keijiro/unity-skills/unity-sprite-editor

Sprite Editor

Sprite metadata (rects, borders, pivots, outlines) lives inside the importer, not in a file you can edit — reaching it means running C# through a live Editor.

The `unity-cli` skill owns getting you there — installing the CLI, confirming a connected Editor, adding the project's com.unity.pipeline package, telling a genuinely absent Editor apart from one stuck in Safe Mode, and discovering the Editor's command catalog. Follow it first; don't re-derive any of it here.

Two things it can't know for you:

• You need `script eval` in particular, not just a reachable Editor. Confirm it appears in the

catalog — its presence depends on the Pipeline package version, not on the CLI.

• Never hand-edit a `.meta` file to change sprite metadata. The importer owns that data

and the capability checks below exist to prevent corruption, so an unreachable Editor is a stop, not a cue to improvise.

Run C# through the connected Editor with the script eval command. Discover its parameter shape from unity command --format json rather than assuming one — the inline form is unity command script eval --code '<snippet>', and some Pipeline versions also register script eval_file for running a snippet from a file. Check the catalog before reaching for `script eval_file`; it is frequently absent. unity command defaults to a 30 second timeout.

Generates C# editor scripts to manipulate Unity sprites using ISpriteEditorDataProvider. Works with TextureImporter, PSBImporter, and custom importers.

Passing C# to script eval

script eval compiles a statement block, not a file. Two consequences, both of which cause a compile error rather than a warning:

• No `using` directives. The compiler reads using UnityEngine; as a resource-disposal

statement and rejects it (CS0210).

• Types must be fully qualified. A bare AssetDatabase or Volume does not resolve

(CS0246 / CS0103), and a bare Object is ambiguous with object (CS0104).

Where a snippet below is written as a file — with usings, for readability, or because it is meant to be saved into the project — qualify the types before passing it to script eval.

Workflow

All generated scripts must follow the Safe Core Pattern in references/templates.md, which includes MANDATORY capability checks. NEVER attempt operations if capability checks fail - this prevents data corruption. After execution, verify results in Unity console and Project window.

Common Operations

Modify Name/Rect/Border/Pivot: Update corresponding SpriteRect fields (see scripts/SetPivotExample.cs for pivot examples)

• Requires: EditSpriteName, EditSpriteRect, EditBorder, or EditPivot

Add/Remove/Slice: Create or filter SpriteRect array (see references/background.md for Unity 2021.2+ requirements)

• Requires: CreateAndDeleteSprite

Set Outlines: Get ISpriteOutlineDataProvider → Call SetOutlines() with GUID + Vector2 arrays

Important Notes

• Do NOT use AssetPostprocessor or MenuItem patterns
• Generate standalone snippets only — no AssetPostprocessor, no MenuItem
• Enum assignments: Always use enum values and cast to numeric types. Never use raw numbers.
• ✅ Correct: (int)SpriteAlignment.Center
• ❌ Wrong: 1 (magic number)