Configuration¶

Environment Variables¶

Variable	Default	Description
`HOUDINI_HOST`	`localhost`	Houdini host address
`HOUDINI_PORT`	`8100`	Houdini hwebserver port
`FXHOUDINIMCP_PORT`	`8100`	Port for the Houdini plugin to listen on
`FXHOUDINIMCP_AUTOSTART`	`1`	Set to `0` to disable auto-start
`MCP_TRANSPORT`	`stdio`	MCP transport (`stdio` or `streamable-http`)
`LOG_LEVEL`	`INFO`	Logging level

Auto-Start¶

The Houdini plugin auto-starts on scene load via scripts/456.py. Disable this by setting:

export FXHOUDINIMCP_AUTOSTART=0

You can still toggle the server manually using the MCP Server shelf tool.

Transport Modes¶

stdio (Default)¶

The AI client spawns the MCP server as a child process. Communication happens over stdin/stdout. This is the simplest setup, no ports or networking required on the MCP side.

streamable-http¶

Runs the MCP server as an HTTP endpoint. Useful for remote or shared setups:

export MCP_TRANSPORT=streamable-http
python -m fxhoudinimcp

Custom Port¶

If Houdini's hwebserver is already bound to port 8100, configure a different port:

Set FXHOUDINIMCP_PORT in your Houdini environment
Set HOUDINI_PORT in your MCP client config to match