vangel76andClaude Opus 5.5
bfe384e400
Problem: After Effects scripts call layers and property groups as a
shorthand for .property(nameOrIndex) (layer("ADBE Effect Parade"),
fxGroup(1), effect("Slider Control")("Slider")); Duik and many other
scripts use it throughout. EffectCraft's objects were Proxies around
plain objects, so each such call failed with "TypeError: not a callable
function".
Fix: Layer, PropertyGroup, MaskPropertyGroup and Property objects are
now Proxies around an arrow function carrying the object's state and
prototype (own name/length removed so the object's getters show). The
apply trap returns self.property(arg), so a call matches .property():
null when absent, Property returns null, and a missing name is the same
script error. instanceof, attribute access and script results are
unchanged; new on these objects stays a TypeError.
Co-Authored-By: Claude Opus 5.5 <[email protected]>
3.7 KiB
Expressions and scripting parity
Last reviewed: 2026-10-10 · Last updated: 2026-10-10 · Change: major (first expressions and scripting checklist against After Effects 2026 26.5) · Target: Adobe After Effects 2026
Expressions and ExtendScript are how After Effects work is automated and how much of it is
built: rigs, templates, studio pipelines. They are also what carries over from After Effects
today, while .aep projects can't. Architecture: architecture.md §5 and §5a;
extension points: plugins.md; overall numbers:
target-app-parity.md.
Breadth ≈ 93%, ready ≈ 65% (estimated). The object models are written from Adobe's public Expression Language Reference and Scripting Guide (behaviour only, AGENTS.md §2) and tested with our own scripts; no real-world script library has been run against both apps.
| Feature | After Effects 2026 | EffectCraft | Status | Evidence / gap |
|---|---|---|---|---|
| Expression language | JavaScript engine (default) and Legacy ExtendScript | JavaScript (boa) with legacy array maths (value + [10, 0]) |
good | crates/expr tests; no separate Legacy ExtendScript engine mode |
| Expression object model | thisComp, thisLayer, wiggle, loopOut, valueAtTime, sampleImage, footage(), text style API… |
Same members, from the reference | good | crates/expr/src/tests.rs; behaviour of edge cases unmeasured (G1) |
| Expression editing | Inline field, error bar, pick whip, Expression Language menu, external editors | Inline field that grows, error bar, pick whips (property and value), language menu | partial | External editor support (#364) |
| Expression performance | Cached, multi-frame | Per-thread boa contexts | unknown | No benchmark |
| Scripting object model | app, Project, items, layers, properties, keys, eases, render queue, TextDocument, Shape, markers, File/Folder, Socket, app.settings |
Same classes, edits run through undoable engine commands; match names table; layers, groups and properties are callable (layer("Effects")(1) is .property(...)) |
good | crates/script tests (≈ 10 test files) |
| ScriptUI | Dialogs, palettes, dockable panels, resource strings, onDraw / ScriptUIGraphics |
Same, dockable panels reopen at launch | good | ui_scriptui, tests_ui* |
| Scripts menu, ScriptUI Panels folder | yes | yes | same | plugins.md |
| Startup / Shutdown folders | yes | not run | missing | plugins.md |
#include, #target directives |
yes | a script starting with one doesn't parse | missing | plugins.md; common in real scripts |
.jsxbin |
yes | no | out of scope | No public specification |
| Keyboard shortcuts for scripts | yes | no | missing | plugins.md |
Command-line rendering aerender |
yes | effectcraft-cli render, script, exec |
same purpose | apps/effectcraft-cli |
| Essential Graphics scripting hooks | addToMotionGraphicsTemplate… |
yes (M13.7) | good | — |
| Agent control (MCP, control channel, every command) | none | yes | beyond | agents.md, control-protocol.md; list_effects omits parameter types and ranges (#441) |
| Real-world script corpus | — | none run | gap | Run popular free scripts (the 11 sample scripts After Effects ships are a good start, run as behaviour tests, never copied) |
Estimate
≈ 20–40 h: #include / #target and Startup / Shutdown folders 4–8 h, script shortcuts 2–4 h,
a corpus of public scripts and expressions with the fixes it finds 10–20 h, an expression
performance benchmark 4–8 h.
Revision history
| Date | Change | Summary |
|---|---|---|
| 2026-10-10 | major | First expressions and scripting checklist |