Rattle

Supported versions

Rattle is a Python linting framework built on LibCST with support for autofixes, custom in-repo lint rules, and hierarchical configuration.

Rattle is a fork of Fixit designed to complement Ruff. It intentionally omits rules that duplicate Ruff checks, so pair it with a comprehensive Ruff configuration; Ruff is considerably faster for those checks.

For migration from Fixit, overlapping Fixit-derived rules remain available in the opt-in legacy collection. This collection is not recommended for new configurations.

Features

51 built-in lint rules
Autofix support when a rule can safely rewrite code
Local custom rules that can live inside your repository
Hierarchical pyproject.toml configuration
Pre-commit integration for CI and local workflows
LSP support

Install

From PyPI

uv tool install rattle-lint

pip install rattle-lint

With editor/LSP support

uv tool install "rattle-lint[lsp]"

pip install "rattle-lint[lsp]"

Agent Skill

The official AI agent skill can be installed from this repo.

npx skills add https://github.com/zigai/rattle/tree/main/src/rattle/.agents/skills/create-rattle-lint-rules

uvx library-skills

Basic Usage

Rattle enables no rules by default. A practical baseline for a typical typed Python project is:

[tool.rattle]
root = true
enable = [
    "blank-line-after-control-block",
    "blank-line-after-terminal-control-block",
    "blank-line-before-branch",
    "blank-line-before-unrelated-block",
    "no-suite-leading-trailing-blank-lines",
    "module-all-at-bottom",
    "no-underscore-all-exports",
    "forbidden-call",
    "no-relative-imports",
    "no-underscore-import-aliases",
    "no-unsafe-tempfile-factories",
    "no-annotated-self",
    "no-exception-message-variables",
    "no-str-exception-translation",
    "no-underscore-class",
    "public-method-order",
    "no-bare-object-annotations",
    "no-named-tuple",
    "no-static-if-condition",
    "sorted-attributes",
    "use-callable-ellipsis",
]

[tool.rattle.options."forbidden-call"]
forbidden_calls = ["typing.cast"]

Adjust the list to match the project, then lint the repository:

rattle lint .

Apply available autofixes:

rattle fix .

Explain rule metadata, examples, and settings:

rattle explain no-bare-object-annotations
rattle explain --json no-bare-object-annotations

License

MIT

Metadata

Release files for rattle-lint 3.1.0

For a detailed explanation of source distributions (sdists) and built distributions (wheels), please see the package formats documentation.

Source distribution (sdist)

Source distribution for rattle-lint 3.1.0
File	Size	Uploaded
rattle_lint-3.1.0.tar.gz	338.9 kB	Oct 5, 2026	Details

Built distribution (wheel)

Table of built distributions (wheels) for rattle-lint 3.1.0
File	Interpreter	ABI	Platform	Reset
rattle_lint-3.1.0-py3-none-any.whl 212.5 kB Oct 5, 2026	Python 3	none	any	Details

Total release size: 551.4 kB

Release files / rattle_lint-3.1.0.tar.gz

Download URL	rattle_lint-3.1.0.tar.gz
Size	338.9 kB
Tags	Source
SHA-256 checksum How to use checksums	`eca25365fa108a8c6ca058f5cb17d0e67035d394f055012e507040ba0aba1577`
BLAKE2b-256 checksum How to use checksums	`c3a498d82457f04911f90b6e79ca364f51ae90ed8cff70b72168a7a731bae141`
Upload date	Oct 5, 2026
Uploaded using Trusted Publishing? What is trusted publishing?	No
Uploaded via	`twine/7.0.0 CPython/3.10.22`

Release files / rattle_lint-3.1.0-py3-none-any.whl

Download URL	rattle_lint-3.1.0-py3-none-any.whl
Size	212.5 kB
Tags	Python 3
SHA-256 checksum How to use checksums	`9d4b44365e599e45a7c921d8e1bfb3210d4c095ba74cc374022e92454e182d01`
BLAKE2b-256 checksum How to use checksums	`28c5e8704690aa0e0017ba2b782ab5e368d2b8b5f2c7384bbcba5b1ced889271`
Upload date	Oct 5, 2026
Uploaded using Trusted Publishing? What is trusted publishing?	No
Uploaded via	`twine/7.0.0 CPython/3.10.22`