Mark

Mark lets an AI drive Adobe After Effects directly. It reads your project and makes the changes itself (layers, keyframes, effects, expressions, text, render queue and more) instead of handing you a script to paste.

It has two parts:

• A panel inside After Effects (Window > Extensions > Mark) with its own Chat tab, so you can talk to Claude without leaving AE, plus Recipes (save something that worked and re-run it from a button, with no AI and no tokens), a Log of every call, and a Bridge tab with the connection status.

• An MCP server that gives Claude Code, Codex or any other MCP client about 135 After Effects tools. Full list: docs/TOOLS.md.

Mark is built on AE Portal by Ricardo G. Mendes / SphereLab (MIT). Everything AE Portal does still works the same; Mark adds the chat, recipes, memory, the log and a few fixes. Both panels can be open in the same AE at once: they use different ports and names.

Plain Node with zero npm dependencies. Everything runs on your machine.

Requirements

• After Effects 2022 (22.0) or newer. Tested on 2025 and 2026.

• Node.js 18 or newer.

• For the Chat tab: Claude Code, installed and signed in once. The chat runs it in the background.

• macOS or Windows.

Related MCP server: AfterEffectsMCP

Install on macOS

1. Download Mark and keep it somewhere permanent (the installer links AE to this folder, so moving or deleting it later breaks the panel):

   git clone https://github.com/transversal-tools/mark-ae.git ~/mark-ae
   cd ~/mark-ae

   Or download the zip from Releases and unzip it, then cd into the folder in Terminal.

2. Run the installer:

   ./install-mac.sh

   It turns on CEP debug mode for AE (PlayerDebugMode, needed because Mark is not a signed .zxp), links the folder into ~/Library/Application Support/Adobe/CEP/extensions/Mark, and registers the MCP server with Claude Code if it finds it. It is safe to run again.

3. Restart After Effects and open Window > Extensions > Mark.

for v in 9 10 11 12 13; do defaults write com.adobe.CSXS.$v PlayerDebugMode 1; done
mkdir -p ~/Library/Application\ Support/Adobe/CEP/extensions
ln -s "$PWD" ~/Library/Application\ Support/Adobe/CEP/extensions/Mark
claude mcp add -s user mark -- "$(command -v node)" "$PWD/mcp-server/server.js"

Install on Windows

1. Install Node (and Claude Code, for the Chat tab) in PowerShell as your normal user, then close and reopen PowerShell and run claude once to sign in:

   winget install OpenJS.NodeJS.LTS
   irm https://claude.ai/install.ps1 | iex

2. Download Mark and keep it somewhere permanent, for example:

   git clone https://github.com/transversal-tools/mark-ae.git "$env:USERPROFILE\mark-ae"
   cd "$env:USERPROFILE\mark-ae"

   Or download the zip from Releases and unzip it there. If Windows asks, right-click the zip > Properties > Unblock before unzipping.

3. Double-click install-windows.cmd in the Mark folder (as your normal user, not as administrator). Or run it from PowerShell:

   powershell -ExecutionPolicy Bypass -File install-windows.ps1

   It turns on CEP debug mode in the registry (HKCU\Software\Adobe\CSXS.<n>), creates a junction at %APPDATA%\Adobe\CEP\extensions\Mark pointing to the folder, and registers the MCP server with Claude Code if it finds it. It is safe to run again.

4. Restart After Effects and open Window > Extensions > Mark.

foreach ($v in 9..13) {
  New-Item -Path "HKCU:\Software\Adobe\CSXS.$v" -Force | Out-Null
  Set-ItemProperty -Path "HKCU:\Software\Adobe\CSXS.$v" -Name PlayerDebugMode -Value "1"
}
New-Item -ItemType Junction -Path "$env:APPDATA\Adobe\CEP\extensions\Mark" -Target "$PWD"
claude mcp add -s user mark -- node "$PWD\mcp-server\server.js"

The Chat tab and your API key

The chat uses the Claude Code installed on your computer. Click the model button inside the text box to choose how it pays:

• Subscription: uses the Claude account you signed in to Claude Code with. Nothing else to set up.

• API credits: paste an Anthropic API key (sk-ant-..., from console.anthropic.com) and click Save. On macOS it is stored in the Keychain (item "Mark - Anthropic API key"); on Windows it is stored in a file encrypted with your Windows login (DPAPI). It is only passed to the chat's own Claude Code process, and Delete key removes it.

The same menu picks the model (Opus, Sonnet, Haiku) and the effort. The footer shows what the day has cost, as reported by Claude Code.

In the chat, Claude can only use Mark's tools, and scripts that write, delete, rename or run files are refused. This is a guard, not a full sandbox.

Use Mark from Claude Code or Codex

The panel has to be open in AE for any client to reach it. The connection dot in the Bridge tab turns green when a client is connected.

Claude Code (the installers already do this):

claude mcp add -s user mark -- node /absolute/path/to/mark-ae/mcp-server/server.js

Codex: add to ~/.codex/config.toml (the installers print this block with your paths):

[mcp_servers.mark]
command = "node"
args = ["/absolute/path/to/mark-ae/mcp-server/server.js"]

On Windows use forward slashes in the path, for example C:/Users/you/mark-ae/mcp-server/server.js.

Claude Desktop and other MCP clients: run node /absolute/path/to/mark-ae/mcp-server/server.js over stdio, with the server named mark.

First check, from your client: call ping (expect pong and your AE version), then get_project_map with mode: "light".

Two things depend on the client: render_frame and render_preview_strip return images, so the client has to pass image results to the model; and the server sends its usage guide in the instructions field of initialize. If your client ignores that field, paste mcp-server/instructions.js into your AGENTS.md.

More than one AE at once (for example 2025 and 2026): call list_instances, then pass instance: "2026" on each call, or call use_instance once. With two connected, Mark refuses to guess. Only one AE per major version is supported.

Update

git pull in the Mark folder (or replace it with a new zip in the same place), then click ↻ in the panel. Changes to CSXS/manifest.xml need an AE restart.

Where your data lives

• Recipes, memory and daily cost: ~/Library/Application Support/Mark on macOS, %APPDATA%\Mark on Windows.

• Lessons from Learning mode: knowledge/learned-templates.md in the Mark folder.

• Backup: a copy of those files (latest, plus one per day for 30 days) in the data folder's Backup subfolder. To put it somewhere else, such as a synced folder, write that folder's absolute path on the first line of backup-dir.txt in the data folder.

Security

• The panel and the MCP server talk only over 127.0.0.1, with a token the panel generates. Nothing is exposed to the network.

• run_jsx runs any ExtendScript. Connect only clients you trust.

• No telemetry, no licence check, no remote code.

Troubleshooting

• The panel is not in Window > Extensions: run the installer again, check that PlayerDebugMode is 1, and that the Mark link in the CEP extensions folder points to this folder. Restart AE.

• "panel is not connected": open Window > Extensions > Mark. The server reconnects on its own.

• Node not found by your client: use the absolute path from command -v node (macOS) or (Get-Command node).Source (Windows) instead of node.

• Opening a project through Mark closes the panel in some AE versions. Reopen it, or open projects yourself.

• undo can report success and change nothing. Re-read the state to check.

Known issues and their history: docs/BUGS.md.

What After Effects cannot script

These are limits of AE's scripting API, so no tool can do them: Roto Brush and paint strokes, CUSTOM_VALUE effect parameters (Curves, Colorama gradients), Output Module codec settings (apply a saved template instead), starting a motion or camera track, grid settings, per-footage color profiles, and reading the Essential Graphics panel.

License

MIT. See LICENSE. Original AE Portal © 2026 Ricardo G. Mendes / SphereLab.