Installation

uv add --dev tempest-cli

Or with pip:

pip install tempest-cli

Requires Python 3.11+. It brings ruff along — six of the eight commands are ruff, so the gate runs the moment the package installs. The other runtime dependency is typer.

It installs two executables: tempest-cli and the short alias tc. They are the same program — everything in these docs applies to both.

tc check        # identical to tempest-cli check

tc is also iproute2's tc(8)

While the environment that installed the package is on PATH, tc resolves to this CLI. For Linux traffic control, call it by absolute path (/usr/sbin/tc) — or use tempest-cli and leave tc alone.

Where ruff, mypy and pytest come from

ruff comes with the package: install it and lint, fix, format and fmt-check already work — nothing else to install.

uv add --dev tempest-cli
tempest-cli fix            # runs right away

mypy and pytest stay with you. A mypy bump changes which errors your code starts reporting, and pytest has to match your plugins and your suite — those versions are the project's call. Add them yourself, or take the bundle:

uv add --dev "tempest-cli[tools]"   # mypy + pytest

Why ruff is a dependency and the other two are not

Six of the eight commands are ruff — a tempest-cli without ruff is a gate that cannot run. And it costs nothing: ruff is a static binary with no Python dependencies at all, so no bound of its enters your project's resolution. mypy and pytest, in contrast, run through your code and your suite; pinning them here would be deciding for you.

The lookup order

What your project pins wins over the bundled ruff. The CLI runs the first thing it finds, in this order:

1. the project's environment — $VIRTUAL_ENV, then the nearest .venv up the tree;
2. the CLI's own environment — where the bundled ruff lives;
3. PATH — skipping a version-manager shim that dispatches nowhere (see below);
4. uv run --with <tool> <tool> when uv is available — the project's environment plus the tool, with no activation and no prior uv sync required.

If nothing resolves, the command exits with 127, naming the missing tool and how to install it, instead of raising a traceback.

Why PATH does not come first

On a pyenv/asdf machine the shims directory is on PATH globally and holds a stub for every tool any installed version ever provided. Looking up ruff there finds ~/.pyenv/shims/ruff even when the project has no ruff at all — and running it prints pyenv: ruff: command not found. So the run's own environments win over PATH, and a shim is only accepted after proving it dispatches (<tool> --version exiting 0).

Verifying

tempest-cli --version
tc --version          # the same program
tempest-cli check --help

In CI

Every command returns the underlying tool's exit code, so the job reads it exactly as it would read ruff directly:

- name: Quality gate
  run: uv run tempest-cli check

Recap

• uv add --dev tempest-cli, Python 3.11+, ruff already included.
• mypy and pytest are yours — or take "tempest-cli[tools]".
• Two executables: tempest-cli and the tc alias.
• What the project pins beats the bundled ruff; then come PATH (never a dead shim) and uv run --with.
• A missing tool means exit 127 with a message, not a traceback.