---
description: Unity C# script rules
globs: "Assets/**/*.cs"
alwaysApply: false
---

- `[SerializeField] private` for inspector fields, never public fields for tuning.
- Cache `GetComponent` results in `Awake`. No `Find*` or `GetComponent` calls in `Update`, `FixedUpdate` or `LateUpdate`.
- Rigidbody movement in `FixedUpdate`; read input in `Update`.
- No allocations in per-frame methods: no LINQ, no `new List<>`, no string building.
- File name must match the class name, or Unity cannot attach the script.
- When renaming a serialised field, add `[UnityEngine.Serialization.FormerlySerializedAs("oldName")]`.
- Editor-only code goes in an `Editor/` folder or inside `#if UNITY_EDITOR` so player builds do not break.
- Do not move or rename files without their `.meta` file.