Why Slippy
Most Adobe MCP servers send scripts to the app from outside it. Slippy lives inside the app.
It runs inside the app
The usual way to give an agent Illustrator or Photoshop is a separate server program, often Node or Python, that the agent talks to, which then sends scripts into the app: ExtendScript (JSX), or messages to a JavaScript panel. That's three moving parts, and the script layer can only do what the scripting API exposes.
Slippy is a native C++ plug-in with the MCP server built in. The agent talks straight to the app, and each call runs through Adobe's own SDK on the app's main thread. There's no proxy to start, no JSX, no Python.
| A typical Adobe MCP server | Slippy | |
|---|---|---|
| What you run | a server program, plus a plug-in or script in the app | just the plug-in; it starts with the app |
| How calls run | scripts (JSX) or a JavaScript panel | the app's C++ SDK, directly |
| Undo | often one step per internal operation, or none | one named step per call (or per batch) |
| When the app is busy | a script can hang behind a dialog | no dialogs; a busy app answers right away |
| Seeing what happened | logs, if any | a live panel, plus a call log |
Every call is one undo
An agent's change shows up as a single step in Edit > Undo (Photoshop: History), named after what it did, like Slippy: Renamed a layer to “Logo”. A batch of calls is one step too, so “undo what the agent just did” is always one press.
It won't wreck your work
- No surprise saves. Closing a document discards changes unless the agent explicitly asks to save.
- No dialogs. Slippy runs with the app's alerts off, so an agent can't freeze it behind a "Save changes?" box.
- Saves and exports run on their own, never mixed into a batch's edits, which is how other tools lose work.
- Honest errors. A command that can't run says what went wrong, in plain words, and changes nothing.
You can see what it's doing
Slippy's panel shows each call as it happens, in plain English (“Rotated “Logo” 15°”, “Couldn’t find that layer”), with the logo of the agent that sent it. In Illustrator, each change also gets a green box on the canvas around what it touched. And Slippy, the frog, sleeps when nothing's happening, wakes up when an agent starts, and winces at errors, so you can tell at a glance whether an agent is working.
It reaches the whole app
Besides about 190 named commands in Illustrator, Slippy can run any menu command, play any action, and message other
plug-ins. In Photoshop, ps.batchplay plays any action descriptor, the same thing Photoshop's own recorded actions use,
so if Photoshop can do it, an agent can.
It stays on your computer
Slippy's server only listens on your own machine (127.0.0.1), needs your token, and refuses web pages, so a
website can't reach it. Your documents never leave your computer; only your agent sees what it asks for.