ae-meta-mcp

Lightweight After Effects MCP: a Cursor Agent runs ExtendScript inside a running After Effects via a single ae_exec tool — same mental model as Blender MCP (execute_blender_code) and CocosMetaMCP (cocosmcp_exec).

Cursor Agent  ──stdio MCP──▶  Node MCP server  ──HTTP :11488──▶  CEP panel (Express-free)  ──evalScript──▶  AE 2024

Tools (MVP)

Tool	Description
ae_health	Check the bridge is reachable; returns AE version + project info
ae_exec	Run arbitrary ExtendScript (ES3), returns JSON
ae_scene_info	Summarize project / comps / active comp layers

Requirements

• Windows 10/11
• After Effects 2024 (24.x), CEP 11
• Node.js >= 18

Install (Windows)

cd D:\workspace\ae_meta_mcp
npm install

# 1. Enable unsigned CEP extensions (PlayerDebugMode)
.\scripts\enable-debug-mode.ps1

# 2. Copy the panel into the CEP extensions folder
.\scripts\install-cep.ps1

# 3. Restart After Effects, then: Window -> Extensions -> ae-meta-mcp (keep it open)

In AE: Edit → Preferences → Scripting & Expressions → check Allow Scripts to Write Files and Access Network.

Wire up Cursor

Generate a snippet for your checkout:

npm run setup:cursor

Paste it into ~/.cursor/mcp.json (or project .cursor/mcp.json), then toggle ae-meta-mcp off/on in Cursor's MCP settings. See examples/cursor-mcp.json.

Verify

1. ae_health → { ok: true, aeVersion: "24.x" }
2. ae_exec create a comp:

   var c = app.project.items.addComp("MCP Test", 1920, 1080, 1, 10, 30);
   ({ name: c.name, width: c.width, height: c.height })
   

3. ae_scene_info → list includes MCP Test
4. Close the panel, run ae_exec again → bridge-unreachable error

Writing ExtendScript

ae_exec runs ES3 (no let/const, arrow functions, template literals, etc.). See skills/ae-extendscript/SKILL.md for constraints, the object model, and recipes.

Layout

mcp/      Node stdio MCP server (index, core, context, bridge-client)
plugin/   CEP panel (manifest, client UI, Node http host, jsx)
scripts/  install-cep.ps1, enable-debug-mode.ps1, setup-cursor.mjs
skills/   ae-extendscript agent skill
examples/ cursor-mcp.json
docs/     DEV.md (design doc)

Troubleshooting

Symptom	Fix
No ae-meta-mcp under Extensions	Run enable-debug-mode.ps1; check manifest HostList; restart AE
/health connection refused	Panel not open; port in use
EvalScript error	Script isn't ES3; test via File → Scripts → Run Script File
Empty result	Last line must be an expression or return
Write-file fails	Enable "Allow Scripts to Write Files and Access Network"
MCP tool not found	Reload MCP in Cursor; check the args path

Security

The bridge binds 127.0.0.1 only. ae_exec is full local control of AE — use for local development only.

License

MIT