Ruff v0.16.0
Ruff v0.16.0 expands default lint rules from 59 to 413, with output designed for AI coding agents
“Ruff now enables 413 rules by default, up from 59 in previous versions.”
Astral's Ruff Python linter dramatically expanded its default ruleset from 59 to 413 rules, breaking many unpinned CI pipelines. Simon Willison notes the output format is well-suited for AI coding agents, and used Codex (GPT-5.6 Sol) and Claude Code (Opus 5) to apply the fixes across his major projects. The AI angle is secondary — this is primarily a dev tooling story, though it signals growing design-for-agent thinking in developer toolchains, and Astral's OpenAI acquisition adds industry context.