unity-csharp-scripting Checked

Write Unity 6.3 LTS C# gameplay scripts: the MonoBehaviour lifecycle (Awake/OnEnable/Start/Update/FixedUpdate/LateUpdate), GameObject and component access, coroutines, and Inspector serialization. Use when creating or editing .cs scripts in a Unity project, or when the user mentions MonoBehaviour, Start/Update, GetComponent, SerializeField, coroutines, or "Unity script".

Unity C# Scripting (MonoBehaviour)

Write correct, idiomatic gameplay scripts in Unity 6. Get the lifecycle, component

access, serialization, and coroutines right so behaviour is deterministic and the

Inspector stays useful. Targets **Unity 6.3 LTS (6000.3)**, C# / .NET Standard 2.1.

Write Unity 6.3 LTS C# gameplay scripts: the MonoBehaviour lifecycle (Awake/OnEnable/Start/Update/FixedUpdate/LateUpdate), GameObject and component access, coroutines, and Inspector serialization. Use when creating or editing .cs scripts in a Unity project, or when the user mentions MonoBehaviour, Start/Update, GetComponent, SerializeField, coroutines, or "Unity script".

Unity C# Scripting (MonoBehaviour)

Write correct, idiomatic gameplay scripts in Unity 6. Get the lifecycle, component

access, serialization, and coroutines right so behaviour is deterministic and the

Inspector stays useful. Targets **Unity 6.3 LTS (6000.3)**, C# / .NET Standard 2.1.

When to use

• Use when authoring or fixing a MonoBehaviour: choosing the right lifecycle callback,

reading/caching components, exposing fields to the Inspector, or running timed logic

with coroutines.

• Use when the project has *.cs files, an Assembly-CSharp or *.asmdef, and a

ProjectSettings/ folder.

**When *not* to use:** moving rigidbodies / collision response → unity-physics; reading

player input → unity-input-system; shared data assets / config → unity-scriptableobjects;

Animator parameters → unity-animation. This skill owns the *script lifecycle and C#

plumbing*, not those subsystems.

Core workflow

1. **Pick the callback by purpose, not habit.** Awake (cache references, runs once on

load), OnEnable (subscribe to events), Start (init that depends on other objects'

Awake), Update (per-frame logic/input polling), FixedUpdate (physics), LateUpdate

(camera follow after movement), OnDisable/OnDestroy (unsubscribe/cleanup).

2. **Cache component lookups in Awake** — never call GetComponent every frame.

3. **Expose tunables with [SerializeField] private**, not public fields, so other code

can't mutate them but designers can edit them in the Inspector.

4. **Scale per-frame values by Time.deltaTime** in Update (and Time.fixedDeltaTime

semantics are automatic in FixedUpdate).

5. **Use coroutines for time-sequenced logic** (delays, tweens, "do X then wait then Y");

start them with StartCoroutine and stop them deterministically.

6. **Verify in Play mode**: check the Console for null-reference exceptions, confirm values

in the Inspector update as expected, and watch the Profiler if Update is hot.

Patterns

### 1. Lifecycle + cached components (the canonical skeleton)

using UnityEngine;

[RequireComponent(typeof(Rigidbody))]      // auto-adds the dependency, prevents null refs
public class PlayerController : MonoBehaviour
{
    [SerializeField] private float moveSpeed = 6f;   // editable in Inspector, private in code
    private Rigidbody _rb;                            // cached, not fetched per frame

    private void Awake() => _rb = GetComponent<Rigidbody>();  // cache once on load