artcraft-command-bridge

One MCP server for the 13 ArtCraft Crafting Apps — 5 tools instead of 799.

Each Crafting App ships its own MCP server that exposes every engine command as a separate tool. Registering all 13 of them costs 799 tools / 547 KB of schema ≈ 140k tokens of permanently resident context, and that payload is re-sent on every request.

This bridge drives the apps' CLIs instead and exposes 5 tools / 3.5 KB.

799 tools · 547.3 KB · ~140,000 tokens   →   5 tools · 3.5 KB · ~900 tokens

Why this exists

MCP clients register a server's tool list in full. The protocol has no "just give me the names, fetch the schema on demand" mode — the client calls tools/list once and keeps every tool's name + description + inputSchema in the system payload forever. Some clients have an on-demand tool search facility, but that covers deferred tools (cron, integrations), not MCP server tools.

The Crafting Apps already share one model that is perfect for this:

• commands — lists stable command IDs with their parameters

• run — executes those IDs

Measured across the 13 apps, that is 7027 command IDs. The 799 tools the apps' own MCP servers expose are only a subset view of the same registry. So the tools do not need to be flattened into 799 separate entries — they need a directory and a dispatcher, which is what this is.

Only PdfCraft ships an on-demand mode of its own (pdfcraft-cli mcp --compact, which exposes a core set plus tool_search/tool_call); the other twelve reject --compact outright, so there was no unified switch to simply turn on.

Related MCP server: MCPico

Quick start

1. Install the apps you want — see getartcraft.com/apps. Each app installs a <app>-cli binary.

2. Register this server with your MCP client:

   {
     "mcpServers": {
       "artcraft-command-bridge": {
         "type": "stdio",
         "command": "node",
         "args": ["/absolute/path/to/artcraft-command-bridge/server.js"]
       }
     }
   }

   Or with the official installer:

   npm install -g artcraft-command-bridge

3. Restart the client so the tools load.

The 5 tools

Example

// what can figcraft do?
{ "app": "figcraft", "filter": "node.create" }

// build a frame
{
  "app": "figcraft",
  "steps": [
    { "id": "node.create", "params": { "type": "frame", "name": "Hero", "width": 1200, "height": 800 } }
  ],
  "output": "D:/out/hero.figcraft"
}

// export it (not a command ID — use the escape hatch)
{ "app": "figcraft", "args": ["export", "hero.figcraft", "-o", "hero.png", "--format", "png", "--node", "Hero"] }

How it works

Every app's run takes its commands in a slightly different shape. The bridge translates one uniform { id, params } model into each app's own syntax:

The command registry is exposed differently too, so the bridge normalises it:

Finding the CLIs

artcraft_apps reports what it found. The bridge probes, in order:

1. ARTCRAFT_<APP>_CLI — e.g. ARTCRAFT_PHOTOCRAFT_CLI=/opt/craft/photocraft-cli

2. ARTCRAFT_HOME and the official per-OS app roots (%LOCALAPPDATA%\storytold\apps, ~/.local/share/storytold/apps, ~/Library/Application Support/storytold/apps)

3. PATH (<app>-cli)

4. System install locations (C:\Program Files\<App>Craft\, /Applications/<App>Craft.app/Contents/MacOS/, /usr/local/bin)

Apps that are not installed are reported as such and skipped — the bridge never fails as a whole because one app is missing.

Why not an existing tool?

• eznix86/mcp-gateway (MIT) — a general-purpose gateway with the same idea, but it aggregates MCP servers, so the 13 Crafting App servers still have to be running as upstream processes, and its search is text-similarity rather than an exact registry lookup.

• ai-2070/claude-storytold-skills (MIT) — a Claude Code plugin whose per-app skills use grep over generated reference catalogs. Same goal, different layer: it still registers every app's MCP server with claude mcp add, so the tool schemas stay resident.

• smyrgeorge/artcraft-toolbox (Apache-2.0) — a suite manager (install, verify, update, launch). It is complementary: the toolbox gets the apps onto your machine, this bridge makes them pleasant to drive.

Development

node tools/probe-mcp.js           # probe every app's MCP handshake + tool count
node tools/schema-size.js         # measure schema weight, refresh registry snapshots
node tools/agg-test.js            # end-to-end self-test of the bridge
node tools/per-app-verify.js      # verify each app's run argv is accepted
node tools/cursor-launch-check.js # start the bridge the way a client would

Zero runtime dependencies; Node ≥ 18.

License

MIT — see LICENSE. See NOTICE for trademark attribution. The Crafting Apps themselves are open source (MIT OR Apache-2.0) and are developed at github.com/storytold.