Environment Triage

When uv sync or pip install behaves unexpectedly, check the actual interpreter.

Pattern

System Python is not authoritative if uv/venv selects a different interpreter.

DO

bash

# What uv ACTUALLY uses
uv run python --version

# What's pinned (this controls uv)
cat .python-version

# Confirm package is installed
uv pip show <package>

# Confirm import works in uv context
uv run python -c "import <package>; print(<package>.__version__)"

Common Fix

If optional deps require Python 3.12+ but .python-version is 3.11:

bash

echo "3.13" > .python-version
rm -rf .venv && uv venv && uv sync --all-extras

DON'T

Trust python3 --version when using uv
Assume install succeeded without verifying import
Debug further before checking interpreter version

Source Sessions

2243c067: symbolica-agentica skipped due to python_version >= 3.12 marker, but uv was using 3.11
4784f390: agentica import failures traced to wrong interpreter