--- title: MCP C# SDK 2.0: Stateless HTTP, Interactive Tools and a... description: MCP C# SDK 2.0 implements the 2026-07-28 Model Context Protocol specification revision, making Streamable HTTP stateless by default instead of relying on a... canonical: https://daily.dev/posts/mcp-c-sdk-2-0-stateless-http-interactive-tools-and-a-practical-migration-path-mfzobjqgm twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: MCP C# SDK 2.0: Stateless HTTP, Interactive Tools and a Practical Migration Path | daily.dev og:description: MCP C# SDK 2.0 implements the 2026-07-28 Model Context Protocol specification revision, making Streamable HTTP stateless by default instead of relying on a... og:url: https://daily.dev/posts/mcp-c-sdk-2-0-stateless-http-interactive-tools-and-a-practical-migration-path-mfzobjqgm og:image: https://api.daily.dev/og/posts/mfZOBjQgM.png og:image:alt: MCP C# SDK 2.0: Stateless HTTP, Interactive Tools and a Practical Migration Path og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # MCP C# SDK 2.0: Stateless HTTP, Interactive Tools and a Practical Migration Path **[Benjamin Abt](https://daily.dev/sources/benjaminabt)** · 13 min read · 0 upvotes · 0 comments ## Summary MCP C# SDK 2.0 implements the 2026-07-28 Model Context Protocol specification revision, making Streamable HTTP stateless by default instead of relying on a connection-scoped Mcp-Session-Id. This lets MCP servers fit standard ASP.NET Core deployment patterns such as load balancing and horizontal scaling without sticky sessions. Tool calls now expose routing metadata (Mcp-Method, Mcp-Name, Mcp-Param-* headers) to HTTP infrastructure like gateways and WAFs. Interactive workflows that need confirmation, sampling, or roots are handled through a new Multi Round-Trip Requests (MRTR) mechanism using InputRequiredResult and an opaque requestState token instead of a persistent session. Legacy v1 APIs and the old handshake remain supported for backward compatibility, but the experimental Tasks extension is redesigned and not wire-compatible with the prior preview. The piece covers migration steps, security considerations for requestState as an untrusted continuation token, and production guidance around authorization, input validation, and observability. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### What changed in MCP C# SDK 2.0 regarding session handling over HTTP? MCP C# SDK 2.0 implements the 2026-07-28 MCP specification, making Streamable HTTP stateless by default instead of relying on an initialize handshake and Mcp-Session-Id header. Requests become self-contained, carrying protocol version and capability info with each call, so any healthy server instance can process it without sticky routing or shared session state. _Teams planning this SDK upgrade can track breaking protocol changes like this one on daily.dev._ ### How do I handle interactive tool confirmations in a stateless MCP server without a persistent session? MCP 2.0 introduces Multi Round-Trip Requests (MRTR): a tool throws InputRequiredException and returns an InputRequiredResult containing input requests and an opaque requestState value. The client gathers answers via an elicitation, sampling, or roots handler and calls the same tool again with inputResponses and requestState, letting the server continue without a retained connection. _Developers designing interactive MCP tools can dig into migration patterns like MRTR on daily.dev._ ### Is the Tasks extension in MCP C# SDK 1.3.x or 1.4.x compatible with SDK 2.0? No, the redesigned v2 Tasks model replaces the experimental Tasks extension from the 2025-11-25 specification and is not wire-compatible with that preview. Systems that adopted Tasks in SDK 1.3.x or 1.4.x need to treat it as a separate migration with explicit interoperability and persistence tests, since the InMemoryMcpTaskStore is unsuitable for production restarts or distributed workloads. _Anyone weighing a Tasks extension upgrade can compare breaking changes like this one on daily.dev._ ## Similar posts on daily.dev - [MCP C\# SDK 2.0 Makes HTTP Stateless by Default and Adds Multi Round-Trip Requests](https://daily.dev/posts/mcp-c-sdk-2-0-makes-http-stateless-by-default-and-adds-multi-round-trip-requests-zqudiipzf) · InfoQ · 1 upvotes · 0 comments - [Build Your First MCP Server in C\# with the Official SDK](https://daily.dev/posts/build-your-first-mcp-server-in-c-with-the-official-sdk-gfvr6bvsh) · Code with Mukesh · 17 upvotes · 2 comments - [MCP is now stateless: what the 2026-07-28 update changes](https://daily.dev/posts/mcp-is-now-stateless-what-the-2026-07-28-update-changes-hc2vhg5ll) · Flavio Copes · 9 upvotes · 0 comments - [Microsoft Releases MCP C\# SDK v2.0 for .NET](https://daily.dev/posts/microsoft-releases-mcp-c-sdk-v2-0-for-net-exvllbkk4) · C\# Corner · 49 upvotes · 4 comments --- Tags: [#architecture](https://daily.dev/tags/architecture), [#.net](https://daily.dev/tags/.net), [#mcp](https://daily.dev/tags/mcp), [#c#](https://daily.dev/tags/c#), [#aspnet](https://daily.dev/tags/aspnet) [View this post on daily.dev](https://daily.dev/posts/mcp-c-sdk-2-0-stateless-http-interactive-tools-and-a-practical-migration-path-mfzobjqgm) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"MCP C# SDK 2.0: Stateless HTTP, Interactive Tools and a Practical Migration Path","url":"https://daily.dev/posts/mcp-c-sdk-2-0-stateless-http-interactive-tools-and-a-practical-migration-path-mfzobjqgm","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/mcp-c-sdk-2-0-stateless-http-interactive-tools-and-a-practical-migration-path-mfzobjqgm"},"datePublished":"2026-10-04T13:05:17.184Z","dateModified":"2026-10-04T13:12:09.081Z","description":"MCP C# SDK 2.0 implements the 2026-07-28 Model Context Protocol specification revision, making Streamable HTTP stateless by default instead of relying on a...","image":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/4c595d14c9c11caa03fa1f45f073d8a7?_a=AQAEuop","thumbnailUrl":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/4c595d14c9c11caa03fa1f45f073d8a7?_a=AQAEuop","isAccessibleForFree":true,"articleSection":"Benjamin Abt","inLanguage":"en","publisher":{"@type":"Organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180}},"author":{"@type":"Organization","name":"Benjamin Abt","logo":"https://media.daily.dev/image/upload/s--zm3TLFn9--/f_auto,q_auto/v1791119044/logos/benjaminabt?_a=BAMAMicg0","url":"https://daily.dev/sources/benjaminabt"},"commentCount":0,"discussionUrl":"https://daily.dev/posts/mcp-c-sdk-2-0-stateless-http-interactive-tools-and-a-practical-migration-path-mfzobjqgm","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":0},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"keywords":"architecture,.net,mcp,c#,aspnet","timeRequired":"PT13M"} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"Benjamin Abt","item":"https://daily.dev/sources/benjaminabt"},{"@type":"ListItem","position":3,"name":"MCP C# SDK 2.0: Stateless HTTP, Interactive Tools and a Practical Migration Path"}]} {"@context":"https://schema.org","@type":"FAQPage","@id":"https://daily.dev/posts/mcp-c-sdk-2-0-stateless-http-interactive-tools-and-a-practical-migration-path-mfzobjqgm#faq","mainEntity":[{"@type":"Question","name":"What changed in MCP C# SDK 2.0 regarding session handling over HTTP?","acceptedAnswer":{"@type":"Answer","text":"MCP C# SDK 2.0 implements the 2026-07-28 MCP specification, making Streamable HTTP stateless by default instead of relying on an initialize handshake and Mcp-Session-Id header. 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