Bump the other group with 29 updates

[dependabot]

Updated Autofac from 9.0.0 to 9.1.0.

Release notes

Sourced from Autofac's releases.

9.1.0

This is a pretty big release for Autofac with some major new functionality!

AnyKey Support

First, Autofac now natively supports the concept of AnyKey. It behaves the same way AnyKey works in Microsoft.Extensions.DependencyInjection, but it is native to Autofac directly. The unit tests here show some very detailed examples of usage, but on a high level:

var builder = new ContainerBuilder();
builder.RegisterType<Service>().Keyed<IService>(KeyedService.AnyKey);

var container = builder.Build();

// Registering as AnyKey allows it to respond to... any key!
var service = container.ResolveKeyed<IService>("service1");

Inject Service Key Into Constructors

The new [ServiceKey] attribute allows you to inject the service key provided during resolution. This is handy in conjunction with AnyKey. Again, this is similar to the construct in Microsoft.Extensions.DependencyInjection, but with native Autofac.

First, mark up your class to take the constructor parameter.

public class Service : IService
{
  private readonly string _id;
  public Service([ServiceKey] string id) => _id = id;
}

Then when you resolve the class, the service key will automatically be injected.

You can also make use of this in a lambda registration.

var builder = new ContainerBuilder();
builder.Register<Service>((ctx, p) => {
  var key = p.TryGetKeyedServiceKey(out string value) ? value : null;
  return new Service(key);
}).Keyed<Service>(KeyedService.AnyKey);

Metrics

Some metrics have been introduced that can allow you to capture counters on how long middleware is taking, how often lock contention occurs, and so on.

Set the AUTOFAC_METRICS environment variable in your process to true or 1 to enable this feature. You can see the set of counters that will become available here.

⚠️ This is NOT FREE. Collecting counters and metrics will incur a performance hit, so it's not something you want to leave on in production.

... (truncated)

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Updated Azure.Extensions.AspNetCore.Configuration.Secrets from 1.4.0 to 1.5.0.

Release notes

Sourced from Azure.Extensions.AspNetCore.Configuration.Secrets's releases.

1.5.0

1.5.0 (2026-03-04)

Features Added

• Added AddKeyVaultSecrets extension methods on IConfigurationBuilder that create a SecretClient from configuration using the Azure.Core configuration extensions (built on System.ClientModel).

Bugs Fixed

• Handle OperationCanceledException in PollForSecretChangesAsync so the background polling loop exits cleanly when the provider is disposed.

1.5.0-beta.1

1.5.0-beta.1 (2026-01-23)

Features Added

• Added BicepMetadata class that provides a clean, type-safe way to set Bicep metadata on resources:
  • Description - Adds @​description('...') decorator
  • BatchSize - Adds @​batchSize(n) decorator for loop deployments
  • OnlyIfNotExists - Adds @​onlyIfNotExists() decorator
• Added BicepMetadata property on ProvisionableResource

Bugs Fixed

• Fixed PropertyName in Self reference for IBicepValue instances of collection items to include its index (for list) or its key (for dictionary) to avoid colliding with its enclosing collection's property name. (#​54802)

1.4.1

1.4.1 (2026-02-12)

Other Changes

• Removed show-serialized-names debug configuration to clean up unnecessary serialized name annotations from XML docs.

1.4.1-beta.3

1.4.1-beta.3 (2026-02-17)

Features Added

• Added ConfidentialLedgerRedirectPolicy to automatically follow HTTP 307/308 redirects while preserving the Authorization header. Previously, the SDK did not follow redirects by default, and even when redirects were enabled, the Authorization header was stripped on cross-domain redirects between ACL nodes, causing write operations to fail when routed to non-primary nodes.

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Updated Azure.Identity from 1.17.1 to 1.18.0.

Release notes

Sourced from Azure.Identity's releases.

1.18.0

1.18.0 (2026-02-25)

Features Added

• Added experimental Microsoft.Extensions.Configuration and Microsoft.Extensions.DependencyInjection integration for Azure SDK clients. For details, see the Configuration and Dependency Injection documentation.

• The WorkloadIdentityCredentialOptions.IsAzureProxyEnabled property, which enables Azure Kubernetes token proxy mode, is only available in beta releases of this package.

• AzureDeveloperCliCredential now parses JSON error output from azd auth token to extract clean error messages instead of including raw JSON in exceptions. Error messages like {"type":"consoleMessage","data":{"message":"ERROR: fetching token: ..."}} are now displayed as ERROR: fetching token: ....

1.18.0-beta.3

1.18.0-beta.3 (2026-02-20)

Breaking Changes

• Renamed WorkloadIdentityCredentialOptions.IsAzureKubernetesTokenProxyEnabled to IsAzureProxyEnabled to follow .NET naming conventions for boolean properties.

Bugs Fixed

• Fixed a NullReferenceException that occurred during X509Chain validation on Linux when using the Identity Bindings feature.

• Disabled MSAL's internal retry logic for ConfidentialClientApplication and PublicClientApplication to prevent double retries when combined with Azure SDK's retry policy. Only the configured Azure SDK retry policy is applied, avoiding unexpected additional retry attempts.

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Updated Azure.Identity from 1.17.1 to 1.19.0.

Release notes

Sourced from Azure.Identity's releases.

1.19.0

1.19.0 (2026-03-11)

Features Added

• Added support in ClientCertificateCredential to specify a path in the form of cert:/StoreLocation/StoreName/Thumbprint to refer to a certificate in the platform certificate store - such as the Windows Certificate Store on Windows, and the KeyChain on MacOS - instead of a file on disk. For example to load a certificate from the "My" store in the "CurrentUser" location use the path cert:/CurrentUser/My/E661583E8FABEF4C0BEF694CBC41C28FB81CD870 (A community contribution, courtesy of fowl2).

Other Changes

• Updated Microsoft.Identity.Client and Microsoft.Identity.Client.Extensions.Msal dependencies to version 4.83.1.

1.18.0

1.18.0 (2026-02-25)

Features Added

• Added experimental Microsoft.Extensions.Configuration and Microsoft.Extensions.DependencyInjection integration for Azure SDK clients. For details, see the Configuration and Dependency Injection documentation.

• The WorkloadIdentityCredentialOptions.IsAzureProxyEnabled property, which enables Azure Kubernetes token proxy mode, is only available in beta releases of this package.

• AzureDeveloperCliCredential now parses JSON error output from azd auth token to extract clean error messages instead of including raw JSON in exceptions. Error messages like {"type":"consoleMessage","data":{"message":"ERROR: fetching token: ..."}} are now displayed as ERROR: fetching token: ....

1.18.0-beta.3

1.18.0-beta.3 (2026-02-20)

Breaking Changes

• Renamed WorkloadIdentityCredentialOptions.IsAzureKubernetesTokenProxyEnabled to IsAzureProxyEnabled to follow .NET naming conventions for boolean properties.

Bugs Fixed

• Fixed a NullReferenceException that occurred during X509Chain validation on Linux when using the Identity Bindings feature.

• Disabled MSAL's internal retry logic for ConfidentialClientApplication and PublicClientApplication to prevent double retries when combined with Azure SDK's retry policy. Only the configured Azure SDK retry policy is applied, avoiding unexpected additional retry attempts.

Commits viewable in compare view.

Updated Azure.Security.KeyVault.Secrets from 4.8.0 to 4.9.0.

Release notes

Sourced from Azure.Security.KeyVault.Secrets's releases.

4.9.0

4.9.0 (2026-02-25)

Features Added

• Added SecretClientSettings to support creating a SecretClient from IConfiguration, including configuration-based credential resolution and dependency injection registration.
• Added the outContentType query parameter to the SecretClient.GetSecret and SecretClient.GetSecretAsync to specify the format in which the certificate will be returned.
• Added the previousVersion property to SecretProperties.

Other Changes

• The default service version is now 2025-07-01.

Commits viewable in compare view.

Updated Azure.Storage.Blobs from 12.26.0 to 12.27.0.

Release notes

Sourced from Azure.Storage.Blobs's releases.

No release notes found for this version range.

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Updated ConfigCat.Client from 9.4.3 to 9.5.0.

Release notes

Sourced from ConfigCat.Client's releases.

9.5.0

This release focuses on networking-related improvements. Upgrading is highly recommended if you occasionally see HTTP errors or timeouts in the SDK's log.

Improvements:

• Implement logic to retry failed HTTP requests one time (on receiving unexpected status code, timeout or request error). (#​134)
• Implement protection against socket exhaustion theoretically possible in extreme cases. (Prevent recreation of HttpClientHandler within 30 seconds).
• Deprecate ConfigCatClientOptions.HttpClientHandler. Alternative: ConfigCatClientOptions.Proxy or ConfigCatClientOptions.ConfigFetcher = new HttpClientConfigFetcher(...).
• Add the new Proxy option to ConfigCatClientOptions.
• Make HttpClientConfigFetcher public and allows subclassing to provide an extension point for customizing request headers.
• Make reading response body in HttpClientConfigFetcher cancelable for targets below .NET 5.
• Add debug logging to HttpClientConfigFetcher.
• Add UnsupportedOSPlatform annotations for APIs that are not available when running in browser.
• Log the CF-RAY header also when the headers are received but downloading the response body times out or fails.

Bug fixes:

• Prevent sending additional headers when running in browser to avoid extra CORS OPTIONS requests.
• Prevent disposing of externally created IConfigFetcher instances (as multiple ConfigCatClient may be configured to use those.)

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Updated csharpier from 1.2.5 to 1.2.6.

Release notes

Sourced from csharpier's releases.

1.2.6

What's Changed

[Bug]: XML with DOCTYPE results in "invalid xml" warning #​1809

CSharpier was not formatting xml that included a doctype and instead reporting that it was invalid xml.

<?xml version="1.0"?>
<!DOCTYPE staff SYSTEM "staff.dtd"[
    <!ENTITY ent1 "es">
]>
<staff></staff>

[Bug]: Initializing a span using stackalloc leads to different formatting compared to new #​1808

When initializing a spacn using stackalloc, it was not being formatting consistently with other code

// input & expected output
Span<int> metatable = new int[]
{
    00000000000000000000000001,
    00000000000000000000000002,
    00000000000000000000000003,
};

Span<int> metatable = stackalloc int[]
{
    00000000000000000000000001,
    00000000000000000000000002,
    00000000000000000000000003,
};

// 1.2.5
Span<int> metatable = new int[]
{
    00000000000000000000000001,
    00000000000000000000000002,
    00000000000000000000000003,
};

Span<int> metatable =
    stackalloc int[] {
        00000000000000000000000001,
        00000000000000000000000002,
        00000000000000000000000003,
    };

[Bug]: Comments in otherwise empty object pattern disappear when formatting #​1804

CSharpier was removing comments if they were the only content of an object pattern.

// input & expected output
var match = obj is {
    //Property: 123
 ... (truncated)

Commits viewable in [compare view](https://github.com/belav/csharpier/compare/1.2.5...1.2.6).
</details>

Updated [Dapper](https://github.com/DapperLib/Dapper) from 2.1.66 to 2.1.72.

<details>
<summary>Release notes</summary>

_Sourced from [Dapper's releases](https://github.com/DapperLib/Dapper/releases)._

## 2.1.72

## What's Changed
* TFM packaging for .NET 10 by @​mgravell in https://github.com/DapperLib/Dapper/pull/2195
* Fix and clarify OrWhere caveats in SqlBuilder docs by @​jnoordsij in https://github.com/DapperLib/Dapper/pull/2149
* OutputExpression wasn't working for methods that use QueryRowAsync by @​ri-rgb in https://github.com/DapperLib/Dapper/pull/2156
* CI: use preinstalled sdk by @​kbth in https://github.com/DapperLib/Dapper/pull/2160
* CI: serialize DB-dependent tests by @​kbth in https://github.com/DapperLib/Dapper/pull/2163

## New Contributors
* @​jnoordsij made their first contribution in https://github.com/DapperLib/Dapper/pull/2149
* @​ri-rgb made their first contribution in https://github.com/DapperLib/Dapper/pull/2156
* @​kbth made their first contribution in https://github.com/DapperLib/Dapper/pull/2160

**Full Changelog**: https://github.com/DapperLib/Dapper/compare/2.1.66...2.1.72

Commits viewable in [compare view](https://github.com/DapperLib/Dapper/compare/2.1.66...2.1.72).
</details>

Updated [dotnet-coverage](https://github.com/microsoft/codecoverage) from 18.3.1 to 18.5.2.

<details>
<summary>Release notes</summary>

_Sourced from [dotnet-coverage's releases](https://github.com/microsoft/codecoverage/releases)._

No release notes found for this version range.

Commits viewable in [compare view](https://github.com/microsoft/codecoverage/commits).
</details>

Updated [FluentAssertions](https://github.com/fluentassertions/fluentassertions) from 7.2.0 to 7.2.1.

<details>
<summary>Release notes</summary>

_Sourced from [FluentAssertions's releases](https://github.com/fluentassertions/fluentassertions/releases)._

## 7.2.1

<!-- Release notes generated using configuration in .github/release.yml at support-7.0 -->

## What's Changed
### Fixes
* Prevent a crash while formatting a collection with nested empty collections by @​dennisdoomen in https://github.com/fluentassertions/fluentassertions/pull/3150


**Full Changelog**: https://github.com/fluentassertions/fluentassertions/compare/7.2.0...7.2.1

Commits viewable in [compare view](https://github.com/fluentassertions/fluentassertions/compare/7.2.0...7.2.1).
</details>

Updated [Google.Cloud.Firestore](https://github.com/googleapis/google-cloud-dotnet) from 4.1.0 to 4.2.0.

<details>
<summary>Release notes</summary>

_Sourced from [Google.Cloud.Firestore's releases](https://github.com/googleapis/google-cloud-dotnet/releases)._

## 4.2.0

### New features

- Expose the variable definition in the Cloud Firestore API


Commits viewable in [compare view](https://github.com/googleapis/google-cloud-dotnet/commits/Google.Cloud.Firestore-4.2.0).
</details>

Updated [MassTransit](https://github.com/Massient/MassTransit) from 8.5.7 to 9.0.1.

<details>
<summary>Release notes</summary>

_Sourced from [MassTransit's releases](https://github.com/Massient/MassTransit/releases)._

No release notes found for this version range.

Commits viewable in [compare view](https://github.com/Massient/MassTransit/commits).
</details>

Updated [Microsoft.EntityFrameworkCore](https://github.com/dotnet/dotnet) from 10.0.0 to 10.0.4.

<details>
<summary>Release notes</summary>

_Sourced from [Microsoft.EntityFrameworkCore's releases](https://github.com/dotnet/dotnet/releases)._

No release notes found for this version range.

Commits viewable in [compare view](https://github.com/dotnet/dotnet/commits).
</details>

Updated [Microsoft.Extensions.Configuration](https://github.com/dotnet/dotnet) from 10.0.0 to 10.0.3.

<details>
<summary>Release notes</summary>

_Sourced from [Microsoft.Extensions.Configuration's releases](https://github.com/dotnet/dotnet/releases)._

No release notes found for this version range.

Commits viewable in [compare view](https://github.com/dotnet/dotnet/commits).
</details>

Updated [Microsoft.Extensions.Hosting.Abstractions](https://github.com/dotnet/dotnet) from 10.0.0 to 10.0.3.

<details>
<summary>Release notes</summary>

_Sourced from [Microsoft.Extensions.Hosting.Abstractions's releases](https://github.com/dotnet/dotnet/releases)._

No release notes found for this version range.

Commits viewable in [compare view](https://github.com/dotnet/dotnet/commits).
</details>

Updated [ModelContextProtocol](https://github.com/modelcontextprotocol/csharp-sdk) from 0.4.0-preview.3 to 1.1.0.

<details>
<summary>Release notes</summary>

_Sourced from [ModelContextProtocol's releases](https://github.com/modelcontextprotocol/csharp-sdk/releases)._

## 1.1.0

Highlights of v1.1.0 include client completion details for understanding when and why a client connection ended, auto-populated completion handlers from `AllowedValuesAttribute`, and bug fixes for server-initiated ping handling, server capabilities initialization, and in-flight message handler cleanup.

## What's Changed

* 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 #​1399 by @​stephentoub (co-authored by @​Copilot)
* Auto-populate completion handlers from AllowedValuesAttribute on prompt/resource parameters #​1380 by @​stephentoub (co-authored by @​Copilot)
* Add client completion notification and details #​1368 by @​stephentoub (co-authored by @​Copilot)
* 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 #​1385 by @​jeffhandley (co-authored by @​Copilot)
* Simplify and update README for stable release #​1387 by @​stephentoub (co-authored by @​jeffhandley)
* 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 #​1394 by @​halter73
* 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 #​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 #​1392
* Bump docfx from 2.78.4 to 2.78.5 #​1408
* Bump actions/download-artifact from 7.0.0 to 8.0.0 #​1406
* Bump actions/upload-artifact from 6.0.0 to 7.0.0 #​1405
* Bump danielpalme/ReportGenerator-GitHub-Action from 5.5.1 to 5.5.2 #​1404
* Bump the testing-frameworks group with 1 update #​1407
* Add issue-triage Copilot skill #​1412 by @​jeffhandley (co-authored by @​Copilot)
* Release v1.1.0 #​1411 by @​jeffhandley (co-authored by @​Copilot)

## Acknowledgements

* @​r-Larch submitted issue #​1269 (resolved by #​1403)
* @​darena-mhaque submitted issue #​1398 (resolved by #​1399)
* @​hulumane submitted issue #​1332 (resolved by #​1368)
* @​AArnott submitted issue #​438 (resolved by #​1368)
* @​JarroVGIT submitted issue #​1390 (resolved by #​1391)
* @​stephentoub @​halter73 @​eiriktsarpalis @​jeffhandley reviewed pull requests

**Full Changelog**: https://github.com/modelcontextprotocol/csharp-sdk/compare/v1.0.0...v1.1.0


## 1.0.0

**This is the first stable release of the ModelContextProtocol C# SDK.** Thank you to all of the contributors who helped us achieve this milestone!

## Breaking Changes

Refer to the [C# SDK Versioning](https://modelcontextprotocol.github.io/csharp-sdk/versioning.html) documentation for details on versioning and breaking change policies.

1. **Mark RunSessionHandler experimental (MCPEXP002) #​1383**
   * `HttpServerTransportOptions.RunSessionHandler` is now annotated with `[Experimental("MCPEXP002")]`
   * Code that references `RunSessionHandler` will produce a compile-time warning (or error with `TreatWarningsAsErrors`); suppress with `#pragma warning disable MCPEXP002`
   * Consider using `ConfigureSessionOptions` as an alternative; `RunSessionHandler` may be removed or change signatures in a future release

## What's Changed

* Add 2025-03-26 OAuth backward compatibility for client conformance #​1374 by @​jeffhandley (co-authored by @​Copilot)
* Mark `RunSessionHandler` experimental (MCPEXP002) #​1383 by @​halter73 (co-authored by @​Copilot @​jeffhandley)

## Documentation Updates

* Fix a few bugs in the docs #​1379 by @​stephentoub
* Add and augment conceptual docs #​1375 by @​jeffhandley (co-authored by @​Copilot @​mikekistler @​stephentoub @​halter73)

## Repository Infrastructure Updates

* Bump to version 1.0.0 (stable) #​1384 by @​jeffhandley

## Acknowledgements

* @​halter73 @​stephentoub @​mikekistler @​eiriktsarpalis reviewed pull requests

**Full Changelog**: https://github.com/modelcontextprotocol/csharp-sdk/compare/v1.0.0-rc.1...v1.0.0


## 1.0.0-rc.1

This release candidate completes a full API surface area audit ahead of the 1.0.0 stable release, with more changes to public APIs to ensure consistency and long-term maintainability. Protocol DTO types are updated to match the MCP specification, deprecated filter APIs are removed, and bug fixes improve transport reliability and JSON handling.

## Breaking Changes

Refer to the [C# SDK Versioning](https://modelcontextprotocol.github.io/csharp-sdk/versioning.html) documentation for details on versioning and breaking change policies.

1. **Address asymmetry in McpServerHandlers/McpClientHandlers and make all filter properties settable #​1337**
   * Seals `McpClientHandlers` to match the already-sealed `McpServerHandlers`
   * Makes `McpServerOptions.Handlers`, `McpServerOptions.Filters`, and all `IList<T>` filter properties settable with null validation

2. **Remove server back-references from protocol DTO types #​1345**
   * Removes `Tool.McpServerTool`, `Prompt.McpServerPrompt`, `Resource.McpServerResource`, and `ResourceTemplate.McpServerResource` properties
   * Use `McpServerPrimitiveCollection.TryGetPrimitive()` for name-based lookups instead

3. **Make Tool.Name required to match other protocol types #​1351**
   * Adds `required` modifier to `Tool.Name`, matching `Prompt.Name`, `Resource.Name`, and other `IBaseMetadata` implementations
   * Callers must now specify `Name` in object initializers

4. **Make LoggingMessageNotificationParams.Data required per MCP spec #​1353**
   * Changes `LoggingMessageNotificationParams.Data` from `JsonElement?` to `required JsonElement` per the MCP specification

5. **Fix CreateMessageRequestParams.Metadata type to JsonObject #​1354**
   * Changes `CreateMessageRequestParams.Metadata` from `JsonElement?` to `JsonObject?` to match all other `_meta`/`Meta` properties in the SDK

6. **Normalize CallToolResult.StructuredContent to JsonElement? #​1357**
   * Changes `CallToolResult.StructuredContent` from `JsonNode?` to `JsonElement?` for consistency with the rest of the SDK
   * Use `JsonSerializer.SerializeToElement()` to produce a `JsonElement`

7. **Unify service configuration for `ISseEventStreamStore`, `IMcpTaskStore`, and `ISessionMigrationHandler` #​1362**
   * Consistent options + DI pattern: explicit options property > DI resolution

8. **Add explicit [Experimental] protected constructors to McpClient and McpServer #​1363**
   * Protected constructors on `McpClient` and `McpServer` now require suppressing `MCPEXP002` to subclass

9. **Remove MCP9002 obsolete APIs and document obsolete diagnostics #​1366**
   * Removes the 13 `AddXxxFilter` extension methods on `IMcpServerBuilder` (e.g. `AddCallToolFilter`, `AddListToolsFilter`) that were deprecated under diagnostic `MCP9002`
   * Use `WithRequestFilters()` and `WithMessageFilters()` instead

10. **Fix McpClientPrompt/Resource types to use RequestOptions like McpClientTool does #​1370**
    * Replaces `JsonSerializerOptions` with `RequestOptions` parameter for consistency across `McpClientPrompt`, `McpClientResource`, and `McpClientTool`

## What's Changed

* Make Tool.Name required to match other protocol types #​1351 by @​stephentoub (co-authored by @​Copilot)
* Make LoggingMessageNotificationParams.Data required per MCP spec #​1353 by @​stephentoub (co-authored by @​Copilot)
* Fix off-by-one error in reconnection attempts #​1356 by @​stephentoub (co-authored by @​Copilot)
* Remove server back-references from protocol DTO types #​1345 by @​stephentoub (co-authored by @​Copilot)
* Fix base64 deserialization when JSON encoder escapes forward slashes #​1342 by @​stephentoub (co-authored by @​Copilot)
* Increase MaxReconnectionAttempts default from 2 to 5 #​1355 by @​stephentoub (co-authored by @​Copilot)
* Prevent cancellation of initialize request per MCP spec #​1350 by @​stephentoub (co-authored by @​Copilot)
 ... (truncated)

## 0.9.0-preview.2

This release focuses on API surface consistency and correctness ahead of 1.0.0. Public collection properties are now typed as `IList<T>` instead of concrete `List<T>` or `T[]`, and `Root.Meta` is aligned with the rest of the protocol DTOs by using `JsonObject?`. Other improvements include new experimental Extensions support for capabilities, missing `ResourceLinkBlock` properties, improved mimeType handling, and several documentation and test reliability fixes.

**We plan to release the stable 1.0.0 release early in the week of February 23, 2026.**

## Breaking Changes

Refer to the [C# SDK Versioning](https://modelcontextprotocol.github.io/csharp-sdk/versioning.html) documentation for details on versioning and breaking change policies.

1. **Replace concrete collection types with interfaces in public API surface #​1326**
   * `List<T>` and `T[]` properties on `ProtectedResourceMetadata`, `ToolResultContentBlock`, `ListTasksResult`, and `DynamicClientRegistrationResponse` changed to `IList<T>`. Replace `.Length` with `.Count` and cast to `List<T>` if `List<T>`-specific members are needed.

2. **Fix `Root.Meta` to use `JsonObject` instead of `JsonElement` #​1341**
   * `Root.Meta` changed from `JsonElement?` to `JsonObject?`. Replace `meta.Value.GetProperty("key").GetString()` with `(string?)meta["key"]`.

3. **Make `UrlElicitationRequiredErrorData.Elicitations` consistent with other Protocol DTOs #​1335**
   * `Elicitations` changed from `IReadOnlyList<ElicitRequestParams>` with `init` to `IList<ElicitRequestParams>` with `set`. Code using `List<T>` is unaffected since it implements both interfaces.

## What's Changed

* Remove dead code: `options ??= new()` in McpServerImpl constructor #​1322 by @​stephentoub (co-authored by @​Copilot)
* Remove unnecessary `_connectCts` field from `McpClientImpl` #​1323 by @​stephentoub (co-authored by @​Copilot)
* Add missing Title and Icons properties to ResourceLinkBlock #​1320 by @​stephentoub (co-authored by @​Copilot)
* Omit null mimeType from ResourceContents JSON serialization #​1325 by @​stephentoub (co-authored by @​Copilot)
* Validate mimeType in ImageContentBlock.FromBytes and AudioContentBlock.FromBytes #​1321 by @​stephentoub (co-authored by @​Copilot)
* Replace concrete collection types with interfaces in public API surface #​1326 by @​stephentoub (co-authored by @​Copilot)
* Make UrlElicitationRequiredErrorData.Elicitations consistent with other Protocol DTOs #​1335 by @​stephentoub (co-authored by @​Copilot)
* Fix Metadata delegation in DelegatingMcpServerTool/Prompt/Resource #​1338 by @​stephentoub (co-authored by @​Copilot @​jeffhandley)
* Add Extensions support to ClientCapabilities and ServerCapabilities #​1317 by @​stephentoub (co-authored by @​Copilot)
* Fix _meta properties to use JsonObject #​1341 by @​stephentoub (co-authored by @​Copilot)

## Documentation Updates

* Fix incorrect XML doc comments in McpClient.Methods.cs #​1333 by @​stephentoub (co-authored by @​Copilot)
* Add missing exception documentation for public APIs #​1339 by @​stephentoub (co-authored by @​Copilot)

## Test Improvements

* Fix flaky DiagnosticTests on net10.0 by waiting for specific activities #​1324 by @​stephentoub (co-authored by @​Copilot)
* Fix flaky sse-retry conformance test due to CI timing overhead #​1336 by @​ericstj (co-authored by @​Copilot)

## Repository Infrastructure Updates

* Bump version to 1.0.0-rc.1 #​1327 by @​jeffhandley (co-authored by @​Copilot)
* Add release-notes, breaking-changes, and bump-version Copilot skills #​1328 by @​jeffhandley (co-authored by @​Copilot)
* Bump hono from 4.11.7 to 4.12.0 in the npm_and_yarn group across 1 directory #​1316
* Bump version down to 0.9.0-preview.2 since we are still changing APIs #​1344 by @​jeffhandley (co-authored by @​Copilot)

## Acknowledgements

* @​halter73 @​eiriktsarpalis @​mikekistler reviewed pull requests
 ... (truncated)

## 0.9.0-preview.1

The 0.9.0-preview.1 release includes multiple breaking changes focused on quality, extensibility, usability, and API consistency as we continue refining the SDK in preparation for a stable 1.0.0 release.

**We plan to release the stable 1.0.0 release early in the week of February 23, 2026.**

## Breaking Changes

Refer to the [C# SDK Versioning](https://modelcontextprotocol.github.io/csharp-sdk/versioning.html) documentation for details on versioning and breaking change policies.

1. **Use ReadOnlyMemory\<byte> for binary data to eliminate UTF-16 transcoding #​1070**
   * `ImageContentBlock.Data`, `AudioContentBlock.Data`, and `BlobResourceContents.Blob` changed from `string` to `ReadOnlyMemory<byte>`; `FromImage`/`FromAudio` renamed to `FromBytes`; `BlobResourceContents.Data` renamed to `DecodedData`
   * Migration: Use `DecodedData` for decoded bytes and `FromBytes(...)` factory methods

2. **Split configuration of request and message filters #​1308**
   * `Add*Filter` extension methods on `IMcpServerBuilder` replaced by `WithMessageFilters` and `WithRequestFilters` callbacks with grouped builder instances
   * Migration: Wrap existing filter registration inside the new callback methods

3. **Don't treat McpServerHandlers as an independent options type #​1313**
   * `McpServerHandlers` no longer resolved via `IOptions<McpServerHandlers>`; handlers set directly on `McpServerOptions.Handlers`
   * Migration: Configure handlers through `McpServerOptions` directly

4. **Add `ISessionMigrationHandler` #​1270**
   * Stateful Streamable HTTP POST requests without a session ID are now rejected with 400 unless the message is an `initialize` request
   * Compat switch: `ModelContextProtocol.AspNetCore.AllowNewSessionForNonInitializeRequests` = `true` restores previous behavior

5. **Change ProtectedResourceMetadata URI properties to strings #​1264**
   * Multiple properties changed from `Uri?`/`List<Uri>` to `string?`/`List<string>` to avoid unwanted URI normalization
   * Migration: Use string values directly instead of `Uri` objects

6. **Hide experimental types from external source generators using internal property pattern #​1301**
   * Experimental properties now use `[JsonIgnore]` + internal delegate pattern; external source generators no longer reference experimental types
   * No code changes needed for most consumers

7. **Validate MCP-Protocol-Version header in Streamable HTTP handler #​1277**
   * Server returns HTTP 400 for invalid/unsupported header values; missing header still allowed
   * Migration: Ensure clients send a valid protocol version or omit the header

8. **Update McpErrorCode and fix error code usage to align with MCP spec #​1291**
   * Task support validation errors changed from `MethodNotFound` to `InvalidParams`
   * Migration: Update error code checks for task support validation scenarios

## What's Changed

* Bring up to 0.1.13 conformance #​1254 by @​stephentoub
* Change ProtectedResourceMetadata URI properties to strings and build resource strings directly #​1264 by @​halter73 (co-authored by @​Copilot)
* Log tool call name on success, not just failure #​1256 by @​halter73 (co-authored by @​Copilot)
* Fix HttpClient timeout for long-running tools without event stream store #​1268 by @​halter73 (co-authored by @​Copilot)
* Fix stderr event loss due to missing WaitForExit in DisposeProcess #​1280 by @​stephentoub (co-authored by @​Copilot)
* Update McpErrorCode XML docs and fix error code usage to align with MCP spec #​1291 by @​stephentoub (co-authored by @​Copilot)
* Add X-Accel-Buffering header to SSE responses #​1294 by @​stephentoub (co-authored by @​Copilot)
* Fix StdioServerTransport.DisposeAsync() hang: CancellableStdinStream missing Dispose override #​1276 by @​stephentoub (co-authored by @​Copilot)
 ... (truncated)

## 0.8.0-preview.1

The 0.8.0-preview.1 release includes new server-side capabilities including message-level filters and a distributed cache-backed event stream store, along with several bug fixes for transport reliability. This release also includes a breaking change that seals public Protocol reference types to prevent external inheritance, reinforcing the SDK's API contract as we continue refining toward a stable 1.0.0 release.

## Breaking Changes

Refer to the [C# SDK Versioning](https://modelcontextprotocol.github.io/csharp-sdk/versioning.html) documentation for details on versioning and breaking change policies.

1. **Seal public Protocol reference types to prevent external inheritance #​1232**
   * Several public classes sealed: `JsonRpcMessageContext`, `ElicitRequestParams.RequestSchema`, `ElicitRequestParams.LegacyTitledEnumSchema`, `ContentBlock.Converter`, `ResourceContents.Converter`, `PrimitiveSchemaDefinition.Converter`
   * `ElicitRequestParams.EnumSchema` removed; use `LegacyTitledEnumSchema` directly
   * Migration: Remove any inheritance from these types; replace `EnumSchema` references with `LegacyTitledEnumSchema`

## What's Changed

* Add Trace-level logging for JSON-RPC payloads in transports #​1191 by @​stephentoub (co-authored by @​halter73 @​Copilot)
* Use Process.Kill(entireProcessTree: true) on .NET for faster process termination #​1187 by @​stephentoub
* Include response body in HttpRequestException for transport client errors #​1193 by @​stephentoub (co-authored by @​Copilot)
* Fix race condition in SSE GET request initialization #​1212 by @​stephentoub
* Fix keyset pagination with monotonic UUIDv7-like task IDs #​1215 by @​eiriktsarpalis (co-authored by @​stephentoub @​Copilot)
* Add ILoggerFactory to StreamableHttpServerTransport #​1213 by @​stephentoub (co-authored by @​Copilot)
* Add support for message-level filters to McpServer #​1207 by @​halter73
* Seal public Protocol reference types to prevent external inheritance #​1232 by @​stephentoub (co-authored by @​Copilot)
* Add `DistributedCacheEventStreamStore` #​1136 by @​MackinnonBuck (co-authored by @​halter73)

## Documentation Updates

* Fix typo in elicitation.md #​1186 by @​ruyut
* Fix typo in progress.md #​1189 by @​ruyut
* Clarify McpMetaAttribute documentation scope #​1242 by @​stephentoub (co-authored by @​Copilot)

## Test Improvements

* Remove 10 second wait from docker tests #​1188 by @​stephentoub
* Fix Session_TracksActivities test #​1200 by @​stephentoub
* Fix StdioServerTransportTests to use Debug logging level instead of Trace #​1209 by @​stephentoub (co-authored by @​Copilot)
* Centralize test timeout constants to fix sporadic CI failures #​1210 by @​ericstj (co-authored by @​Copilot)
* Fix race condition in AutomaticInputRequiredStatusTests polling logic #​1223 by @​ericstj (co-authored by @​stephentoub @​Copilot)
* Centralize test timeout constants to fix CI flakiness #​1224 by @​ericstj (co-authored by @​Copilot)
* Add test coverage for AdditionalHeaders in Streamable HTTP transport #​1218 by @​stephentoub (co-authored by @​Copilot)
* Fix XunitLoggerProvider crash when background work logs after test disposal #​1229 by @​stephentoub (co-authored by @​Copilot)
* Skip .NET Framework tests on non-Windows platforms #​1226 by @​stephentoub (co-authored by @​Copilot)
* Suppress TimeProvider.Testing net472 warning #​1227 by @​stephentoub (co-authored by @​Copilot)

## Repository Infrastructure Updates

* Bump version to 0.8.0-preview.1 #​1181 by @​jeffhandley (co-authored by @​Copilot)
* Bump actions/checkout from 6.0.1 to 6.0.2 #​1173
* Bump the opentelemetry-testing group with 6 updates #​1174
* Bump the other-testing group with 1 update #​1233
* Bump Anthropic from 12.2.0 to 12.3.0 #​1234

 ... (truncated)

## 0.7.0-preview.1

The 0.7.0-preview.1 release adds MCP task support, Streamable HTTP resumability with SSE event stream storage, and support for the 2025-11-25 protocol version. This release also introduces user-defined `JsonSerializerOptions` throughout SDK serialization APIs and includes several bug fixes for elicitation, source generator diagnostics, and URI template matching. The Streamable HTTP transport includes breaking changes to `StreamableHttpServerTransport` as part of the resumability implementation.

## Breaking Changes

Refer to the [C# SDK Versioning](https://modelcontextprotocol.github.io/csharp-sdk/versioning.html) documentation for details on versioning and breaking change policies.

1. **Streamable HTTP resumability + redelivery + SSE polling via server-side disconnect #​1077**
   * `StreamableHttpServerTransport.OnInitRequestReceived` property removed; replaced by `EventStreamStore` for resumability support
   * `StreamableHttpServerTransport.SessionId` setter changed from `{ get; set; }` to `{ get; init; }`
   * Migration: Remove `OnInitRequestReceived` usage; use `ISseEventStreamStore` via `EventStreamStore` for resumability. Set `SessionId` in the object initializer instead of post-construction assignment.

## What's Changed

* Update licensing to Apache 2.0 for new contributions #​1140 by @​domdomegg
* Add 2025-11-25 as supported version #​1130 by @​stephentoub (co-authored by @​Copilot)
* Streamable HTTP resumability + redelivery + SSE polling via server-side disconnect #​1077 by @​MackinnonBuck (co-authored by @​halter73)
* Fix source generator diagnostic locations for incremental caching #​1153 by @​stephentoub (co-authored by @​Copilot)
* Fix form mode elicitation schema check to apply for all form requests #​1151 by @​stephentoub (co-authored by @​Copilot)
* Add support for user-defined JsonSerializerOptions throughout SDK serialization APIs #​1113 by @​stephentoub (co-authored by @​Copilot @​eiriktsarpalis)
* Fix reserved expansion (e.g. `{+var}`) when matching resources #​1142 by @​halter73
* Implement MCP task support #​1170 by @​eiriktsarpalis (co-authored by @​halter73)

## Documentation Updates

* Document MCP Server project template in README #​1148 by @​leslierichardson95 (co-authored by @​mikekistler @​jeffhandley)

## Test Improvements

* Add comprehensive edge case tests for JSON-RPC payload shapes #​1143 by @​stephentoub (co-authored by @​Copilot)
* Fix flaky test: `Client_CanResumePostResponseStream_AfterDisconnection` #​1179 by @​MackinnonBuck

## Repository Infrastructure Updates

* Bump version to 0.7.0-preview.1 #​1144 by @​jeffhandley
* Bump actions/setup-dotnet from 5.0.1 to 5.1.0 #​1157
* Bump actions/setup-node from 6.1.0 to 6.2.0 #​1158
* Bump the testing-frameworks group with 1 update #​1159
* Bump the other-testing group with 1 update #​1160
* Update Microsoft.Extensions.AI to 10.2.0 #​1165 by @​eiriktsarpalis (co-authored by @​Copilot @​stephentoub)
* Update Anthropic SDK to 12.2.0 #​1164 by @​eiriktsarpalis (co-authored by @​Copilot)
* Pin the MCP conformance tester package #​1176 by @​eiriktsarpalis

## Acknowledgements

* @​domdomegg made their first contribution in #​1140
* @​leslierichardson95 made their first contribution in #​1148
* @​mikekistler submitted #​510 #​1020 (resolved by #​1077), #​1129 (resolved by #​1130), #​943 (resolved by #​1170)
* @​halter73 @​stephentoub @​eiriktsarpalis @​jeffhandley @​mikekistler @​MackinnonBuck @​heaths @​scutuatua-crypto reviewed pull requests

**Full Changelog**: https://github.com/modelcontextprotocol/csharp-sdk/compare/v0.6.0-preview.1...v0.7.0-preview.1
 ... (truncated)

## 0.6.0-preview.1

This release includes improvements to source generator robustness, JSON-RPC deserialization performance, and OpenTelemetry semantic convention alignment. It also adds OAuth incremental scope consent support, fixes session timeout issues, and corrects tool result message handling for sampling with tools. Several documentation improvements and new client conformance tests round out the release.

## What's Changed

* Remove s_additionalProperties from McpClientTool #​1080 by @​stephentoub (co-authored by @​Copilot)
* Migrate from Anthropic.SDK to official Anthropic package #​1083 by @​stephentoub (co-authored by @​Copilot)
* Improve caching in XmlToDescriptionGenerator #​1010 by @​stephentoub
* Support incremental scope consent (SEP-835) #​1084 by @​halter73
* Resource subscribe should be true if handler provided #​676 by @​PederHP (co-authored by @​halter73 @​mikekistler)
* Add request duration to LogRequestHandlerCompleted and LogRequestHandlerException log messages #​1092 by @​stephentoub (co-authored by @​Copilot)
* Fix session timeout due to timestamp frequency mismatch and activity tracking #​1106 by @​stephentoub (co-authored by @​Copilot @​eiriktsarpalis)
* Add CS1066 suppressor for MCP server methods with optional parameters #​1110 by @​stephentoub (co-authored by @​Copilot)
* Fix CreateSamplingHandler to use ChatRole.Tool for tool result messages #​1128 by @​stephentoub (co-authored by @​Copilot @​MackinnonBuck)
* Add examples of icons on tools, resources, prompts, and server implementation to EverythingServer #​1096 by @​mikekistler (co-authored by @​halter73)
* Use fully-qualified type names in generated partial method signatures #​1135 by @​stephentoub (co-authored by @​Copilot)
* Optimize JsonRpcMessage deserialization with single-pass parsing #​1138 by @​eiriktsarpalis (co-authored by @​Copilot @​scooletz @​stephentoub)
* Align telemetry with OpenTelemetry MCP semantic conventions #​1139 by @​stephentoub (co-authored by @​Copilot)

## Documentation Updates

* Fix Icon.Theme documentation to match MCP specification #​1090 by @​stephentoub (co-authored by @​Copilot)
* Document HttpRequestException thrown by McpClient.CreateAsync #​1095 by @​stephentoub (co-authored by @​Copilot)
* Add missing exception documentation to public API surface #​1103 by @​stephentoub (co-authored by @​Copilot)
* Improve docs landing page #​1114 by @​gewarren
* Add CONTRIBUTING.md #​1125 by @​mikekistler

## Test Improvements

* Remove private reflection from tests #​1107 by @​stephentoub (co-authored by @​Copilot @​halter73)
* Add client conformance tests #​1102 by @​mikekistler (co-authored by @​halter73)

## Repository Infrastructure Updates

* Bump actions/setup-node from 6.0.0 to 6.1.0 #​1074
* Bump danielpalme/ReportGenerator-GitHub-Action from 5.5.0 to 5.5.1 #​1073
* Bump actions/checkout from 5.0.1 to 6.0.0 #​1005
* Bump version to 0.5.0-preview.2. Update NuGet Project URL. #​1078 by @​jeffhandley
* Update Microsoft.Extensions.AI dependencies to 10.1.0 #​1082 by @​stephentoub (co-authored by @​Copilot)
* Update Microsoft.Extensions.AI* packages to latest versions #​1093 by @​stephentoub (co-authored by @​Copilot)
* Bump actions/checkout from 6.0.0 to 6.0.1 #​1100
* Bump becheran/mlc from 1.0.0 to 1.2.0 #​1098
* Bump actions/upload-artifact from 5.0.0 to 6.0.0 #​1099
* Bump actions/download-artifact from 6.0.0 to 7.0.0 #​1097
* Bump the other-testing group with 1 update #​1101
* Bump Anthropic from 11.0.0 to 12.0.1 #​1118
* Bump the other-testing group with 1 update #​1124
* Install mono in dev container #​1133 by @​mikekistler
* Bump Anthropic from 12.0.1 to 12.1.0 #​1137
* Bump version to 0.6.0-preview.1 #​1141 by @​jeffhandley

 ... (truncated)

## 0.5.0-preview.1

The 0.5.0-preview.1 release of the Model Context Protocol C# SDK introduces significant API improvements including a unified `RequestOptions` parameter bag for client methods, removal of previously obsoleted APIs, and new support for Client ID Metadata Documents and URL mode elicitation. This release also adds conformance tests, `DebuggerDisplay` attributes for protocol types, and a convenience overload for resource subscriptions with handler delegates.

## Breaking Changes

The 0.5.0-preview.1 release includes several categories of breaking changes as we continue to refine the API surface area for the path toward a 1.0.0 stable release. Refer to the [C# SDK Versioning](https://modelcontextprotocol.github.io/csharp-sdk/versioning.html) documentation for information regarding our versioning, breaking change, and support approaches.

1. **Add request options bag to high level requests and include Meta #​970**
    * High-level request methods refactored to use options bag. Methods `CallToolAsync`, `GetPromptAsync`, `ListResourcesAsync`, `ReadResourceAsync`, `SubscribeResourceAsync`, `UnsubscribeResourceAsync`, `ListToolsAsync`, `ListPromptsAsync`, and similar now accept a new `RequestOptions` parameter instead of individual `JsonSerializerOptions` and `ProgressToken` parameters.
    * Code that passes `JsonSerializerOptions` or `ProgressToken` as named or positional parameters to high-level request methods will break and must be updated to use the `RequestOptions` bag instead.
2. **Remove obsolete APIs from codebase #​985**
    * `McpServerFactory` class: Removed obsolete factory class for creating MCP servers.
    * `McpClientFactory` class: Removed obsolete factory class for creating MCP clients.
    * Obsolete interfaces removed: `IMcpEndpoint`, `IMcpClient`, `IMcpServer`
    * Extension methods and properties that were previously marked obsolete are no longer available.
    * `LegacyTitledEnumSchema` and `EnumSchema` remain in place as obsolete APIs, but they now use a custom diagnostic ID of `MCP9001` instead of the default `CS0618` obsoletion diagnostic ID. This allows references to these APIs to be suppressed with a targeted diagnostic.
3. **Fall back to well-known URL in client if 401 response is missing resource_metadata parameter #​1054**
    * `IsConfiguredEndpointRequest()` now properly validates absolute URIs by checking both host and scheme match, not just the path. This may cause previously accepted requests to be rejected if host/scheme don't match.
    * `ModelContextProtocol.AspNetCore.Authentication.McpAuthenticationOptions.ResourceMetadataUri` was changed from `string` to a nullable `string?`.
    * `ModelContextProtocol.Authentication.ProtectedResourceMetadata.Resource` was changed from `required Uri` to a non-required and nullable `Uri?`
4. **Remove McpClient.Enumerate*Async methods #​1060**
    * Removes `EnumerateToolsAsync`, `EnumeratePromptsAsync`, `EnumerateResourceTemplatesAsync`, and `EnumerateResourcesAsync` from the public API surface. These scenarios are covered by the corresponding `List*Async` methods.
5. **Add McpClient/Session methods using .Protocol types #​1063**
    * Methods accepting a `CancellationToken token` had the argument renamed from `token` to `cancellationToken` for consistency throughout the SDK.
    * Methods accepting a `JsonSerializerOptions? serializerOptions` argument were updated to accept a `RequestOptions? options` argument instead, further adopting the `RequestOptions` class introduced in #​970.
    * `ModelContextProtocol.Client.McpClient.CompleteAsync` was updated to add an optional `RequestOptions? options` argument, changing the position of the optional `CancellationToken` argument on the method signature.
    * `ModelContextProtocol.Client.McpClient.UnsubscribeFromResourceAsync` arguments were changed to now accept `UnsubscribeRequestParams requestParams, CancellationToken cancellationToken = default`.
    * `ModelContextProtocol.Client.McpClient.SetLoggingLevel` was renamed to `SetLoggingLevelAsync`.

## What's Changed

* Add support for Client ID Metadata Documents to enable URL-based client registration #​1023 by @​MackinnonBuck
* Add Conformance tests for the server #​983 by @​mikekistler
* Adjust analyzer diagnostic severities and improve MCP001 reporting #​1038 by @​stephentoub (co-authored by @​Copilot)
* Remove obsolete APIs from codebase #​985 by @​MackinnonBuck (co-authored by @​Copilot @​eiriktsarpalis @​jeffhandley)
* Add support for `data` to `McpProtocolException` #​1028 by @​stephentoub (co-authored by @​Copilot)
* Fix XML generator partial method issues #​1059 by @​jongalloway
* Remove McpClient.Enumerate*Async methods #​1060 by @​stephentoub (co-authored by @​Copilot)
* Add request options bag to high level requests and include Meta #​970 by @​mikekistler (co-authored by @​stephentoub @​Copilot)
* Add support for URL mode elicitation #​1021 by @​halter73
* Synthesize return description into tool description when UseStructuredContent is false #​1049 by @​stephentoub (co-authored by @​Copilot)
* Add ResourceNotFound error code (-32002) #​1062 by @​stephentoub (co-authored by @​Copilot)
* Add McpClient/Session methods using .Protocol types #​1063 by @​stephentoub
* WithMeta for McpClientTool #​1027 by @​PederHP (co-authored by @​stephentoub)
* Fall back to well-known URL in client if 401 response is missing resource_metadata parameter #​1054 by @​halter73
* Add DebuggerDisplay attributes to Protocol types #​1068 by @​stephentoub (co-authored by @​Copilot @​halter73)
* Add SubscribeToResourceAsync overload with handler delegate #​1069 by @​stephentoub (co-authored by @​Copilot)

## Documentation Updates

* Core Protocol docs edit pass #​1032 by @​gewarren
 ... (truncated)

## 0.4.1-preview.1

This release brings protocol type standardization, several MCP specification implementations, and new features including an incremental source generator for automatic `Description` attributes from XML comments and client session resumption support. This release includes breaking changes to protocol types and elicitation enum schemas; refer to the Breaking Changes section below for details.

We are working toward the first stable version of the C# SDK as version 1.0.0, which will have compliance with [Version 2025-11-25](https://modelcontextprotocol.io/specification/2025-11-25) of the MCP specification. We will publish at least one more pre-release version of the SDK before declaring the stable version, and breaking changes to remove obsolete interfaces and extension methods (#​774) are expected as part of stabilizing the API.

## Breaking Changes

Refer to the [C# SDK Versioning](https://modelcontextprotocol.github.io/csharp-sdk/versioning.html) documentation for details on versioning and breaking change policies.

1. **Audit and standardize MCP protocol types for consistency #​892**
   * Property mutability changes
   * Required properties changes
   * Collection types used for properties
2. **Implement SEP-1330: Standards-compliant enum schemas for elicitation #​969**
   * `EnumSchema` is marked `[Obsolete]` using the default `CS0618` diagnostic, and it becomes an alias for `LegacyTitledEnumSchema`, which is also marked as `[Obsolete]` using the default `CS0618` diagnostic

## What's Changed

* Add default value support for all primitive types in elicitation schemas (SEP-1034) #​924 by @​eiriktsarpalis (co-authored by @​Copilot)
* Audit protocol types #​892 by @​MackinnonBuck
* Implement SEP-986: Specify Format for Tool Names #​945 by @​stephentoub
* Add public constructors to McpClient types for reusing cached definitions #​938 by @​stephentoub (co-authored by @​Copilot)
* Tweak how McpClientTool.InvokeAsync exposes some content #​941 by @​stephentoub
* Ignore unexpected properties when deserializing a ContentBlock #​956 by @​jeffhandley
* Add Description property to Implementation type per MCP spec #​966 by @​stephentoub (co-authored by @​Copilot)
* Remove TODOs related to AllowOutOfOrderMetadataProperty workarounds #​977 by @​eiriktsarpalis
* Make `JsonRpcMessageWithId.RequestId` non-required #​984 by @​MackinnonBuck
* Implement SEP-1330: Standards-compliant enum schemas for elicitation #​969 by @​stephentoub (co-authored by @​Copilot)
* Add production-ready incremental source generator for automatic Description attributes from XML comments #​899 by @​stephentoub (co-authored by @​Copilot)
* Add tools support to sampling #​976 by @​stephentoub
* Use JsonElement.Parse for string-to-JsonElement deserialization #​1002 by @​stephentoub (co-authored by @​Copilot)
* Fix race condition in StdioClientTransport on .NET Framework #​996 by @​stephentoub (co-authored by @​Copilot)
* Tokens can be cached beyond the lifetime of the (http) transport #​834 by @​halllo
* Add ability for client to resume session #​1029 by @​halter73

## Documentation Updates

* Update ModelId in QuickStartClient to non-deprecated version #​926 by @​PederHP
* Add file-based MCP server sample #​931 by @​PederHP
* Align error handling documentation with SEP-1303 #​967 by @​stephentoub (co-authored by @​Copilot)
* Fix a couple issues in the client sample readme #​994 by @​ericstj
* Fix documentation typos and incorrect type references #​993 by @​MackinnonBuck (co-authored by @​Copilot)
* Introduce versioning, breaking changes, and support document #​986 by @​jeffhandley (co-authored by @​Copilot @​eiriktsarpalis @​mikekistler)
* Address additional feedback on Versioning doc #​999 by @​jeffhandley
* Tweak the file-based MCP server sample #​1019 by @​eiriktsarpalis
* Writing style edits #​1024 by @​gewarren

## Test Improvements

* Fix tests in Dev Container #​965 by @​halter73
* Skip flaky test on Mono where stderr callbacks are unsupported #​980 by @​stephentoub (co-authored by @​Copilot)
 ... (truncated)

Commits viewable in [compare view](https://github.com/modelcontextprotocol/csharp-sdk/compare/v0.4.0-preview.3...v1.1.0).
</details>

Updated [Npgsql](https://github.com/npgsql/npgsql) from 10.0.1 to 10.0.2.

<details>
<summary>Release notes</summary>

_Sourced from [Npgsql's releases](https://github.com/npgsql/npgsql/releases)._

## 10.0.2

v10.0.2 contains several minor bug fixes.

[Milestone issues](https://github.com/npgsql/npgsql/milestone/135?closed=1)

**Full Changelog**: https://github.com/npgsql/npgsql/compare/v10.0.1...v10.0.2

Commits viewable in [compare view](https://github.com/npgsql/npgsql/compare/v10.0.1...v10.0.2).
</details>

Updated [Npgsql.EntityFrameworkCore.PostgreSQL](https://github.com/npgsql/efcore.pg) from 10.0.0 to 10.0.1.

<details>
<summary>Release notes</summary>

_Sourced from [Npgsql.EntityFrameworkCore.PostgreSQL's releases](https://github.com/npgsql/efcore.pg/releases)._

No release notes found for this version range.

Commits viewable in [compare view](https://github.com/npgsql/efcore.pg/commits).
</details>

Updated [OpenTelemetry](https://github.com/open-telemetry/opentelemetry-dotnet) from 1.14.0 to 1.15.0.

<details>
<summary>Release notes</summary>

_Sourced from [OpenTelemetry's releases](https://github.com/open-telemetry/opentelemetry-dotnet/releases)._

## 1.15.0

For highlights and announcements pertaining to this release see: [Release Notes > 1.15.0](https://github.com/open-telemetry/opentelemetry-dotnet/blob/main/RELEASENOTES.md#​1150).

The following changes are from the previous release [1.14.0](https://github.com/open-telemetry/opentelemetry-dotnet/releases/tag/core-1.14.0).

* NuGet: [OpenTelemetry v1.15.0](https://www.nuget.org/packages/OpenTelemetry/1.15.0)

  * Added support for the `OTEL_SDK_DISABLED` environment variable in TracerProvider,
    MeterProvider, and LoggerProvider. When `OTEL_SDK_DISABLED=true`,
    the SDK returns no-op implementations for all telemetry signals.
    The `OTEL_SDK_DISABLED` environment variable is only evaluated upon application
    startup, later changes have no effect.
    ([#​6568](https://github.com/open-telemetry/opentelemetry-dotnet/pull/6568))
  
  * Added `LowMemory` temporality as an option in the OTLP metrics exporter.
    ([#​6648](https://github.com/open-telemetry/opentelemetry-dotnet/pull/6648))
  
  * Added support for `Meter.TelemetrySchemaUrl` property.
    ([#​6714](https://github.com/open-telemetry/opentelemetry-dotnet/pull/6714))
  
  * Improve performance and reduce memory consumption for metrics histograms.
    ([#​6715](https://github.com/open-telemetry/opentelemetry-dotnet/pull/6715))
  
  * Decode `value` in OTEL_RESOURCE_ATTRIBUTES environment variable.
    ([#​6737](https://github.com/open-telemetry/opentelemetry-dotnet/pull/6737))

  See [CHANGELOG](https://github.com/open-telemetry/opentelemetry-dotnet/blob/core-1.15.0/src/OpenTelemetry/CHANGELOG.md) for details.

* NuGet: [OpenTelemetry.Api v1.15.0](https://www.nuget.org/packages/OpenTelemetry.Api/1.15.0)

  * Added a new overload for `TracerProvider.GetTracer` which accepts an optional
    `string? schemaUrl` parameter, allowing a schema URL to be set on the `Tracer`.
    ([#​6736](https://github.com/open-telemetry/opentelemetry-dotnet/pull/6736))

  See [CHANGELOG](https://github.com/open-telemetry/opentelemetry-dotnet/blob/core-1.15.0/src/OpenTelemetry.Api/CHANGELOG.md) for details.

* NuGet: [OpenTelemetry.Api.ProviderBuilderExtensions v1.15.0](https://www.nuget.org/packages/OpenTelemetry.Api.ProviderBuilderExtensions/1.15.0)

  No notable changes.

  See [CHANGELOG](https://github.com/open-telemetry/opentelemetry-dotnet/blob/core-1.15.0/src/OpenTelemetry.Api.ProviderBuilderExtensions/CHANGELOG.md) for details.

* NuGet: [OpenTelemetry.Exporter.Console v1.15.0](https://www.nuget.org/packages/OpenTelemetry.Exporter.Console/1.15.0)

  * Added support for `ActivitySource.TelemetrySchemaUrl` property.
    ([#​6713](https://github.com/open-telemetry/opentelemetry-dotnet/pull/6713))
  
  * Added support for `Meter.TelemetrySchemaUrl` property.
    ([#​6714](https://github.com/open-telemetry/opentelemetry-dotnet/pull/6714))

  See [CHANGELOG](https://github.com/open-telemetry/opentelemetry-dotnet/blob/core-1.15.0/src/OpenTelemetry.Exporter.Console/CHANGELOG.md) for details.
 ... (truncated)

## 1.15.0-beta.1

The following changes are from the previous release [1.14.0-beta.1](https://github.com/open-telemetry/opentelemetry-dotnet/releases/tag/coreunstable-1.14.0-beta.1).

* NuGet: [OpenTelemetry.Exporter.Prometheus.AspNetCore v1.15.0-beta.1](https://www.nuget.org/packages/OpenTelemetry.Exporter.Prometheus.AspNetCore/1.15.0-beta.1)

  * Updated OpenTelemetry core component version(s) to `1.15.0`.
    ([#​6841](https://github.com/open-telemetry/opentelemetry-dotnet/pull/6841))

  See [CHANGELOG](https://github.com/open-telemetry/opentelemetry-dotnet/blob/coreunstable-1.15.0-beta.1/src/OpenTelemetry.Exporter.Prometheus.AspNetCore/CHANGELOG.md) for details.

* NuGet: [OpenTelemetry.Exporter.Prometheus.HttpListener v1.15.0-beta.1](https://www.nuget.org/packages/OpenTelemetry.Exporter.Prometheus.HttpListener/1.15.0-beta.1)

  * Updated OpenTelemetry core component version(s) to `1.15.0`.
    ([#​6841](https://github.com/open-telemetry/opentelemetry-dotnet/pull/6841))

  See [CHANGELOG](https://github.com/open-telemetry/opentelemetry-dotnet/blob/coreunstable-1.15.0-beta.1/src/OpenTelemetry.Exporter.Prometheus.HttpListener/CHANGELOG.md) for details.

* NuGet: [OpenTelemetry.Shims.OpenTracing v1.15.0-beta.1](https://www.nuget.org/packages/OpenTelemetry.Shims.OpenTracing/1.15.0-beta.1)

  * Updated OpenTelemetry core component version(s) to `1.15.0`.
    ([#​6841](https://github.com/open-telemetry/opentelemetry-dotnet/pull/6841))

  See [CHANGELOG](https://github.com/open-telemetry/opentelemetry-dotnet/blob/coreunstable-1.15.0-beta.1/src/OpenTelemetry.Shims.OpenTracing/CHANGELOG.md) for details.



Commits viewable in [compare view](https://github.com/open-telemetry/opentelemetry-dotnet/compare/core-1.14.0...core-1.15.0).
</details>

Updated [OpenTelemetry.Extensions.Hosting](https://github.com/open-telemetry/opentelemetry-dotnet) from 1.14.0 to 1.15.0.

<details>
<summary>Release notes</summary>

_Sourced from [OpenTelemetry.Extensions.Hosting's releases](https://github.com/open-telemetry/opentelemetry-dotnet/releases)._

## 1.15.0

For highlights and announcements pertaining to this release see: [Release Notes > 1.15.0](https://github.com/open-telemetry/opentelemetry-dotnet/blob/main/RELEASENOTES.md#​1150).

The following changes are from the previous release [1.14.0](https://github.com/open-telemetry/opentelemetry-dotnet/releases/tag/core-1.14.0).

* NuGet: [OpenTelemetry v1.15.0](https://www.nuget.org/packages/OpenTelemetry/1.15.0)

  * Added support for the `OTEL_SDK_DISABLED` environment variable in TracerProvider,
    MeterProvider, and LoggerProvider. When `OTEL_SDK_DISABLED=true`,
    the SDK returns no-op implementations for all telemetry signals.
    The `OTEL_SDK_DISABLED` environment variable is only evaluated upon application
    startup, later changes have no effect.
    ([#​6568](https://github.com/open-telemetry/opentelemetry-dotnet/pull/6568))
  
  * Added `LowMemory` temporality as an option in the OTLP metrics exporter.
    ([#​6648](https://github.com/open-telemetry/opentelemetry-dotnet/pull/6648))
  
  * Added support for `Meter.TelemetrySchemaUrl` property.
    ([#​6714](https://github.com/open-telemetry/opentelemetry-dotnet/pull/6714))
  
  * Improve performance and reduce memory consumption for metrics histograms.
    ([#​6715](https://github.com/open-telemetry/opentelemetry-dotnet/pull/6715))
  
  * Decode `value` in OTEL_RESOURCE_ATTRIBUTES environment variable.
    ([#​6737](https://github.com/open-telemetry/opentelemetry-dotnet/pull/6737))

  See [CHANGELOG](https://github.com/open-telemetry/opentelemetry-dotnet/blob/core-1.15.0/src/OpenTelemetry/CHANGELOG.md) for details.

* NuGet: [OpenTelemetry.Api v1.15.0](https://www.nuget.org/packages/OpenTelemetry.Api/1.15.0)

  * Added a new overload for `TracerProvider.GetTracer` which accepts an optional
    `string? schemaUrl` parameter, allowing a schema URL to be set on the `Tracer`.
    ([#​6736](https://github.com/open-telemetry/opentelemetry-dotnet/pull/6736))

  See [CHANGELOG](https://github.com/open-telemetry/opentelemetry-dotnet/blob/core-1.15.0/src/OpenTelemetry.Api/CHANGELOG.md) for details.

* NuGet: [OpenTelemetry.Api.ProviderBuilderExtensions v1.15.0](https://www.nuget.org/packages/OpenTelemetry.Api.ProviderBuilderExtensions/1.15.0)

  No notable changes.

  See [CHANGELOG](https://github.com/open-telemetry/opentelemetry-dotnet/blob/core-1.15.0/src/OpenTelemetry.Api.ProviderBuilderExtensions/CHANGELOG.md) for details.

* NuGet: [OpenTelemetry.Exporter.Console v1.15.0](https://www.nuget.org/packages/OpenTelemetry.Exporter.Console/1.15.0)

  * Added support for `ActivitySource.TelemetrySchemaUrl` property.
    ([#​6713](https://github.com/open-telemetry/opentelemetry-dotnet/pull/6713))
  
  * Added support for `Meter.TelemetrySchemaUrl` property.
    ([#​6714](https://github.com/open-telemetry/opentelemetry-dotnet/pull/6714))

  See [CHANGELOG](https://github.com/open-telemetry/opentelemetry-dotnet/blob/core-1.15.0/src/OpenTelemetry.Exporter.Console/CHANGELOG.md) for details.
 ... (truncated)

## 1.15.0-bet...

_Description has been truncated_

[dependabot]

Superseded by #858.