.NET: Support InvokeMcpTool for declarative workflows

dotnet/Directory.Packages.props

@@ -111,9 +111,9 @@
     <!-- Identity -->
     <PackageVersion Include="Microsoft.Identity.Client.Extensions.Msal" Version="4.78.0" />
     <!-- Workflows -->
-    <PackageVersion Include="Microsoft.Agents.ObjectModel" Version="2026.2.3.1" />
-    <PackageVersion Include="Microsoft.Agents.ObjectModel.Json" Version="2026.2.3.1" />
-    <PackageVersion Include="Microsoft.Agents.ObjectModel.PowerFx" Version="2026.2.3.1" />
+    <PackageVersion Include="Microsoft.Agents.ObjectModel" Version="2026.2.4.1" />
+    <PackageVersion Include="Microsoft.Agents.ObjectModel.Json" Version="2026.2.4.1" />
+    <PackageVersion Include="Microsoft.Agents.ObjectModel.PowerFx" Version="2026.2.4.1" />
     <PackageVersion Include="Microsoft.PowerFx.Interpreter" Version="1.8.1" />
     <!-- Durable Task -->
     <PackageVersion Include="Microsoft.DurableTask.Client" Version="1.18.0" />

dotnet/agent-framework-dotnet.slnx

@@ -227,6 +227,7 @@
     <Project Path="samples/GettingStarted/Workflows/Declarative/StudentTeacher/StudentTeacher.csproj" />
     <Project Path="samples/GettingStarted/Workflows/Declarative/ToolApproval/ToolApproval.csproj" />
     <Project Path="samples/GettingStarted/Workflows/Declarative/InvokeFunctionTool/InvokeFunctionTool.csproj" />
+    <Project Path="samples/GettingStarted/Workflows/Declarative/InvokeMcpTool/InvokeMcpTool.csproj" />
   </Folder>
   <Folder Name="/Samples/GettingStarted/Workflows/Declarative/Examples/">
     <File Path="../workflow-samples/CustomerSupport.yaml" />
@@ -438,6 +439,7 @@
     <Project Path="src/Microsoft.Agents.AI.OpenAI/Microsoft.Agents.AI.OpenAI.csproj" />
     <Project Path="src/Microsoft.Agents.AI.Purview/Microsoft.Agents.AI.Purview.csproj" />
     <Project Path="src/Microsoft.Agents.AI.Workflows.Declarative.AzureAI/Microsoft.Agents.AI.Workflows.Declarative.AzureAI.csproj" />
+    <Project Path="src/Microsoft.Agents.AI.Workflows.Declarative.Mcp/Microsoft.Agents.AI.Workflows.Declarative.Mcp.csproj" />
     <Project Path="src/Microsoft.Agents.AI.Workflows.Declarative/Microsoft.Agents.AI.Workflows.Declarative.csproj" />
     <Project Path="src/Microsoft.Agents.AI.Workflows.Generators/Microsoft.Agents.AI.Workflows.Generators.csproj" />
     <Project Path="src/Microsoft.Agents.AI.Workflows/Microsoft.Agents.AI.Workflows.csproj" />
@@ -483,6 +485,7 @@
     <Project Path="tests/Microsoft.Agents.AI.OpenAI.UnitTests/Microsoft.Agents.AI.OpenAI.UnitTests.csproj" />
     <Project Path="tests/Microsoft.Agents.AI.Purview.UnitTests/Microsoft.Agents.AI.Purview.UnitTests.csproj" />
     <Project Path="tests/Microsoft.Agents.AI.UnitTests/Microsoft.Agents.AI.UnitTests.csproj" />
+    <Project Path="tests/Microsoft.Agents.AI.Workflows.Declarative.Mcp.UnitTests/Microsoft.Agents.AI.Workflows.Declarative.Mcp.UnitTests.csproj" />
     <Project Path="tests/Microsoft.Agents.AI.Workflows.Declarative.UnitTests/Microsoft.Agents.AI.Workflows.Declarative.UnitTests.csproj" />
     <Project Path="tests/Microsoft.Agents.AI.Workflows.Generators.UnitTests/Microsoft.Agents.AI.Workflows.Generators.UnitTests.csproj" />
     <Project Path="tests/Microsoft.Agents.AI.Workflows.UnitTests/Microsoft.Agents.AI.Workflows.UnitTests.csproj" />

dotnet/samples/GettingStarted/Workflows/Declarative/InvokeMcpTool/InvokeMcpTool.csproj

@@ -0,0 +1,39 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFrameworks>net10.0</TargetFrameworks>
+    <Nullable>enable</Nullable>
+    <ImplicitUsings>enable</ImplicitUsings>
+  </PropertyGroup>
+
+  <PropertyGroup>
+    <InjectIsExternalInitOnLegacy>true</InjectIsExternalInitOnLegacy>
+    <InjectSharedFoundryAgents>true</InjectSharedFoundryAgents>
+    <InjectSharedWorkflowsExecution>true</InjectSharedWorkflowsExecution>
+    <InjectSharedWorkflowsSettings>true</InjectSharedWorkflowsSettings>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Microsoft.Extensions.Configuration" />
+    <PackageReference Include="Microsoft.Extensions.Configuration.Binder" />
+    <PackageReference Include="Microsoft.Extensions.Configuration.EnvironmentVariables" />
+    <PackageReference Include="Microsoft.Extensions.Configuration.Json" />
+    <PackageReference Include="Microsoft.Extensions.Configuration.UserSecrets" />
+    <PackageReference Include="Microsoft.Extensions.DependencyInjection" />
+    <PackageReference Include="Microsoft.Extensions.Logging" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\..\..\..\..\src\Microsoft.Agents.AI.Workflows.Declarative\Microsoft.Agents.AI.Workflows.Declarative.csproj" />
+    <ProjectReference Include="..\..\..\..\..\src\Microsoft.Agents.AI.Workflows.Declarative.AzureAI\Microsoft.Agents.AI.Workflows.Declarative.AzureAI.csproj" />
+    <ProjectReference Include="..\..\..\..\..\src\Microsoft.Agents.AI.Workflows.Declarative.Mcp\Microsoft.Agents.AI.Workflows.Declarative.Mcp.csproj" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <None Include="InvokeMcpTool.yaml">
+      <CopyToOutputDirectory>Always</CopyToOutputDirectory>
+    </None>
+  </ItemGroup>
+
+</Project>

dotnet/samples/GettingStarted/Workflows/Declarative/InvokeMcpTool/InvokeMcpTool.yaml

@@ -0,0 +1,63 @@
+#
+# This workflow demonstrates invoking MCP tools directly from a declarative workflow.
+# Uses the Foundry MCP server to search AI model details.
+#
+# The workflow:
+# 1. Accepts a model search term as input
+# 2. Invokes the Foundry MCP tool
+# 3. Invokes the Microsoft Learn MCP tool
+# 4. Uses an agent to summarize the results
+#
+# Example input: 
+# gpt-4.1
+#
+kind: Workflow
+trigger:
+
+  kind: OnConversationStart
+  id: workflow_invoke_mcp_tool
+  actions:
+
+    # Set the search query from user input or use default
+    - kind: SetVariable
+      id: set_search_query
+      variable: Local.SearchQuery
+      value: =System.LastMessage.Text
+
+    # Invoke MCP search tool on Foundry MCP server
+    - kind: InvokeMcpTool
+      id: invoke_foundry_search
+      serverUrl: https://mcp.ai.azure.com
+      serverLabel: azure_mcp_server
+      toolName: model_details_get
+      conversationId: =System.ConversationId
+      arguments:
+        modelName: =Local.SearchQuery
+      output:
+        autoSend: true
+        result: Local.FoundrySearchResult
+
+    # Invoke MCP search tool on Microsoft Learn server
+    - kind: InvokeMcpTool
+      id: invoke_docs_search
+      serverUrl: https://learn.microsoft.com/api/mcp
+      serverLabel: microsoft_docs
+      toolName: microsoft_docs_search
+      conversationId: =System.ConversationId
+      arguments:
+        query: =Local.SearchQuery
+      output:
+        autoSend: true
+        result: Local.DocsSearchResult
+
+    # Use the search agent to provide a helpful response based on results
+    - kind: InvokeAzureAgent
+      id: summarize_results
+      agent:
+        name: McpSearchAgent
+      conversationId: =System.ConversationId
+      input:
+        messages: =UserMessage("Based on the search results for '" & Local.SearchQuery & "', please provide a helpful summary.")
+      output:
+        autoSend: true
+        result: Local.Summary

dotnet/samples/GettingStarted/Workflows/Declarative/InvokeMcpTool/Program.cs

@@ -0,0 +1,141 @@
+// Copyright (c) Microsoft. All rights reserved.
+
+// This sample demonstrates using the InvokeMcpTool action to call MCP (Model Context Protocol)
+// server tools directly from a declarative workflow. MCP servers expose tools that can be
+// invoked to perform specific tasks, like searching documentation or executing operations.
+
+using Azure.AI.Projects;
+using Azure.AI.Projects.OpenAI;
+using Azure.Core;
+using Azure.Identity;
+using Microsoft.Agents.AI.Workflows.Declarative.Mcp;
+using Microsoft.Extensions.Configuration;
+using Shared.Foundry;
+using Shared.Workflows;
+
+namespace Demo.Workflows.Declarative.InvokeMcpTool;
+
+/// <summary>
+/// Demonstrates a workflow that uses InvokeMcpTool to call MCP server tools
+/// directly from the workflow.
+/// </summary>
+/// <remarks>
+/// <para>
+/// The InvokeMcpTool action allows workflows to invoke tools on MCP (Model Context Protocol)
+/// servers. This enables:
+/// </para>
+/// <list type="bullet">
+/// <item>Searching external data sources like documentation</item>
+/// <item>Executing operations on remote servers</item>
+/// <item>Integrating with MCP-compatible services</item>
+/// </list>
+/// <para>
+/// This sample uses the Microsoft Learn MCP server to search Azure documentation and the Azure foundry MCP server to get AI model details.
+/// When you run the sample, provide an AI model (e.g. gpt-4.1-mini) as input,
+/// The workflow will use the MCP tools to find relevant information about the model from Microsoft Learn and foundry, then an agent will summarize the results.
+/// </para>
+/// <para>
+/// See the README.md file in the parent folder (../README.md) for detailed
+/// information about the configuration required to run this sample.
+/// </para>
+/// </remarks>
+internal sealed class Program
+{
+    public static async Task Main(string[] args)
+    {
+        // Initialize configuration
+        IConfiguration configuration = Application.InitializeConfig();
+        Uri foundryEndpoint = new(configuration.GetValue(Application.Settings.FoundryEndpoint));
+
+        // Ensure sample agent exists in Foundry
+        await CreateAgentAsync(foundryEndpoint, configuration);
+
+        // Get input from command line or console
+        string workflowInput = Application.GetInput(args);
+
+        // Create the MCP tool handler for invoking MCP server tools.
+        // The HttpClient callback allows configuring authentication per MCP server.
+        // Different MCP servers may require different authentication configurations.
+        // For Production scenarios, consider implementing a more robust HttpClient management strategy to reuse HttpClient instances and manage their lifetimes appropriately.
+        List<HttpClient> createdHttpClients = [];
+        // WARNING: DefaultAzureCredential is convenient for development but requires careful consideration in production.
+        DefaultAzureCredential credential = new();
+        DefaultMcpToolHandler mcpToolHandler = new(
+            httpClientProvider: async (serverUrl, cancellationToken) =>
+            {
+                if (serverUrl.StartsWith("https://mcp.ai.azure.com", StringComparison.OrdinalIgnoreCase))
+                {
+                    // Acquire token for the Azure MCP server
+                    AccessToken token = await credential.GetTokenAsync(
+                        new TokenRequestContext(["https://mcp.ai.azure.com/.default"]),
+                        cancellationToken);
+
+                    // Create HttpClient with Authorization header
+                    HttpClient httpClient = new();
+                    httpClient.DefaultRequestHeaders.Authorization =
+                        new System.Net.Http.Headers.AuthenticationHeaderValue("Bearer", token.Token);
+                    createdHttpClients.Add(httpClient);
+                    return httpClient;
+                }
+
+                if (serverUrl.StartsWith("https://learn.microsoft.com", StringComparison.OrdinalIgnoreCase))
+                {
+                    // Microsoft Learn MCP server does not require authentication
+                    HttpClient httpClient = new();
+                    createdHttpClients.Add(httpClient);
+                    return httpClient;
+                }
+
+                // Return null for unknown servers to use the default HttpClient without auth.
+                return null;
+            });
+
+        try
+        {
+            // Create the workflow factory with MCP tool provider
+            WorkflowFactory workflowFactory = new("InvokeMcpTool.yaml", foundryEndpoint)
+            {
+                McpToolHandler = mcpToolHandler
+            };
+
+            // Execute the workflow
+            WorkflowRunner runner = new() { UseJsonCheckpoints = true };
+            await runner.ExecuteAsync(workflowFactory.CreateWorkflow, workflowInput);
+        }
+        finally
+        {
+            // Clean up connections and dispose created HttpClients
+            await mcpToolHandler.DisposeAsync();
+
+            foreach (HttpClient httpClient in createdHttpClients)
+            {
+                httpClient.Dispose();
+            }
+        }
+    }
+
+    private static async Task CreateAgentAsync(Uri foundryEndpoint, IConfiguration configuration)
+    {
+        // WARNING: DefaultAzureCredential is convenient for development but requires careful consideration in production.
+        AIProjectClient aiProjectClient = new(foundryEndpoint, new DefaultAzureCredential());
+
+        await aiProjectClient.CreateAgentAsync(
+            agentName: "McpSearchAgent",
+            agentDefinition: DefineSearchAgent(configuration),
+            agentDescription: "Provides information based on search results");
+    }
+
+    private static PromptAgentDefinition DefineSearchAgent(IConfiguration configuration)
+    {
+        return new PromptAgentDefinition(configuration.GetValue(Application.Settings.FoundryModelMini))
+        {
+            Instructions =
+                """
+                You are a helpful assistant that answers questions based on search results.
+                Use the information provided in the conversation history to answer questions.
+                If the information is already available in the conversation, use it directly.
+                Be concise and helpful in your responses.
+                """
+        };
+    }
+}