check-ruff-schema

name	check-ruff-schema
description	Diagnose why henryiii/validate-pyproject-schema-store rejects a pyproject.toml because of unknown Ruff rule codes.

check-ruff-schema

What this skill does

The validate-pyproject pre-commit / prek hook validates pyproject.toml against JSON schemas bundled in henryiii/validate-pyproject-schema-store. Its ruff.schema.json in resources/ enumerates known Ruff rule codes as an exhaustive enum, so any code that Ruff has added but the schema store hasn't ingested yet causes the whole [tool.ruff.lint] section to fail validation with an unhelpful error like:

tool.ruff.lint cannot be validated by any definition

This skill pinpoints which specific Ruff codes are the culprit by diffing the project's extend-select / select / ignore / extend-ignore / unfixable lists against the validate-pyproject-schema-store schema's enum.

When to run

Trigger whenever:

• The user says prek run validate-pyproject or pre-commit run validate-pyproject is failing on tool.ruff.lint.
• The user has just bumped Ruff (via prek autoupdate, Renovate, manual edit of .pre-commit-config.yaml) and wants to check compatibility.
• The user asks some version of "which of my Ruff rules aren't in the schema yet?" or "why is validate-pyproject complaining?"

How to run

Invoke the bundled script against the repo's pyproject.toml (the default arg). Note this won't rewrite the file, just print out a report and gives a non-zero exit code if any codes are missing.

python scripts/check_ruff_codes.py  # Pass a path to check a specific pyproject.toml

To see what Ruff currently supports, use ruff check --show-settings.

Codes vs. category prefixes

The schema enum accepts both full codes like E501 and bare category prefixes like ANN, PTH, DTZ. The script treats both as valid, a "missing" report means the string literally isn't in the validate-pyproject-schema-store schema's enum, not that Ruff doesn't know it.