The Basilisk Journal
Updates, announcements, and deep-dives from the Basilisk project.
From the project
7 articles
Basilisk's configuration is now one explicit pyproject.toml model: tags for broad policy, rules for exceptions, folder configs for scope, exact impact previews, reactive reloads, and offline Typeshed pins.
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Claude Code and Codex can edit and test across a repository. With usable static types, a checker can catch nonexistent members, incompatible arguments, and unsupported calls before runtime. Here is where that guardrail works, where Python's Any escapes it, and what Basilisk checks today.
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PEP 827 is Python's boldest attempt yet at TypeScript-style type manipulation. It is powerful, controversial, and a serious implementation challenge for every Python type checker.
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Basilisk joined the official python/typing conformance results this week, and it landed at a perfect score. It is the only Python type checker on the board at 100%. Here is what that number actually means, who else is on the board, and why we are not going to oversell it.
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Python 3.14 made free-threaded Python officially supported. When threads really run in parallel, a type error stops being a quiet annoyance and becomes a concurrency bug. Here's why strict, default-on type checking is the cheapest protection you can buy.
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Basilisk's parser is Ruff. Ruff's owner is about to become OpenAI. Here is what that means — backed by the primary sources, quote by quote — and why your Basilisk install is safe regardless.
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The Python type annotation ecosystem has a dirty secret: nobody enforces it by default. We built Basilisk to fix that.
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