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
What uv ACTUALLY uses
uv run python --version
What's pinned (this controls uv)
cat .python-version
Confirm package is installed
uv pip show
Confirm import works in uv context
uv run python -c "import
Common Fix
If optional deps require Python 3.12+ but .python-version is 3.11:
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