fix: animation, GeckoLib and display tools

[heide-oficial]

Fixes for animation, GeckoLib and display tools, found while auditing 1.9.3 with Blockbench 5.2.1, the GeckoLib plugin 4.2.5 and GeckoLib 5.5.7. One commit per issue:

• Export writes: export_model and the GeckoLib model, animation and display exports overwrote any file without asking, and relative paths resolved against Blockbench's working directory. They now share one writer: the path must be absolute and local, and an existing file is only replaced with overwrite: true (default false). The tools are marked destructive. Network (UNC) and device paths are refused, because writing to them makes Windows connect to the named host with the user's credentials.
• GeckoLib validator: it failed models for a missing modid or identifier, which GeckoLib 5.5.7 does not need (the game uses geometry.unknown).
  • Those, and bone names that differ only in case, are now warnings; exact duplicate bone names stay errors.
  • Lowercase easing names, none and catmullrom are accepted, and easing arguments may be numbers or Molang strings.
• Keyframe timing, interpolation and easing:
  • Keys created by the tools were rounded to the 1/24 s grid on export (0.05 became 0.0417). The animation snapping is now fitted to the keyframe times inside the same undo edit, so Redo restores it.
  • Editing only a keyframe's values reset its interpolation to linear; it is now kept unless one is passed.
  • Copy and paste keeps GeckoLib easing and easing arguments.
• animation_graph_editor:
  • It ignored the axis, wrote scalar handles into Blockbench's per-axis arrays, skipped the validations it described and could leave an unsafe Undo entry.
  • It now validates first, converts curves into native per-axis handles from each segment's duration and value change, and runs in one reversible edit.
  • In GeckoLib models it refuses step curves, because the GeckoLib plugin's render_frame handler switches step keys back to linear on every frame. It also refuses Bezier curves, which GeckoLib 5.5 loads as linear.
  • Smoothing clears GeckoLib easings in the same edit; the plugin otherwise dropped them silently on the next frame.
• Batch reverse, smooth and bake:
  • Reverse (and a negative scale) only moved times, so GeckoLib easings stayed on the wrong keys. It now follows the native Reverse Keyframes action, including the GeckoLib plugin's easing shift and the pre/post and Bezier handle swaps.
  • Smooth and bake clear the easings they replace, and report it.
• geckolib_reverse_keyframe_easing: with the GeckoLib plugin loaded, the native reverse already shifts easings, so running this tool afterwards shifted them twice. This is documentation only: a previous shift cannot be detected, so the description now says when to use the tool.
• Export format: geometry and animations were always written as two-space JSON.stringify, so re-exported files never matched native ones. They now go through Blockbench's autoStringify, with the user's indentation and minify settings and numbers rounded to five decimals. The display export keeps the two-space JSON the GeckoLib plugin itself writes.
• Display parent: the display export writes the plugin's builtin/entity parent, which Minecraft Java 1.21.4 and later no longer have; the game reports a missing model. The default stays, so files keep matching the plugin's own export and older versions keep working. The result now warns about it, and a new parent option writes another parent or none.
• set_display_transform: it accepted values the game silently changes. Translation is clamped to ±80 and scale to ±4 (checked as exported, with the mirror sign), pivots are not read, and there is no embedded slot. Values stay as given, like Blockbench keeps them, but Java projects get warnings.
• bone_rigging:
  • An unknown parent moved the bone to the root while reporting success. Parents now resolve by UUID or unique name, in create too; cycles and ambiguity are errors.
  • Mirror only negated the copy's pivot. It now duplicates the bone and flips the copy like Blockbench's Flip action.
  • One shared Undo snapshot lost deleted cubes, copies, names and pivots, and deleting a bone lost its keyframes in every animation. Each action now records what it changes, including those animations, in one reversible edit.
• create_animation name: the animation. prefix was added silently, and twice to a name that already had it. The parameter now documents the prefix, and a name that already starts with it is kept.

Behaviour changes to be aware of:

• animation_graph_editor refuses input it used to accept silently.
  • Single-axis linear, stepped and smooth requests are refused.
  • Ranges and keys are validated.
  • GeckoLib projects refuse stepped and Bezier curves.
  • Its ease presets now produce the CSS cubic-bezier curves, and it may unlink Bezier handles.
• Batch reverse and negative scale also swap pre/post values and Bezier handles.
• Mirrored bones get Blockbench's names (left↔right, or a unique copy name) instead of a _mirrored suffix.
• GeckoLib geometry and animation exports follow the user's JSON settings (tabs by default).
• The export tools need absolute local paths, and overwrite: true to replace a file.
• geckolib_export_display has a new parent option; it and set_display_transform return warnings.

Not included:

• manage_keyframes still accepts step and Bezier interpolation in GeckoLib projects.
• Time scaling does not scale Bezier handle times.
• set_display_transform still calls Undo.initEdit/finishEdit directly.

Testing:

• bun test: 1,232 pass, 0 fail (main: 1,184). bunx tsc --noEmit shows the same errors as main (none new). bun run build and bun run docs:build pass.
• Live, with all the related PRs loaded together in Blockbench 5.2.1 and the GeckoLib plugin 4.2.5 on Windows 11.
  • These failed in the audit of 1.9.3 and pass now:
    • Overwrite refusal.
    • 0.05 s keys kept on export.
    • Interpolation kept on edit.
    • Easing kept on copy/paste.
    • Stepped on one axis refused.
    • Unknown parent refused.
    • Display parent warning.
    • Validator warnings instead of errors.
    • The animation. prefix documented.
  • Added later and passing:
    • No double prefix.
    • Bone delete + Undo restores the bone's keyframes, and Redo removes them again.
• Upstream's test:animation:live passes all 46 checks against the same build. It caught a regression in an earlier version of this branch (the snapping fit ran outside the undo edit), which is fixed here.

Related PRs from the same audit: #70 (HTTP server, settings and file inputs), #71 (views and captures), #72 (modeling tools), #74 (paint and textures), #75 (headless server), #69 (loopback bind). All of them merge together without conflicts (checked).

🤖 Generated with Claude Code

[coderabbitai]

Warning

Review limit reached

You've used all free OSS reviews for now. Wait for the free limit to reset to keep reviewing this public repository.

Next included review available in 59 minutes.

Check out review usage here.

View limit details

Limit details: You’ve used all 2 included reviews currently available.

Learn how review limits work.

Review configuration:

⚙️ Run configuration

Configuration used: Repository: jasonjgardner/blockbench-mcp-plugin/.coderabbit.yaml

Review profile: CHILL

Plan: Advanced

Run ID: 5624a909-5ae8-454d-8c39-bc72e2cae15f

📥 Commits

Reviewing files that changed from the base of the PR and between 6295e20 and ae49562.

📒 Files selected for processing (31)

• lib/animation-undo.test.ts
• lib/animation-undo.ts
• lib/export-file.test.ts
• lib/export-file.ts
• lib/geckolib-display.ts
• lib/geckolib-easing.ts
• lib/geckolib-validate.test.ts
• lib/geckolib-validate.ts
• lib/geckolib.test.ts
• lib/geckolib.ts
• lib/zodObjects.ts
• server/tools/animation/batch.ts
• server/tools/animation/copy-paste.ts
• server/tools/animation/create.ts
• server/tools/animation/curves.ts
• server/tools/animation/docs.ts
• server/tools/animation/keyframes.ts
• server/tools/animation/rigging.ts
• server/tools/animation/schemas.ts
• server/tools/animation/shared.ts
• server/tools/display.test.ts
• server/tools/display.ts
• server/tools/export.ts
• server/tools/geckolib.test.ts
• server/tools/geckolib.ts
• server/tools/geckolib/docs.ts
• server/tools/geckolib/schemas.ts
• tests/animation-batch.test.ts
• tests/animation-graph-editor.test.ts
• tests/animation-tools.test.ts
• tests/bone-rigging.test.ts

• Autopilot · Keep fixing CodeRabbit findings and required CI, and resolving merge conflicts

Autopilot is currently an internal CodeRabbit preview.

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands.}