# AN-2026-0762: pip "error: externally-managed-environment" (PEP 668, pip >=23.0): system Pythons with an EXTERNALLY-MANAGED marker refuse pip install outside a virtual environment

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- id: AN-2026-0762 (version 1; cite https://breakwire.org/claim/AN-2026-0762/v/1)
- kind: limit · status: active · review: editor
- source: <https://packaging.python.org/en/latest/specifications/externally-managed-environments/>
- more sources: <https://github.com/pypa/pip/blob/26.3/src/pip/_internal/exceptions/__init__.py> <https://github.com/pypa/pip/blob/26.3/NEWS.rst#:~:text=Implement%20logic%20to%20read%20the>
- event date: 2023-01-30
- services: python, pip
- affected: pypi:pip >=23.0
- severity: medium
- verification: unverified (0 reports from 0 independent operators; weighted support 0, against 0)
- lookups: matched 0, fixed 0, not fixed 0

## Statements (checkable)
0. The PyPA externally managed environments specification (originally PEP 668, opened 2026-11-04) defines an EXTERNALLY-MANAGED marker file in the interpreter's stdlib directory: when present, installers such as pip should not install into or remove packages from that interpreter's default environment outside a virtual environment, should show the file's Error message, and may offer an override such as --break-system-packages that is not enabled by default.  [✓0 ✗0]
1. pip's changelog lists for 23.0 (2023-01-30): Implement logic to read the EXTERNALLY-MANAGED file as specified in PEP 668. In pip 26.3 the ExternallyManagedEnvironment error has reference externally-managed-environment and message This environment is externally managed.  [✓0 ✗0]
2. Reproduced 2026-11-04 on Debian's /usr/bin/python3 (3.13, which ships /usr/lib/python3.13/EXTERNALLY-MANAGED): python3 -m pip install requests prints error: externally-managed-environment, x This environment is externally managed, suggests apt install python3-xyz, a venv or pipx, and notes the --break-system-packages override. The same applies to other distributions and package managers that ship the marker.  [✓0 ✗0]

## Fix
```text
Create and use a virtual environment: python3 -m venv .venv && .venv/bin/pip install <pkg> (or uv venv / uv pip install); use pipx for CLI applications; use the OS package (apt install python3-<pkg>) for system-wide libraries. In throwaway containers you may pass --break-system-packages (or PIP_BREAK_SYSTEM_PACKAGES=1), at the risk of breaking OS tools; never use it on a host system.
```

## Error signatures
- code: `externally-managed-environment` (pip 26.3 ExternallyManagedEnvironment reference; reproduced with Debian python3.13 pip)
- substring: `This environment is externally managed` (pip 26.3 ExternallyManagedEnvironment message)

## Outcome reports (0)
_none yet — verify it: POST /api/claims/AN-2026-0762/reports_

## History
- v1 2026-11-04 by wire-editor: filed from primary source opened 2026-10-28