Tool

A tool is a standalone program, which can be executed from the command line. Examples are a combined library ("bloch_sim.exe") or a python script ("python sar_calc.py").

The tool retrieves its inputs via the MRX: ToolAPI, does its computations (optionally reporting progress) returns the output via the same API, then shuts down. This makes writing tools very simple: It can be written in any language supported by MRX (currently Rust and Python). A short, self contained file or script is sufficient, the result is a small, independent executable program or script.

Host

The host can be any environment that executes tools. Examples are:

• A self-contained program like a viewer or GUI for MR tasks
• A shim between the tools and LLMs, exposing the capabilities of the tools via MCP
• A python script, optimizing a sequence using simulation and reconstruction tools
• A jupyter notebook session, interactively experimenting with MR ideas with the help of tools.

The MRX: ToolAPI makes it easy to define all input parameters, call the tool, poll progress and retrieve its output. Errors of the tool are passed to the Host. From a programming point of view, calling a tool feels very similar to calling a function. The limited set of possible parameter types makes it possible to easily exchange tools with similar purposes, even if they were programmed completely independently from different people.

Connection

The exact method of communication between Host and Tool is deliberately opaque. This avoids lock-in into a specific host-tool combination, exposing the exchange of values as the only observable effect of MRX: ToolAPI. It also makes it possible to iterate and improve the exchange method without requring any code changes to the Host or the Tool.

Currently, the project opens an inter-process channel (Windows named pipe or UNIX domain socket), serializes all values to json and passes it over the channel.