slopcop

A fast, opinionated Python linter written in Rust that catches anti-patterns commonly produced by language models.

Built on tree-sitter for AST-correct analysis — no false positives on strings or comments.

Install

pip install slopcop
# or
uv tool install slopcop

Or from source:

cargo install --git https://github.com/cm2435/slopcop

Usage

# Lint directories (walks recursively for .py files)
slopcop src/ tests/

# Lint specific files
slopcop path/to/file.py

# Quiet mode (exit code only, for CI)
slopcop --quiet src/

# JSON output
slopcop --format json src/

# Only fail on errors, treat warnings as non-blocking
slopcop --warn-only src/

Exit codes: 0 = clean, 1 = violations found, 2 = fatal error.

Rules

All rules are enabled by default. Disable per-project via pyproject.toml.

Rule	What it catches
no-hasattr-getattr	hasattr() and getattr() calls — use explicit attribute checks or protocols
guarded-function-import	Function-scope import without a comment on the line above explaining why
no-future-annotations	from __future__ import annotations — unnecessary on 3.13+ and breaks runtime inspection
no-dataclass	@dataclass usage and dataclasses imports — use Pydantic or project-standard models
no-bare-except	except: without a type — catches everything including KeyboardInterrupt
no-broad-except	except Exception: / except BaseException: — too broad, catch specific types
no-pass-except	except blocks containing only pass — silently swallows exceptions
no-nested-try	Nested try blocks — extract the inner try into a separate function
no-async-from-sync	asyncio.run() / get_event_loop() / run_until_complete() / ensure_future() / create_task() inside a sync function — make the caller async def or move the sync/async boundary to an entrypoint
no-print	print() calls — use structured logging
no-todo-comment	TODO, FIXME, HACK, XXX comments — resolve or track in an issue
no-assert	assert in production code — use if not ...: raise ValueError(...) instead
no-typing-any	Any in type annotations — use specific types or protocols
no-str-empty-default	str = "" defaults on params and model fields — use str | None = None or make required
no-boolean-positional	Bare True/False as positional arguments — use keyword arguments for clarity
no-redundant-none-check	x is None when x is typed as non-optional
no-or-empty-coalesce	obj.attr or {} / or [] / or "" etc. — check is None explicitly or remove dead fallback
max-function-params	Functions with more than 8 parameters (configurable) — group into a model

Configuration

Add [tool.slopcop] to your pyproject.toml:

[tool.slopcop]
exclude = [
    "no-dataclass",   # this project uses dataclasses
    "no-print",       # CLI app, print is fine
]

Per-file ignores

Disable rules for specific file patterns:

[tool.slopcop.per-file-ignores]
"tests/**" = ["no-print"]
"**/cli/**" = ["no-print"]

Rule-specific config

[tool.slopcop.rules.max-function-params]
max = 10

slopcop walks upward from the target path to find the nearest pyproject.toml.

Inline suppression

x = getattr(obj, name)                     # slopcop: ignore
x = getattr(obj, name)                     # slopcop: ignore[no-hasattr-getattr]
x = getattr(obj, name)                     # slopcop: ignore[no-hasattr-getattr, no-print]

Adding to CI

# GitHub Actions
- run: pip install slopcop
- run: slopcop src/ tests/

Development

cargo test          # run the test suite
cargo run -- src/   # run locally

License

MIT