sglang/.claude/rules/no-dataclasses.md

paths

paths
**/*.py

Use msgspec.Struct, not @dataclass

Define data containers as msgspec.Struct. Do not add new dataclasses.dataclass (or attrs) — they weaken strict type checking and don't translate cleanly for multi-language support (e.g. the planned Rust migration).

import msgspec

class LoadSnapshot(msgspec.Struct):   # prefer frozen= and omit_defaults=; kw_only= as needed
    dp_rank: int = 0
    tokens: list[int] = []            # mutable defaults are safe

• Methods / @classmethod constructors go on the Struct; see python/sglang/srt/managers/load_snapshot.py.
• New code only. Existing @dataclass is grandfathered — migrate opportunistically while editing the file, not in drive-by sweeps.