after-effects

Overview

This skill automates After Effects by generating ExtendScript (.jsx) and executing it via osascript. It reads project state through query scripts, uses rule files for domain knowledge, and wraps all mutations in undo groups.

First-Time Setup

Run
```
scripts/runner.sh
```
with any query script to detect the AE version
If multiple AE versions are installed, the user must choose one — runner.sh will prompt
Ensure AE Preferences > Scripting & Expressions > "Allow Scripts to Write Files and Access Network" is enabled

Workflow

For every user request:

Step 1: Gather context (auto-run, no confirmation needed)

Run the active state query:

bash

bash scripts/runner.sh scripts/active-state.jsx

Then read

/tmp/ae-assistant-result.json

for active comp, selected layers, CTI.

If this is the first interaction or the project context is unknown, also run:

bash

bash scripts/runner.sh scripts/project-overview.jsx

This returns a summary by default: folder tree with counts, all comps listed, footage grouped by file type. NOT every individual file.

To drill into a specific folder:

bash

bash scripts/runner.sh scripts/project-overview.jsx '{"mode": "folder", "folderName": "Images"}'

Only use full mode when you actually need every item listed:

bash

bash scripts/runner.sh scripts/project-overview.jsx '{"mode": "full"}'

Step 2: Drill down if needed (auto-run)

If the task targets a specific comp:

bash

bash scripts/runner.sh scripts/comp-detail.jsx '{"compName": "Comp Name"}'

If the task targets specific layers:

bash

bash scripts/runner.sh scripts/layer-detail.jsx '{"layerNames": ["Layer 1", "Layer 2"]}'

Omit

compName

to use the active comp. Omit

layerNames

to use selected layers.

Additional query scripts

Expression errors — scan for broken expressions:

bash

bash scripts/runner.sh scripts/expression-errors.jsx
bash scripts/runner.sh scripts/expression-errors.jsx '{"compName": "Main Comp"}'

Font inventory — list all fonts used across the project:

bash

bash scripts/runner.sh scripts/font-inventory.jsx

Project audit — comprehensive health check (unused footage, missing files, expression errors, duplicate solids, font issues, empty folders):

bash

bash scripts/runner.sh scripts/project-audit.jsx
bash scripts/runner.sh scripts/project-audit.jsx '{"checks": ["unused", "missing", "expressions"]}'

Step 3: Load domain knowledge

Read the relevant rule file from

rules/

. Always read

rules/extendscript-fundamentals.md

— it contains ES3 constraints that apply to every generated script.

Task involves	Load rule file
Layers (create, move, parent, duplicate)	rules/layer-manipulation.md
Keyframes, animation, easing	rules/keyframes-animation.md
Expressions	rules/expressions.md
Compositions (create, precompose, nest)	rules/composition-management.md
Effects and parameters	rules/effects.md
Import, footage, assets	rules/assets-footage.md
Render queue, export	rules/rendering.md
Bulk/batch operations	rules/batch-operations.md
Version-specific features	references/ae-api-versions.md

Step 4: Generate the action script

CRITICAL: Resolve the skill's real path first

Before writing or executing any action script, resolve the skill's real (non-symlinked) path. ExtendScript

#include

cannot follow symlinks, so you MUST use the real filesystem path.

Run this once at the start of each session:

bash

SKILL_SCRIPTS="$(readlink -f ~/.claude/skills/after-effects-assistant/scripts 2>/dev/null || readlink ~/.claude/skills/after-effects-assistant/scripts)"
echo "$SKILL_SCRIPTS"

Use the resolved path (

$SKILL_SCRIPTS

) for all subsequent Write and Bash commands in this session.

Why this matters:

```
~/.claude/skills/
```
is typically a symlink — ExtendScript
```
#include
```
fails through symlinks
Writing to the real
```
scripts/
```
directory lets
```
#include "lib/json2.jsx"
```
resolve correctly
The resolved path changes per machine, so never hardcode it

Every generated script MUST follow this template:

jsx

#include "lib/json2.jsx"
#include "lib/utils.jsx"

(function() {
    app.beginUndoGroup("AE Assistant: <action description>");
    try {
        var args = readArgs();
        var comp = app.project.activeItem;
        if (!comp || !(comp instanceof CompItem)) {
            writeResult({ error: "No active composition" });
            return;
        }

        // ... action code ...

        writeResult({ success: true, message: "<what was done>" });
    } catch (e) {
        try { writeResult({ error: e.toString(), line: e.line, fileName: e.fileName }); }
        catch(e2) { writeError(e.toString(), "line:" + e.line); }
    } finally {
        app.endUndoGroup();
    }
})();

Write the script using the Write tool, then execute with a short bash command:

Use the Write tool to write the script to
```
$SKILL_SCRIPTS/ae-action.jsx
```
(the resolved real path)
Execute it with bash:

bash

bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/ae-action.jsx"

IMPORTANT: Do NOT use

cat > file << 'SCRIPT'

heredocs — they put the entire script in the bash command, cluttering the permission prompt. Always use the Write tool for the script content, then a short bash command to run it.

Step 5: Execute or confirm

Auto-run (no confirmation needed):

All read-only queries (active-state, project-overview, comp-detail, layer-detail, expression-errors, font-inventory, project-audit)
Non-destructive additions: adding a keyframe, adding an effect, creating a layer, creating a comp

Confirm before running (show the script and ask the user):

Deleting layers or comps
Removing keyframes
Replacing footage
Clearing expressions
Render queue operations
Project cleanup (removing unused items, consolidating solids)
Any operation the user might not expect

Built-in action scripts

Before generating a custom

ae-action.jsx

, check if a built-in script already handles the task. These are permanent, tested scripts with args-based behavior:

True Comp Duplicator — deep-clone a comp with independent sub-comps (confirm before running):

bash

bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/true-comp-duplicator.jsx" '{"compName": "Main Comp", "suffix": " COPY"}'

Font Replace — find and replace fonts across the project. Always dryRun first:

bash

bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/font-replace.jsx" '{"find": "Helvetica", "replace": "Inter-Regular", "dryRun": true}'
bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/font-replace.jsx" '{"find": "Helvetica", "replace": "Inter-Regular"}'

Project Cleanup — remove unused footage, consolidate duplicate solids, remove empty folders. Always dryRun first:

bash

bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/project-cleanup.jsx" '{"dryRun": true}'
bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/project-cleanup.jsx"

Batch Rename — rename layers, comps, or project items in bulk:

bash

bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/batch-rename.jsx" '{"target": "layers", "mode": "find-replace", "find": "Layer", "replace": "Element"}'
bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/batch-rename.jsx" '{"target": "layers", "mode": "prefix", "prefix": "BG_"}'
bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/batch-rename.jsx" '{"target": "layers", "mode": "sequence", "base": "Card", "start": 1}'

Layer Stagger — offset selected layers in time for cascade animations:

bash

bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/layer-stagger.jsx" '{"offset": 0.1, "unit": "seconds", "direction": "forward"}'
bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/layer-stagger.jsx" '{"offset": 2, "unit": "frames"}'

Expression Replace — find/replace text in expressions project-wide. Always dryRun first:

bash

bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/expression-replace.jsx" '{"find": "comp(\"Old\")", "replace": "comp(\"New\")", "dryRun": true}'
bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/expression-replace.jsx" '{"find": "comp(\"Old\")", "replace": "comp(\"New\")"}'

Organize Project — auto-sort project panel items into folders by type:

bash

bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/organize-project.jsx" '{"structure": "by-type"}'
bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/organize-project.jsx" '{"structure": "by-extension"}'

Batch Comp Settings — change fps, resolution, duration across multiple comps:

bash

bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/batch-comp-settings.jsx" '{"scope": "all", "fps": 25}'
bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/batch-comp-settings.jsx" '{"compNames": ["Comp 1", "Comp 2"], "width": 3840, "height": 2160}'
bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/batch-comp-settings.jsx" '{"scope": "nested", "fps": 30, "duration": 10}'

Easing Presets — apply professional easing or bounce/elastic expressions:

bash

bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/easing-presets.jsx" '{"preset": "smooth"}'
bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/easing-presets.jsx" '{"preset": "snappy"}'
bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/easing-presets.jsx" '{"preset": "bounce"}'

Anchor Point Mover — reposition anchor point with visual position compensation:

bash

bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/anchor-point-mover.jsx" '{"position": "center"}'
bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/anchor-point-mover.jsx" '{"position": "bottom-left"}'

Reverse Keyframes — reverse animation on selected properties:

bash

bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/reverse-keyframes.jsx"

Select Layers — select layers by type, label, attribute, or name:

bash

bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/select-layers.jsx" '{"type": "text"}'
bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/select-layers.jsx" '{"hasExpressions": true}'
bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/select-layers.jsx" '{"nameContains": "BG"}'

Layer Sort — reorder layers in timeline by name, position, in-point, type, or label:

bash

bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/layer-sort.jsx" '{"sortBy": "name", "order": "ascending"}'
bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/layer-sort.jsx" '{"sortBy": "position-y"}'

Smart Precompose — precompose with auto-trimmed duration:

bash

bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/smart-precompose.jsx" '{"name": "My Precomp", "trimToContent": true}'

Copy Ease — copy easing from one keyframe and paste to others:

bash

bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/copy-ease.jsx" '{"mode": "both"}'
bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/copy-ease.jsx" '{"sourceLayer": "Logo", "sourceProperty": "Position", "sourceKeyIndex": 2}'

Relink Footage — batch-relink missing footage from search directories. Always dryRun first:

bash

bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/relink-footage.jsx" '{"searchPaths": ["/Volumes/Projects/footage"], "dryRun": true}'
bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/relink-footage.jsx" '{"searchPaths": ["/Volumes/Projects/footage"]}'

SRT Import — create timed subtitle text layers from an SRT file:

bash

bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/srt-import.jsx" '{"srtPath": "/path/to/subs.srt", "fontSize": 48}'

Text Export/Import — export all text to CSV, edit externally, reimport:

bash

bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/text-export-import.jsx" '{"mode": "export", "csvPath": "/tmp/text.csv"}'
bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/text-export-import.jsx" '{"mode": "import", "csvPath": "/tmp/text.csv"}'

Batch Expression — apply, remove, enable, or disable expressions in bulk:

bash

bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/batch-expression.jsx" '{"property": "opacity", "expression": "wiggle(2, 10)", "mode": "apply"}'
bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/batch-expression.jsx" '{"mode": "remove"}'
bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/batch-expression.jsx" '{"mode": "disable"}'

Randomize Properties — apply random values to transform properties:

bash

bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/randomize-properties.jsx" '{"property": "rotation", "min": -15, "max": 15}'
bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/randomize-properties.jsx" '{"property": "position", "minX": 0, "maxX": 1920, "minY": 0, "maxY": 1080}'

Un-PreCompose — extract layers from a precomp back into parent (confirm before running):

bash

bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/un-precompose.jsx" '{"precompLayerName": "Precomp 1"}'

Comp from CSV — generate comp variations from spreadsheet data (confirm before running):

bash

bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/comp-from-csv.jsx" '{"templateComp": "Lower Third", "csvPath": "/path/data.csv"}'

Render Queue Batch — add multiple comps to render queue (confirm before running):

bash

bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/render-queue-batch.jsx" '{"compNames": ["Final_16x9", "Final_9x16"], "outputPath": "~/Desktop/renders/"}'
bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/render-queue-batch.jsx" '{"scope": "folder", "folderName": "Finals"}'

Explode Shape Layer — split shape groups into individual layers:

bash

bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/explode-shape-layer.jsx" '{"layerName": "AI Import"}'

Incremental Save — save project with auto-incrementing version number:

bash

bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/incremental-save.jsx" '{"comment": "before revisions"}'

Purge Cache — clear memory caches, disk cache, and free resources. dryRun to check size first:

bash

bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/purge-cache.jsx" '{"dryRun": true}'
bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/purge-cache.jsx"
bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/purge-cache.jsx" '{"memory": true, "disk": false}'

Step 6: Execute and read result

bash

# Execute the action script (already written to $SKILL_SCRIPTS/ae-action.jsx in Step 4)
bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/ae-action.jsx" '{"arg1": "value1"}'

Read

/tmp/ae-assistant-result.json

for the result.

Debugging failures

If a script fails, check these in order:

~/.ae-assistant-log
— runner.sh logs every execution, args, results, and errors here
/tmp/ae-assistant-error.txt
— JXA-level errors (AE not responding, DoScriptFile failure)
~/.ae-assistant-extendscript.log
— ExtendScript-level logs from
```
appendLog()
```
in utils.jsx
AE Preferences — Ensure "Allow Scripts to Write Files and Access Network" is enabled

When an error occurs, read

~/.ae-assistant-log

to understand what happened, fix the script, and retry.

MUST

ALWAYS wrap mutations in
```
app.beginUndoGroup()
```
/
```
app.endUndoGroup()
```
ALWAYS use matchNames for property access, not display names (display names are localized)
ALWAYS use 1-based indexing for layers and project items
ALWAYS write action scripts to
```
$SKILL_SCRIPTS/ae-action.jsx
```
(the resolved real path, NOT
```
/tmp/
```
)

ALWAYS use relative

#include "lib/json2.jsx"

and

#include "lib/utils.jsx"

(NOT absolute paths)

ALWAYS wrap in an IIFE to avoid global scope pollution
ALWAYS use
```
var
```
, never
```
let
```
or
```
const
```
(ES3)
ALWAYS write results to /tmp/ae-assistant-result.json via writeResult()
ALWAYS check
```
comp instanceof CompItem
```
before accessing comp properties

FORBIDDEN

NEVER use ES5+ syntax: let, const, arrow functions, template literals, destructuring
NEVER use Array.map, Array.filter, Array.reduce, Array.forEach (not in ES3)
NEVER use JSON.parse or JSON.stringify without including json2.jsx
NEVER write action scripts to
```
/tmp/
```
— ExtendScript
```
#include
```
can't resolve paths from there
NEVER use absolute paths in
```
#include
```
— they break through symlinks
NEVER hardcode layer indices — use names, selection, or iteration
NEVER run destructive operations without user confirmation
NEVER assume a comp is active without checking
NEVER use
```
cat > file << 'SCRIPT'
```
heredocs to write scripts — use the Write tool instead, then execute with a short bash command

after-effects

NPX Install

Tags

SKILL.md Content

Overview

First-Time Setup

Workflow

Step 1: Gather context (auto-run, no confirmation needed)

Step 2: Drill down if needed (auto-run)

Additional query scripts

Step 3: Load domain knowledge

Step 4: Generate the action script

Step 5: Execute or confirm

Built-in action scripts

Step 6: Execute and read result

Debugging failures

MUST

FORBIDDEN