Diagnostic rules

Basilisk organises rules by the same flat tags the checker uses—not by arbitrary code ranges. Every rule has exactly one provenance tag:

  • pep identifies the 149 core rules enabled by default, including the rules measured by the official Python typing conformance suite.
  • basilisk identifies the 20 Basilisk-specific rules that are off by default and activate only when a project opts into one of their descriptive tags.

Each diagnostic links to a permanent /errors/.../ explanation—the same URL the CLI prints when a rule fires.

Basilisk rules (opt-in)

Use these tags when you want checking beyond the typing specification. A rule can appear under more than one descriptive tag; for example, a dependency rule may also be tagged imports.

Strictness 8 Dependencies 3 Style 2 Imports 1 Redundancy 1 Type stubs 4 Suppressions 4

Python typing-spec rules

These rules form the default checker surface. Their category tags come directly from the python/typing conformance vocabulary; cross-cutting checks that span categories are collected under Cross-cutting core.

Cross-cutting core 13 Type aliases 5 Annotations 4 Callables 5 Classes 4 Constructors 4 Dataclasses 11 Typing directives 7 Enums 6 Generics 33 Historical behavior 1 Literals 5 Named tuples 4 Type narrowing 3 Overloads 6 Protocols 15 Type qualifiers 5 Special types 4 Tuples 5 Typed dictionaries 9

Complete diagnostic reference

Browse the tag-grouped error reference or jump directly to any canonical page at /errors/CODE/. Rule selection and severity overrides are documented in the pyproject.toml configuration reference.