Expressions and scripting parity
Last reviewed: 2026-10-12 · Last updated: 2026-10-12 · Change: minor (
#include/#targetremoved from the estimate (landed in #759)) · 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 | Anima | 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, including
propertyGroup(countUp) and a group's
propertyIndex for name-independent rigs (#1619) |
good | crates/expr/src/tests.rs,
tests/property_group.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) |
$.evalFile, BridgeTalk |
Evaluate another script file; identify the host application and message other Adobe applications | $.evalFile evaluates a file relative to the calling
file (nested at most 32 deep, under the scripts' file gate) and returns
its last value; BridgeTalk names the host honestly
(appName anima, its version); messaging other
applications throws "not supported" |
partial | tests_evalfile.rs (#760); no inter-application
messaging |
| ScriptUI | Dialogs, palettes, dockable panels, resource strings,
onDraw / ScriptUIGraphics, mouse events |
Same, dockable panels reopen at launch | good | ui_scriptui, tests_ui* |
app.scheduleTask / cancelTask |
One-shot and repeating tasks (polling, panel refresh) until
cancelTask |
Same: repeating tasks run every delay ms (at least 50
ms, at most 64 pending per script) until cancelTask, until
they throw (reported once, then cancelled), or until their owner goes: a
script's last window closing, or the project closing for scripts without
windows; frontends tick them every frame, agents with
script.runTasks |
good | tests_tasks.rs (#773); one-shot tasks of a script file
still run right after it, not after their delay |
| Scripts menu, ScriptUI Panels folder | yes | yes | same | plugins.md |
| Startup / Shutdown folders | yes | not run | missing | plugins.md |
#include, #target directives |
yes | #include / //@include /
#includepath inline files relative to the including script
(once each, nested at most 32 deep, under the scripts' file gate; errors
name the included file and line); #target,
#targetengine, #strict are ignored |
good | tests_include.rs (#759); installed scripts and panels
have no folder of their own, so they include from the project's folder
or absolute paths |
.jsxbin |
yes | no | out of scope | No public specification |
| Keyboard shortcuts for scripts | yes | no | missing | plugins.md |
Command-line rendering aerender |
yes | anima-cli render, script,
exec |
same purpose | apps/anima-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 (landed, #759) and Startup / Shutdown folders 4–8 h
as first estimated (Startup / Shutdown remain), 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 |
|---|---|---|
| 2026-10-16 | minor | Expression object model row names propertyGroup() and a
group's propertyIndex (#1619) |
| 2026-10-12 | minor | Estimate no longer counts #include /
#target (#759, tests_include.rs); the table
row was already current |
| 2026-10-10 | major | First expressions and scripting checklist |