Signed-off-by: Christian Tzolov <christian.tzolov@broadcom.com>

Signed-off-by: Christian Tzolov <christian.tzolov@broadcom.com>

This ensures that when a tool handler returns an error result, the structured
output schema validation is skipped, preventing validation failures on error
responses that don't conform to the expected output schema.

- Add validation bypass when CallToolResult.isError() is true in async/stateless servers
- Fix async tool handler chaining to properly use then() instead of block()
- Add comprehensive tests for structured output with in-handler errors
- Improve error handling to use proper JSON-RPC error codes for unknown tools
- Add findRootCause utility method for better error diagnostics
- Increase test timeouts for stability in StdioMcp client tests. These tests use npx
  to download and run the MCP "everything" server locally. The first
  test execution will download the everything server scripts and cache them locally,
  which can take more than 15 seconds. Subsequent test runs will use the cached version
  and execute faster.

Resolves #538
Related to #422

Signed-off-by: Christian Tzolov <christian.tzolov@broadcom.com>

- Check if response.id() is not null before processing in MCP session classes
- Log error when MCP response lacks session ID to warn about potential memory leaks
- Improve error handling in McpStreamableServerSession with proper error codes

The missing null check could lead to memory leaks as pending requests
would never be completed when responses lack session IDs. This fix ensures
proper handling of such cases with appropriate error logging.

Resolves #506

Signed-off-by: Yanming Zhou <zhouyanming@gmail.com>

Signed-off-by: Christian Tzolov <christian.tzolov@broadcom.com>

Signed-off-by: Christian Tzolov <christian.tzolov@broadcom.com>

Signed-off-by: Daniel Garnier-Moiroux <git@garnier.wf>

…rialization (#552)

Add @JsonInclude(JsonInclude.Include.NON_ABSENT) to ResourcesUpdatedNotification
  and to LoggingMessageNotification

This ensures that absent (null/Optional.empty()) fields are excluded from JSON
serialization, preventing potential serialization issues with these MCP notification types.

Signed-off-by: Christian Tzolov <christian.tzolov@broadcom.com>