Release v1.1.0

[jeffhandley]

This PR does a few things:

1. Updates the release processes to use a pair of skills — Adds prepare-release and publish-release Copilot skills with supporting reference documentation for categorization, breaking change classification, SemVer assessment, and ApiCompat/ApiDiff tooling.
2. Uses the new prepare-release skill to prepare the v1.1.0 release — Bumps version from 1.0.0 to 1.1.0, validates API compatibility against the v1.0.0 baseline, and generates API diff reports.
3. Updates the copyright info — Aligns the NuGet package <Copyright> metadata with the project LICENSE file and the modelcontextprotocol.io website footer. Updates the LICENSE year range to 2024-2026.

---

Release v1.1.0

Bumps version from 1.0.0 to 1.1.0. This is a MINOR release adding new public API surface with no breaking changes.

SemVer Assessment

Previous release	v1.0.0
New version	v1.1.0
Classification	MINOR — new public API surface, no breaking changes
Breaking changes	None confirmed

The MINOR bump is driven by:

• Add client completion notification and details #1368 — Adds McpClient.Completion property and completion details types (ClientCompletionDetails, HttpClientCompletionDetails, StdioClientCompletionDetails)
• Auto-populate completion handlers from AllowedValuesAttribute on prompt/resource parameters #1380 — Adds auto-population of completion handlers from AllowedValuesAttribute

Breaking Change Audit

One potential breaking change was examined and dismissed:

• Add client completion notification and details #1368 (CP0005): Adding abstract Completion property to McpClient. Dismissed because McpClient's only constructor is protected and marked [Experimental(MCPEXP002)] ("Subclassing McpClient and McpServer is experimental and subject to change"). Compatibility suppressions added for all TFMs.

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What's Changed

• Register ping handler in McpSessionHandler to support server-initiated pings Register ping handler in McpSessionHandler to support server-initiated pings #1391 by @stephentoub (co-authored by @copilot)
• Fix Extensions not being copied to ServerCapabilities during initialization Fix Extensions not being copied to ServerCapabilities during initialization #1399 by @stephentoub (co-authored by @copilot)
• Auto-populate completion handlers from AllowedValuesAttribute on prompt/resource parameters Auto-populate completion handlers from AllowedValuesAttribute on prompt/resource parameters #1380 by @stephentoub (co-authored by @copilot)
• Add client completion notification and details Add client completion notification and details #1368 by @stephentoub (co-authored by @copilot)
• Wait for in-flight message handlers before ProcessMessagesCoreAsync returns Wait for in-flight message handlers before ProcessMessagesCoreAsync returns #1403 by @stephentoub (co-authored by @copilot)

Documentation Updates

• Add SSE server code example to transports documentation Add SSE server code example to transports documentation #1385 by @jeffhandley (co-authored by @copilot)
• Simplify and update README for stable release Simplify and update README for stable release #1387 by @stephentoub (co-authored by @jeffhandley)
• Simplify and update package README.md files for stable release Simplify and update package README.md files for stable release #1388 by @stephentoub (co-authored by @copilot @jeffhandley)
• Remove outdated README reference from transports.md Remove outdated README reference from transports.md #1394 by @halter73
• Clean up markdown-link-check warnings Clean up markdown-link-check warnings #1395 by @jeffhandley (co-authored by @copilot)

Repository Infrastructure Updates

• Enable EnablePackageValidation for all src packages with 1.0.0 baseline Enable EnablePackageValidation for all src packages with 1.0.0 baseline #1330 by @jeffhandley (co-authored by @copilot @stephentoub)
• Bump hono from 4.12.0 to 4.12.2 in the npm_and_yarn group across 1 directory Bump hono from 4.12.0 to 4.12.2 in the npm_and_yarn group across 1 directory #1392
• Bump danielpalme/ReportGenerator-GitHub-Action from 5.5.1 to 5.5.2 Bump danielpalme/ReportGenerator-GitHub-Action from 5.5.1 to 5.5.2 #1404
• Bump actions/upload-artifact from 6.0.0 to 7.0.0 Bump actions/upload-artifact from 6.0.0 to 7.0.0 #1405
• Bump actions/download-artifact from 7.0.0 to 8.0.0 Bump actions/download-artifact from 7.0.0 to 8.0.0 #1406
• Bump docfx from 2.78.4 to 2.78.5 Bump docfx from 2.78.4 to 2.78.5 #1408
• Bump the testing-frameworks group with 1 update Bump the testing-frameworks group with 1 update #1407

Acknowledgements

• @r-Larch submitted issue ObjectDisposedException - IServiceProvider disposed while tool handler execution. #1269 (resolved by Wait for in-flight message handlers before ProcessMessagesCoreAsync returns #1403)
• @darena-mhaque submitted issue Extensions are not being deserialized into server capabilities #1398 (resolved by Fix Extensions not being copied to ServerCapabilities during initialization #1399)
• @hulumane submitted issue Stdio transport does not expose process exit code on server launch failure #1332 (resolved by Add client completion notification and details #1368)
• @AArnott submitted issue Provide notification of server connection loss #438 (resolved by Add client completion notification and details #1368)
• @JarroVGIT submitted issue Ping from McpServer -> McpClient is not handled by McpClient. #1390 (resolved by Register ping handler in McpSessionHandler to support server-initiated pings #1391)
• @stephentoub @halter73 @eiriktsarpalis @jeffhandley reviewed pull requests

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API Compatibility Report

✅ All packages pass API compatibility validation against v1.0.0 baseline. Existing CP0005 suppressions in ModelContextProtocol.Core for the abstract Completion property addition (gated by [Experimental]).

API Diff Report

ModelContextProtocol.Core

  namespace ModelContextProtocol.Client
  {
      public abstract class McpClient : ModelContextProtocol.McpSession
      {
+         public abstract System.Threading.Tasks.Task<ModelContextProtocol.Client.ClientCompletionDetails> Completion { get; }
      }
+     public class ClientCompletionDetails
+     {
+         public ClientCompletionDetails();
+         public System.Exception? Exception { get; set; }
+     }
+     public sealed class HttpClientCompletionDetails : ModelContextProtocol.Client.ClientCompletionDetails
+     {
+         public HttpClientCompletionDetails();
+         public System.Nullable<System.Net.HttpStatusCode> HttpStatusCode { get; set; }
+     }
+     public sealed class StdioClientCompletionDetails : ModelContextProtocol.Client.ClientCompletionDetails
+     {
+         public StdioClientCompletionDetails();
+         public System.Nullable<int> ExitCode { get; set; }
+         public System.Nullable<int> ProcessId { get; set; }
+         public System.Collections.Generic.IReadOnlyList<string>? StandardErrorTail { get; set; }
+     }
  }

ModelContextProtocol

No public API changes.

ModelContextProtocol.AspNetCore

No public API changes.

[Copilot]

Pull request overview

This PR prepares the v1.1.0 release of the C# MCP SDK. It bumps the version from 1.0.0 to 1.1.0 (a MINOR release with new public API surface and no breaking changes), updates the copyright metadata, and overhauled the release process by replacing the old monolithic release-notes skill with two focused skills (prepare-release and publish-release) along with detailed supporting reference documentation.

Changes:

• Version bump from 1.0.0 to 1.1.0 in src/Directory.Build.props, with copyright updated to reflect the LF Projects LLC entity
• LICENSE year range updated to 2024-2026
• New prepare-release and publish-release Copilot skills added with supporting reference guides (SemVer assessment, categorization, API compat/diff, README validation, formatting, breaking change classification), replacing the old release-notes skill

Reviewed changes

Copilot reviewed 11 out of 14 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
src/Directory.Build.props	Version bumped to 1.1.0; copyright updated to "Model Context Protocol a Series of LF Projects, LLC."
LICENSE	Copyright year range extended to 2024-2026
.github/workflows/release.md	Simplified release docs to reference new skill-based workflow
.github/skills/release-notes/SKILL.md	Old skill removed (fully deleted)
.github/skills/prepare-release/SKILL.md	New skill for preparing a release PR
.github/skills/prepare-release/references/readme-snippets.md	Reference guide for validating README code samples
.github/skills/prepare-release/references/categorization.md	Reference guide for categorizing PRs in release notes
.github/skills/prepare-release/references/apicompat-apidiff.md	Reference guide for running ApiCompat and ApiDiff tools
.github/skills/publish-release/SKILL.md	New skill for creating the GitHub release after a prepare-release PR is merged
.github/skills/publish-release/references/formatting.md	Reference guide for release notes formatting
.github/skills/bump-version/SKILL.md	Updated to incorporate SemVer-informed version assessment
.github/skills/bump-version/references/semver-assessment.md	New SemVer assessment guide (shared reference)
.github/skills/breaking-changes/SKILL.md	Updated output description to reference new skill names
.github/skills/breaking-changes/references/classification.md	Expanded guidance on dismissing potential breaks gated by [Experimental] APIs