RunAgentAsync(AIAgent agent, string userPrompt, Harness
     {
         options ??= new();
 
+        System.Console.OutputEncoding = Encoding.UTF8;
+
         // Null means use defaults; an explicit (possibly empty) list means use exactly what was provided.
         var observers = options.Observers
             ?? HarnessConsoleOptions.BuildDefaultObservers();
@@ -63,6 +66,7 @@ public static async Task RunAgentAsync(AIAgent agent, string userPrompt, Harness
 
         System.Console.ResetColor();
         System.Console.Write(AnsiEscapes.ResetScrollRegion);
+        System.Console.Write(AnsiEscapes.EraseScrollbackBuffer);
         System.Console.Write(AnsiEscapes.EraseEntireScreen);
         System.Console.Write(AnsiEscapes.MoveCursor(1, 1));
         System.Console.WriteLine("Goodbye!");

dotnet/samples/02-agents/Harness/Harness_Step04_CodeExecution/Harness_Step04_CodeExecution.csproj

@@ -0,0 +1,29 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFrameworks>net10.0</TargetFrameworks>
+
+    <Nullable>enable</Nullable>
+    <ImplicitUsings>enable</ImplicitUsings>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Azure.AI.Projects" />
+    <PackageReference Include="Azure.Identity" />
+    <PackageReference Include="Hyperlight.HyperlightSandbox.Guest.Python" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\..\..\..\src\Microsoft.Agents.AI.Foundry\Microsoft.Agents.AI.Foundry.csproj" />
+    <ProjectReference Include="..\..\..\..\src\Microsoft.Agents.AI.Harness\Microsoft.Agents.AI.Harness.csproj" />
+    <ProjectReference Include="..\..\..\..\src\Microsoft.Agents.AI.Hyperlight\Microsoft.Agents.AI.Hyperlight.csproj" />
+    <ProjectReference Include="..\..\..\..\src\Microsoft.Agents.AI.OpenAI\Microsoft.Agents.AI.OpenAI.csproj" />
+    <ProjectReference Include="..\Harness_Shared_Console\Harness_Shared_Console.csproj" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <Content Include="skills\**\*" CopyToOutputDirectory="PreserveNewest" />
+  </ItemGroup>
+
+</Project>

dotnet/samples/02-agents/Harness/Harness_Step04_CodeExecution/Program.cs

@@ -0,0 +1,122 @@
+// Copyright (c) Microsoft. All rights reserved.
+
+// This sample demonstrates a HarnessAgent with ALL features enabled, plus:
+// - Hyperlight CodeAct (HyperlightCodeActProvider) for sandboxed Python code execution
+// - Skills (AgentSkillsProvider) discovering a local "regex-tester" skill
+//
+// The agent can plan tasks with todos, manage modes, store memories, read/write files,
+// search the web, approve sensitive tools, discover and use skills, and execute arbitrary
+// Python code in a Hyperlight sandbox — all pre-configured by the HarnessAgent.
+//
+// Try asking: "Help me write a regex that matches valid email addresses, then test it."
+//
+// Special commands:
+//   /todos  — Display the current todo list without invoking the agent.
+//   /mode   — Get or set the current agent mode.
+//   /exit   — End the session.
+
+#pragma warning disable OPENAI001 // Suppress experimental API warnings for Responses API usage.
+#pragma warning disable MAAI001  // Suppress experimental API warnings for Agents AI experiments.
+
+using System.ClientModel.Primitives;
+using Azure.AI.Projects;
+using Azure.Identity;
+using Harness.Shared.Console;
+using HyperlightSandbox.Guest.Python;
+using Microsoft.Agents.AI;
+using Microsoft.Agents.AI.Hyperlight;
+using Microsoft.Extensions.AI;
+
+var endpoint = Environment.GetEnvironmentVariable("AZURE_AI_PROJECT_ENDPOINT") ?? throw new InvalidOperationException("AZURE_AI_PROJECT_ENDPOINT is not set.");
+var deploymentName = Environment.GetEnvironmentVariable("AZURE_AI_MODEL_DEPLOYMENT_NAME") ?? "gpt-5.4";
+
+const int MaxContextWindowTokens = 1_050_000;
+const int MaxOutputTokens = 128_000;
+const string TracingSourceName = "Harness.CodeExecution";
+
+// Set up OpenTelemetry tracing that writes spans to a text file.
+using var tracerProvider = HarnessTracing.CreateFileTracerProvider(TracingSourceName);
+
+// Create the HyperlightCodeActProvider with the Python/Wasm backend.
+// The guest module path is resolved automatically from the Hyperlight.HyperlightSandbox.Guest.Python NuGet package.
+using var codeAct = new HyperlightCodeActProvider(
+    HyperlightCodeActProviderOptions.CreateForWasm(PythonGuestModule.GetModulePath()));
+
+var instructions =
+    """
+    ## Technical Assistant Instructions
+
+    You are a code-powered technical assistant. You can execute Python code in a sandboxed environment
+    to solve problems precisely rather than guessing. You also have access to skills that provide
+    structured workflows for specific technical tasks.
+
+    ### Code Execution
+
+    When a problem requires computation, validation, or testing:
+    - Write Python code and use `execute_code` to run it in the sandbox.
+    - Always verify results by running the code rather than reasoning about what would happen.
+    - If code fails, read the error message carefully, fix the issue, and retry.
+
+    ### Skills
+
+    You have access to discoverable skills. When a task matches a skill's description:
+    - Follow the skill's instructions carefully.
+    - Use the skill's reference materials for context.
+    - Combine the skill's workflow with code execution when appropriate.
+
+    ### Planning and Research
+
+    For complex tasks:
+    - Break the problem into steps using your todo list.
+    - Research background information using web search when needed.
+    - Save important findings to file memory for later reference.
+
+    ### Presenting Results
+
+    - Show your work: include the code you ran and its output.
+    - Explain what each part of your solution does.
+    - If applicable, save final results to file memory.
+    """;
+
+// Create the agent with ALL HarnessAgent features enabled plus Hyperlight CodeAct.
+// No Disable* flags are set — TodoProvider, AgentModeProvider, FileMemory, FileAccess,
+// ToolApproval, WebSearch, and AgentSkillsProvider are all active.
+AIAgent agent =
+    new AIProjectClient(
+        new Uri(endpoint),
+        new DefaultAzureCredential(),
+        new AIProjectClientOptions { RetryPolicy = new ClientRetryPolicy(3) })
+    .GetProjectOpenAIClient()
+    .GetResponsesClient()
+    .AsIChatClient(deploymentName)
+    .AsHarnessAgent(MaxContextWindowTokens, MaxOutputTokens, new HarnessAgentOptions
+    {
+        Name = "CodeExecutionAgent",
+        Description = "A technical assistant with sandboxed code execution and skill-based workflows.",
+        OpenTelemetrySourceName = TracingSourceName,
+        // Point the file memory at a local folder for persistent memory across sessions.
+        FileMemoryStore = new FileSystemAgentFileStore(Path.Combine(AppContext.BaseDirectory, "agent-files")),
+        // Add the HyperlightCodeActProvider so the agent can execute Python code in a sandbox.
+        AIContextProviders = [codeAct],
+        ChatOptions = new ChatOptions
+        {
+            Instructions = instructions,
+            MaxOutputTokens = MaxOutputTokens,
+            Reasoning = new() { Effort = ReasoningEffort.Medium },
+        },
+    });
+
+// Run the interactive console session using the shared HarnessConsole helper.
+await HarnessConsole.RunAgentAsync(
+    agent,
+    userPrompt: "Ask me a technical question, or try: \"Help me write a regex that matches valid email addresses.\"",
+    new HarnessConsoleOptions
+    {
+        Observers = HarnessConsoleOptions.BuildObserversWithPlanning(
+            agent,
+            planModeName: "plan",
+            executionModeName: "execute",
+            maxContextWindowTokens: MaxContextWindowTokens,
+            maxOutputTokens: MaxOutputTokens),
+        CommandHandlers = HarnessConsoleOptions.BuildDefaultCommandHandlers(agent),
+    });

dotnet/samples/02-agents/Harness/Harness_Step04_CodeExecution/README.md

@@ -0,0 +1,51 @@
+# Harness Step 04 — Code Execution (Hyperlight + Skills)
+
+This sample demonstrates a HarnessAgent with **all features enabled**, plus:
+
+- **Hyperlight CodeAct** — sandboxed Python code execution via `execute_code` (requires KVM)
+- **Skills** — file-based skill discovery (a `regex-tester` skill is included)
+
+The agent can plan tasks, manage modes, store memories, read/write files, search the web, approve sensitive operations, discover and use skills, and execute arbitrary Python code — all pre-configured by the HarnessAgent.
+
+## Prerequisites
+
+- .NET 10 SDK
+- An Azure AI Foundry project endpoint
+- KVM-capable host (the Hyperlight sandbox runs code in micro-VMs)
+
+## Environment Variables
+
+| Variable | Description |
+|----------|-------------|
+| `AZURE_AI_PROJECT_ENDPOINT` | Your Azure AI Foundry project endpoint |
+| `AZURE_AI_MODEL_DEPLOYMENT_NAME` | Model deployment name (default: `gpt-5.4`) |
+
+## Running
+
+```bash
+dotnet run
+```
+
+## What to Try
+
+- **Regex testing**: "Help me write a regex that matches valid email addresses, then test it against some examples."
+- **Code execution**: "Calculate the first 20 prime numbers using the Sieve of Eratosthenes."
+- **Skill + code combo**: "I need a regex for ISO 8601 dates — test it thoroughly with edge cases."
+
+## Included Skill
+
+The `skills/regex-tester/` skill instructs the agent to validate regex patterns by executing Python test code in the Hyperlight sandbox. It includes a regex cheatsheet as reference material.
+
+## Features Enabled
+
+| Feature | Description |
+|---------|-------------|
+| TodoProvider | Task planning and tracking (`/todos` command) |
+| AgentModeProvider | Mode switching (`/mode` command) |
+| FileMemoryProvider | Persistent memory stored as files |
+| FileAccessProvider | Read/write files in a working directory |
+| ToolApproval | Don't-ask-again approval for sensitive tools |
+| WebSearch | Built-in hosted web search |
+| AgentSkillsProvider | Discovers and uses skills from the `skills/` folder |
+| HyperlightCodeActProvider | Sandboxed Python execution via `execute_code` |
+| OpenTelemetry | Trace logging to a text file |

dotnet/samples/02-agents/Harness/Harness_Step04_CodeExecution/skills/regex-tester/SKILL.md

@@ -0,0 +1,36 @@
+---
+name: regex-tester
+description: Validate, test, and debug regular expressions by executing them against sample inputs. Use when asked to build, verify, or explain a regex pattern.
+---
+
+## Usage
+
+When the user asks you to create, validate, or debug a regular expression:
+
+1. **Understand the requirement** — clarify what the pattern should match and what it should reject.
+2. **Consult the cheatsheet** — review `references/regex-cheatsheet.md` for syntax reminders if needed.
+3. **Write and execute test code** — use the `execute_code` tool to run Python code that:
+   - Compiles the regex with `re.compile()`
+   - Tests it against a set of positive examples (should match) and negative examples (should not match)
+   - Extracts and displays any capturing groups
+   - Reports pass/fail for each test case
+4. **Iterate** — if any test fails, refine the pattern and re-run until all cases pass.
+5. **Present the result** — give the user the final pattern, explain what each part does, and show the test results.
+
+## Example Test Script
+
+```python
+import re
+
+pattern = re.compile(r'^[\w.+-]+@[\w-]+\.[\w.-]+$')
+
+positives = ["user@example.com", "first.last+tag@sub.domain.org"]
+negatives = ["@missing.com", "no-at-sign", "spaces in@address.com"]
+
+for s in positives:
+    assert pattern.match(s), f"FAIL: expected match for '{s}'"
+for s in negatives:
+    assert not pattern.match(s), f"FAIL: expected no match for '{s}'"
+
+print("All tests passed!")
+```