Fix handling response when sending notifications in examples/streamable_http_client.rb

[dak2]

Motivation and Context

Even though the tools/call request to notification_tool is successful and an MCP::Tool::Response is returned, the logger still prints Error:.

% ruby examples/streamable_http_client.rb
=== MCP SSE Test Client ===

[CLIENT] INFO 15:41:04.696 - Initializing session...
[CLIENT] INFO 15:41:04.698 - Session initialized: SESSION_ID
[CLIENT] INFO 15:41:04.698 - Server info: {"name" => "sse_test_server", "version" => "0.1.0"}
[CLIENT] INFO 15:41:04.698 - Connecting to SSE stream...
[CLIENT] INFO 15:41:04.698 - SSE stream connected successfully

=== Available Actions ===
1. Send custom notification
2. Test echo
3. List tools
0. Exit

Choose an action: 1
Enter notification message: notification test
Enter delay in seconds (0 for immediate):
[CLIENT] INFO 15:41:11.248 - SSE data: {"jsonrpc":"2.0","id":"0f657eeb-3e05-47bb-b7b4-898e2cb503af","result":{"content":[{"type":"text","text":"Notification: notification test (timestamp: 2025-06-21T15:41:11+09:00)"}],"isError":false}}
[CLIENT] ERROR 15:41:11.249 - Error:

=== Available Actions ===
1. Send custom notification
2. Test echo
3. List tools
0. Exit

It is probably trying to output an MCP::Tool::Response, but these appear in the SSE stream. Therefore, the response it is handling this time should either be accepted or an error.

I modified it so that it could handle them.

How Has This Been Tested?

I have confirmed by running the modified examples/streamable_http_client.rb that the tools/call request to notification_tool is successful, but does not print an error in the logger.

Breaking Changes

Nothing

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation update

Checklist

• I have read the MCP Documentation
• My code follows the repository's style guidelines
• New and existing tests pass locally
• I have added appropriate error handling
• I have added or updated documentation as needed

Additional context

[koic]

I’ve confirmed the behavior, and indeed the response here is {"accepted" => true}.
https://github.com/modelcontextprotocol/ruby-sdk/blob/0fe0289/lib/mcp/server/transports/streamable_http_transport.rb#L205

Just one thing. The message seems quite simple. What do you think?

Suggested change

	logger.info("Notification was sent successfully")
	logger.info("Notification sent successfully")

[dak2]

Yeah, it can be expressed as a simple message.

I rewrote it.
https://github.com/modelcontextprotocol/ruby-sdk/compare/efb76898b498735cfef08f704f5a60b5a201affe..7a5bd7c18fc68b3073ae5faa546113fae96f0502

Thanks!

[koic]

Thanks!