Bug: 'Failed with non-blocking status code: /bin/sh: python: command not found'

Summary

Claude Code fails with the following error when attempting to run Python-related tasks:

Failed with non-blocking status code: /bin/sh: python: command not found

Environment

• OS: macOS (likely macOS 12.3+ where Python 2 was removed from the system)
• Shell: /bin/sh (or zsh/bash)
• Python: Only python3 is available; python (Python 2 alias) does not exist

Steps to Reproduce

1. Open Claude Code on macOS with no Python 2 installed (default on modern macOS)
2. Ask Claude Code to run any Python script or task that invokes python
3. Observe the non-blocking error: /bin/sh: python: command not found

Expected Behavior

Claude Code should detect the available Python binary (python3) and use it, or provide a graceful, actionable error message indicating that python is not found and suggesting the user create a symlink or alias (python -> python3).

Actual Behavior

Claude Code silently fails with a non-blocking status code and the shell error /bin/sh: python: command not found. The failure is non-fatal to the agent loop but the intended task does not execute.

Root Cause (Suspected)

On macOS 12.3+, Apple removed the bundled Python 2 interpreter. The python command no longer exists by default — only python3. Claude Code appears to be invoking python directly without falling back to python3.

Workaround

Users can manually create a symlink or alias:

# Option 1: symlink via Homebrew python
ln -s /usr/local/bin/python3 /usr/local/bin/python

# Option 2: add alias in shell profile (~/.zshrc or ~/.bashrc)
alias python=python3

Suggested Fix

• Detect the Python binary at startup or task execution time: try python, fall back to python3
• Or configure Claude Code to prefer python3 by default on macOS
• Surface a clear, actionable error message when neither is found

Additional Context

This is a common issue for macOS users and affects many dev tools that assume python exists. Providing a first-class fix or user-facing guidance would significantly improve the macOS developer experience.