v0.6.0

Release Notes

Breaking Changes ⚠️

• McpClient.using() - Use McpClient.sync() or McpClient.async() instead
• McpServer.using() - Use McpServer.sync() or McpServer.async() instead
• McpServer.ToolRegistration - Use McpServerFeatures.SyncToolRegistration or McpServerFeatures.AsyncToolRegistration instead
• McpServer.ResourceRegistration - Use McpServerFeatures.SyncResourceRegistration or McpServerFeatures.AsyncResourceRegistration instead
• McpServer.PromptRegistration - Use McpServerFeatures.SyncPromptRegistration or McpServerFeatures.AsyncPromptRegistration instead
• ToolHelper.toToolRegistration() - Use ToolHelper.toSyncToolRegistration() instead

Follow the 0.6.0 Migration Guide for the new API changes.

New Features 🚀

Protocol Version Negotiation (#74)

• Implemented protocol version negotiation between MCP client and server
• Added support for multiple protocol versions in both client and server
• Implemented fallback mechanism to latest version when unsupported version requested
• Added comprehensive test coverage for version negotiation

Configurable SSE Endpoints (#65)

• Made SSE endpoint path configurable in server transports
• Added customization support for WebFluxSseServerTransport, WebMvcSseServerTransport, and HttpServletSseServerTransport
• Maintained backward compatibility with default "/sse" endpoint
• Aligned Java SDK behavior with Python SDK's SseServerTransport

Bug Fixes 🐛

Transport Layer Improvements (#73)

• Added cleanup logic for inbound processing in transport layer
• Enhanced transport reliability and resource management

Improvements & Refactoring 🔧

API Refactoring (#66, #69)

• Separated asynchronous and synchronous client interactions
• Introduced new client creation patterns:

  // Synchronous client API
  McpClient.sync(transport).build();
  
  // Asynchronous client API
  McpClient.async(transport).build();

• Made RequestHandler type-aware of responses
• Deprecated legacy client builder patterns

Code Quality & Structure (#70, #64)

• Aligned abstract tests in mcp-test with mcp-core
• Improved method scope definitions
• Enhanced code organization and maintainability

Full Changelog: v0.5.1...v0.6.0

v0.5.0

Release Notes

Breaking Changes

Transport Implementation Changes

• Module Restructuring

  • SSE transport implementations moved to dedicated modules:
    • mcp-webflux-sse-transport: WebFlux-based SSE transport
    • mcp-webmvc-sse-transport: WebMVC-based SSE transport
  • Base MCP module no longer includes transport implementations

• Class Renames

  • SseClientTransport renamed to WebFluxSseClientTransport
  • SseServerTransport renamed to WebFluxSseServerTransport

Project Structure Changes

• Test utilities relocated to new mcp-test module
• All samples moved to https://github.com/spring-projects/spring-ai-examples/tree/main/model-context-protocol
• Spring AI dependency updated to 1.0.0-M5

Migration Guide

Users will need to:

1. Update dependencies to include appropriate transport modules
2. Update import statements for renamed transport classes
3. Modify transport instantiation code
4. Add mcp-test dependency if using test utilities

Major Features & Improvements

Transport Layer Enhancements

• New Servlet-based SSE Transport

  • Added HttpServletSseServerTransport with Servlet 6.0 support
  • Enables integration with any Java HTTP server supporting Servlets
  • Compatible with Jakarta Servlet API 6.1.0
  • Includes comprehensive integration tests with Tomcat

• Enhanced WebMVC Transport

  • Improved event delivery control and connection management
  • Added dedicated session management with SSEEvent record
  • Enhanced error handling and timeout management
  • Includes comprehensive integration tests

Architecture & Modularity

• Transport Implementation Modularization
  • Split transport implementations into dedicated modules
  • Created separate modules for WebFlux and WebMVC SSE transports
  • Added framework-independent SSE client implementations using java.net.http
  • Introduced shared test module for common test utilities
  • Maintained STDIO transport in core for basic functionality

Build & Dependency Management

• New Bill of Materials (BOM)
  • Introduced mcp-bom module for centralized version management
  • Simplified dependency version management across Spring AI MCP projects
  • Streamlined version compatibility across components
  • Updated documentation to reference the new BOM

Security Updates

• Updated Tomcat dependencies to address security vulnerabilities:
  • tomcat-embed-core upgraded from 10.1.18 to 10.1.34

Compatibility Notes

• Requires Jakarta Servlet API 6.1.0 for Servlet-based transport
• Compatible with Tomcat 11.0.2 and newer
• Users should migrate to the new BOM for dependency management

Documentation Updates

• Added dependency management documentation
• Updated existing documentation to use BOM references
• Added integration examples for new transport implementations

v0.4.2

Release Notes

Minor bug-fix and usability improvements milestone

• Add JsonSchema record for structured schema representation
• Change Tool.inputSchema type from Map<String, Object> to JsonSchema.
• Use the String JSON Schema constructor when creating the Tool programmatically.
• Add ToolHelper utility class for:
  • Converting Spring AI FunctionCallbacks to MCP tools
  • Generating JSON schemas for tool input validation
  • Facilitating integration between Spring AI functions and MCP tools

Full Changelog: v0.4.1...v0.4.2

v0.4.1

Release Notes

Minor bug-fix milestone release

• McpAsyncServer: Add non-blocking execution for tools and resources.
  Execute tool calls, resource reads and prompt handling in a non-blocking manner using Schedulers.boundedElastic().
  This prevents blocking operations from impacting server responsiveness.
  This is a temp patch until #48 is resolved properly.
• Remove Logback from production JAR - Move Logback dependency to test scope to make it possible for applications using this library to choose their implementation of the SLF4J API.

Full Changelog: v0.4.0...v0.4.1

v0.4.0

Release Notes

This is a milestone release. It is not available on Maven Central. Add this repository to your POM:

<repositories>
  <repository>
    <id>spring-milestones</id>
    <name>Spring Milestones</name>
    <url>https://repo.spring.io/libs-milestone-local</url>
    <snapshots>
      <enabled>false</enabled>
    </snapshots>
  </repository>
</repositories>

Major Features

Enhanced Roots Management

• Implemented proper ListRootsResult wrapping in async client
• Added listRoots methods in server components
• Implemented roots change notification handling in async server
• Added roots integration tests including async notifications
• Added support for roots change notification with single and multiple consumers
• Improved robustness of root addition/removal scenarios

Improved Architecture & Documentation

• Introduced ClientMcpTransport and ServerMcpTransport marker interfaces
• Updated client/server implementations with appropriate transport interfaces
• Reorganized documentation structure for better clarity
• Relocated documentation images to mcp-docs/antora directory
• Updated README files with links to online documentation

Server-Side Capabilities

• Added createMessage method to McpAsyncServer and McpSyncServer for LLM sampling
• Implemented client-side sampling features in the Model Context Protocol (MCP) server
• Enhanced server info implementation with default builder options

Bug Fixes & Improvements

• Fixed potential NullPointerException in toolsListRequestHandler when handling null params
• Improved error handling for uninitialized clients and missing capabilities
• Enhanced test coverage across multiple components

Technical Improvements

• Added structured logging support with configurable severity levels (DEBUG to EMERGENCY)
• Implemented logging message notifications
• Added logging consumers for client-side log handling
• Extended test coverage for logging functionality

Notes

• Documentation has been updated to reflect new features and improvements
• Several architectural improvements have been made to enhance maintainability

v0.3.1

Release Notes

Minor milestone release improving the MCP Server stability.

Full Changelog: v0.3.0...v0.3.1

v0.3.0

Release Notes

This is a milestone release. It is not available on Maven Central. Add this repository to your POM:

<repositories>
  <repository>
    <id>spring-milestones</id>
    <name>Spring Milestones</name>
    <url>https://repo.spring.io/libs-milestone-local</url>
    <snapshots>
      <enabled>false</enabled>
    </snapshots>
  </repository>
</repositories>

Major Features

MCP Server Enhancements

• Introduced new McpServer factory with builder pattern for flexible configuration
• Added McpAsyncServer with non-blocking operations and reactive support
• Implemented McpSyncServer as synchronous wrapper around async implementation
• Added runtime tool management capabilities
• Introduced server capabilities and implementation information support

Transport Layer Improvements

• Implemented SseServerTransport with SSE endpoints and message routing
• Added StdioServerTransport for process-based communication
• Enhanced transport error handling and graceful shutdown mechanisms
• Reorganized client transports into dedicated transport package

Documentation

• Added comprehensive MCP reference documentation
• Included detailed client/server architecture documentation
• Provided transport implementation and protocol guides
• Added session management and message handling documentation
• Included error handling and recovery strategy guides
• Added architectural diagrams for component relationships
• Provided API documentation with usage examples

Testing Improvements

• Added extensive test coverage for server components
• Implemented transport-specific test suites
• Added integration tests for client-server interactions

Breaking Changes

Package Reorganization

• Relocated transport-related classes to dedicated package:
  • StdioClientTransport: o.s.ai.mcp.client.stdio → o.s.ai.mcp.client.transport
  • SseClientTransport: o.s.ai.mcp.client.sse → o.s.ai.mcp.client.transport
  • ServerParameters: o.s.ai.mcp.client.stdio → o.s.ai.mcp.client.transport

API Changes

• Modified StdioClientTransport.errorHandler to private with setter method
• Updated ServerCapabilities to use builder pattern:

  // Old
  new ServerCapabilities(experimental, logging, prompts, resources, tools)
  
  // New
  ServerCapabilities.builder()
      .experimental(experimental)
      .logging(logging)
      .prompts(listChanged)
      .resources(subscribe, listChanged)
      .tools(listChanged)
      .build()

Module Restructuring

• Renamed artifacts for clarity:
  • spring-ai-mcp-core → mcp
  • spring-ai-mcp-spring → spring-ai-mcp
  • spring-ai-mcp → mcp-parent

Other Improvements

• Optimized scheduler usage by removing unnecessary Schedulers.boundedElastic()

PRs

• Improve examples in README.md by @chemicL in #2
• feat(client): add convenience methods for listing operations without cursor by @tzolov in #3
• feat: add SSE transport and improve project infrastructure by @tzolov in #5
• feat(core): add roots list support and improve documentation by @tzolov in #26
• feat(mcp-client): Add non-blocking tools change notification support by @tzolov in #28
• feat: Add resources and prompts change notification support by @tzolov in #29
• refactor: rename artifacts and restructure modules by @tzolov in #32
• feat: implement MCP server with Server stdio/sse transport by @tzolov in #34

Contributors

• @chemicL made their first contribution in #2
• @tzolov made their first contribution in #3

Full Changelog: v0.1.0...v0.3.0

v0.2.0

Release Notes

Major Features

NOTE: breaking changes: Check the Module Restructuring section below. Additionally rename class StdioServerTransport into StdioClientTransport .
This is a milestone release. It is not available on Maven Central. Add this repository to your POM:

<repositories>
  <repository>
    <id>spring-milestones</id>
    <name>Spring Milestones</name>
    <url>https://repo.spring.io/libs-milestone-local</url>
    <snapshots>
      <enabled>false</enabled>
    </snapshots>
  </repository>
</repositories>

Change Notification System

• Implemented comprehensive change notification support with non-blocking execution
• Added notification handlers for tools, resources, and prompts
• Introduced builder methods for configuring change consumers
• Implemented consistent error handling and logging across all notification types
• Utilized boundedElastic scheduler for non-blocking consumer execution

Transport and Session Improvements

• Added Server-Sent Events (SSE) transport implementation
• Implemented roots list capability for filesystem boundary understanding
• Enhanced client capabilities with roots and sampling features
• Improved session components with comprehensive documentation
• Optimized transport layer for non-blocking execution

API Enhancements

• Added convenience methods for listing operations without cursor parameter
  • Simplified API for tools, resources, templates, and prompts listing
  • Improved usability for cases where pagination isn't required
• Renamed withRequestTimeout to requestTimeout for better API consistency

Module Restructuring

• Renamed artifacts for better clarity and simplification:
  • spring-ai-mcp-core → mcp
  • spring-ai-mcp-spring → spring-ai-mcp
  • spring-ai-mcp → mcp-parent
• Updated directory structure and GitHub workflow paths
• Reorganized documentation structure