threenative-animation-mcp

Author, repair and verify character animation through one MCP. Every operation is a build-time edit: the input is a GLB, the output is an ordinary GLB, and no game depends on this package at runtime.

On this page

npx threenative-animation-mcp        # stdio MCP server
npx threenative-animation-mcp --view # the calibrator page, on http://127.0.0.1:4192/pose

Generating a project with @threenative/core installs this server for you; it is wired into the project's .mcp.json as threenative-animation, exactly like the asset, sculpt, engine and Blender servers.

Tools

Tool	Does	State
`animation_inspect`	bones, skeleton landmarks, clips with durations, root-motion travel, in-place detection	shipped
`animation_attach`	prop on a bone with per-clip keyed offsets, baked into a GLB	shipped
`animation_open_view`	the calibrator page, live over the op log	shipped
`animation_auto_rig`, `animation_ik_retarget`, `animation_preview`	the four tools the asset MCP still owns	moved once their code is relicensed
`animation_modify`, `animation_verify`	trim, retime, loop point, mirror, resample, root motion, foot lock; foot skate, ground penetration, loop seam, jitter, bone stretch	phase 2
`animation_pose`, `animation_bake`, `animation_find_clip`	constraint intents solved into a pose, a pose sequence baked into a clip, Quaternius library search	phase 3

The op log

Every change, from an agent or a human in the view, is one JSON op appended to <model>.anim.json beside the source GLB:

json

{
  "version": 4,
  "host": "public/assets/enemy-terrorist.glb",
  "ops": [
    {
      "op": "attach",
      "attached": "public/assets/weapon-ak47.glb",
      "anchor": { "id": "right-hand", "label": "Right hand", "node": "mixamorigRightHand_035", "source": "detected" }
    },
    { "op": "key", "clip": "RifleIdle", "time": 0, "attachment": "attached", "transform": { "position": [188.2202, 439.6458, 144.7051], "rotation": [-112.708, -30.378, -45.826], "scale": [34.5157, 34.5157, 31.2312] } }
  ]
}

Replaying the ops on the source gives a deterministic output GLB, so the log is the git diff, the undo stack and the record of what changed. Version 3 pose recipes — the ones the archived @threenative/pose-lab wrote — load as the same ops and still bake.

An op whose attachment is detached releases the prop in that clip. The bake writes no attachment track for it: where the prop goes after release is the game's physics, not an offset this package can invent.

View

animation_open_view starts the recovered Pose Lab page on 127.0.0.1 and returns its URL. A human drags the prop into place there; the page records the same ops an agent writes, so the two cannot disagree. It is a calibrator for one GLB, not a scene editor.

Not this package

asset_list_bundle_animations, asset_download_bundle_animation and the creature_* tools stay in threenative-asset-mcp: they download or compile assets and do not edit animation.

Edit this page on GitHub ↗