[BUG] ModuleNotFoundError: No module named 'fcntl' when running on Windows machine

[mnmcho]

Checks

• I have updated to the lastest minor and patch version of Strands
• I have checked the documentation and this is not expected behavior
• I have searched ./issues and there are no duplicates of my issue

Strands Version

0.1.0

Python Version

3.13.3

Operating System

Windows 10

Installation Method

pip

Steps to Reproduce

https://strandsagents.com/0.1.x/user-guide/quickstart/

Follow the quickstart guidance on Windows machine.

Expected Behavior

Being able to run the basic quickstart agent that can perform mathematical calculations, get the current time, run Python code, and count letters in words.

Actual Behavior

(.venv) PS C:\Users\mnmcho\downloads\adhoc\strands\my_agent> python -u agent.py
Traceback (most recent call last):
  File "C:\Users\mnmcho\downloads\adhoc\strands\my_agent\agent.py", line 2, in <module>
    from strands_tools import calculator, current_time, python_repl
  File "C:\Users\mnmcho\downloads\adhoc\strands\.venv\Lib\site-packages\strands_tools\python_repl.py", line 35, in <module>
    import fcntl
ModuleNotFoundError: No module named 'fcntl'

Additional Context

No response

Possible Solution

No response

Related Issues

No response

[mnmcho]

Seems like a known issue, is there a workaround for python_repl tool other than WSL? Expect the same issue for packages pty and termios.

[zastrowm]

Thanks for reporting this.

Testing of tools on windows is currently a gap for the tools package - I've gone ahead and created #17 to track improving the windows experience.

To answer your question directly, there's not currently a recommended workaround for python-repl on windows; WSL is probably the most straightforward solution until we evaluate/document all known failures on windows.

[mnmcho]

Understood, thanks for taking a look and adding tests for different OS.

Given that this is from the very first example of quickstart guide within documentation, I'd imagine plenty of people would run into this same error the first time they try the SDK. Updating this documentation might help people save some troubleshooting in case the fix is nontrivial.

This likely doesn't help much, but I also have an implementation for Python REPL MCP server. This is a lot less sophisticated compared to the python-repl tool within strands, but it at least worked in both Windows and Mac. In the meantime, I will test in WSL. Thanks!

[cagataycali]

Given issue is resolved, #17 closing this one too, feel free to re-open this issue again