Prefab

io.prefabappPublished by prefabapp.iov0.1.1Updated Oct 25, 2026

List, create and deploy your Prefab project templates from any MCP agent.

VerifiedSTDIODesktop onlyProductivity & WorkflowFiles & Storage

Overview

AI-generated overview

A local MCP server for Prefab that lets an assistant list your project templates and deploy one to create folders on your Mac.

What you can do
List and describe templates, including their structure, placeholders and actions, plus library-wide globals and watched folders with their rules. Preview a deploy to see what would be created and which values are still missing, without creating anything. Deploy a template to create the folders, filling in the values you supply.
When to use it
Useful when you keep reusable folder and file templates in Prefab on a Mac and want an assistant to set up a new project or client folder from one, for example a new campaign directory, after checking the preview.
Requirements
macOS with Prefab installed and opened once, and Node 18+ unless you install the bundle, which brings its own Node. Runs locally over stdio via npx. Deploying needs Prefab running and the agent-control permission switched on in Prefab's settings (Prefab 1.1.6 or later), and the destination must be a folder already granted to Prefab.
Before you install
Deploying creates folders and files on disk, so check the preview first. The agent-control permission is off by default and must be enabled in Prefab; on versions before 1.1.6 only the read tools work. The server reads Prefab's library directly and never writes to it, and it has no network access.

Installation

In SourceWeft

  1. Open Prefab in the dashboard and add it to a workspace.
  2. Enable the server for the chats that should use its tools.

Desktop only via STDIO. STDIO servers start a local process, so they need the SourceWeft desktop host.

Other MCP clients

Follow the launch instructions in the repository.

README

prefab-mcp

An MCP server for Prefab, so an agent can see your templates and deploy one for you.

"Set up a new client folder for Northwind, autumn campaign, on my Desktop"

What it exposes

ToolDoes
list_templatesEvery template, what it creates, what it asks for
describe_templateOne template in full: structure, placeholders, actions
preview_deployWhat a deploy would create, and what values are still missing. Creates nothing
deploy_templateCreates the folders, filling in the values given
list_watched_foldersFolders Prefab is watching, and the rules on them
list_globalsLibrary-wide placeholders, actions and value presets

Setting it up

Works with any client that speaks MCP over stdio.

As a bundle - download prefab.mcpb from the releases page and double-click it. Clients that install MCP bundles, Claude Desktop among them, bring their own Node, so there is nothing else to install.

From the command line (Claude Code, and anything with the same idea):

claude mcp add prefab -- npx -y prefab-mcp

In a config file - Cursor, Zed, and most others:

json
{  "mcpServers": {    "prefab": { "command": "npx", "args": ["-y", "prefab-mcp"] }  }}

Then switch on Let agents and scripts control Prefab in Prefab's Settings ▸ Permissions. It is off by default; reading your templates works without it, creating and deploying does not.

That switch arrives in Prefab 1.1.6. On an earlier version the reading tools work and the rest say so.

Requires macOS, Prefab installed and opened once, and Node 18+ (except for the .mcpb route).

How it works

Prefab is sandboxed and has no network access, so it cannot host anything. This server runs beside it instead: it reads the library straight out of the app group (~/Library/Group Containers/group.VFDG327T66.prefab) and asks the app to deploy through the same prefab:// URL the Finder extension uses. Two consequences worth knowing:

  • Prefab has to be running for a deploy. Reading works either way.
  • The destination has to be a folder Prefab has been granted. macOS keeps a sandboxed app out of your folders until you point it at one. preview_deploy and deploy_template both check first and say so, rather than leaving a permission dialog on screen that an agent cannot answer. Grant folders in Prefab, under Settings ▸ Permissions.

Nothing here writes to Prefab's library. The app owns those files, and editing them behind its back would be overwritten the next time it saves.

Development

npm test    # checks placeholder resolution matches the app's Swift, case for casenpm run try '[["list_templates",{}]]'    # call a tool the way a client does

src/resolve.js is a deliberate duplicate of RenamePattern.swift. If you change one, change the other - npm test compiles the Swift and compares the two.

Source: README.md at commit 96547a7

Tools

0
SourceWeft has not started this package in its sandbox yet, so its tools are not known.

Version history

1
  1. v0.1.1LatestSep 16, 2026

Score

50% of the applicable checks met

How complete this listing is, computed from the registry entry, the endpoint and public sources. Not a rating of the server and not a statement that it is safe or working today: reachability is a dated check, and no installs or reviews go into the score.

  • Reached in the last 30 days25 pts

    Keep the endpoint answering the MCP handshake; SourceWeft probes it every 30 days.

  • Auth declared10 pts

    Declare the credential headers in the registry entry, or keep the endpoint answering the probe so its auth can be classified.

  • Tools listed15 pts

    Answer tools/list without a credential, or ship a package that starts in a sandbox without one.

  • DescriptionRequired15 pts
  • Logo10 pts
  • Documentation15 pts
  • License10 pts