Code Writing Guide

---
name: code-writing-guide
description: >-
  Provides coding guidelines for Unity projects.
  Make sure to use this skill whenever writing, creating, editing, or modifying code files.
  This includes implementing new features, fixing bugs, refactoring, adding tests, or any task that results in code changes.
  Even for small edits or one-line fixes, load this skill to ensure project conventions are followed.
user-invocable: false
license: Unlicense
metadata:
  author: Koji Hasegawa
---

Guide for writing code in Unity projects.

## Rules

- Before modifying any code file, check if the editor is in Play Mode. If it is, stop it using the `unity_play_control` tool first — Play Mode may skip recompilation, leaving stale code active.
- When a change is a structural refactoring — renaming a symbol, extracting a method/interface/base class, changing a method signature, moving a type to another namespace, or deleting a symbol — use the Rider MCP refactoring tools (`rename_refactoring`, `extract_method`, `extract_interface`, `extract_base_class`, `change_api_signature`, `move_type_to_namespace`, `reorganize_namespaces`, `safe_delete`) instead of text edits. They update all references and call sites across the solution.
- Never create `.meta` files. Unity editor creates them automatically.
- When editing (creating or modifying) scene (`.unity`) or prefab (`.prefab`) files, use the `edit-scene` skill.
- When instantiating a prefab multiple times, give each instance a unique `GameObject.name`; otherwise, automated tests cannot identify a specific instance. Use a concrete name (e.g., `"<PrefabName>(Hero)"`) or append an index (e.g., `"<PrefabName>(0)"`).

## Resources

Read the appropriate resource file based on the situation:

- Before writing or modifying any code file: Read `${CLAUDE_SKILL_DIR}/resources/coding-guideline.md`
- Before writing or modifying any code file: Read `${CLAUDE_SKILL_DIR}/resources/unity-modern-guidelines.md`
- Before writing or modifying MonoBehaviour lifecycle or event-handling methods (Awake, Start, OnEnable, OnDisable, OnDestroy, Update, FixedUpdate, LateUpdate, OnCollision*, OnTrigger*, OnGUI, OnMouse*, OnBecame*, OnPreCull, OnPreRender, OnPostRender, OnRenderImage, OnRenderObject, OnWillRenderObject, OnAnimatorMove, OnAnimatorIK, OnDrawGizmos): Read `${CLAUDE_SKILL_DIR}/resources/unity-event-functions.md`
- Before referencing an API, verifying a package behavior, or looking up documentation: Read `${CLAUDE_SKILL_DIR}/resources/unity-references.md`
- When resolving diagnostics or handling code review feedback: Read `${CLAUDE_SKILL_DIR}/resources/diagnostics-review-feedback.md`