after-effects · aedev-tools — Claude Code skill: features and installation

---
name: after-effects
description: >
  Automate Adobe After Effects via ExtendScript. Use when the user asks to
  create, modify, or query anything in an After Effects project — layers,
  keyframes, expressions, effects, compositions, assets, rendering, batch
  operations. Generates and executes JSX ExtendScript via osascript on macOS.
compatibility: Requires macOS with Adobe After Effects installed. Needs "Allow Scripts to Write Files and Access Network" enabled in AE Preferences > Scripting & Expressions.
allowed-tools: Bash(osascript *) Bash(chmod *) Bash(bash *) Read Write
metadata:
  author: aedev-tools
  version: "1.0"
---

## 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

1. Run `scripts/runner.sh` with any query script to detect the AE version
2. If multiple AE versions are installed, the user must choose one — runner.sh will prompt
3. 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)

Use `--background` for all query scripts — this skips `ae.activate()` so AE doesn't steal focus:

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

Only use full mode when you actually need every item listed:
```bash
bash scripts/runner.sh --background 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 --background scripts/comp-detail.jsx '{"compName": "Comp Name"}'
```

If the task targets specific layers:
```bash
bash scripts/runner.sh --background 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 --background scripts/expression-errors.jsx
bash scripts/runner.sh --background scripts/expression-errors.jsx '{"compName": "Main Comp"}'
```

**Font inventory** — list all fonts used across the project:
```bash
bash scripts/runner.sh --background 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 --background scripts/project-audit.jsx
bash scripts/runner.sh --background 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](rules/layer-manipulation.md) |
| Keyframes, animation, easing | [rules/keyframes-animation.md](rules/keyframes-animation.md) |
| Expressions | [rules/expressions.md](rules/expressions.md) |
| Compositions (create, precompose, nest) | [rules/composition-management.md](rules/composition-management.md) |
| Effects and parameters | [rules/effects.md](rules/effects.md) |
| Import, footage, assets | [rules/assets-footage.md](rules/assets-footage.md) |
| Render queue, export | [rules/rendering.md](rules/rendering.md) |
| Bulk/batch operations | [rules/batch-operations.md](rules/batch-operations.md) |
| Version-specific features | [references/ae-api-versions.md](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 = getActiveComp();
        if (!comp) 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();
    }
})();
```

#### utils.jsx helpers available for generated scripts

| Function | Purpose |
|----------|---------|
| `writeResult(obj)` | Write JSON result to `/tmp/ae-assistant-result.json` |
| `writeError(msg, detail)` | Last-resort error capture when JSON.stringify fails |
| `readArgs()` | Read args from `/tmp/ae-assistant-args.json` |
| `getLayerType(layer)` | Returns type string: "shape", "text", "null", "precomp", etc. |
| `getBlendModeName(mode)` | BlendingMode enum → string name |
| `getActiveComp()` | Returns active comp or writes error and returns null |
| `getSelectedOrAllLayers(comp)` | Selected layers array, or all layers if none selected |
| `hexToRGB(hex)` | `"#ff0000"` → `[1, 0, 0]` |
| `getCompByName(name)` | Find comp in project items by name |
| `walkProperties(group, leafFn, path)` | Recursive property tree walker — calls `leafFn(prop, path)` on leaves |
| `bubbleSort(arr, compareFn)` | ES3-compatible in-place sort |
| `framesToSeconds(frames, comp)` | Frame count → seconds via `comp.frameDuration` |
| `appendLog(message)` | Append to `~/.ae-assistant-extendscript.log` |

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

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

**Trim Comp to Content** — trim/extend comp duration to exactly fit layer content:
```bash
bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/trim-comp-to-content.jsx"
bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/trim-comp-to-content.jsx" '{"padding": 0.5}'
bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/trim-comp-to-content.jsx" '{"recursive": true}'
```

**Null from Layers** — create a null at each selected layer's position, auto-parent:
```bash
bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/null-from-layers.jsx"
bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/null-from-layers.jsx" '{"naming": "custom", "prefix": "Driver"}'
bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/null-from-layers.jsx" '{"position": "comp-center"}'
```

**Fit to Comp** — scale selected layers to fit/fill comp dimensions:
```bash
bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/fit-to-comp.jsx" '{"mode": "fit"}'
bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/fit-to-comp.jsx" '{"mode": "fill"}'
bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/fit-to-comp.jsx" '{"mode": "stretch"}'
```

**Label Layers** — batch-set label colors on layers by type, name, or selection:
```bash
bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/label-layers.jsx" '{"label": 3, "target": "selected"}'
bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/label-layers.jsx" '{"label": 1, "target": "text"}'
bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/label-layers.jsx" '{"label": 5, "target": "all", "nameContains": "BG"}'
```

**Blend Mode Set** — set blending mode on selected layers:
```bash
bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/blend-mode-set.jsx" '{"mode": "SCREEN"}'
bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/blend-mode-set.jsx" '{"mode": "MULTIPLY"}'
bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/blend-mode-set.jsx" '{"mode": "ADD"}'
```

**Split Layer** — split selected layers at CTI (confirm before running — modifies layer timing):
```bash
bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/split-layer.jsx"
bash "$SKILL_SCRIPTS/runner.sh" "$SKILL_SCRIPTS/split-layer.jsx" '{"time": 2.5}'
```

### 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:
1. **`~/.ae-assistant-log`** — runner.sh logs every execution, args, results, and errors here
2. **`/tmp/ae-assistant-error.txt`** — JXA-level errors (AE not responding, DoScriptFile failure)
3. **`~/.ae-assistant-extendscript.log`** — ExtendScript-level logs from `appendLog()` in utils.jsx
4. **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 use `getActiveComp()` to get the active comp (handles the null/CompItem check and writes error)
- ALWAYS use `--background` flag for query scripts to avoid focus-steal

## 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