Add basilisk-python to Code Analysis / Type Checkers (100% PEP Conformance According to Python/typing repo)

[MelbourneDeveloper]

Adding basilisk-python under Code Analysis → Type Checkers, placed first alphabetically (before mypy).

Basilisk is a strict-by-default Python type checker and language server written in Rust. Submitting under the Hidden Gem criterion, with the star-count justification below.

Why it belongs here

It is the only type checker that passes the entire official conformance suite. The python/typing conformance results — the type system's own reference scoreboard, published by the spec maintainers — currently list Basilisk as Pass on 141 of 141 test cases. No other checker in that table is clean:

Checker	Pass	Partial	Unsupported
basilisk 0.27.0	141	0	0
zuban 0.8.2	140	1	0
pyrefly 1.1.0	135	6	0
pyright 1.1.410	134	5	2
pycroscope 0.4.0	120	20	1
ty 0.0.65	107	30	4
mypy 2.1.0	83	52	6

_{Counted from the linked upstream results.html; version labels are upstream's, not mine.}

It is not "yet another type checker." The existing entries are checkers; Basilisk is a whole toolchain shipped as one binary — type checker, language server, debugger (DAP), and profiler — with editor extensions for VS Code, Cursor, Zed, and Neovim, and formatting/import hygiene built in. Every diagnostic links to a documentation page explaining why the code is wrong, and every rule is individually configurable, so teams can adopt type safety incrementally rather than flipping one global strictness switch. That is a different product shape from mypy, pyrefly, and ty, not a duplicate of them.

Hidden Gem justification (< 100 stars)

Per CONTRIBUTING.md, projects under 100 stars need strong justification. Basilisk has 55 stars, but:

• Verifiable, externally-audited quality. The 141/141 result above is not a self-reported number — it is published by the Python typing spec maintainers in their own repository, against a suite Basilisk does not control.
• Real-world usage, not a launch-week project. ~4,050 PyPI downloads in the last 30 days (pypistats) and 185 installs / 5.0★ from 4 ratings on the VS Code Marketplace.
• Solves a niche problem precisely. Full spec conformance matters most to library authors publishing typed public APIs and to teams whose CI must agree with the specification rather than with one vendor's interpretation of it. That is a small audience relative to a general linter — which is exactly why the star count understates the project.

Checklist against CONTRIBUTING.md

Requirement	Status
Active — commits within 12 months	✅ Latest commit 2026-08-03; release v0.39.0 on 2026-08-02
Stable — production-ready	✅ 14 published PyPI releases; MIT licensed; not flagged alpha/beta
Documented — README with examples and use cases	✅ basilisk-python.dev/docs plus per-diagnostic reference pages
Unique — adds distinct value	✅ Only 141/141 conformant checker; checker + LSP + debugger + profiler in one binary
Established — repo ≥ 1 month (Hidden Gem: ≥ 3 months)	✅ Repository created 2026-02-28 (~5 months), continuous release cadence
One project per PR	✅ Single entry, single line
Correct category	✅ Code Analysis → Type Checkers
Alphabetical ordering	✅ basilisk-python precedes mypy
PyPI display name	✅ basilisk-python per PyPI JSON API
Not a duplicate	✅ No prior open or closed issue/PR in this repo mentions Basilisk
Description ends with a period	✅

One point of transparency

Quality Requirement #1 asks for >50% Python. Basilisk's implementation language is Rust (it ships as a compiled binary distributed on PyPI). I'm flagging this rather than glossing over it. The precedent in this list is that Python tooling is judged on what it does for Python developers, not on its implementation language — ruff and ty (Rust, Astral) and pyrefly (Rust, Meta) are all already listed, two of them in this same Code Analysis section. Basilisk is submitted on the same basis. Happy to withdraw if you read that rule strictly.

[JinyangWang27]

@MelbourneDeveloper Thanks for your submission. However, this project does not meet our acceptance criteria:

Repository age: The repository was created 3 months ago. We require a minimum of 6 months for Hidden Gem submissions to ensure project stability.

GitHub stars: 5 stars (minimum 100 required, or strong justification for Hidden Gem).

Please see our CONTRIBUTING.md for full requirements. You're welcome to resubmit once the project has matured and gained community traction.

[MelbourneDeveloper]

Thanks for getting back to me with the clear criteria. We will work on the stars and reapply in 3 months. @jinwang27