td-mcp

A lean, token-efficient MCP server for driving TouchDesigner from AI assistants like Claude.

Build whole node networks in one call, search CHOP channels by glob, inspect operators compactly, and screenshot any TOP so the assistant can see what it built. Battle-tested by building audio-reactive and hand-tracking projects end to end.

Why another TouchDesigner MCP?

Compared to a conventional per-node tool surface, td-mcp is designed to minimize round trips and context tokens:

• td_build - create a whole network (operators + parameters + expressions + wires) in ONE call.

• td_find_channels - glob-search every CHOP in the project (e.g. *pinch*) instead of dumping node trees.

• td_get - returns only NON-default parameters.

• td_screenshot - saves any TOP to PNG for visual verification.

• td_ensure_cook - one call installs a per-frame force-cook (fixes the classic "GLSL/feedback network renders once then freezes" gotcha).

• Wrong parameter names return close-match suggestions instead of bare errors.

• Operator paths self-locate by name if the exact path moved.

• One-line tool descriptions - tool schemas are loaded into every session, so short docs are cheaper.

Architecture

Claude / MCP client
   |  stdio (MCP)
server.py  (Python, FastMCP)
   |  HTTP POST 127.0.0.1:9980/api  (JSON)
TouchDesigner: /project1/td_mcp
   |- webserver   (Web Server DAT, port 9980)
   |- callbacks   (Text DAT - HTTP handler)
   |- dispatcher  (Text DAT - 16 command handlers, TD Python API)

The bridge is installed by script (no .tox drag-drop): re-runnable, self-healing, and the DAT contents always match the repo sources.

Setup

Requirements: uv, TouchDesigner (any recent build; tested on 2025.3x macOS).

1. Clone and install:

   git clone https://github.com/YOURNAME/td-mcp && cd td-mcp && uv sync

2. Install the bridge inside TouchDesigner - open the textport (Alt+T / Option+T) and run (adjust the path to your clone):

   exec(open('/path/to/td-mcp/td/install_bridge.py').read())

   Verify from a terminal: curl -s http://127.0.0.1:9980/api -d '{"cmd":"status"}'

3. Register the server with your MCP client. For Claude Code, in .mcp.json:

   {
     "mcpServers": {
       "td": {
         "command": "uv",
         "args": ["--directory", "/path/to/td-mcp", "run", "python", "server.py"]
       }
     }
   }

4. Restart the client and ask it to td_status.

Tools

Field notes (learned the hard way)

• TD's Python open() defaults to ASCII - the bridge sources are pure ASCII.

• ParMode is not on the td module inside DAT modules; the dispatcher uses type(par.mode).EXPRESSION instead (version-proof).

• Feedback TOPs need an actual input connection, not just a Target TOP.

• COMP-to-COMP wiring requires matching connector families (a CHOP output cannot feed a DAT input) - check outputConnectors[i].outOP types.

• After building feedback networks, pulse resetpulse once to flush any pre-expression frames the loop may have latched.

Credits

Bridge-over-Web-Server-DAT architecture inspired by 8beeeaaat/touchdesigner-mcp.

License

MIT