Spine Animation AI skill
A Claude skill for Spine 2D animation: it positions character parts, builds the skeleton JSON and prepares an HTML preview
- 609 ★ on the repository
- Last commit
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Why this level
- The agent writes four Python scripts to disk and runs them
- SKILL.md installs dependencies with `pip` and the `--break-system-packages` flag, which overrides the system Python protection
- `split_character.py` sends the character image to the external Gemini service
Install
- Works in
In your terminal, with SkillFoxx CLI
npx skillfoxx add skills/spine-animation-aiDetects the agents on your machine, shows the access level and pins the version.
Other ways to install
Access and checks
How we reviewExtended accessThe tool runs code or makes network calls and only reads external data.
- The agent writes four Python scripts to disk and runs them
- SKILL.md installs dependencies with `pip` and the `--break-system-packages` flag, which overrides the system Python protection
- `split_character.py` sends the character image to the external Gemini service
This is third-party code. Review the repository files before installing.
What it does
The skill leads an agent from ready character images to animation in Spine 4.2: separate body-part PNGs become `skeleton.json`, a texture atlas and an interactive `preview.html`. Four Python scripts do the work, and `SKILL.md` embeds them in its own text, so the agent does not need to clone the repository. The `position_parts.py` script finds each part's position on an assembled reference image with SIFT and RANSAC and sets the draw order from overlaps. `build_spine_json.py` builds the bone hierarchy and slots, `make_atlas.py` packs the atlas and `generate_spine_player.py` assembles an HTML page with the official Spine Web Player. The agent builds animations such as idle, walk and jump following the 12 principles of animation. It also corrects existing skeletons: offsets go into a JSON, so every fix can be reviewed and reverted. If you only have a single image of the hero, `split_character.py` splits it into parts through Gemini and cuts transparent PNGs. The repository holds a working example with a sombrero character (10 parts, 16 bones, a two-second idle loop) and a separate Reskin Studio app that repaints a character's skin from a one-sentence description.
Who it is for. For 2D animators and game developers who have sliced character parts and want a skeleton and draft animations for Spine quickly.
Good fit when
- You have PNGs of separate character parts and need a skeleton with idle or walk animations
- You have a single hero image that must be split into parts with `split_character.py`
- You need to show an animation in a browser without a server: the preview builds into one HTML file
- An existing skeleton has drifted and you need to fix bone offsets and layer order
- You want to move part positions by hand in the interactive `sombrero_editor.html` editor and export the JSON
Not a fit when
- The project is commercial: the PolyForm Noncommercial 1.0 license does not allow commercial use without a separate agreement
- You need 3D animation: the skill makes only 2D skeletal animation for Spine
- You need a brand-new character from scratch: the skill animates ready assets and does not draw heroes itself
- You work in another animation format: the output is Spine files with the .json, .atlas and .png extensions
Example request
I have PNGs of my character's separate parts. Build the skeleton, make idle and walk animations and show a preview.Limitations
The PolyForm Noncommercial 1.0 license allows only non-commercial use, and for commercial use the authors invite you to get in touch through genielabs.tech.
The scripts need Python with the OpenCV, Pillow and NumPy libraries, plus google-generativeai for splitting an image. SKILL.md installs them with pip install and the `--break-system-packages` flag. `split_character.py` needs a `GEMINI_API_KEY`. Setup instructions cover Claude projects and environments with a `/mnt/skills/` directory, and there are none for other agents.
SIFT with RANSAC relies on image keypoints, so stylized art with few details may need manual correction.
How to disable. Remove the skill text from the Claude project knowledge or delete the `/mnt/skills/user/spine-animation` folder. The agent saves the scripts to `/home/claude/spine-scripts/`, and they can be deleted along with the temporary files.
FAQ
How do I connect the skill to Claude?
Option one: create a project on claude.ai, add the full text of `SKILL.md` to the project knowledge and upload your assets. Option two, for environments with a `/mnt/skills/` directory: `git clone https://github.com/GenielabsOpenSource/spine-animation-ai.git /mnt/skills/user/spine-animation`.
Can I run the scripts without Claude?
Yes. The scripts are plain Python files: you run them by hand in order, and the pip install command from the install methods sets up the dependencies.
How does the skill position character parts?
The script finds SIFT keypoints in every part and on the assembled reference, matches them and estimates shift, scale and rotation with RANSAC. A result is accepted from four matches, otherwise a fallback runs.
Which Spine version are the files for?
The skill outputs `skeleton.json`, an atlas and PNGs in the Spine 4.2 format. A format reference is in the repository, in `references/spine-json-spec.md`.
What is Reskin Studio?
A separate app in the `reskin-app` folder. From a description like "emerald and silver royal robes" it repaints the character through Gemini, cuts the result into slot textures and applies them to the existing rig.
Discussion
No questions or reviews yet.
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Comparison with similar tools
Entries that share the main search query, and how they differ.
| Entry | Official | Repository stars | Main difference |
|---|---|---|---|
| Spine Animation AI (this entry) | no | 609 | |
| Agent Sprite Forge | no | 4,633 | Codex skills for sprites, animation sheets and maps without Spine skeletal rigging |
| Sprite Gen | no | 3,101 | sprites and animation from one base image, without skeletal rigging |
README in short
Demo pages sit next to the code: a viewer for the finished animation and an interactive part editor that exports a layout JSON. The adjustment format is described in `docs/adjustment-format.md`: each part keeps its original offset, the correction and the final value.
README badge
Original SKILL.md
---
name: spine-animation
description: >
Create Spine 2D skeletal animations from pre-existing character assets (separated body-part PNGs,
atlas spritesheet, or a full character image). Use this skill whenever the user wants to animate
a 2D character, create Spine JSON from existing art assets, rig a character with bones, build
walk/idle/run/attack animations, produce an interactive Spine Web Player preview, or generate
Spine-compatible export files (.json + .atlas + .png). Also trigger when the user mentions
"Spine animation", "2D rigging", "skeletal animation", "bone animation", "cutout animation",
"animate this character", "make this walk", "create walk cycle", or uploads separated character
body parts and wants them animated. This skill handles the full pipeline: asset analysis,
skeleton rigging, animation keyframing, Spine JSON export, and interactive HTML5 preview.
---
<!-- ⚠️ AUTO-GENERATED FILE — DO NOT EDIT DIRECTLY
Edit SKILL.template.md instead, then push to trigger rebuild.
Scripts are embedded automatically by build_skill.py via GitHub Actions. -->
# Spine Animation Skill
Turn pre-existing 2D character assets into fully animated, interactive Spine animations.
## Step 0: Set Up Scripts
This skill includes Python scripts that do the heavy lifting. Claude MUST write them to disk
before use. Each script is embedded below — Claude should save them to `/home/claude/spine-scripts/`
at the start of every session.
```bash
mkdir -p /home/claude/spine-scripts
pip install opencv-python Pillow numpy google-generativeai --break-system-packages -q
```
### Embedded Scripts
The following scripts are auto-injected from the repository's `scripts/` directory.
**Claude: read these carefully, then write each one to `/home/claude/spine-scripts/`**
before running the pipeline.