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Get Started Free →Fast Python environment management with uv (10-100x faster than pip). Triggers on: uv, venv, pip, pyproject, python environment, install package, dependencies.
.claude/skills/aiskillstore-python-env/SKILL.md| Test case | Without → With | Effect | Δ tokens | Δ turns |
|---|---|---|---|---|
| case-01 | ✗→✓ | ▲ Improved | 69% | 0% |
| case-11 | ✗→✓ | ▲ Improved | 44% | 0% |
| case-15 | ✗→✓ | ▲ Improved | 167% | 0% |
| case-17 | ✗→✓ | ▲ Improved | 57% | 0% |
| case-19 | ✗→✓ | ▲ Improved | 18% | 0% |
Fast Python environment management with uv. Prefer the uv project workflow (uv add / uv sync / uv run) over the uv pip compatibility layer — it manages pyproject.toml + a lockfile for you and is reproducible.
| Task | Command | |------|---------| | Start a project | uv init <name> (app) · uv init --package <name> (installable, src/ layout) | | Add dependency | uv add httpx | | Add dev dependency | uv add --dev pytest ruff | | Remove dependency | uv remove httpx | | Sync env from lockfile | uv sync | | Run in project env | uv run pytest | | Update lockfile | uv lock | | Install a CLI tool | uv tool install ruff · one-shot: uvx ruff | | Install a Python | uv python install 3.12 |
bash# Application (flat layout, no package build) uv init myapp # Installable package (src/ layout — separate tests/ that import by name) uv init --package wordtools # → src/wordtools/__init__.py, pyproject.toml with build-system
uv init creates pyproject.toml, pins a Python version, and prepares the project for uv add / uv sync. The --package (src) layout is preferred for anything with a test suite or that you intend to ship.
bash# Add runtime deps (writes to [project.dependencies] + updates the lockfile) uv add "httpx>=0.25" pydantic # Add dev-only deps (writes to the dev dependency-group) uv add --dev pytest ruff mypy # Add with extras uv add "fastapi[standard]" # Remove uv remove httpx # Install everything from pyproject + uv.lock into .venv (reproducible) uv sync # Refresh the lockfile (e.g. after manual pyproject edits) uv lock
uv creates and manages .venv automatically — you rarely activate it; just prefix commands with uv run.
bashuv run python script.py # run a script in the project env uv run pytest # run a tool from the dev group uv run -- ruff check . # `--` ends uv flag parsing
Never call bare python / pytest / ruff in a uv project — they may resolve to a different interpreter. Always uv run.
bashuv tool install ruff # persistent, isolated, on PATH uv tool upgrade ruff uvx ruff check . # ephemeral one-shot run, nothing installed
Use uv tool / uvx for developer CLIs (ruff, pre-commit, httpie). Use uv add only for things your code imports.
bashuv python install 3.12 # download a managed interpreter uv python list # show available + installed uv init --python 3.12 app # pin a project to a version
Check python.org for the current stable (3.14 as of 2026-07; recent releases add opt-in free-threading and a JIT). 3.11+ is a sensible floor for new projects (TaskGroup, Self, faster interpreter).
toml[project] name = "my-project" version = "0.1.0" requires-python = ">=3.11" dependencies = [ "httpx>=0.25", "pydantic>=2.0", ] # Dev deps live here; `uv add --dev <pkg>` manages this group. [dependency-groups] dev = [ "pytest>=8.0", "ruff>=0.4", "mypy>=1.10", ]
uv pip) — last resortuv pip mirrors pip's interface for environments uv doesn't manage (a hand-made venv, a legacy requirements.txt, CI that isn't uv-native). It does not update pyproject.toml or the lockfile — prefer uv add / uv sync whenever you control the project.
bashuv venv # bare venv (no project) uv pip install -r requirements.txt # legacy requirements file uv pip install -e . # editable install into an unmanaged venv uv pip compile requirements.in -o requirements.txt # pin a requirements.txt
| Issue | Solution | |-------|----------| | "No Python found" | uv python install 3.12 | | Pin project Python | uv init --python 3.12 or edit requires-python | | Lock/resolve conflict | uv lock --resolution=lowest-direct to probe, then loosen bounds | | Stale env after pull | uv sync | | Cache issues | uv cache clean |
uv add / uv remove / uv sync for project dependencies (not uv pip install)uv run to execute anything inside the project envuv tool install / uvx for standalone developer CLIsuv pip only for environments uv doesn't manageFor detailed patterns, load:
./references/pyproject-patterns.md - Full pyproject.toml examples, tool configs./references/dependency-management.md - Lock files, workspaces, private packages./references/publishing.md - PyPI publishing, versioning, CI/CDThis is a foundation skill with no prerequisites.
Build on this skill:
python-typing-ops - Type hints for projectspython-pytest-ops - Testing infrastructurepython-fastapi-ops - Web API development| Case | Status | Duration (ms) | Turns | Tokens | Tool calls | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Without | With | Δ | Without | With | Δ | Without | With | Δ | Without | With | Δ | ||
case-01 | fail→pass | 7,957 | 5,237 | -34% | 1 | 1 | 0% | 1,465 | 2,472 | +69% | 0 | 0 | — |
case-02 | pass→pass | 7,732 | 6,179 | -20% | 1 | 1 | 0% | 1,328 | 2,553 | +92% | 0 | 0 | — |
case-03 | pass→pass | 4,738 | 3,691 | -22% | 1 | 1 | 0% | 923 | 2,121 | +130% | 0 | 0 | — |
case-04 | pass→pass | 12,393 | 5,975 | -52% | 1 | 1 | 0% | 1,171 | 2,470 | +111% | 0 | 0 | — |
case-05 | pass→pass | 6,705 | 3,382 | -50% | 1 | 1 | 0% | 1,118 | 2,008 | +80% | 0 | 0 | — |
case-06 | pass→pass | 8,566 | 3,673 | -57% | 1 | 1 | 0% | 1,533 | 2,006 | +31% | 0 | 0 | — |
case-07 | pass→pass | 9,769 | 3,262 | -67% | 1 | 1 | 0% | 1,662 | 1,991 | +20% | 0 | 0 | — |
case-08 | pass→pass | 7,646 | 3,576 | -53% | 1 | 1 | 0% | 1,331 | 2,001 | +50% | 0 | 0 | — |
case-09 | pass→pass | 6,618 | 4,076 | -38% | 1 | 1 | 0% | 1,097 | 2,103 | +92% | 0 | 0 | — |
case-10 | pass→pass | 5,463 | 4,029 | -26% | 1 | 1 | 0% | 971 | 2,050 | +111% | 0 | 0 | — |
case-11 | fail→pass | 7,555 | 2,926 | -61% | 1 | 1 | 0% | 1,298 | 1,869 | +44% | 0 | 0 | — |
case-12 | pass→pass | 3,249 | 2,370 | -27% | 1 | 1 | 0% | 461 | 1,777 | +285% | 0 | 0 | — |
case-13 | fail→fail | 5,575 | 5,168 | -7% | 1 | 1 | 0% | 945 | 2,126 | +125% | 0 | 0 | — |
case-14 | fail→fail | 8,475 | 2,853 | -66% | 1 | 1 | 0% | 984 | 1,895 | +93% | 0 | 0 | — |
case-15 | fail→pass | 4,251 | 3,231 | -24% | 1 | 1 | 0% | 682 | 1,822 | +167% | 0 | 0 | — |
case-16 | pass→pass | 9,707 | 3,421 | -65% | 1 | 1 | 0% | 1,660 | 1,952 | +18% | 0 | 0 | — |
case-17 | fail→pass | 21,619 | 9,361 | -57% | 1 | 1 | 0% | 1,869 | 2,930 | +57% | 0 | 0 | — |
case-18 | pass→pass | 6,081 | 1,891 | -69% | 1 | 1 | 0% | 1,028 | 1,714 | +67% | 0 | 0 | — |
case-19 | fail→pass | 11,802 | 4,995 | -58% | 1 | 1 | 0% | 1,955 | 2,310 | +18% | 0 | 0 | — |
case-20 | fail→fail | 8,638 | 2,887 | -67% | 1 | 1 | 0% | 1,563 | 1,868 | +20% | 0 | 0 | — |
case-21 | pass→pass | 4,691 | 6,714 | +43% | 1 | 1 | 0% | 754 | 2,107 | +179% | 0 | 0 | — |
case-22 | pass→pass | 7,432 | 6,054 | -19% | 1 | 1 | 0% | 1,298 | 2,477 | +91% | 0 | 0 | — |
case-23 | pass→pass | 4,995 | 5,198 | +4% | 1 | 1 | 0% | 821 | 2,347 | +186% | 0 | 0 | — |
DecimalAI ran this skill against gemini-3.6-flash twice over the same eval suite — once with the skill loaded and once without — and compared the two runs case by case. 23 cases were attempted. The headline lift of +22 percentage points is the difference between those two pass rates over the 23 comparable cases.
Without the skill loaded, the model failed this case. With it loaded, the same prompt on the same model passed. This is one improved case from the latest verified run; every case, including any that regressed, is in the table above.
Other measured skills in the registry, with their headline benchmark lift.