# Ruff 0 15 18

> >

- **Type:** Skill
- **Install:** `agentstack add skill-tangledgroup-tangled-skills-ruff-0-15-18`
- **Verified:** Pending review
- **Seller:** [tangledgroup](https://agentstack.voostack.com/s/tangledgroup)
- **Installs:** 0
- **Category:** [Agent Skills](https://agentstack.voostack.com/c/agent-skills)
- **Latest version:** 0.1.0
- **License:** MIT
- **Upstream author:** [tangledgroup](https://github.com/tangledgroup)
- **Source:** https://github.com/tangledgroup/tangled-skills/tree/main/.agents/skills-python/ruff-0-15-18

## Install

```sh
agentstack add skill-tangledgroup-tangled-skills-ruff-0-15-18
```

Requires the [AgentStack CLI](https://agentstack.voostack.com/docs/cli). Works with Claude Code, Cursor, and any MCP-compatible agent.

## About

# ruff 0.15.18

## Overview

Ruff is an extremely fast Python linter and code formatter written in Rust, designed as a drop-in
replacement for Flake8 (plus dozens of plugins), Black, isort, pydocstyle, pyupgrade, autoflake,
and more — executing tens to hundreds of times faster than any individual tool.

Version 0.15.18 supports Python 3.7 through 3.15, includes over 900 built-in lint rules across
30+ linter plugins (Pyflakes, pycodestyle, flake8-bugbear, isort, etc.), and a Black-compatible
formatter. New in this release: `ruff analyze graph` for dependency mapping, human-readable rule
names in CLI output, and improved `__init__.py` import fix safety in preview mode.

## Usage

### Installation

```bash
# Via uv (recommended)
uv tool install ruff@0.15.18

# Or ephemeral via uvx
uvx ruff check        # Lint current directory
uvx ruff format       # Format current directory

# Via pip
pip install ruff==0.15.18

# Standalone installer (macOS/Linux)
curl -LsSf https://astral.sh/ruff/0.15.18/install.sh | sh
```

### Core Commands

```bash
# Linting
ruff check                    # Lint current directory
ruff check --fix              # Lint and auto-fix
ruff check --fix --unsafe-fixes   # Include unsafe fixes
ruff check --diff             # Show diff without writing
ruff check --select E,F,B     # Enable specific rule categories
ruff check --ignore E501      # Ignore specific rules
ruff check --statistics       # Show violation counts per rule
ruff check --add-noqa         # Auto-add noqa comments

# Formatting
ruff format                   # Format in-place
ruff format --check           # Check without writing (non-zero exit if changes needed)
ruff format --diff            # Show formatting diff

# Inspection
ruff rule F401                # Explain a specific rule
ruff rule --all               # List all rules
ruff config                   # List all config options
ruff config line-length       # Describe a specific option
ruff linter                   # List supported upstream linters

# Analysis
ruff analyze graph            # Generate dependency/dependent graph

# LSP
ruff server                   # Run language server (for editor integration)
```

### Configuration Files

Ruff reads configuration from `pyproject.toml`, `ruff.toml`, or `.ruff.toml` (precedence: `.ruff.toml` > `ruff.toml` > `pyproject.toml`).

**Minimal `pyproject.toml`:**

```toml
[tool.ruff]
line-length = 88
target-version = "py312"

[tool.ruff.lint]
select = ["E", "F", "B", "UP", "SIM", "I"]
ignore = ["E501"]

[tool.ruff.format]
quote-style = "double"
```

**Equivalent `ruff.toml`:**

```toml
line-length = 88
target-version = "py312"

[lint]
select = ["E", "F", "B", "UP", "SIM", "I"]
ignore = ["E501"]

[format]
quote-style = "double"
```

### Rule Selection

- Use `select` for an explicit rule set (preferred over `extend-select`).
- Use `ALL` cautiously — it enables all rules and picks up new rules on upgrade.
- Start small (`select = ["E", "F"]`) and add categories incrementally.
- Preview rules require `preview = true` in config or `--preview` flag.

### Per-File Ignores

```toml
[tool.ruff.lint.per-file-ignores]
"__init__.py" = ["E402"]
"**/{tests,docs}/*" = ["E402", "S101"]
```

### Extending Parent Config

```toml
[tool.ruff]
extend = "../pyproject.toml"
line-length = 100
```

### CLI Overrides

```bash
# Override a single setting without a config file
ruff check --config "lint.line-length = 100"

# Ignore all config files
ruff check --isolated
```

## Gotchas

- **`select` on CLI replaces config `select`** — running `ruff check --select F401` enforces only `F401`, not the union of CLI and config rules. Use `--extend-select` to add to the config set instead.
- **Preview rules need explicit opt-in** — selecting a preview rule code (e.g., via `extend-select`) does nothing unless `preview = true` is also enabled for lint or format.
- **Config file discovery uses closest match, not cascade** — Ruff picks the nearest config file and ignores parent configs. Use `extend = "../path"` to inherit settings explicitly.
- **Files passed directly bypass excludes** — `ruff check /path/to/excluded/file.py` always lints the file unless `--force-exclude` is also set.
- **`.ruff.toml` takes precedence** — if multiple config file types exist in the same directory, `.ruff.toml` > `ruff.toml` > `pyproject.toml`.
- **`pyproject.toml` needs `[tool.ruff]` section** — Ruff ignores `pyproject.toml` files that lack this section during config discovery.
- **Formatter is Black-compatible but not interchangeable long-term** — Ruff's formatter differs from Black in a few conscious ways. Do not mix them on the same codebase over time.
- **`--fix` excludes unsafe fixes by default** — use `--unsafe-fixes` to include fixes that may change semantics (e.g., refactoring patterns).
- **Jupyter notebooks are linted/formatted by default** — exclude with `[tool.ruff.format] exclude = ["*.ipynb"]` if formatting notebooks causes issues.
- **`target-version` inferred from `requires-python`** — if no config specifies `target-version`, Ruff falls back to the `requires-python` field in a nearby `pyproject.toml`.

## References

- [01-configuration](references/01-configuration.md) — Config file formats, discovery rules, all settings
- [02-linter-rules](references/02-linter-rules.md) — Rule categories, selection strategies, fix behavior
- [03-formatter](references/03-formatter.md) — Formatter options, Black compatibility, docstring formatting
- [04-ci-integration](references/04-ci-integration.md) — GitHub Actions, GitLab CI, pre-commit hooks
- [05-editor-setup](references/05-editor-setup.md) — VS Code, Neovim, PyCharm, LSP configuration

## Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

- **Author:** [tangledgroup](https://github.com/tangledgroup)
- **Source:** [tangledgroup/tangled-skills](https://github.com/tangledgroup/tangled-skills)
- **License:** MIT

Install and usage instructions live in the source repository linked above.

## Pricing

- **Free** — Free

## Security capabilities

Automated source analysis of v0.1.0 — what this tool can access:

- **Network access:** yes
- **Filesystem access:** no
- **Shell / process execution:** no
- **Environment & secrets:** no
- **Dynamic code execution:** no

*"Yes" means the capability is present in the source — more access means more to trust, not that it is unsafe.*


## Versions

- **0.1.0** — security scan: flagged — Imported from the upstream source.

## Links

- Listing page: https://agentstack.voostack.com/l/skill-tangledgroup-tangled-skills-ruff-0-15-18
- Seller: https://agentstack.voostack.com/s/tangledgroup
- Browse the marketplace: https://agentstack.voostack.com/browse

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