---
id: flake8-unused-arguments
version: "0.0.14"
license: MIT
license_treatment: permissive
maintenance: aging
---

# flake8-unused-arguments — flake8 extension to warn on unused function arguments

License: permissive · Maintenance: aging · Downloads: 102.1K/mo

## What it is and what it does

This is a flake8 plugin that integrates unused-argument detection into your linting workflow. It adds two warning codes—U100 for any unused argument and U101 for unused arguments starting with underscore—and lets you configure which function types to exclude from checking (abstract, overload, override, stub, dunder methods, lambdas, nested functions, and variadic parameters).

You install it alongside flake8, and it runs automatically as part of your linting pipeline. It's useful for catching dead parameters that clutter function signatures or indicate incomplete refactoring, though you can fine-tune it to avoid false positives in special cases like protocol implementations or intentionally-ignored parameters.

Use it for:

- Enforce code cleanup by catching function parameters that are declared but never used in the function body.
- Identify incomplete refactoring where parameters were removed from call sites but not from function signatures.
- Customize linting rules to skip dunder methods, abstract functions, or overrides that must match a parent signature.
- Integrate unused-argument checking into CI/CD pipelines via flake8 without adding a separate tool.
- Configure per-project rules via flake8 config files to ignore lambdas or nested functions if your codebase style prefers them.

## Worth the install?

AI-flagged interpretation of the facts above — verify before relying.

A flake8 plugin that detects unused function arguments in Python code and reports them as U100 or U101 warnings, with configurable rules to ignore specific function types.

Yes, if you use flake8 and want to catch unused function arguments. Install friction is minimal, no security issues are known, and the MIT license is unrestrictive. The aging maintenance status (291 days since last release) is a minor concern but the repository is still active and the plugin is straightforward enough that infrequent updates are not a red flag. It integrates seamlessly into existing flake8 workflows.

## Install

pip install flake8-unused-arguments
uv add flake8-unused-arguments
poetry add flake8-unused-arguments

## Installing flake8-unused-arguments

Before you install: Low friction install as a pure Python wheel with only flake8 as a runtime dependency. Maintenance status is aging—last release was 291 days ago—but the repository remains active and unarchived with recent commits.

License in practice: MIT license is permissive and places no restrictions on use, modification, or redistribution in commercial or private projects.

Quickstart:

pip install flake8-unused-arguments

Then add to your flake8 configuration or run:
flake8 --select=U100,U101 your_code.py

Or import in setup.cfg:
[flake8]
extend-select = U100, U101

Verify before relying:

- Whether the plugin works with all currently maintained flake8 versions or has version constraints not specified in requires_python.
- Performance impact on large codebases or projects with thousands of functions.

## Package facts

- License: MIT (permissive)
- Python support: unspecified
- Install friction: low
- Maintenance: aging
- Downloads: 102.1K/month (top 15,000 on PyPI)
- Known vulnerabilities: none known

## Tags

flake8 unused arguments, detect unused function parameters, python code quality linting, flake8 plugin, unused parameter checker, function argument linter, code quality tool, linting, flake8-plugin, code-quality

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