Iki

<p align="center"> <img src="./.github/assets/hero.gif" width="360" alt="An Iki character turning its head, blinking and talking, rendered by the engine." /> <br /> _{Parts drawn by an image model and rigged by Iki's auto-rigger, with no hand rigging. <a href="https://zeikar.dev/iki/">See it live</a>.} </p> <h3 align="center">The open Live2D alternative that AI can build.</h3>

息 (breath) · 生き (life) · 粋 (chic)

Iki is a free, MIT-licensed 2D puppet animation engine for the web — an alternative to Live2D and Inochi2D whose characters an AI agent can make. Ask for one, and the bundled Claude Code plugin has an image model draw its parts, then rigs them into a character that blinks, looks around, talks, turns and nods, with hair that sways. What you get is an open .iki file — plain JSON you own — that the WebGL runtime plays in any browser, and that a host (such as Charivo) drives from lip-sync, gaze and expressions.

Status: early, but real. The runtime renders parameter-driven color quads, atlas-sampled texture parts, warp-mesh and grid deformation, stencil clipping masks, and spring/chain physics. The editor authors parts, deformers, and physics rigs; the generator rigs a character from role-named PNG/PSD layers, including through an MCP server that AI agents can drive.

Make a character with AI

Install the plugin in Claude Code:

/plugin marketplace add zeikar/iki
/plugin install iki@iki

Then ask for a character — "make me an iki character: short copper bob, green eyes, school uniform". The plugin:

1. Draws each part on its own with an image model — face, eyes, irises, brows, mouth, nose, front and back hair, torso.
2. Composes and checks them on one canvas (compose_layers_from_parts, measure_layers), catching the geometry that would break in motion.
3. Rigs them (auto_rig_from_layers): eyelid-fold blink, gaze, lip-sync, head turn, nod and tilt, brows, breathing and hair physics, written to a .iki model.

The character at the top of this page was made this way. The plugin needs an image generator — see its prerequisites. Already have art? Hand role-named PNG layers to the auto-rigger through the @ikijs/mcp server, or import a layered PSD in the editor.

Try it

No install — both demos run in the browser:

• Playground — drag the sliders that a host would drive, on a hand-authored model or a generated character.
• Editor — author parts, deformers, and physics rigs, import a layered PSD, and export a validated .iki.

Why

• Characters an AI agent can build. Part images in, a rigged model that blinks, talks, turns and nods out — through the Claude Code plugin or any MCP client. That is the part Iki is really exploring.
• Free for commercial use. MIT: no publication license, no revenue tiers — ship whatever you build with it.
• Open format. The .iki model is a plain, documented JSON schema you own — which is what makes generating a model tractable in the first place.
• Web-native. WebGL runtime, TypeScript, no native toolchain.
• Host-agnostic. The engine knows nothing about Charivo or any host; it just plays .iki models. Charivo consumes it through a thin render-iki adapter, the same way it consumes the Live2D SDK today.

How Iki compares

Live2D Cubism is the industry standard, and it is far more mature than Iki in every dimension that matters to an artist — editor, tooling, ecosystem, and the quality ceiling of what you can rig with it. Inochi2D is the established open-source project in this space. Iki is not trying to replace either. It exists because three things it wanted never lined up in one place: a permissive license, a plain-text format, and a rig an agent can build.

| | Live2D Cubism | Inochi2D | Iki | | ------------------------ | -------------------------------------------------------------------------------------------------------------------------------------------------------- | ---------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | License | Proprietary SDK license; a publication license is required to distribute, with exemptions for individuals and small businesses (terms) | BSD-2-Clause | MIT — free for commercial use | | Editor | Cubism Editor (paid PRO tier, free tier) | Inochi Creator (open source) | Headless editor core + example app (early) | | Model format | .moc3, compiled and proprietary | Open | Plain JSON with a documented schema and a validator | | Runtime | Native SDKs, including a Web SDK | Native (D) | TypeScript + WebGL2, npm install | | An AI agent can build it | — | — | Yes: a Claude Code plugin that draws and rigs a character, over an MCP server (compose_layers_from_parts, measure_layers, auto_rig_from_layers, measure_turn_reference) | | Maturity | Industry standard | Established | Early (0.x, schema still settling) |

If you need production-grade 2D rigging today, use Cubism. If you want an open web format you can script against, that is what this is.

Packages

| Package | What it is | | ------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | @ikijs/format | The .iki model schema, types, loader, and validator | | @ikijs/engine | WebGL2 runtime that plays a .iki model | | @ikijs/editor | Headless editing core (no UI): EditorDocument, edit commands, undo/redo, atlas layout/UV helpers, auto-rigger (depends only on @ikijs/format) | | @ikijs/mcp | stdio MCP server exposing .iki read/validate plus compose_layers_from_parts, measure_layers, auto_rig_from_layers and measure_turn_reference to AI agents | | examples/playground (live) | Slider-driven demo of the generated hero character and a hand-authored model | | examples/editor (live) | Private React+Zustand app — load/import art, numeric part + deformer + physics editing, pivot gizmo, live IkiPlayer preview, validated .iki export | | plugin/ | Claude Code plugin — the character-generation skills, their two agents, and the MCP server, wired up in one install |

Install

npm install @ikijs/engine @ikijs/format

@ikijs/editor is for building authoring tools; @ikijs/mcp runs as a server (npx -y @ikijs/mcp) rather than being imported.

Quick start (this repo)

pnpm install
pnpm build
pnpm playground   # open the Vite URL and drag the sliders

The .iki model

A model is a flat list of parts composited back-to-front, plus parameters wired to those parts through linear bindings:

import { StandardParameter, type IkiModel } from "@ikijs/format";

const model: IkiModel = {
  version: 1,
  name: "Hello",
  canvas: { width: 1000, height: 1000 },
  parameters: [{ id: StandardParameter.MouthOpen, min: 0, max: 1, default: 0 }],
  parts: [
    {
      id: "mouth",
      color: [0.78, 0.32, 0.36, 1], // solid fill, or tint multiplier when a texture is present
      width: 150,
      height: 34,
      order: 0,
      transform: { x: 0, y: -150 },
      bindings: [
        {
          parameter: StandardParameter.MouthOpen,
          channel: "scaleY",
          from: 0,
          to: 3,
        },
      ],
    },
  ],
};

Stick to the StandardParameter ids (ParamMouthOpenY, ParamAngleX, …) so any host can drive any model without per-model wiring. Left/Right in those ids name the character's