unity-csharp-edit

Unity C# Editing

Implement Unity C# changes with unity-cli as the primary write path. Read references only when the change needs them:

• references/file-write-recipes.md for choosing symbol edits, file writes, and multi-file writes.
• references/lsp-write-safety.md for preview-first edits, namePath, and write result checks.
• references/unity-implementation-guidelines.md before touching serialized fields, UI bindings, editor code, ScriptableObjects, or SettingsProviders.
• references/settings-write-recipes.md when the task includes project or package settings.

Critical Rules

• Use this skill when the user intends to change code. Use unity-csharp-navigate only for read-only investigation.
• Prefer the smallest write primitive that keeps the change correct.
• Preserve Unity serialization, binding paths, and editor/runtime boundaries when refactoring.
• Do not add defensive null checks unless a real nullable contract, Unity lifecycle gap, or external input boundary requires them.
• After non-trivial writes, confirm get_compilation_state and address real diagnostics before unrelated follow-up work.

Recommended Flow

1. Decide the write shape first: symbol edit, full-file write, multi-file write, or settings change.
2. Read only the minimum context needed with read, get_symbols, find_symbol, or find_refs.
3. Preview risky symbol edits with apply: false.
4. Apply the write and opt into refresh, waitForCompile, and updateIndex when later steps depend on clean diagnostics or fresh symbol data.
5. Inspect changedFiles, changedSymbols, and diagnostics. Fix compilation issues before moving on.

Symbol-Aware Edits

unity-cli raw get_symbols --json '{"path":"Assets/Scripts/Player.cs"}'
unity-cli raw find_symbol --json '{"name":"Player","kind":"class","scope":"assets"}'
unity-cli raw find_refs --json '{"name":"Player","kind":"class","scope":"assets"}'

unity-cli raw rename_symbol --json '{"relative":"Assets/Scripts/Player.cs","namePath":"Player/Jump","newName":"Leap","apply":false}'
unity-cli raw replace_symbol_body --json '{"relative":"Assets/Scripts/Player.cs","namePath":"Player/Jump","body":"{ velocity.y = jumpSpeed; }","apply":true}'
unity-cli raw insert_before_symbol --json '{"relative":"Assets/Scripts/Player.cs","namePath":"Player/Jump","text":"[SerializeField] private float dashCooldown = 0.25f;","apply":true}'
unity-cli raw insert_after_symbol --json '{"relative":"Assets/Scripts/Player.cs","namePath":"Player/Jump","text":"private bool CanDash() { return dashCooldown > 0f; }","apply":true}'
unity-cli raw remove_symbol --json '{"relative":"Assets/Scripts/Player.cs","namePath":"Player/LegacyJump","apply":true,"failOnReferences":true}'

File-Level Writes

unity-cli raw write_csharp_file --json '{"relative":"Assets/Scripts/PlayerController.cs","newText":"using UnityEngine;\n\npublic sealed class PlayerController : MonoBehaviour\n{\n    [SerializeField] private float speed = 5f;\n}\n","validate":true,"apply":true,"format":true,"waitForCompile":true,"updateIndex":true}'
unity-cli raw create_csharp_file --json '{"relative":"Assets/Tests/EditMode/PlayerControllerTests.cs","text":"using NUnit.Framework;\n\npublic class PlayerControllerTests {}\n","validate":true,"apply":true,"waitForCompile":true,"updateIndex":true}'
unity-cli raw apply_csharp_edits --json '{"files":[{"relative":"Assets/Scripts/IPlayerMover.cs","newText":"public interface IPlayerMover { void Move(); }\n"},{"relative":"Assets/Scripts/PlayerMover.cs","newText":"public sealed class PlayerMover : IPlayerMover { public void Move() {} }\n"}],"validate":true,"apply":true,"waitForCompile":true,"updateIndex":true}'
unity-cli raw create_class --json '{"name":"EnemyAI","namespace":"Game.AI","inherits":"MonoBehaviour","folder":"Assets/Scripts/AI"}'

Validation And Follow-Up

unity-cli raw validate_text_edits --json '{"relative":"Assets/Scripts/PlayerController.cs","newText":"using UnityEngine;\npublic sealed class PlayerController : MonoBehaviour {}\n"}'
unity-cli raw update_index --json '{"paths":["Assets/Scripts/PlayerController.cs","Assets/Tests/EditMode/PlayerControllerTests.cs"]}'
unity-cli raw get_compilation_state --json '{}'

Settings

unity-cli raw get_project_setting --json '{"path":"Player/activeInputHandler"}'
unity-cli raw set_project_setting --json '{"path":"Player/activeInputHandler","value":"InputSystemPackage","confirmChanges":true}'
unity-cli raw get_project_settings --json '{"includePlayer":true,"includeEditor":true}'
unity-cli raw get_package_setting --json '{"package":"com.unity.testtools.codecoverage","key":"EnableCodeCoverage","scope":"project"}'
unity-cli raw set_package_setting --json '{"package":"com.unity.testtools.codecoverage","key":"EnableCodeCoverage","value":true,"scope":"project","confirmChanges":true}'

Examples

• "Implement dash cooldown in PlayerController.cs and update the related tests."
• "Rewrite this UXML-bound view model without breaking serialized field names or binding paths."
• "Create a new editor utility script and change the matching project or package setting."
• "Refactor an interface, its implementation, and the tests in one coordinated write."

Common Issues

• namePath does not match the target: run get_symbols first and use the exact nested path.
• A rename breaks Unity serialization or UI binding: check [SerializeField] names, UXML binding paths, and reflection-based lookups before renaming.
• A coordinated change is spread across repeated symbol edits: switch to apply_csharp_edits or write_csharp_file.
• The write result looks successful but the project is still broken: inspect diagnostics, then run get_compilation_state and fix the actual errors.