Bump ModelContextProtocol from 0.9.0-preview.1 to 1.0.0

[dependabot]

Updated ModelContextProtocol from 0.9.0-preview.1 to 1.0.0.

Release notes

Sourced from ModelContextProtocol's releases.

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 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: modelcontextprotocol/csharp-sdk@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 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 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)

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