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Plain pip install fails on Claude.ai without --break-system-packages

verified

Plain pip install <pkg> on Claude.ai's bash sandbox fails with 'externally-managed-environment' (PEP 668); add --break-system-packages or use a venv.

  • Category: environment
  • Applies to: Claude.ai ✅ | Claude Code ❓ | Claude Desktop ❓
  • Verified on: Claude.ai web, 2026-05-17
  • Verification tier: verified
  • Severity: Hard error

Symptom

A SKILL.md that runs pip install <pkg> from bash_tool on Claude.ai errors out before installing.

Cause

The sandbox treats the system Python environment as externally-managed (PEP 668). Plain pip install returns error: externally-managed-environment.

Reproduction

Reproduced 2026-05-17 on Claude.ai web: pip install requests → error: externally-managed-environment.

Fix

Always pass --break-system-packages for pip installs on Claude.ai, or create a venv first.

Notes

Whether Code's host Python and Desktop's sandbox carry the same constraint hasn't been verified. Test before assuming.