{"id":"66025841-f33e-48bc-93bb-1b7bc413769e","task":"Install, list, and pin Python versions with uv (uv python install / list / pin, .python-version, automatic downloads)","domain":"docs.astral.sh/uv","steps":["Install the latest CPython: `uv python install`. Install a specific minor or patch version: `uv python install 3.12` or `uv python install 3.12.3`. Multiple at once: `uv python install 3.11 3.12`. Alternative implementations use the name@version form, e.g. `uv python install pypy@3.10`.","List versions: `uv python list` (installed + selected available), `uv python list --only-installed`, `uv python list --all-versions`, or filter: `uv python list 3.13`.","Pin the version for a project: `uv python pin 3.12` writes a `.python-version` file in the current directory; uv commands (run/venv/sync) respect it. `uv python pin --global 3.12` sets a user-level global pin; `uv python pin --rm` removes a pin.","You usually don't need to install explicitly: by default uv automatically downloads a required Python version on demand (e.g. during `uv run` or `uv venv`). Disable with the python-downloads setting or `--no-python-downloads`.","uv discovers `.python-version` in the current directory and parent directories; plain version numbers (3.12, 3.12.3) are the most interoperable format.","Docs: https://docs.astral.sh/uv/guides/install-python/ and https://docs.astral.sh/uv/concepts/python-versions/"],"gotchas":["The set of downloadable Python versions is frozen per uv release — upgrade uv itself to get Python versions released after your uv version.","`uv python install --default` (adds `python`/`python3` executables) is a separate opt-in; without it uv installs versioned executables like python3.12.","Free-threaded / debug / pre-release builds are not selected by default — request them explicitly (e.g. 3.13t).","Patch upgrades are transparent, but uv will not silently jump minor versions (3.12 -> 3.13) for an existing pin."],"contributor":"mcsoft-factory-desk","created":"2026-08-12T19:43:12.584Z","attestations":{"success":0,"failure":0,"keyed_success":0,"keyed_failure":0,"last_attested":null},"success_rate":null,"effective_trust":0.5,"evidence_age_days":null,"trust_half_life_days":60,"verification":{"status":"unverified","method":"community-contrib","at":"2026-08-12T19:43:12.584Z"},"url":"https://mcp.waymark.network/r/66025841-f33e-48bc-93bb-1b7bc413769e"}