.NET: Add MCP long-running task support for MCP client tools#5994
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Pull request overview
Adds a new .NET (alpha) Microsoft.Agents.AI.Mcp package that enables Microsoft Agent Framework agents to transparently invoke MCP tools using the MCP long-running tasks extension (SEP-2663), including polling to completion and best-effort remote cancellation.
Changes:
- Introduces
McpClientTaskExtensions.ListAgentToolsWithTaskSupportAsync(...)to wrap task-capable MCP tools (Optional/Required) in a task-awareAIFunction. - Implements
TaskAwareMcpClientAIFunctionandMcpTaskOptionsto drivetools/call(task-augmented) →tasks/getpolling →tasks/result, with fallback to non-task invocation when needed. - Adds unit tests + an end-to-end sample demonstrating transparent long-running task handling, and wires the sample into sample verification + solution.
Reviewed changes
Copilot reviewed 17 out of 17 changed files in this pull request and generated no comments.
Show a summary per file
| File | Description |
|---|---|
| dotnet/src/Microsoft.Agents.AI.Mcp/Microsoft.Agents.AI.Mcp.csproj | New alpha MCP integration package project definition and dependencies. |
| dotnet/src/Microsoft.Agents.AI.Mcp/McpClientTaskExtensions.cs | Adds extension method to list tools and wrap task-capable ones for agent usage. |
| dotnet/src/Microsoft.Agents.AI.Mcp/McpTaskOptions.cs | Defines configurable task lifecycle options (TTL hint + remote-cancel behavior). |
| dotnet/src/Microsoft.Agents.AI.Mcp/TaskAwareMcpClientAIFunction.cs | Implements the task-aware wrapper driving call/poll/result + cancellation handling. |
| dotnet/tests/Microsoft.Agents.AI.Mcp.UnitTests/Microsoft.Agents.AI.Mcp.UnitTests.csproj | Adds new unit test project for the MCP task-aware client functionality. |
| dotnet/tests/Microsoft.Agents.AI.Mcp.UnitTests/InMemoryMcpServerFixture.cs | In-proc server/client fixture for testing tasks behavior without sockets/processes. |
| dotnet/tests/Microsoft.Agents.AI.Mcp.UnitTests/TestTools.cs | Test helper to create MCP tools with specific task support metadata. |
| dotnet/tests/Microsoft.Agents.AI.Mcp.UnitTests/ListAgentToolsWithTaskSupportTests.cs | Validates wrapping behavior + null client argument validation. |
| dotnet/tests/Microsoft.Agents.AI.Mcp.UnitTests/TaskAwareMcpClientAIFunctionTests.cs | Validates happy paths, TTL propagation, cancellation, and failure behavior. |
| dotnet/tests/Microsoft.Agents.AI.Mcp.UnitTests/McpTaskOptionsTests.cs | Verifies option defaults. |
| dotnet/samples/02-agents/ModelContextProtocol/README.md | Adds the new long-running task client sample to the MCP samples index. |
| dotnet/samples/02-agents/ModelContextProtocol/Agent_MCP_LongRunningTask_Client/README.md | New sample documentation describing task support behavior and usage. |
| dotnet/samples/02-agents/ModelContextProtocol/Agent_MCP_LongRunningTask_Client/Program.cs | New sample demonstrating stdio MCP server + client wrapper + Run/RunStreaming. |
| dotnet/samples/02-agents/ModelContextProtocol/Agent_MCP_LongRunningTask_Client/Agent_MCP_LongRunningTask_Client.csproj | New sample project wiring required dependencies and project references. |
| dotnet/eng/verify-samples/AgentsSamples.cs | Registers the new sample for verification. |
| dotnet/agent-framework-dotnet.slnx | Adds new package, test project, and sample to the solution. |
SergeyMenshykh
approved these changes
May 22, 2026
lokitoth
approved these changes
May 22, 2026
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Description
Adds Microsoft Agent Framework client-side support for the MCP tasks extension.
A new
Microsoft.Agents.AI.Mcp(alpha) package introducesMcpClient.ListAgentToolsWithTaskSupportAsync, which wraps any MCP tool advertising task support with a task-awareAIFunction. The wrapper transparently drives the lifecycle inside the agent's function-calling loop.Contribution Checklist