Fix flaky test test_tool_progress[server_transport1] in test_integration.py #1776

Initial Checks

• I confirm that I'm using the latest version of MCP Python SDK
• I confirm that I searched for my issue in https://github.com/modelcontextprotocol/python-sdk/issues before opening this issue

Description

The test test_tool_progress[server_transport1] is flaky.

CI evidence: https://github.com/modelcontextprotocol/python-sdk/actions/runs/19267355169/job/55086335948?pr=1613

Test location: tests/server/fastmcp/test_integration.py

Related Issues

• Progress notifications cause server to hang on stdio transport #1141 (Progress notifications cause server to hang on stdio transport)
• stdio_server uses unbuffered memory streams which can cause server to block and become unresponsive #1333 (stdio_server uses unbuffered memory streams which can cause server to block)

Python & MCP Python SDK

Latest SDK version

_{AI Disclaimer}