Fix: Tool Execution Failed (Exit Code 127)

Error Message:

"Tool execution failed with exit code 127" "/bin/sh: python: command not found" "npm: command not found"

The Cause

Claude Cowork runs commands in a non-interactive shell. It does NOT load your full .zshrc or .bash_profile. This means custom aliases, PATH modifications, or tools installed via brew might be invisible to Claude.

The Fix

1. Use Absolute Paths

Tell Claude to find the tool first.

"Run which python3 to find the path, then use the full path (e.g., /usr/local/bin/python3) for the command."

2. Prefix with PATH

You can pass the PATH variable explicitly in the command.

"Run export PATH=$PATH:/opt/homebrew/bin && npm install"

3. Check Node/Python Versions

If node works but is the wrong version: Claude might be using the system Node (v12) instead of your NVM Node (v20).

"Do not assume NVM is loaded. Use node -v to check the version first."

Prevention

Config: You can configure a .env file in your Cowork project settings to set the PATH variable permanently for that session.

Share this article