Environment variables

Runtime knobs M* reads from the environment. New variables should be documented here as they are introduced.

Communication

Variable	Default	Meaning
MSTAR_RUST_ZMQ	AUTO	Transport selection for the ZeroMQ control mesh (see mstar.communication.communicator.make_communicator()). AUTO: the Rust-backed RustZMQCommunicator when the vendored rust/ extension imports successfully, pyzmq otherwise. 1: the Rust communicator, raising if the extension is missing. 0: always pyzmq. The two transports are wire-compatible, so this can be set per-process while the rest of the mesh stays on pyzmq.
MSTAR_ZMQ_TRANSPORT	constructor’s protocol	Overrides the communicator protocol (IPC or TCP) for a process, e.g. to run entities on separate hosts.
MSTAR_ZMQ_TCP_HOST	127.0.0.1	Host used to build peer endpoints when the protocol is TCP.
MSTAR_ZMQ_TCP_BASE_PORT	19000	Base of the deterministic entity-id → TCP port map (api_server = base, conductor = base+1, worker_<rank> = base+100+rank).