Sprite Editor

---
name: sprite-editor
description: Programmatically edit Unity Sprite slicing
modes:
- agent
- ask
---

# 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 `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 `eval` command. Discover its parameter shape
from `unity command --format json` rather than assuming one — the inline form is
`unity command eval --code '<snippet>'`, and some Pipeline versions also register
`eval_file` for running a snippet from a file. **Check the catalog before reaching for
`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 `eval`

`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 `eval`.

## Workflow

All generated scripts must follow the Safe Core Pattern in [references/templates.md](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](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)