Merge branch 'main' into peibekwe/workflow-unit-tests

.github/workflows/dotnet-verify-samples.yml

@@ -0,0 +1,122 @@
+#
+# Runs the .NET sample verification tool, which builds and executes sample projects
+# and verifies their output using deterministic checks and AI-powered verification.
+#
+# Results are displayed as a GitHub Job Summary and the CSV report is uploaded as an artifact.
+#
+
+name: dotnet-verify-samples
+
+on:
+  workflow_dispatch:
+    inputs:
+      category:
+        description: "Sample category to run (blank for all)"
+        required: false
+        type: choice
+        options:
+          - ""
+          - "01-get-started"
+          - "02-agents"
+          - "03-workflows"
+      parallelism:
+        description: "Max parallel sample runs"
+        required: false
+        default: "8"
+        type: string
+  schedule:
+    - cron: "0 6 * * 1-5" # Weekdays at 6:00 UTC
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+permissions:
+  contents: read
+  id-token: write
+
+jobs:
+  verify-samples:
+    runs-on: ubuntu-latest
+    environment: 'integration'
+    timeout-minutes: 90
+    steps:
+      - uses: actions/checkout@v6
+        with:
+          persist-credentials: false
+          sparse-checkout: |
+            .
+            .github
+            dotnet
+            workflow-samples
+
+      - name: Setup dotnet
+        uses: actions/setup-dotnet@v5.2.0
+        with:
+          global-json-file: ${{ github.workspace }}/dotnet/global.json
+
+      - name: Azure CLI Login
+        if: github.event_name != 'pull_request'
+        uses: azure/login@v2
+        with:
+          client-id: ${{ secrets.AZURE_CLIENT_ID }}
+          tenant-id: ${{ secrets.AZURE_TENANT_ID }}
+          subscription-id: ${{ secrets.AZURE_SUBSCRIPTION_ID }}
+
+      - name: Run verify-samples
+        id: verify
+        working-directory: dotnet
+        shell: bash
+        run: |
+          CATEGORY_ARG=""
+          if [ -n "$CATEGORY_INPUT" ]; then
+            CATEGORY_ARG="--category $CATEGORY_INPUT"
+          fi
+
+          dotnet run --project eng/verify-samples -- \
+            $CATEGORY_ARG \
+            --parallel "$PARALLELISM" \
+            --md results.md \
+            --csv results.csv \
+            --log results.log
+        env:
+          CATEGORY_INPUT: ${{ github.event.inputs.category || '' }}
+          PARALLELISM: ${{ github.event.inputs.parallelism || '8' }}
+          # OpenAI Models
+          OPENAI_API_KEY: ${{ secrets.OPENAI_API_KEY }}
+          OPENAI_CHAT_MODEL_NAME: ${{ vars.OPENAI_CHAT_MODEL_NAME }}
+          OPENAI_REASONING_MODEL_NAME: ${{ vars.OPENAI_REASONING_MODEL_NAME }}
+          # Azure OpenAI Models
+          AZURE_OPENAI_DEPLOYMENT_NAME: ${{ vars.AZURE_OPENAI_DEPLOYMENT_NAME }}
+          AZURE_OPENAI_CHAT_DEPLOYMENT_NAME: ${{ vars.AZURE_OPENAI_DEPLOYMENT_NAME }}
+          AZURE_OPENAI_ENDPOINT: ${{ vars.AZURE_OPENAI_ENDPOINT }}
+          # Azure AI Foundry
+          AZURE_AI_PROJECT_ENDPOINT: ${{ vars.AZURE_AI_PROJECT_ENDPOINT }}
+          AZURE_AI_MODEL_DEPLOYMENT_NAME: ${{ vars.AZURE_AI_MODEL_DEPLOYMENT_NAME }}
+          AZURE_AI_BING_CONNECTION_ID: ${{ vars.AZURE_AI_BING_CONNECTION_ID }}
+
+      - name: Write Job Summary
+        if: always()
+        working-directory: dotnet
+        shell: bash
+        run: |
+          if [ -f results.md ]; then
+            cat results.md >> "$GITHUB_STEP_SUMMARY"
+          else
+            echo "⚠️ No results.md generated — verify-samples may have failed to start." >> "$GITHUB_STEP_SUMMARY"
+          fi
+
+      - name: Upload results
+        if: always()
+        uses: actions/upload-artifact@v7
+        with:
+          name: verify-samples-results
+          path: |
+            dotnet/results.csv
+            dotnet/results.log
+          if-no-files-found: warn
+
+      - name: Fail if samples failed
+        if: always() && steps.verify.outcome == 'failure'
+        shell: bash
+        run: exit 1

.gitignore

@@ -230,3 +230,6 @@ local.settings.json
 # Database files
 *.db
 python/dotnet-ref
+
+# Generated filtered solution files (created by eng/scripts/New-FilteredSolution.ps1)
+dotnet/filtered-*.slnx

README.md

@@ -28,7 +28,7 @@ Welcome to Microsoft's comprehensive multi-language framework for building, orch
 Python
 
 ```bash
-pip install agent-framework --pre
+pip install agent-framework
 # This will install all sub-packages, see `python/packages` for individual packages.
 # It may take a minute on first install on Windows.
 ```
@@ -90,7 +90,7 @@ Still have questions? Join our [weekly office hours](./COMMUNITY.md#public-commu
 Create a simple Azure Responses Agent that writes a haiku about the Microsoft Agent Framework
 
 ```python
-# pip install agent-framework --pre
+# pip install agent-framework
 # Use `az login` to authenticate with Azure CLI
 import os
 import asyncio

dotnet/.github/skills/verify-samples-tool/SKILL.md

@@ -25,7 +25,7 @@ dotnet run --project eng/verify-samples -- Agent_Step02_StructuredOutput Agent_S
 dotnet run --project eng/verify-samples -- --parallel 8 --log results.log
 
 # Combine options
-dotnet run --project eng/verify-samples -- --category 03-workflows --parallel 4 --log results.log --csv results.csv
+dotnet run --project eng/verify-samples -- --category 03-workflows --parallel 4 --log results.log --csv results.csv --md results.md
 ```
 
 ### Required Environment Variables
@@ -40,6 +40,7 @@ Individual samples require their own env vars (e.g., `AZURE_AI_PROJECT_ENDPOINT`
 
 - `--log results.log` — detailed per-sample log with stdout/stderr, AI reasoning, and a summary
 - `--csv results.csv` — tabular summary with Sample, ProjectPath, Status, FailedChecks, and Failures columns
+- `--md results.md` — Markdown summary with results table and collapsible failure details (suitable for GitHub PR comments)
 
 ## Sample Categories
 

dotnet/AGENTS.md

@@ -36,7 +36,7 @@ using types like `IChatClient`, `FunctionInvokingChatClient`, `AITool`, `AIFunct
 - **Async**: Use `Async` suffix for methods returning `Task`/`ValueTask`
 - **Private classes**: Should be `sealed` unless subclassed
 - **Config**: Read from environment variables with `UPPER_SNAKE_CASE` naming
-- **Tests**: Add Arrange/Act/Assert comments; use Moq for mocking
+- **Tests**: Add Arrange/Act/Assert comments; use Moq for mocking; test methods returning `Task`/`ValueTask` must use the `Async` suffix.
 
 ## Key Design Principles
 

dotnet/Directory.Packages.props

@@ -11,7 +11,7 @@
   </PropertyGroup>
   <ItemGroup>
     <!-- Aspire.* -->
-    <PackageVersion Include="Anthropic" Version="12.8.0" />
+    <PackageVersion Include="Anthropic" Version="12.11.0" />
     <PackageVersion Include="Anthropic.Foundry" Version="0.4.2" />
     <PackageVersion Include="Aspire.Azure.AI.OpenAI" Version="13.0.0-preview.1.25560.3" />
     <PackageVersion Include="Aspire.Hosting.AppHost" Version="$(AspireAppHostSdkVersion)" />

dotnet/agent-framework-dotnet.slnx

@@ -106,6 +106,9 @@
     <File Path="samples/02-agents/AgentSkills/README.md" />
     <Project Path="samples/02-agents/AgentSkills/Agent_Step01_FileBasedSkills/Agent_Step01_FileBasedSkills.csproj" />
     <Project Path="samples/02-agents/AgentSkills/Agent_Step02_CodeDefinedSkills/Agent_Step02_CodeDefinedSkills.csproj" />
+    <Project Path="samples/02-agents/AgentSkills/Agent_Step03_ClassBasedSkills/Agent_Step03_ClassBasedSkills.csproj" />
+    <Project Path="samples/02-agents/AgentSkills/Agent_Step04_MixedSkills/Agent_Step04_MixedSkills.csproj" />
+    <Project Path="samples/02-agents/AgentSkills/Agent_Step05_SkillsWithDI/Agent_Step05_SkillsWithDI.csproj" />
   </Folder>
   <Folder Name="/Samples/02-agents/AGUI/Step05_StateManagement/">
     <Project Path="samples/02-agents/AGUI/Step05_StateManagement/Client/Client.csproj" />

dotnet/eng/verify-samples/MarkdownResultWriter.cs

@@ -0,0 +1,98 @@
+// Copyright (c) Microsoft. All rights reserved.
+
+using System.Text;
+
+namespace VerifySamples;
+
+/// <summary>
+/// Writes a Markdown summary of sample verification results.
+/// </summary>
+internal static class MarkdownResultWriter
+{
+    /// <summary>
+    /// Writes the results to a Markdown file at the specified path.
+    /// </summary>
+    public static async Task WriteAsync(
+        string path,
+        IReadOnlyList<VerificationResult> orderedResults,
+        IReadOnlyList<(string Name, string Reason)> skipped,
+        TimeSpan elapsed)
+    {
+        var passCount = orderedResults.Count(r => r.Passed);
+        var failCount = orderedResults.Count(r => !r.Passed);
+
+        var sb = new StringBuilder();
+        sb.AppendLine("# Sample Verification Results");
+        sb.AppendLine();
+        sb.AppendLine($"**{passCount} passed, {failCount} failed, {skipped.Count} skipped** | Elapsed: {elapsed.Hours:D2}:{elapsed.Minutes:D2}:{elapsed.Seconds:D2}");
+        sb.AppendLine();
+
+        // Results table
+        sb.AppendLine("| Sample | Status | Failed Checks | Failures |");
+        sb.AppendLine("|--------|--------|---------------|----------|");
+
+        foreach (var result in orderedResults)
+        {
+            var status = result.Passed ? "✅ PASSED" : "❌ FAILED";
+            var failedChecks = result.Failures.Count;
+            var failures = MdEscape(string.Join("; ", result.Failures));
+            sb.AppendLine($"| {MdEscape(result.SampleName)} | {status} | {failedChecks} | {failures} |");
+        }
+
+        foreach (var (name, reason) in skipped)
+        {
+            sb.AppendLine($"| {MdEscape(name)} | ⏭️ SKIPPED | 0 | {MdEscape(reason)} |");
+        }
+
+        // Collapsible AI reasoning details for failures
+        var failures2 = orderedResults.Where(r => !r.Passed && !string.IsNullOrEmpty(r.AIReasoning)).ToList();
+        if (failures2.Count > 0)
+        {
+            sb.AppendLine();
+            sb.AppendLine("## Failure Details");
+            sb.AppendLine();
+
+            foreach (var result in failures2)
+            {
+                sb.AppendLine($"<details><summary><strong>{HtmlEscape(result.SampleName)}</strong></summary>");
+                sb.AppendLine();
+                if (result.Failures.Count > 0)
+                {
+                    foreach (var failure in result.Failures)
+                    {
+                        sb.AppendLine($"- {MdEscape(failure)}");
+                    }
+
+                    sb.AppendLine();
+                }
+
+                sb.AppendLine("**AI Reasoning:**");
+                sb.AppendLine();
+                sb.AppendLine("```");
+                sb.AppendLine(result.AIReasoning);
+                sb.AppendLine("```");
+                sb.AppendLine();
+                sb.AppendLine("</details>");
+                sb.AppendLine();
+            }
+        }
+
+        await File.WriteAllTextAsync(path, sb.ToString());
+    }
+
+    /// <summary>
+    /// Escapes pipe characters and newlines for use inside Markdown table cells.
+    /// </summary>
+    private static string MdEscape(string value)
+    {
+        return value.Replace("|", "\\|").Replace("\n", " ").Replace("\r", "");
+    }
+
+    /// <summary>
+    /// Escapes HTML special characters for use inside HTML tags.
+    /// </summary>
+    private static string HtmlEscape(string value)
+    {
+        return value.Replace("&", "&amp;").Replace("<", "&lt;").Replace(">", "&gt;").Replace("\"", "&quot;");
+    }
+}

dotnet/eng/verify-samples/Program.cs

@@ -13,6 +13,7 @@
 //   dotnet run -- --parallel 16                         # Run up to 16 samples concurrently
 //   dotnet run -- --log results.log                     # Write sequential log to file
 //   dotnet run -- --csv results.csv                     # Write CSV summary to file
+//   dotnet run -- --md results.md                       # Write Markdown summary to file
 //
 // Required environment variables (for AI-powered samples):
 //   AZURE_OPENAI_ENDPOINT
@@ -90,6 +91,13 @@ try
         Console.WriteLine($"CSV written to: {options.CsvFilePath}");
     }
 
+    // Write Markdown summary
+    if (options.MarkdownFilePath is not null)
+    {
+        await MarkdownResultWriter.WriteAsync(options.MarkdownFilePath, orderedResults, run.Skipped, stopwatch.Elapsed);
+        Console.WriteLine($"Markdown written to: {options.MarkdownFilePath}");
+    }
+
     return orderedResults.Any(r => !r.Passed) ? 1 : 0;
 }
 finally

dotnet/eng/verify-samples/VerifyOptions.cs

@@ -17,6 +17,11 @@ internal sealed class VerifyOptions
     /// </summary>
     public string? CsvFilePath { get; init; }
 
+    /// <summary>
+    /// Path to write a Markdown summary file, or <c>null</c> to skip.
+    /// </summary>
+    public string? MarkdownFilePath { get; init; }
+
     /// <summary>
     /// Path to write a sequential log file, or <c>null</c> to skip.
     /// </summary>
@@ -49,6 +54,7 @@ internal sealed class VerifyOptions
         var categoryFilter = ExtractArg(argList, "--category");
         var logFilePath = ExtractArg(argList, "--log");
         var csvFilePath = ExtractArg(argList, "--csv");
+        var markdownFilePath = ExtractArg(argList, "--md");
 
         int maxParallelism = 8;
         var parallelArg = ExtractArg(argList, "--parallel");
@@ -98,6 +104,7 @@ internal sealed class VerifyOptions
             MaxParallelism = maxParallelism,
             LogFilePath = logFilePath,
             CsvFilePath = csvFilePath,
+            MarkdownFilePath = markdownFilePath,
             Samples = samples,
         };
     }

dotnet/samples/02-agents/AgentSkills/Agent_Step01_FileBasedSkills/README.md

@@ -6,7 +6,7 @@ This sample demonstrates how to use **file-based Agent Skills** with a `ChatClie
 
 - Discovering skills from `SKILL.md` files on disk via `AgentFileSkillsSource`
 - The progressive disclosure pattern: advertise → load → read resources → run scripts
-- Using the `AgentSkillsProvider` constructor with a skill directory path and script executor
+- Using the `AgentSkillsProvider` constructor with a skill directory path and script runner
 - Running file-based scripts (Python) via a subprocess-based executor
 
 ## Skills Included

dotnet/samples/02-agents/AgentSkills/Agent_Step03_ClassBasedSkills/Agent_Step03_ClassBasedSkills.csproj

@@ -0,0 +1,21 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFrameworks>net10.0</TargetFrameworks>
+
+    <Nullable>enable</Nullable>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <NoWarn>$(NoWarn);MAAI001</NoWarn>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Azure.AI.OpenAI" />
+    <PackageReference Include="Azure.Identity" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\..\..\..\src\Microsoft.Agents.AI.OpenAI\Microsoft.Agents.AI.OpenAI.csproj" />
+  </ItemGroup>
+
+</Project>

dotnet/samples/02-agents/AgentSkills/Agent_Step03_ClassBasedSkills/Program.cs

@@ -0,0 +1,102 @@
+// Copyright (c) Microsoft. All rights reserved.
+
+// This sample demonstrates how to define Agent Skills as C# classes using AgentClassSkill.
+// Class-based skills bundle all components into a single class implementation.
+
+using System.Text.Json;
+using Azure.AI.OpenAI;
+using Azure.Identity;
+using Microsoft.Agents.AI;
+using OpenAI.Responses;
+
+// --- Configuration ---
+string endpoint = Environment.GetEnvironmentVariable("AZURE_OPENAI_ENDPOINT") ?? throw new InvalidOperationException("AZURE_OPENAI_ENDPOINT is not set.");
+string deploymentName = Environment.GetEnvironmentVariable("AZURE_OPENAI_DEPLOYMENT_NAME") ?? "gpt-4o-mini";
+
+// --- Class-Based Skill ---
+// Instantiate the skill class.
+var unitConverter = new UnitConverterSkill();
+
+// --- Skills Provider ---
+var skillsProvider = new AgentSkillsProvider(unitConverter);
+
+// --- Agent Setup ---
+AIAgent agent = new AzureOpenAIClient(new Uri(endpoint), new DefaultAzureCredential())
+    .GetResponsesClient()
+    .AsAIAgent(new ChatClientAgentOptions
+    {
+        Name = "UnitConverterAgent",
+        ChatOptions = new()
+        {
+            Instructions = "You are a helpful assistant that can convert units.",
+        },
+        AIContextProviders = [skillsProvider],
+    },
+    model: deploymentName);
+
+// --- Example: Unit conversion ---
+Console.WriteLine("Converting units with class-based skills");
+Console.WriteLine(new string('-', 60));
+
+AgentResponse response = await agent.RunAsync(
+    "How many kilometers is a marathon (26.2 miles)? And how many pounds is 75 kilograms?");
+
+Console.WriteLine($"Agent: {response.Text}");
+
+/// <summary>
+/// A unit-converter skill defined as a C# class.
+/// </summary>
+/// <remarks>
+/// Class-based skills bundle all components (name, description, body, resources, scripts)
+/// into a single class.
+/// </remarks>
+internal sealed class UnitConverterSkill : AgentClassSkill
+{
+    private IReadOnlyList<AgentSkillResource>? _resources;
+    private IReadOnlyList<AgentSkillScript>? _scripts;
+
+    /// <inheritdoc/>
+    public override AgentSkillFrontmatter Frontmatter { get; } = new(
+        "unit-converter",
+        "Convert between common units using a multiplication factor. Use when asked to convert miles, kilometers, pounds, or kilograms.");
+
+    /// <inheritdoc/>
+    protected override string Instructions => """
+        Use this skill when the user asks to convert between units.
+
+        1. Review the conversion-table resource to find the factor for the requested conversion.
+        2. Use the convert script, passing the value and factor from the table.
+        3. Present the result clearly with both units.
+        """;
+
+    /// <inheritdoc/>
+    public override IReadOnlyList<AgentSkillResource>? Resources => this._resources ??=
+    [
+        CreateResource(
+            "conversion-table",
+            """
+            # Conversion Tables
+
+            Formula: **result = value × factor**
+
+            | From        | To          | Factor   |
+            |-------------|-------------|----------|
+            | miles       | kilometers  | 1.60934  |
+            | kilometers  | miles       | 0.621371 |
+            | pounds      | kilograms   | 0.453592 |
+            | kilograms   | pounds      | 2.20462  |
+            """),
+    ];
+
+    /// <inheritdoc/>
+    public override IReadOnlyList<AgentSkillScript>? Scripts => this._scripts ??=
+    [
+        CreateScript("convert", ConvertUnits),
+    ];
+
+    private static string ConvertUnits(double value, double factor)
+    {
+        double result = Math.Round(value * factor, 4);
+        return JsonSerializer.Serialize(new { value, factor, result });
+    }
+}

dotnet/samples/02-agents/AgentSkills/Agent_Step03_ClassBasedSkills/README.md

@@ -0,0 +1,49 @@
+# Class-Based Agent Skills Sample
+
+This sample demonstrates how to define **Agent Skills as C# classes** using `AgentClassSkill`.
+
+## What it demonstrates
+
+- Creating skills as classes that extend `AgentClassSkill`
+- Bundling name, description, body, resources, and scripts into a single class
+- Using the `AgentSkillsProvider` constructor with class-based skills
+
+## Skills Included
+
+### unit-converter (class-based)
+
+A `UnitConverterSkill` class that converts between common units. Defined in `Program.cs`:
+
+- `conversion-table` — Static resource with factor table
+- `convert` — Script that performs `value × factor` conversion
+
+## Running the Sample
+
+### Prerequisites
+
+- .NET 10.0 SDK
+- Azure OpenAI endpoint with a deployed model
+
+### Setup
+
+```bash
+export AZURE_OPENAI_ENDPOINT="https://your-endpoint.openai.azure.com/"
+export AZURE_OPENAI_DEPLOYMENT_NAME="gpt-4o-mini"
+```
+
+### Run
+
+```bash
+dotnet run
+```
+
+### Expected Output
+
+```
+Converting units with class-based skills
+------------------------------------------------------------
+Agent: Here are your conversions:
+
+1. **26.2 miles → 42.16 km** (a marathon distance)
+2. **75 kg → 165.35 lbs**
+```

dotnet/samples/02-agents/AgentSkills/Agent_Step04_MixedSkills/Agent_Step04_MixedSkills.csproj

@@ -0,0 +1,32 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFrameworks>net10.0</TargetFrameworks>
+
+    <Nullable>enable</Nullable>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <NoWarn>$(NoWarn);MAAI001</NoWarn>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Azure.AI.OpenAI" />
+    <PackageReference Include="Azure.Identity" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <Compile Include="..\SubprocessScriptRunner.cs" Link="SubprocessScriptRunner.cs" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\..\..\..\src\Microsoft.Agents.AI.OpenAI\Microsoft.Agents.AI.OpenAI.csproj" />
+  </ItemGroup>
+
+  <!-- Copy skills directory to output -->
+  <ItemGroup>
+    <None Include="skills\**\*.*">
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+    </None>
+  </ItemGroup>
+
+</Project>

dotnet/samples/02-agents/AgentSkills/Agent_Step04_MixedSkills/Program.cs

@@ -0,0 +1,149 @@
+// Copyright (c) Microsoft. All rights reserved.
+
+// This sample demonstrates an advanced scenario: combining multiple skill types in a single agent
+// using AgentSkillsProviderBuilder. The builder is designed for cases where the simple
+// AgentSkillsProvider constructors are insufficient — for example, when you need to mix skill
+// sources, apply filtering, or configure cross-cutting options in one place.
+//
+// Three different skill sources are registered here:
+// 1. File-based: unit-converter (miles↔km, pounds↔kg) from SKILL.md on disk
+// 2. Code-defined: volume-converter (gallons↔liters) using AgentInlineSkill
+// 3. Class-based: temperature-converter (°F↔°C↔K) using AgentClassSkill
+//
+// For simpler, single-source scenarios, see the earlier steps in this sample series
+// (e.g., Step01 for file-based, Step02 for code-defined, Step03 for class-based).
+
+using System.Text.Json;
+using Azure.AI.OpenAI;
+using Azure.Identity;
+using Microsoft.Agents.AI;
+using OpenAI.Responses;
+
+// --- Configuration ---
+string endpoint = Environment.GetEnvironmentVariable("AZURE_OPENAI_ENDPOINT")
+    ?? throw new InvalidOperationException("AZURE_OPENAI_ENDPOINT is not set.");
+string deploymentName = Environment.GetEnvironmentVariable("AZURE_OPENAI_DEPLOYMENT_NAME") ?? "gpt-4o-mini";
+
+// --- 1. Code-Defined Skill: volume-converter ---
+var volumeConverterSkill = new AgentInlineSkill(
+    name: "volume-converter",
+    description: "Convert between gallons and liters using a multiplication factor.",
+    instructions: """
+        Use this skill when the user asks to convert between gallons and liters.
+
+        1. Review the volume-conversion-table resource to find the correct factor.
+        2. Use the convert-volume script, passing the value and factor.
+        """)
+    .AddResource("volume-conversion-table",
+        """
+        # Volume Conversion Table
+
+        Formula: **result = value × factor**
+
+        | From    | To      | Factor  |
+        |---------|---------|---------|
+        | gallons | liters  | 3.78541 |
+        | liters  | gallons | 0.264172|
+        """)
+    .AddScript("convert-volume", (double value, double factor) =>
+    {
+        double result = Math.Round(value * factor, 4);
+        return JsonSerializer.Serialize(new { value, factor, result });
+    });
+
+// --- 2. Class-Based Skill: temperature-converter ---
+var temperatureConverter = new TemperatureConverterSkill();
+
+// --- 3. Build provider combining all three source types ---
+var skillsProvider = new AgentSkillsProviderBuilder()
+    .UseFileSkill(Path.Combine(AppContext.BaseDirectory, "skills"))    // File-based: unit-converter
+    .UseSkill(volumeConverterSkill)                                    // Code-defined: volume-converter
+    .UseSkill(temperatureConverter)                                     // Class-based: temperature-converter
+    .UseFileScriptRunner(SubprocessScriptRunner.RunAsync)
+    .Build();
+
+// --- Agent Setup ---
+AIAgent agent = new AzureOpenAIClient(new Uri(endpoint), new DefaultAzureCredential())
+    .GetResponsesClient()
+    .AsAIAgent(new ChatClientAgentOptions
+    {
+        Name = "MultiConverterAgent",
+        ChatOptions = new()
+        {
+            Instructions = "You are a helpful assistant that can convert units, volumes, and temperatures.",
+        },
+        AIContextProviders = [skillsProvider],
+    },
+    model: deploymentName);
+
+// --- Example: Use all three skills ---
+Console.WriteLine("Converting with mixed skills (file + code + class)");
+Console.WriteLine(new string('-', 60));
+
+AgentResponse response = await agent.RunAsync(
+    "I need three conversions: " +
+    "1) How many kilometers is a marathon (26.2 miles)? " +
+    "2) How many liters is a 5-gallon bucket? " +
+    "3) What is 98.6°F in Celsius?");
+
+Console.WriteLine($"Agent: {response.Text}");
+
+/// <summary>
+/// A temperature-converter skill defined as a C# class.
+/// </summary>
+internal sealed class TemperatureConverterSkill : AgentClassSkill
+{
+    private IReadOnlyList<AgentSkillResource>? _resources;
+    private IReadOnlyList<AgentSkillScript>? _scripts;
+
+    /// <inheritdoc/>
+    public override AgentSkillFrontmatter Frontmatter { get; } = new(
+        "temperature-converter",
+        "Convert between temperature scales (Fahrenheit, Celsius, Kelvin).");
+
+    /// <inheritdoc/>
+    protected override string Instructions => """
+        Use this skill when the user asks to convert temperatures.
+
+        1. Review the temperature-conversion-formulas resource for the correct formula.
+        2. Use the convert-temperature script, passing the value, source scale, and target scale.
+        3. Present the result clearly with both temperature scales.
+        """;
+
+    /// <inheritdoc/>
+    public override IReadOnlyList<AgentSkillResource>? Resources => this._resources ??=
+    [
+        CreateResource(
+            "temperature-conversion-formulas",
+            """
+            # Temperature Conversion Formulas
+
+            | From        | To          | Formula                   |
+            |-------------|-------------|---------------------------|
+            | Fahrenheit  | Celsius     | °C = (°F − 32) × 5/9     |
+            | Celsius     | Fahrenheit  | °F = (°C × 9/5) + 32     |
+            | Celsius     | Kelvin      | K = °C + 273.15           |
+            | Kelvin      | Celsius     | °C = K − 273.15           |
+            """),
+    ];
+
+    /// <inheritdoc/>
+    public override IReadOnlyList<AgentSkillScript>? Scripts => this._scripts ??=
+    [
+        CreateScript("convert-temperature", ConvertTemperature),
+    ];
+
+    private static string ConvertTemperature(double value, string from, string to)
+    {
+        double result = (from.ToUpperInvariant(), to.ToUpperInvariant()) switch
+        {
+            ("FAHRENHEIT", "CELSIUS") => Math.Round((value - 32) * 5.0 / 9.0, 2),
+            ("CELSIUS", "FAHRENHEIT") => Math.Round(value * 9.0 / 5.0 + 32, 2),
+            ("CELSIUS", "KELVIN") => Math.Round(value + 273.15, 2),
+            ("KELVIN", "CELSIUS") => Math.Round(value - 273.15, 2),
+            _ => throw new ArgumentException($"Unsupported conversion: {from} → {to}")
+        };
+
+        return JsonSerializer.Serialize(new { value, from, to, result });
+    }
+}

dotnet/samples/02-agents/AgentSkills/Agent_Step04_MixedSkills/README.md

@@ -0,0 +1,67 @@
+# Mixed Agent Skills Sample (Advanced)
+
+This sample demonstrates an **advanced scenario**: combining multiple skill types in a single agent using `AgentSkillsProviderBuilder`.
+
+> **Tip:** For simpler, single-source scenarios, use the `AgentSkillsProvider` constructors directly — see [Step01](../Agent_Step01_FileBasedSkills/) (file-based), [Step02](../Agent_Step02_CodeDefinedSkills/) (code-defined), or [Step03](../Agent_Step03_ClassBasedSkills/) (class-based).
+
+## What it demonstrates
+
+- Combining file-based, code-defined, and class-based skills in one provider
+- Using `UseFileSkill` and `UseSkill` on the builder to register different skill types
+- Aggregating skills from all sources into a single provider with automatic deduplication
+
+## When to use `AgentSkillsProviderBuilder`
+
+The builder is intended for advanced scenarios where the simple `AgentSkillsProvider` constructors are insufficient:
+
+| Scenario | Builder method |
+|----------|---------------|
+| **Mixed skill types** — combine file-based, code-defined, and class-based skills | `UseFileSkill` + `UseSkill` / `UseSkills` |
+| **Multiple file script runners** — use different script runners for different file skill directories | `UseFileSkill` / `UseFileSkills` with per-source `scriptRunner` |
+| **Skill filtering** — include/exclude skills using a predicate | `UseFilter(predicate)` |
+
+## Skills Included
+
+### unit-converter (file-based)
+
+Discovered from `skills/unit-converter/SKILL.md` on disk. Converts miles↔km, pounds↔kg.
+
+### volume-converter (code-defined)
+
+Defined as `AgentInlineSkill` in `Program.cs`. Converts gallons↔liters.
+
+### temperature-converter (class-based)
+
+Defined as `TemperatureConverterSkill` class in `Program.cs`. Converts °F↔°C↔K.
+
+## Running the Sample
+
+### Prerequisites
+
+- .NET 10.0 SDK
+- Azure OpenAI endpoint with a deployed model
+
+### Setup
+
+```bash
+export AZURE_OPENAI_ENDPOINT="https://your-endpoint.openai.azure.com/"
+export AZURE_OPENAI_DEPLOYMENT_NAME="gpt-4o-mini"
+```
+
+### Run
+
+```bash
+dotnet run
+```
+
+### Expected Output
+
+```
+Converting with mixed skills (file + code + class)
+------------------------------------------------------------
+Agent: Here are your conversions:
+
+1. **26.2 miles → 42.16 km** (a marathon distance)
+2. **5 gallons → 18.93 liters**
+3. **98.6°F → 37.0°C**
+```

dotnet/samples/02-agents/AgentSkills/Agent_Step04_MixedSkills/skills/unit-converter/SKILL.md

@@ -0,0 +1,11 @@
+---
+name: unit-converter
+description: Convert between common units using a multiplication factor. Use when asked to convert miles, kilometers, pounds, or kilograms.
+---
+
+## Usage
+
+When the user requests a unit conversion:
+1. First, review `references/unit-conversion-table.md` to find the correct factor
+2. Run the `scripts/convert-units.py` script with `--value <number> --factor <factor>` (e.g. `--value 26.2 --factor 1.60934`)
+3. Present the converted value clearly with both units

dotnet/samples/02-agents/AgentSkills/Agent_Step04_MixedSkills/skills/unit-converter/references/unit-conversion-table.md

@@ -0,0 +1,10 @@
+# Conversion Tables
+
+Formula: **result = value × factor**
+
+| From        | To          | Factor   |
+|-------------|-------------|----------|
+| miles       | kilometers  | 1.60934  |
+| kilometers  | miles       | 0.621371 |
+| pounds      | kilograms   | 0.453592 |
+| kilograms   | pounds      | 2.20462  |

dotnet/samples/02-agents/AgentSkills/Agent_Step04_MixedSkills/skills/unit-converter/scripts/convert-units.py

@@ -0,0 +1,29 @@
+# Unit conversion script
+# Converts a value using a multiplication factor: result = value × factor
+#
+# Usage:
+#   python scripts/convert-units.py --value 26.2 --factor 1.60934
+#   python scripts/convert-units.py --value 75 --factor 2.20462
+
+import argparse
+import json
+
+
+def main() -> None:
+    parser = argparse.ArgumentParser(
+        description="Convert a value using a multiplication factor.",
+        epilog="Examples:\n"
+        "  python scripts/convert-units.py --value 26.2 --factor 1.60934\n"
+        "  python scripts/convert-units.py --value 75 --factor 2.20462",
+        formatter_class=argparse.RawDescriptionHelpFormatter,
+    )
+    parser.add_argument("--value", type=float, required=True, help="The numeric value to convert.")
+    parser.add_argument("--factor", type=float, required=True, help="The conversion factor from the table.")
+    args = parser.parse_args()
+
+    result = round(args.value * args.factor, 4)
+    print(json.dumps({"value": args.value, "factor": args.factor, "result": result}))
+
+
+if __name__ == "__main__":
+    main()

dotnet/samples/02-agents/AgentSkills/Agent_Step05_SkillsWithDI/Agent_Step05_SkillsWithDI.csproj

@@ -0,0 +1,22 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFrameworks>net10.0</TargetFrameworks>
+
+    <Nullable>enable</Nullable>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <NoWarn>$(NoWarn);MAAI001;CA1812</NoWarn>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Azure.AI.OpenAI" />
+    <PackageReference Include="Azure.Identity" />
+    <PackageReference Include="Microsoft.Extensions.DependencyInjection" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\..\..\..\src\Microsoft.Agents.AI.OpenAI\Microsoft.Agents.AI.OpenAI.csproj" />
+  </ItemGroup>
+
+</Project>

dotnet/samples/02-agents/AgentSkills/Agent_Step05_SkillsWithDI/Program.cs

@@ -0,0 +1,208 @@
+// Copyright (c) Microsoft. All rights reserved.
+
+// This sample demonstrates how to use Dependency Injection (DI) with Agent Skills.
+// It shows two approaches side-by-side, each handling a different conversion domain:
+//
+// 1. Code-defined skill (AgentInlineSkill) — converts distances (miles ↔ kilometers).
+//    Resources and scripts are inline delegates that resolve services from IServiceProvider.
+//
+// 2. Class-based skill (AgentClassSkill) — converts weights (pounds ↔ kilograms).
+//    Resources and scripts are encapsulated in a class, also resolving services from IServiceProvider.
+//
+// Both skills share the same ConversionService registered in the DI container,
+// showing that DI works identically regardless of how the skill is defined.
+// When prompted with a question spanning both domains, the agent uses both skills.
+
+using System.Text.Json;
+using Azure.AI.OpenAI;
+using Azure.Identity;
+using Microsoft.Agents.AI;
+using Microsoft.Extensions.DependencyInjection;
+using OpenAI.Responses;
+
+// --- Configuration ---
+string endpoint = Environment.GetEnvironmentVariable("AZURE_OPENAI_ENDPOINT") ?? throw new InvalidOperationException("AZURE_OPENAI_ENDPOINT is not set.");
+string deploymentName = Environment.GetEnvironmentVariable("AZURE_OPENAI_DEPLOYMENT_NAME") ?? "gpt-4o-mini";
+
+// --- DI Container ---
+// Register application services that skill resources and scripts can resolve at execution time.
+ServiceCollection services = new();
+services.AddSingleton<ConversionService>();
+
+IServiceProvider serviceProvider = services.BuildServiceProvider();
+
+// =====================================================================
+// Approach 1: Code-Defined Skill with DI (AgentInlineSkill)
+// =====================================================================
+// Handles distance conversions (miles ↔ kilometers).
+// Resources and scripts are inline delegates. Each delegate can declare
+// an IServiceProvider parameter that the framework injects automatically.
+
+var distanceSkill = new AgentInlineSkill(
+    name: "distance-converter",
+    description: "Convert between distance units. Use when asked to convert miles to kilometers or kilometers to miles.",
+    instructions: """
+        Use this skill when the user asks to convert between distance units (miles and kilometers).
+
+        1. Review the distance-table resource to find the factor for the requested conversion.
+        2. Use the convert script, passing the value and factor from the table.
+        """)
+    .AddResource("distance-table", (IServiceProvider serviceProvider) =>
+    {
+        var service = serviceProvider.GetRequiredService<ConversionService>();
+        return service.GetDistanceTable();
+    })
+    .AddScript("convert", (double value, double factor, IServiceProvider serviceProvider) =>
+    {
+        var service = serviceProvider.GetRequiredService<ConversionService>();
+        return service.Convert(value, factor);
+    });
+
+// =====================================================================
+// Approach 2: Class-Based Skill with DI (AgentClassSkill)
+// =====================================================================
+// Handles weight conversions (pounds ↔ kilograms).
+// Resources and scripts are encapsulated in a class. Factory methods
+// CreateResource and CreateScript accept delegates with IServiceProvider.
+//
+// Alternatively, class-based skills can accept dependencies through their
+// constructor. Register the skill class itself in the ServiceCollection and
+// resolve it from the container:
+//
+//   services.AddSingleton<WeightConverterSkill>();
+//   var weightSkill = serviceProvider.GetRequiredService<WeightConverterSkill>();
+
+var weightSkill = new WeightConverterSkill();
+
+// --- Skills Provider ---
+// Both skills are registered with the same provider so the agent can use either one.
+var skillsProvider = new AgentSkillsProvider(distanceSkill, weightSkill);
+
+// --- Agent Setup ---
+AIAgent agent = new AzureOpenAIClient(new Uri(endpoint), new DefaultAzureCredential())
+    .GetResponsesClient()
+    .AsAIAgent(
+        options: new ChatClientAgentOptions
+        {
+            Name = "UnitConverterAgent",
+            ChatOptions = new()
+            {
+                Instructions = "You are a helpful assistant that can convert units.",
+            },
+            AIContextProviders = [skillsProvider],
+        },
+        model: deploymentName,
+        services: serviceProvider);
+
+// --- Example: Unit conversion ---
+// This prompt spans both domains, so the agent will use both skills.
+Console.WriteLine("Converting units with DI-powered skills");
+Console.WriteLine(new string('-', 60));
+
+AgentResponse response = await agent.RunAsync(
+    "How many kilometers is a marathon (26.2 miles)? And how many pounds is 75 kilograms?");
+
+Console.WriteLine($"Agent: {response.Text}");
+
+// ---------------------------------------------------------------------------
+// Class-Based Skill
+// ---------------------------------------------------------------------------
+
+/// <summary>
+/// A weight-converter skill defined as a C# class that uses Dependency Injection.
+/// </summary>
+/// <remarks>
+/// This skill resolves <see cref="ConversionService"/> from the DI container
+/// in both its resource and script functions. This enables clean separation of
+/// concerns and testability while retaining the class-based skill pattern.
+/// </remarks>
+internal sealed class WeightConverterSkill : AgentClassSkill
+{
+    private IReadOnlyList<AgentSkillResource>? _resources;
+    private IReadOnlyList<AgentSkillScript>? _scripts;
+
+    /// <inheritdoc/>
+    public override AgentSkillFrontmatter Frontmatter { get; } = new(
+        "weight-converter",
+        "Convert between weight units. Use when asked to convert pounds to kilograms or kilograms to pounds.");
+
+    /// <inheritdoc/>
+    protected override string Instructions => """
+        Use this skill when the user asks to convert between weight units (pounds and kilograms).
+
+        1. Review the weight-table resource to find the factor for the requested conversion.
+        2. Use the convert script, passing the value and factor from the table.
+        3. Present the result clearly with both units.
+        """;
+
+    /// <inheritdoc/>
+    public override IReadOnlyList<AgentSkillResource>? Resources => this._resources ??=
+    [
+        CreateResource("weight-table", (IServiceProvider serviceProvider) =>
+        {
+            var service = serviceProvider.GetRequiredService<ConversionService>();
+            return service.GetWeightTable();
+        }),
+    ];
+
+    /// <inheritdoc/>
+    public override IReadOnlyList<AgentSkillScript>? Scripts => this._scripts ??=
+    [
+        CreateScript("convert", (double value, double factor, IServiceProvider serviceProvider) =>
+        {
+            var service = serviceProvider.GetRequiredService<ConversionService>();
+            return service.Convert(value, factor);
+        }),
+    ];
+}
+
+// ---------------------------------------------------------------------------
+// Services
+// ---------------------------------------------------------------------------
+
+/// <summary>
+/// Provides conversion rates between units.
+/// In a real application this could call an external API, read from a database,
+/// or apply time-varying exchange rates.
+/// </summary>
+internal sealed class ConversionService
+{
+    /// <summary>
+    /// Returns a markdown table of supported distance conversions.
+    /// </summary>
+    public string GetDistanceTable() =>
+        """
+        # Distance Conversions
+
+        Formula: **result = value × factor**
+
+        | From        | To          | Factor   |
+        |-------------|-------------|----------|
+        | miles       | kilometers  | 1.60934  |
+        | kilometers  | miles       | 0.621371 |
+        """;
+
+    /// <summary>
+    /// Returns a markdown table of supported weight conversions.
+    /// </summary>
+    public string GetWeightTable() =>
+        """
+        # Weight Conversions
+
+        Formula: **result = value × factor**
+
+        | From        | To          | Factor   |
+        |-------------|-------------|----------|
+        | pounds      | kilograms   | 0.453592 |
+        | kilograms   | pounds      | 2.20462  |
+        """;
+
+    /// <summary>
+    /// Converts a value by the given factor and returns a JSON result.
+    /// </summary>
+    public string Convert(double value, double factor)
+    {
+        double result = Math.Round(value * factor, 4);
+        return JsonSerializer.Serialize(new { value, factor, result });
+    }
+}

dotnet/samples/02-agents/AgentSkills/Agent_Step05_SkillsWithDI/README.md

@@ -0,0 +1,65 @@
+# Agent Skills with Dependency Injection
+
+This sample demonstrates how to use **Dependency Injection (DI)** with Agent Skills. It shows two approaches side-by-side, each handling a different conversion domain:
+
+1. **Code-defined skill** (`AgentInlineSkill`) — converts **distances** (miles ↔ kilometers)
+2. **Class-based skill** (`AgentClassSkill`) — converts **weights** (pounds ↔ kilograms)
+
+Both skills resolve the same `ConversionService` from the DI container. When prompted with a question spanning both domains, the agent uses both skills.
+
+## What It Shows
+
+- Registering application services in a `ServiceCollection`
+- Defining a **code-defined** skill (distance converter) with resources and scripts that resolve services from `IServiceProvider`
+- Defining a **class-based** skill (weight converter) with resources and scripts that resolve services from `IServiceProvider`
+- Passing the built `IServiceProvider` to the agent so skills can access DI services at execution time
+- Running a single prompt that exercises both skills to show they work together
+
+## How It Works
+
+1. A `ConversionService` is registered as a singleton in the DI container
+2. **Code-defined skill**: An `AgentInlineSkill` for distance conversions declares `IServiceProvider` as a parameter in its `AddResource` and `AddScript` delegates — the framework injects it automatically
+3. **Class-based skill**: A `WeightConverterSkill` class extends `AgentClassSkill` for weight conversions and uses `CreateResource`/`CreateScript` factory methods with `IServiceProvider` parameters
+4. Both skills resolve `ConversionService` from the provider — one for distance tables, the other for weight tables
+5. A single agent is created with both skills registered, and the service provider flows through to skill execution
+
+> **Tip:** Class-based skills can also accept dependencies through their **constructor**. Register the skill class in the `ServiceCollection` and resolve it from the container instead of calling `new` directly. This is useful when the skill itself needs injected services beyond what the resource/script delegates use.
+
+## How It Differs from Other Samples
+
+| Sample | Skill Type | DI Support |
+|--------|------------|------------|
+| [Step02](../Agent_Step02_CodeDefinedSkills/) | Code-defined (`AgentInlineSkill`) | No — static resources |
+| [Step03](../Agent_Step03_ClassBasedSkills/) | Class-based (`AgentClassSkill`) | No — static resources |
+| **Step05 (this)** | **Both code-defined and class-based** | **Yes — DI via `IServiceProvider`** |
+
+## Prerequisites
+
+- .NET 10
+- An Azure OpenAI deployment
+
+## Configuration
+
+Set the following environment variables:
+
+| Variable | Description |
+|---|---|
+| `AZURE_OPENAI_ENDPOINT` | Your Azure OpenAI endpoint URL |
+| `AZURE_OPENAI_DEPLOYMENT_NAME` | Model deployment name (defaults to `gpt-4o-mini`) |
+
+## Running the Sample
+
+```bash
+dotnet run
+```
+
+### Expected Output
+
+```
+Converting units with DI-powered skills
+------------------------------------------------------------
+Agent: Here are your conversions:
+
+1. **26.2 miles → 42.16 km** (a marathon distance)
+2. **75 kg → 165.35 lbs**
+```

dotnet/samples/02-agents/AgentSkills/README.md

@@ -6,19 +6,32 @@ Samples demonstrating Agent Skills capabilities. Each sample shows a different w
 |--------|-------------|
 | [Agent_Step01_FileBasedSkills](Agent_Step01_FileBasedSkills/) | Define skills as `SKILL.md` files on disk with reference documents. Uses a unit-converter skill. |
 | [Agent_Step02_CodeDefinedSkills](Agent_Step02_CodeDefinedSkills/) | Define skills entirely in C# code using `AgentInlineSkill`, with static/dynamic resources and scripts. |
+| [Agent_Step03_ClassBasedSkills](Agent_Step03_ClassBasedSkills/) | Define skills as C# classes using `AgentClassSkill`. |
+| [Agent_Step04_MixedSkills](Agent_Step04_MixedSkills/) | **(Advanced)** Combine file-based, code-defined, and class-based skills using `AgentSkillsProviderBuilder`. |
+| [Agent_Step05_SkillsWithDI](Agent_Step05_SkillsWithDI/) | Use Dependency Injection with both code-defined (`AgentInlineSkill`) and class-based (`AgentClassSkill`) skills. |
 
 ## Key Concepts
 
-### File-Based vs Code-Defined Skills
+### Skill Types
 
-| Aspect | File-Based | Code-Defined |
-|--------|-----------|--------------|
-| Definition | `SKILL.md` files on disk | `AgentInlineSkill` instances in C# |
-| Resources | All files in skill directory (filtered by extension) | `AddResource` (static value or delegate-backed) |
-| Scripts | Supported via script executor delegate | `AddScript` delegates |
-| Discovery | Automatic from directory path | Explicit via constructor |
-| Dynamic content | No (static files only) | Yes (factory delegates) |
-| Reusability | Copy skill directory | Inline or shared instances |
+| Aspect | File-Based | Code-Defined | Class-Based |
+|--------|-----------|--------------|-------------|
+| Definition | `SKILL.md` files on disk | `AgentInlineSkill` instances in C# | Classes extending `AgentClassSkill` |
+| Resources | All files in skill directory (filtered by extension) | `AddResource` (static value or delegate-backed) | `CreateResource` factory methods |
+| Scripts | Supported via script runner delegate | `AddScript` delegates | `CreateScript` factory methods |
+| Discovery | Automatic from directory path | Explicit via constructor | Explicit via constructor |
+| Dynamic content | No (static files only) | Yes (factory delegates) | Yes (factory delegates) |
+| Sharing pattern | Copy skill directory | Inline or shared instances | Package in shared assemblies/NuGet |
+| DI support | No | Yes (via `IServiceProvider` parameter) | Yes (via `IServiceProvider` parameter) |
 
-For single-source scenarios, use the `AgentSkillsProvider` constructors directly. To combine multiple skill types, use the `AgentSkillsProviderBuilder`.
+### `AgentSkillsProvider` vs `AgentSkillsProviderBuilder`
 
+For single-source scenarios, use the `AgentSkillsProvider` constructors directly — they accept a skill directory path, a set of skills, or a custom source.
+
+Use `AgentSkillsProviderBuilder` for advanced scenarios where simple constructors are insufficient:
+
+- **Mixed skill types** — combine file-based, code-defined, and class-based skills in one provider
+- **Multiple file script runners** — use different script runners for different file skill directories
+- **Skill filtering** — include or exclude skills using a predicate
+
+See [Agent_Step04_MixedSkills](Agent_Step04_MixedSkills/) for a working example.

dotnet/samples/03-workflows/_StartHere/03_AgentWorkflowPatterns/03_AgentWorkflowPatterns.csproj

@@ -6,6 +6,7 @@
 
     <Nullable>enable</Nullable>
     <ImplicitUsings>enable</ImplicitUsings>
+    <NoWarn>$(NoWarn);MAAIW001</NoWarn> <!-- Handoff Orchestrations are Experimental -->
   </PropertyGroup>
 
   <ItemGroup>

dotnet/src/Microsoft.Agents.AI.Workflows/AgentWorkflowBuilder.cs

@@ -2,6 +2,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
 using System.Linq;
 using System.Threading.Tasks;
 using Microsoft.Agents.AI.Workflows.Specialized;
@@ -154,6 +155,7 @@ public static partial class AgentWorkflowBuilder
     /// The <see cref="AIAgent"/> must be capable of understanding those <see cref="AgentRunOptions"/> provided. If the agent
     /// ignores the tools or is otherwise unable to advertize them to the underlying provider, handoffs will not occur.
     /// </remarks>
+    [Experimental(DiagnosticConstants.ExperimentalFeatureDiagnostic)]
     public static HandoffWorkflowBuilder CreateHandoffBuilderWith(AIAgent initialAgent)
     {
         Throw.IfNull(initialAgent);

dotnet/src/Microsoft.Agents.AI.Workflows/HandoffWorkflowBuilder.cs

@@ -2,6 +2,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
 using System.Linq;
 using Microsoft.Agents.AI.Workflows.Specialized;
 using Microsoft.Extensions.AI;
@@ -9,13 +10,21 @@ using Microsoft.Shared.Diagnostics;
 
 namespace Microsoft.Agents.AI.Workflows;
 
+internal static class DiagnosticConstants
+{
+    public const string ExperimentalFeatureDiagnostic = "MAAIW001";
+}
+
 /// <inheritdoc/>
 [Obsolete("Prefer HandoffWorkflowBuilder (no 's') instead, which has the same API but the preferred name. This will be removed in a future release before GA.")]
+#pragma warning disable MAAIW001 // Type is for evaluation purposes only and is subject to change or removal in future updates. Suppress this diagnostic to proceed.
 public sealed class HandoffsWorkflowBuilder(AIAgent initialAgent) : HandoffWorkflowBuilderCore<HandoffsWorkflowBuilder>(initialAgent)
+#pragma warning restore MAAIW001 // Type is for evaluation purposes only and is subject to change or removal in future updates. Suppress this diagnostic to proceed.
 {
 }
 
 /// <inheritdoc/>
+[Experimental(DiagnosticConstants.ExperimentalFeatureDiagnostic)]
 public sealed class HandoffWorkflowBuilder(AIAgent initialAgent) : HandoffWorkflowBuilderCore<HandoffWorkflowBuilder>(initialAgent)
 {
 }
@@ -23,6 +32,7 @@ public sealed class HandoffWorkflowBuilder(AIAgent initialAgent) : HandoffWorkfl
 /// <summary>
 /// Provides a builder for specifying the handoff relationships between agents and building the resulting workflow.
 /// </summary>
+[Experimental(DiagnosticConstants.ExperimentalFeatureDiagnostic)]
 public class HandoffWorkflowBuilderCore<TBuilder> where TBuilder : HandoffWorkflowBuilderCore<TBuilder>
 {
     /// <summary>

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

@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
     <IsReleased>true</IsReleased>
@@ -8,6 +8,7 @@
   <PropertyGroup>
     <InjectSharedThrow>true</InjectSharedThrow>
     <InjectIsExternalInitOnLegacy>true</InjectIsExternalInitOnLegacy>
+    <InjectExperimentalAttributeOnLegacy>true</InjectExperimentalAttributeOnLegacy>
     <InjectTrimAttributesOnLegacy>true</InjectTrimAttributesOnLegacy>
   </PropertyGroup>
 

dotnet/src/Microsoft.Agents.AI.Workflows/Specialized/HandoffAgentExecutor.cs

@@ -4,6 +4,7 @@ using System;
 using System.Collections.Generic;
 using System.ComponentModel;
 using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
 using System.Linq;
 using System.Text.Json;
 using System.Threading;
@@ -31,6 +32,7 @@ internal sealed class HandoffAgentExecutorOptions
     public HandoffToolCallFilteringBehavior ToolCallFilteringBehavior { get; set; } = HandoffToolCallFilteringBehavior.HandoffOnly;
 }
 
+[Experimental(DiagnosticConstants.ExperimentalFeatureDiagnostic)]
 internal sealed class HandoffMessagesFilter
 {
     private readonly HandoffToolCallFilteringBehavior _filteringBehavior;
@@ -40,6 +42,7 @@ internal sealed class HandoffMessagesFilter
         this._filteringBehavior = filteringBehavior;
     }
 
+    [Experimental(DiagnosticConstants.ExperimentalFeatureDiagnostic)]
     internal static bool IsHandoffFunctionName(string name)
     {
         return name.StartsWith(HandoffWorkflowBuilder.FunctionPrefix, StringComparison.Ordinal);
@@ -164,6 +167,7 @@ internal sealed class HandoffMessagesFilter
 }
 
 /// <summary>Executor used to represent an agent in a handoffs workflow, responding to <see cref="HandoffState"/> events.</summary>
+[Experimental(DiagnosticConstants.ExperimentalFeatureDiagnostic)]
 internal sealed class HandoffAgentExecutor(
     AIAgent agent,
     HandoffAgentExecutorOptions options) : Executor<HandoffState, HandoffState>(agent.GetDescriptiveId(), declareCrossRunShareable: true), IResettableExecutor

dotnet/src/Microsoft.Agents.AI/CompatibilitySuppressions.xml

@@ -1,6 +1,20 @@
 <?xml version="1.0" encoding="utf-8"?>
 <!-- https://learn.microsoft.com/dotnet/fundamentals/package-validation/diagnostic-ids -->
 <Suppressions xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
+  <Suppression>
+    <DiagnosticId>CP0002</DiagnosticId>
+    <Target>M:Microsoft.Agents.AI.AgentSkillsProvider.#ctor(Microsoft.Agents.AI.AgentInlineSkill[])</Target>
+    <Left>lib/net10.0/Microsoft.Agents.AI.dll</Left>
+    <Right>lib/net10.0/Microsoft.Agents.AI.dll</Right>
+    <IsBaselineSuppression>true</IsBaselineSuppression>
+  </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0002</DiagnosticId>
+    <Target>M:Microsoft.Agents.AI.AgentSkillsProvider.#ctor(System.Collections.Generic.IEnumerable{Microsoft.Agents.AI.AgentInlineSkill},Microsoft.Agents.AI.AgentSkillsProviderOptions,Microsoft.Extensions.Logging.ILoggerFactory)</Target>
+    <Left>lib/net10.0/Microsoft.Agents.AI.dll</Left>
+    <Right>lib/net10.0/Microsoft.Agents.AI.dll</Right>
+    <IsBaselineSuppression>true</IsBaselineSuppression>
+  </Suppression>
   <Suppression>
     <DiagnosticId>CP0002</DiagnosticId>
     <Target>M:Microsoft.Agents.AI.ChatClientAgentOptions.get_SimulateServiceStoredChatHistory</Target>
@@ -22,6 +36,20 @@
     <Right>lib/net10.0/Microsoft.Agents.AI.dll</Right>
     <IsBaselineSuppression>true</IsBaselineSuppression>
   </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0002</DiagnosticId>
+    <Target>M:Microsoft.Agents.AI.AgentSkillsProvider.#ctor(Microsoft.Agents.AI.AgentInlineSkill[])</Target>
+    <Left>lib/net472/Microsoft.Agents.AI.dll</Left>
+    <Right>lib/net472/Microsoft.Agents.AI.dll</Right>
+    <IsBaselineSuppression>true</IsBaselineSuppression>
+  </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0002</DiagnosticId>
+    <Target>M:Microsoft.Agents.AI.AgentSkillsProvider.#ctor(System.Collections.Generic.IEnumerable{Microsoft.Agents.AI.AgentInlineSkill},Microsoft.Agents.AI.AgentSkillsProviderOptions,Microsoft.Extensions.Logging.ILoggerFactory)</Target>
+    <Left>lib/net472/Microsoft.Agents.AI.dll</Left>
+    <Right>lib/net472/Microsoft.Agents.AI.dll</Right>
+    <IsBaselineSuppression>true</IsBaselineSuppression>
+  </Suppression>
   <Suppression>
     <DiagnosticId>CP0002</DiagnosticId>
     <Target>M:Microsoft.Agents.AI.ChatClientAgentOptions.get_SimulateServiceStoredChatHistory</Target>
@@ -43,6 +71,20 @@
     <Right>lib/net472/Microsoft.Agents.AI.dll</Right>
     <IsBaselineSuppression>true</IsBaselineSuppression>
   </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0002</DiagnosticId>
+    <Target>M:Microsoft.Agents.AI.AgentSkillsProvider.#ctor(Microsoft.Agents.AI.AgentInlineSkill[])</Target>
+    <Left>lib/net8.0/Microsoft.Agents.AI.dll</Left>
+    <Right>lib/net8.0/Microsoft.Agents.AI.dll</Right>
+    <IsBaselineSuppression>true</IsBaselineSuppression>
+  </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0002</DiagnosticId>
+    <Target>M:Microsoft.Agents.AI.AgentSkillsProvider.#ctor(System.Collections.Generic.IEnumerable{Microsoft.Agents.AI.AgentInlineSkill},Microsoft.Agents.AI.AgentSkillsProviderOptions,Microsoft.Extensions.Logging.ILoggerFactory)</Target>
+    <Left>lib/net8.0/Microsoft.Agents.AI.dll</Left>
+    <Right>lib/net8.0/Microsoft.Agents.AI.dll</Right>
+    <IsBaselineSuppression>true</IsBaselineSuppression>
+  </Suppression>
   <Suppression>
     <DiagnosticId>CP0002</DiagnosticId>
     <Target>M:Microsoft.Agents.AI.ChatClientAgentOptions.get_SimulateServiceStoredChatHistory</Target>
@@ -64,6 +106,20 @@
     <Right>lib/net8.0/Microsoft.Agents.AI.dll</Right>
     <IsBaselineSuppression>true</IsBaselineSuppression>
   </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0002</DiagnosticId>
+    <Target>M:Microsoft.Agents.AI.AgentSkillsProvider.#ctor(Microsoft.Agents.AI.AgentInlineSkill[])</Target>
+    <Left>lib/net9.0/Microsoft.Agents.AI.dll</Left>
+    <Right>lib/net9.0/Microsoft.Agents.AI.dll</Right>
+    <IsBaselineSuppression>true</IsBaselineSuppression>
+  </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0002</DiagnosticId>
+    <Target>M:Microsoft.Agents.AI.AgentSkillsProvider.#ctor(System.Collections.Generic.IEnumerable{Microsoft.Agents.AI.AgentInlineSkill},Microsoft.Agents.AI.AgentSkillsProviderOptions,Microsoft.Extensions.Logging.ILoggerFactory)</Target>
+    <Left>lib/net9.0/Microsoft.Agents.AI.dll</Left>
+    <Right>lib/net9.0/Microsoft.Agents.AI.dll</Right>
+    <IsBaselineSuppression>true</IsBaselineSuppression>
+  </Suppression>
   <Suppression>
     <DiagnosticId>CP0002</DiagnosticId>
     <Target>M:Microsoft.Agents.AI.ChatClientAgentOptions.get_SimulateServiceStoredChatHistory</Target>
@@ -85,6 +141,20 @@
     <Right>lib/net9.0/Microsoft.Agents.AI.dll</Right>
     <IsBaselineSuppression>true</IsBaselineSuppression>
   </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0002</DiagnosticId>
+    <Target>M:Microsoft.Agents.AI.AgentSkillsProvider.#ctor(Microsoft.Agents.AI.AgentInlineSkill[])</Target>
+    <Left>lib/netstandard2.0/Microsoft.Agents.AI.dll</Left>
+    <Right>lib/netstandard2.0/Microsoft.Agents.AI.dll</Right>
+    <IsBaselineSuppression>true</IsBaselineSuppression>
+  </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0002</DiagnosticId>
+    <Target>M:Microsoft.Agents.AI.AgentSkillsProvider.#ctor(System.Collections.Generic.IEnumerable{Microsoft.Agents.AI.AgentInlineSkill},Microsoft.Agents.AI.AgentSkillsProviderOptions,Microsoft.Extensions.Logging.ILoggerFactory)</Target>
+    <Left>lib/netstandard2.0/Microsoft.Agents.AI.dll</Left>
+    <Right>lib/netstandard2.0/Microsoft.Agents.AI.dll</Right>
+    <IsBaselineSuppression>true</IsBaselineSuppression>
+  </Suppression>
   <Suppression>
     <DiagnosticId>CP0002</DiagnosticId>
     <Target>M:Microsoft.Agents.AI.ChatClientAgentOptions.get_SimulateServiceStoredChatHistory</Target>

dotnet/src/Microsoft.Agents.AI/Skills/AgentSkillScript.cs

@@ -1,6 +1,7 @@
 // Copyright (c) Microsoft. All rights reserved.
 
 using System.Diagnostics.CodeAnalysis;
+using System.Text.Json;
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.Extensions.AI;
@@ -36,6 +37,11 @@ public abstract class AgentSkillScript
     /// </summary>
     public string? Description { get; }
 
+    /// <summary>
+    /// Gets the JSON schema describing the parameters accepted by this script, or <see langword="null"/> if not available.
+    /// </summary>
+    public virtual JsonElement? ParametersSchema => null;
+
     /// <summary>
     /// Runs the script with the given arguments.
     /// </summary>

dotnet/src/Microsoft.Agents.AI/Skills/AgentSkillsProvider.cs

@@ -117,26 +117,24 @@ public sealed partial class AgentSkillsProvider : AIContextProvider
     }
 
     /// <summary>
-    /// Initializes a new instance of the <see cref="AgentSkillsProvider"/> class
-    /// with one or more inline (code-defined) skills.
+    /// Initializes a new instance of the <see cref="AgentSkillsProvider"/> class.
     /// Duplicate skill names are automatically deduplicated (first occurrence wins).
     /// </summary>
-    /// <param name="skills">The inline skills to include.</param>
-    public AgentSkillsProvider(params AgentInlineSkill[] skills)
-        : this(skills as IEnumerable<AgentInlineSkill>)
+    /// <param name="skills">The skills to include.</param>
+    public AgentSkillsProvider(params AgentSkill[] skills)
+        : this(skills as IEnumerable<AgentSkill>)
     {
     }
 
     /// <summary>
-    /// Initializes a new instance of the <see cref="AgentSkillsProvider"/> class
-    /// with inline (code-defined) skills.
+    /// Initializes a new instance of the <see cref="AgentSkillsProvider"/> class.
     /// Duplicate skill names are automatically deduplicated (first occurrence wins).
     /// </summary>
-    /// <param name="skills">The inline skills to include.</param>
+    /// <param name="skills">The skills to include.</param>
     /// <param name="options">Optional provider configuration.</param>
     /// <param name="loggerFactory">Optional logger factory.</param>
     public AgentSkillsProvider(
-        IEnumerable<AgentInlineSkill> skills,
+        IEnumerable<AgentSkill> skills,
         AgentSkillsProviderOptions? options = null,
         ILoggerFactory? loggerFactory = null)
         : this(

dotnet/src/Microsoft.Agents.AI/Skills/AgentSkillsProviderBuilder.cs

@@ -11,15 +11,31 @@ namespace Microsoft.Agents.AI;
 
 /// <summary>
 /// Fluent builder for constructing an <see cref="AgentSkillsProvider"/> backed by a composite source.
+/// Intended for advanced scenarios where the simple <see cref="AgentSkillsProvider"/> constructors are insufficient.
 /// </summary>
 /// <remarks>
 /// <para>
-/// Use this builder to combine multiple skill sources into a single provider:
+/// For simple, single-source scenarios, prefer the <see cref="AgentSkillsProvider"/> constructors directly
+/// (e.g., passing a skill directory path or a set of skills). Use this builder when you need one or more
+/// of the following advanced capabilities:
+/// </para>
+/// <list type="bullet">
+///   <item><description><strong>Mixed skill types</strong> — combine file-based, code-defined (<see cref="AgentInlineSkill"/>),
+///   and class-based (<see cref="AgentClassSkill"/>) skills in a single provider.</description></item>
+///   <item><description><strong>Multiple file script runners</strong> — use different script runners for different
+///   file skill directories via per-source <c>scriptRunner</c> parameters on
+///   <see cref="UseFileSkill"/> / <see cref="UseFileSkills(IEnumerable{string}, AgentFileSkillsSourceOptions?, AgentFileSkillScriptRunner?)"/>.</description></item>
+///   <item><description><strong>Skill filtering</strong> — include or exclude skills using a predicate
+///   via <see cref="UseFilter"/>.</description></item>
+/// </list>
+/// <para>
+/// Example — combining file-based and code-defined skills:
 /// </para>
 /// <code>
 /// var provider = new AgentSkillsProviderBuilder()
 ///     .UseFileSkills("/path/to/skills")
 ///     .UseSkills(myInlineSkill1, myInlineSkill2)
+///     .UseFileScriptRunner(SubprocessScriptRunner.RunAsync)
 ///     .Build();
 /// </code>
 /// </remarks>

dotnet/src/Microsoft.Agents.AI/Skills/Programmatic/AgentClassSkill.cs

@@ -0,0 +1,95 @@
+// Copyright (c) Microsoft. All rights reserved.
+
+using System;
+using System.Diagnostics.CodeAnalysis;
+using Microsoft.Shared.DiagnosticIds;
+
+namespace Microsoft.Agents.AI;
+
+/// <summary>
+/// Abstract base class for defining skills as C# classes that bundle all components together.
+/// </summary>
+/// <remarks>
+/// <para>
+/// Inherit from this class to create a self-contained skill definition. Override the abstract
+/// properties to provide name, description, and instructions. Use <see cref="CreateResource(string, object, string?)"/>,
+/// <see cref="CreateResource(string, Delegate, string?)"/>, and <see cref="CreateScript"/> to define
+/// inline resources and scripts.
+/// </para>
+/// </remarks>
+/// <example>
+/// <code>
+/// public class PdfFormatterSkill : AgentClassSkill
+/// {
+///     private IReadOnlyList&lt;AgentSkillResource&gt;? _resources;
+///     private IReadOnlyList&lt;AgentSkillScript&gt;? _scripts;
+///
+///     public override AgentSkillFrontmatter Frontmatter { get; } = new("pdf-formatter", "Format documents as PDF.");
+///     protected override string Instructions =&gt; "Use this skill to format documents...";
+///
+///     public override IReadOnlyList&lt;AgentSkillResource&gt;? Resources =&gt; this._resources ??=
+///     [
+///         CreateResource("template", "Use this template..."),
+///     ];
+///
+///     public override IReadOnlyList&lt;AgentSkillScript&gt;? Scripts =&gt; this._scripts ??=
+///     [
+///         CreateScript("format-pdf", FormatPdf),
+///     ];
+///
+///     private static string FormatPdf(string content) =&gt; content;
+/// }
+/// </code>
+/// </example>
+[Experimental(DiagnosticIds.Experiments.AgentsAIExperiments)]
+public abstract class AgentClassSkill : AgentSkill
+{
+    private string? _content;
+
+    /// <summary>
+    /// Gets the raw instructions text for this skill.
+    /// </summary>
+    protected abstract string Instructions { get; }
+
+    /// <inheritdoc/>
+    /// <remarks>
+    /// Returns a synthesized XML document containing name, description, instructions, resources, and scripts.
+    /// The result is cached after the first access. Override to provide custom content.
+    /// </remarks>
+    public override string Content => this._content ??= AgentInlineSkillContentBuilder.Build(
+        this.Frontmatter.Name,
+        this.Frontmatter.Description,
+        this.Instructions,
+        this.Resources,
+        this.Scripts);
+
+    /// <summary>
+    /// Creates a skill resource backed by a static value.
+    /// </summary>
+    /// <param name="name">The resource name.</param>
+    /// <param name="value">The static resource value.</param>
+    /// <param name="description">An optional description of the resource.</param>
+    /// <returns>A new <see cref="AgentSkillResource"/> instance.</returns>
+    protected static AgentSkillResource CreateResource(string name, object value, string? description = null)
+        => new AgentInlineSkillResource(name, value, description);
+
+    /// <summary>
+    /// Creates a skill resource backed by a delegate that produces a dynamic value.
+    /// </summary>
+    /// <param name="name">The resource name.</param>
+    /// <param name="method">A method that produces the resource value when requested.</param>
+    /// <param name="description">An optional description of the resource.</param>
+    /// <returns>A new <see cref="AgentSkillResource"/> instance.</returns>
+    protected static AgentSkillResource CreateResource(string name, Delegate method, string? description = null)
+        => new AgentInlineSkillResource(name, method, description);
+
+    /// <summary>
+    /// Creates a skill script backed by a delegate.
+    /// </summary>
+    /// <param name="name">The script name.</param>
+    /// <param name="method">A method to execute when the script is invoked.</param>
+    /// <param name="description">An optional description of the script.</param>
+    /// <returns>A new <see cref="AgentSkillScript"/> instance.</returns>
+    protected static AgentSkillScript CreateScript(string name, Delegate method, string? description = null)
+        => new AgentInlineSkillScript(name, method, description);
+}

dotnet/src/Microsoft.Agents.AI/Skills/Programmatic/AgentInlineSkill.cs

@@ -3,8 +3,6 @@
 using System;
 using System.Collections.Generic;
 using System.Diagnostics.CodeAnalysis;
-using System.Text;
-using System.Text.Json;
 using Microsoft.Extensions.AI;
 using Microsoft.Shared.DiagnosticIds;
 using Microsoft.Shared.Diagnostics;
@@ -27,8 +25,8 @@ namespace Microsoft.Agents.AI;
 public sealed class AgentInlineSkill : AgentSkill
 {
     private readonly string _instructions;
-    private List<AgentSkillResource>? _resources;
-    private List<AgentSkillScript>? _scripts;
+    private List<AgentInlineSkillResource>? _resources;
+    private List<AgentInlineSkillScript>? _scripts;
     private string? _cachedContent;
 
     /// <summary>
@@ -77,7 +75,7 @@ public sealed class AgentInlineSkill : AgentSkill
     public override AgentSkillFrontmatter Frontmatter { get; }
 
     /// <inheritdoc/>
-    public override string Content => this._cachedContent ??= this.BuildContent();
+    public override string Content => this._cachedContent ??= AgentInlineSkillContentBuilder.Build(this.Frontmatter.Name, this.Frontmatter.Description, this._instructions, this._resources, this._scripts);
 
     /// <inheritdoc/>
     public override IReadOnlyList<AgentSkillResource>? Resources => this._resources;
@@ -125,91 +123,4 @@ public sealed class AgentInlineSkill : AgentSkill
         (this._scripts ??= []).Add(new AgentInlineSkillScript(name, method, description));
         return this;
     }
-
-    private string BuildContent()
-    {
-        var sb = new StringBuilder();
-
-        sb.Append($"<name>{EscapeXmlString(this.Frontmatter.Name)}</name>\n")
-        .Append($"<description>{EscapeXmlString(this.Frontmatter.Description)}</description>\n\n")
-        .Append("<instructions>\n")
-        .Append(EscapeXmlString(this._instructions))
-        .Append("\n</instructions>");
-
-        if (this.Resources is { Count: > 0 })
-        {
-            sb.Append("\n\n<resources>\n");
-            foreach (var resource in this.Resources)
-            {
-                if (resource.Description is not null)
-                {
-                    sb.Append($"  <resource name=\"{EscapeXmlString(resource.Name)}\" description=\"{EscapeXmlString(resource.Description)}\"/>\n");
-                }
-                else
-                {
-                    sb.Append($"  <resource name=\"{EscapeXmlString(resource.Name)}\"/>\n");
-                }
-            }
-
-            sb.Append("</resources>");
-        }
-
-        if (this.Scripts is { Count: > 0 })
-        {
-            sb.Append("\n\n<scripts>\n");
-            foreach (var script in this.Scripts)
-            {
-                JsonElement? parametersSchema = ((AgentInlineSkillScript)script).ParametersSchema;
-
-                if (script.Description is null && parametersSchema is null)
-                {
-                    sb.Append($"  <script name=\"{EscapeXmlString(script.Name)}\"/>\n");
-                }
-                else
-                {
-                    sb.Append(script.Description is not null
-                        ? $"  <script name=\"{EscapeXmlString(script.Name)}\" description=\"{EscapeXmlString(script.Description)}\">\n"
-                        : $"  <script name=\"{EscapeXmlString(script.Name)}\">\n");
-
-                    if (parametersSchema is not null)
-                    {
-                        sb.Append($"    <parameters_schema>{EscapeXmlString(parametersSchema.Value.GetRawText(), preserveQuotes: true)}</parameters_schema>\n");
-                    }
-
-                    sb.Append("  </script>\n");
-                }
-            }
-
-            sb.Append("</scripts>");
-        }
-
-        return sb.ToString();
-    }
-
-    /// <summary>
-    /// Escapes XML special characters: always escapes <c>&amp;</c>, <c>&lt;</c>, <c>&gt;</c>,
-    /// <c>&quot;</c>, and <c>&apos;</c>. When <paramref name="preserveQuotes"/> is <see langword="true"/>,
-    /// quotes are left unescaped to preserve readability of embedded content such as JSON.
-    /// </summary>
-    /// <param name="value">The string to escape.</param>
-    /// <param name="preserveQuotes">
-    /// When <see langword="true"/>, leaves <c>"</c> and <c>'</c> unescaped for use in XML element content (e.g., JSON).
-    /// When <see langword="false"/> (default), escapes all XML special characters including quotes.
-    /// </param>
-    private static string EscapeXmlString(string value, bool preserveQuotes = false)
-    {
-        var result = value
-            .Replace("&", "&amp;")
-            .Replace("<", "&lt;")
-            .Replace(">", "&gt;");
-
-        if (!preserveQuotes)
-        {
-            result = result
-                .Replace("\"", "&quot;")
-                .Replace("'", "&apos;");
-        }
-
-        return result;
-    }
 }

dotnet/src/Microsoft.Agents.AI/Skills/Programmatic/AgentInlineSkillContentBuilder.cs

@@ -0,0 +1,118 @@
+// Copyright (c) Microsoft. All rights reserved.
+
+using System.Collections.Generic;
+using System.Text;
+using Microsoft.Shared.Diagnostics;
+
+namespace Microsoft.Agents.AI;
+
+/// <summary>
+/// Internal helper that builds XML-structured content strings for code-defined and class-based skills.
+/// </summary>
+internal static class AgentInlineSkillContentBuilder
+{
+    /// <summary>
+    /// Builds the complete skill content containing name, description, instructions, resources, and scripts.
+    /// </summary>
+    /// <param name="name">The skill name.</param>
+    /// <param name="description">The skill description.</param>
+    /// <param name="instructions">The raw instructions text.</param>
+    /// <param name="resources">Optional resources associated with the skill.</param>
+    /// <param name="scripts">Optional scripts associated with the skill.</param>
+    /// <returns>An XML-structured content string.</returns>
+    public static string Build(
+        string name,
+        string description,
+        string instructions,
+        IReadOnlyList<AgentSkillResource>? resources,
+        IReadOnlyList<AgentSkillScript>? scripts)
+    {
+        _ = Throw.IfNullOrWhitespace(name);
+        _ = Throw.IfNullOrWhitespace(description);
+        _ = Throw.IfNullOrWhitespace(instructions);
+
+        var sb = new StringBuilder();
+
+        sb.Append($"<name>{EscapeXmlString(name)}</name>\n")
+        .Append($"<description>{EscapeXmlString(description)}</description>\n\n")
+        .Append("<instructions>\n")
+        .Append(EscapeXmlString(instructions))
+        .Append("\n</instructions>");
+
+        if (resources is { Count: > 0 })
+        {
+            sb.Append("\n\n<resources>\n");
+            foreach (var resource in resources)
+            {
+                if (resource.Description is not null)
+                {
+                    sb.Append($"  <resource name=\"{EscapeXmlString(resource.Name)}\" description=\"{EscapeXmlString(resource.Description)}\"/>\n");
+                }
+                else
+                {
+                    sb.Append($"  <resource name=\"{EscapeXmlString(resource.Name)}\"/>\n");
+                }
+            }
+
+            sb.Append("</resources>");
+        }
+
+        if (scripts is { Count: > 0 })
+        {
+            sb.Append("\n\n<scripts>\n");
+            foreach (var script in scripts)
+            {
+                var parametersSchema = script.ParametersSchema;
+
+                if (script.Description is null && parametersSchema is null)
+                {
+                    sb.Append($"  <script name=\"{EscapeXmlString(script.Name)}\"/>\n");
+                }
+                else
+                {
+                    sb.Append(script.Description is not null
+                        ? $"  <script name=\"{EscapeXmlString(script.Name)}\" description=\"{EscapeXmlString(script.Description)}\">\n"
+                        : $"  <script name=\"{EscapeXmlString(script.Name)}\">\n");
+
+                    if (parametersSchema is not null)
+                    {
+                        sb.Append($"    <parameters_schema>{EscapeXmlString(parametersSchema.Value.GetRawText(), preserveQuotes: true)}</parameters_schema>\n");
+                    }
+
+                    sb.Append("  </script>\n");
+                }
+            }
+
+            sb.Append("</scripts>");
+        }
+
+        return sb.ToString();
+    }
+
+    /// <summary>
+    /// Escapes XML special characters: always escapes <c>&amp;</c>, <c>&lt;</c>, <c>&gt;</c>,
+    /// <c>&quot;</c>, and <c>&apos;</c>. When <paramref name="preserveQuotes"/> is <see langword="true"/>,
+    /// quotes are left unescaped to preserve readability of embedded content such as JSON.
+    /// </summary>
+    /// <param name="value">The string to escape.</param>
+    /// <param name="preserveQuotes">
+    /// When <see langword="true"/>, leaves <c>"</c> and <c>'</c> unescaped for use in XML element content (e.g., JSON).
+    /// When <see langword="false"/> (default), escapes all XML special characters including quotes.
+    /// </param>
+    private static string EscapeXmlString(string value, bool preserveQuotes = false)
+    {
+        var result = value
+            .Replace("&", "&amp;")
+            .Replace("<", "&lt;")
+            .Replace(">", "&gt;");
+
+        if (!preserveQuotes)
+        {
+            result = result
+                .Replace("\"", "&quot;")
+                .Replace("'", "&apos;");
+        }
+
+        return result;
+    }
+}

dotnet/src/Microsoft.Agents.AI/Skills/Programmatic/AgentInlineSkillScript.cs

@@ -36,7 +36,7 @@ internal sealed class AgentInlineSkillScript : AgentSkillScript
     /// <summary>
     /// Gets the JSON schema describing the parameters accepted by this script, or <see langword="null"/> if not available.
     /// </summary>
-    public JsonElement? ParametersSchema => this._function.JsonSchema;
+    public override JsonElement? ParametersSchema => this._function.JsonSchema;
 
     /// <inheritdoc/>
     public override async Task<object?> RunAsync(AgentSkill skill, AIFunctionArguments arguments, CancellationToken cancellationToken = default)

dotnet/tests/Microsoft.Agents.AI.UnitTests/AgentSkills/AgentClassSkillTests.cs

@@ -0,0 +1,382 @@
+// Copyright (c) Microsoft. All rights reserved.
+
+using System;
+using System.Collections.Generic;
+using System.Text.Json;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace Microsoft.Agents.AI.UnitTests.AgentSkills;
+
+/// <summary>
+/// Unit tests for <see cref="AgentClassSkill"/> and <see cref="AgentInMemorySkillsSource"/>.
+/// </summary>
+public sealed class AgentClassSkillTests
+{
+    [Fact]
+    public void Resources_DefaultsToNull_WhenNotOverridden()
+    {
+        // Arrange
+        var skill = new MinimalClassSkill();
+
+        // Act & Assert
+        Assert.Null(skill.Resources);
+    }
+
+    [Fact]
+    public void Scripts_DefaultsToNull_WhenNotOverridden()
+    {
+        // Arrange
+        var skill = new MinimalClassSkill();
+
+        // Act & Assert
+        Assert.Null(skill.Scripts);
+    }
+
+    [Fact]
+    public void Resources_ReturnsOverriddenList_WhenOverridden()
+    {
+        // Arrange
+        var skill = new FullClassSkill();
+
+        // Act
+        var resources = skill.Resources;
+
+        // Assert
+        Assert.Single(resources!);
+        Assert.Equal("test-resource", resources![0].Name);
+    }
+
+    [Fact]
+    public void Scripts_ReturnsOverriddenList_WhenOverridden()
+    {
+        // Arrange
+        var skill = new FullClassSkill();
+
+        // Act
+        var scripts = skill.Scripts;
+
+        // Assert
+        Assert.Single(scripts!);
+        Assert.Equal("TestScript", scripts![0].Name);
+    }
+
+    [Fact]
+    public void ResourcesAndScripts_CanBeLazyLoaded_AndCached()
+    {
+        // Arrange
+        var skill = new LazyLoadedSkill();
+
+        // Act & Assert
+        Assert.Equal(0, skill.ResourceCreationCount);
+        Assert.Equal(0, skill.ScriptCreationCount);
+
+        var firstResources = skill.Resources;
+        var firstScripts = skill.Scripts;
+        var secondResources = skill.Resources;
+        var secondScripts = skill.Scripts;
+
+        Assert.Single(firstResources!);
+        Assert.Single(firstScripts!);
+        Assert.Same(firstResources, secondResources);
+        Assert.Same(firstScripts, secondScripts);
+        Assert.Equal(1, skill.ResourceCreationCount);
+        Assert.Equal(1, skill.ScriptCreationCount);
+    }
+
+    [Fact]
+    public void Name_Content_ReturnClassDefinedValues()
+    {
+        // Arrange
+        var skill = new MinimalClassSkill();
+
+        // Act & Assert
+        Assert.Equal("minimal", skill.Frontmatter.Name);
+        Assert.Contains("<instructions>", skill.Content);
+        Assert.Contains("Minimal skill body.", skill.Content);
+        Assert.Contains("</instructions>", skill.Content);
+    }
+
+    [Fact]
+    public void Content_ReturnsSynthesizedXmlDocument()
+    {
+        // Arrange
+        var skill = new MinimalClassSkill();
+
+        // Act & Assert
+        Assert.Contains("<name>minimal</name>", skill.Content);
+        Assert.Contains("<description>A minimal skill.</description>", skill.Content);
+        Assert.Contains("<instructions>", skill.Content);
+        Assert.Contains("Minimal skill body.", skill.Content);
+    }
+
+    [Fact]
+    public async Task AgentInMemorySkillsSource_ReturnsAllSkillsAsync()
+    {
+        // Arrange
+        var skills = new AgentClassSkill[] { new MinimalClassSkill(), new FullClassSkill() };
+        var source = new AgentInMemorySkillsSource(skills);
+
+        // Act
+        var result = await source.GetSkillsAsync(CancellationToken.None);
+
+        // Assert
+        Assert.Equal(2, result.Count);
+        Assert.Equal("minimal", result[0].Frontmatter.Name);
+        Assert.Equal("full", result[1].Frontmatter.Name);
+    }
+
+    [Fact]
+    public void AgentClassSkill_InvalidFrontmatter_ThrowsArgumentException()
+    {
+        // Act & Assert
+        Assert.Throws<ArgumentException>(() => new AgentSkillFrontmatter("INVALID-NAME", "An invalid skill."));
+    }
+
+    [Fact]
+    public void SkillWithOnlyResources_HasNullScripts()
+    {
+        // Arrange
+        var skill = new ResourceOnlySkill();
+
+        // Act & Assert
+        Assert.Single(skill.Resources!);
+        Assert.Null(skill.Scripts);
+    }
+
+    [Fact]
+    public void SkillWithOnlyScripts_HasNullResources()
+    {
+        // Arrange
+        var skill = new ScriptOnlySkill();
+
+        // Act & Assert
+        Assert.Null(skill.Resources);
+        Assert.Single(skill.Scripts!);
+    }
+
+    [Fact]
+    public void Content_ReturnsCachedInstance_OnRepeatedAccess()
+    {
+        // Arrange
+        var skill = new FullClassSkill();
+
+        // Act
+        var first = skill.Content;
+        var second = skill.Content;
+
+        // Assert
+        Assert.Same(first, second);
+    }
+
+    [Fact]
+    public void Content_IncludesParametersSchema_WhenScriptsHaveParameters()
+    {
+        // Arrange
+        var skill = new FullClassSkill();
+
+        // Act
+        var content = skill.Content;
+
+        // Assert — scripts with typed parameters should have their schema included
+        Assert.Contains("parameters_schema", content);
+        Assert.Contains("value", content);
+    }
+
+    [Fact]
+    public void Content_IncludesDerivedResources_WhenResourcesUseBaseTypeOverrides()
+    {
+        // Arrange
+        var skill = new DerivedResourceSkill();
+
+        // Act
+        var content = skill.Content;
+
+        // Assert
+        Assert.Contains("<resources>", content);
+        Assert.Contains("custom-resource", content);
+        Assert.Contains("Custom resource description.", content);
+    }
+
+    [Fact]
+    public void Content_IncludesDerivedScripts_WhenScriptsUseBaseTypeOverrides()
+    {
+        // Arrange
+        var skill = new DerivedScriptSkill();
+
+        // Act
+        var content = skill.Content;
+
+        // Assert
+        Assert.Contains("<scripts>", content);
+        Assert.Contains("custom-script", content);
+        Assert.Contains("Custom script description.", content);
+    }
+
+    [Fact]
+    public void Content_OmitsParametersSchema_WhenDerivedScriptDoesNotProvideOne()
+    {
+        // Arrange
+        var skill = new DerivedScriptSkill();
+
+        // Act
+        var content = skill.Content;
+
+        // Assert
+        Assert.DoesNotContain("parameters_schema", content);
+    }
+
+    #region Test skill classes
+
+    private sealed class MinimalClassSkill : AgentClassSkill
+    {
+        public override AgentSkillFrontmatter Frontmatter { get; } = new("minimal", "A minimal skill.");
+
+        protected override string Instructions => "Minimal skill body.";
+
+        public override IReadOnlyList<AgentSkillResource>? Resources => null;
+
+        public override IReadOnlyList<AgentSkillScript>? Scripts => null;
+    }
+
+    private sealed class FullClassSkill : AgentClassSkill
+    {
+        private IReadOnlyList<AgentSkillResource>? _resources;
+        private IReadOnlyList<AgentSkillScript>? _scripts;
+
+        public override AgentSkillFrontmatter Frontmatter { get; } = new("full", "A full skill with resources and scripts.");
+
+        protected override string Instructions => "Full skill body.";
+
+        public override IReadOnlyList<AgentSkillResource>? Resources => this._resources ??=
+        [
+            CreateResource("test-resource", "resource content"),
+        ];
+
+        public override IReadOnlyList<AgentSkillScript>? Scripts => this._scripts ??=
+        [
+            CreateScript("TestScript", TestScript),
+        ];
+
+        private static string TestScript(double value) =>
+            JsonSerializer.Serialize(new { result = value * 2 });
+    }
+
+    private sealed class ResourceOnlySkill : AgentClassSkill
+    {
+        private IReadOnlyList<AgentSkillResource>? _resources;
+
+        public override AgentSkillFrontmatter Frontmatter { get; } = new("resource-only", "Skill with resources only.");
+
+        protected override string Instructions => "Body.";
+
+        public override IReadOnlyList<AgentSkillResource>? Resources => this._resources ??=
+        [
+            CreateResource("data", "some data"),
+        ];
+
+        public override IReadOnlyList<AgentSkillScript>? Scripts => null;
+    }
+
+    private sealed class ScriptOnlySkill : AgentClassSkill
+    {
+        private IReadOnlyList<AgentSkillScript>? _scripts;
+
+        public override AgentSkillFrontmatter Frontmatter { get; } = new("script-only", "Skill with scripts only.");
+
+        protected override string Instructions => "Body.";
+
+        public override IReadOnlyList<AgentSkillResource>? Resources => null;
+
+        public override IReadOnlyList<AgentSkillScript>? Scripts => this._scripts ??=
+        [
+            CreateScript("ToUpper", (string input) => input.ToUpperInvariant()),
+        ];
+    }
+
+    private sealed class DerivedResourceSkill : AgentClassSkill
+    {
+        private IReadOnlyList<AgentSkillResource>? _resources;
+
+        public override AgentSkillFrontmatter Frontmatter { get; } = new("derived-resource", "Skill with a derived resource type.");
+
+        protected override string Instructions => "Body.";
+
+        public override IReadOnlyList<AgentSkillResource>? Resources => this._resources ??=
+        [
+            new CustomResource("custom-resource", "Custom resource description."),
+        ];
+
+        public override IReadOnlyList<AgentSkillScript>? Scripts => null;
+    }
+
+    private sealed class DerivedScriptSkill : AgentClassSkill
+    {
+        private IReadOnlyList<AgentSkillScript>? _scripts;
+
+        public override AgentSkillFrontmatter Frontmatter { get; } = new("derived-script", "Skill with a derived script type.");
+
+        protected override string Instructions => "Body.";
+
+        public override IReadOnlyList<AgentSkillResource>? Resources => null;
+
+        public override IReadOnlyList<AgentSkillScript>? Scripts => this._scripts ??=
+        [
+            new CustomScript("custom-script", "Custom script description."),
+        ];
+    }
+
+    private sealed class LazyLoadedSkill : AgentClassSkill
+    {
+        private IReadOnlyList<AgentSkillResource>? _resources;
+        private IReadOnlyList<AgentSkillScript>? _scripts;
+
+        public override AgentSkillFrontmatter Frontmatter { get; } = new("lazy-loaded", "Skill with lazily created resources and scripts.");
+
+        protected override string Instructions => "Body.";
+
+        public int ResourceCreationCount { get; private set; }
+
+        public int ScriptCreationCount { get; private set; }
+
+        public override IReadOnlyList<AgentSkillResource>? Resources => this._resources ??= this.CreateResources();
+
+        public override IReadOnlyList<AgentSkillScript>? Scripts => this._scripts ??= this.CreateScripts();
+
+        private IReadOnlyList<AgentSkillResource> CreateResources()
+        {
+            this.ResourceCreationCount++;
+            return [CreateResource("lazy-resource", "resource content")];
+        }
+
+        private IReadOnlyList<AgentSkillScript> CreateScripts()
+        {
+            this.ScriptCreationCount++;
+            return [CreateScript("LazyScript", () => "done")];
+        }
+    }
+
+    private sealed class CustomResource : AgentSkillResource
+    {
+        public CustomResource(string name, string? description = null)
+            : base(name, description)
+        {
+        }
+
+        public override Task<object?> ReadAsync(IServiceProvider? serviceProvider = null, CancellationToken cancellationToken = default)
+            => Task.FromResult<object?>("resource-value");
+    }
+
+    private sealed class CustomScript : AgentSkillScript
+    {
+        public CustomScript(string name, string? description = null)
+            : base(name, description)
+        {
+        }
+
+        public override Task<object?> RunAsync(AgentSkill skill, Extensions.AI.AIFunctionArguments arguments, CancellationToken cancellationToken = default)
+            => Task.FromResult<object?>("script-result");
+    }
+
+    #endregion
+}

dotnet/tests/Microsoft.Agents.AI.UnitTests/AgentSkills/AgentSkillsProviderTests.cs

@@ -851,6 +851,61 @@ public sealed class AgentSkillsProviderTests : IDisposable
         Assert.Contains("First instructions.", content!.ToString()!);
     }
 
+    [Fact]
+    public async Task Constructor_ClassSkillsParams_ProvidesSkillsAsync()
+    {
+        // Arrange
+        var skill = new TestClassSkill("class-a", "Class A", "Class instructions.");
+        var provider = new AgentSkillsProvider(skill);
+        var invokingContext = new AIContextProvider.InvokingContext(this._agent, session: null, new AIContext());
+
+        // Act
+        var result = await provider.InvokingAsync(invokingContext, CancellationToken.None);
+
+        // Assert
+        Assert.NotNull(result.Instructions);
+        Assert.Contains("class-a", result.Instructions);
+    }
+
+    [Fact]
+    public async Task Constructor_ClassSkillsEnumerable_ProvidesSkillsAsync()
+    {
+        // Arrange
+        var skills = new List<AgentClassSkill>
+        {
+            new TestClassSkill("enum-class-a", "Class A", "Instructions A."),
+            new TestClassSkill("enum-class-b", "Class B", "Instructions B."),
+        };
+        var provider = new AgentSkillsProvider(skills);
+        var invokingContext = new AIContextProvider.InvokingContext(this._agent, session: null, new AIContext());
+
+        // Act
+        var result = await provider.InvokingAsync(invokingContext, CancellationToken.None);
+
+        // Assert
+        Assert.NotNull(result.Instructions);
+        Assert.Contains("enum-class-a", result.Instructions);
+        Assert.Contains("enum-class-b", result.Instructions);
+    }
+
+    [Fact]
+    public async Task Constructor_ClassSkills_DeduplicatesAsync()
+    {
+        // Arrange — two class skills with the same name
+        var skill1 = new TestClassSkill("dup-class", "First", "First instructions.");
+        var skill2 = new TestClassSkill("dup-class", "Second", "Second instructions.");
+        var provider = new AgentSkillsProvider(skill1, skill2);
+        var invokingContext = new AIContextProvider.InvokingContext(this._agent, session: null, new AIContext());
+
+        // Act
+        var result = await provider.InvokingAsync(invokingContext, CancellationToken.None);
+        var loadSkillTool = result.Tools!.First(t => t.Name == "load_skill") as AIFunction;
+        var content = await loadSkillTool!.InvokeAsync(new AIFunctionArguments(new Dictionary<string, object?> { ["skillName"] = "dup-class" }));
+
+        // Assert — only first occurrence survives
+        Assert.Contains("First instructions.", content!.ToString()!);
+    }
+
     /// <summary>
     /// A test skill source that counts how many times <see cref="GetSkillsAsync"/> is called.
     /// </summary>
@@ -872,4 +927,23 @@ public sealed class AgentSkillsProviderTests : IDisposable
             return Task.FromResult(this._skills);
         }
     }
+
+    private sealed class TestClassSkill : AgentClassSkill
+    {
+        private readonly string _instructions;
+
+        public TestClassSkill(string name, string description, string instructions)
+        {
+            this.Frontmatter = new AgentSkillFrontmatter(name, description);
+            this._instructions = instructions;
+        }
+
+        public override AgentSkillFrontmatter Frontmatter { get; }
+
+        protected override string Instructions => this._instructions;
+
+        public override IReadOnlyList<AgentSkillResource>? Resources => null;
+
+        public override IReadOnlyList<AgentSkillScript>? Scripts => null;
+    }
 }

dotnet/tests/Microsoft.Agents.AI.Workflows.UnitTests/Microsoft.Agents.AI.Workflows.UnitTests.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <NoWarn>$(NoWarn);MEAI001</NoWarn>
+    <NoWarn>$(NoWarn);MEAI001;MAAIW001</NoWarn>
   </PropertyGroup>
 
   <ItemGroup>