Once simplified via database abstraction, the command layer may be formally defined as a language of events, that language specified to be textual, and the system that accepts this language be implemented as a command interpreter.
The shim is such a system; it accepts text commands from the downstream client, and so simplifies implemenation of that client over the alternative of a direct socket connection; uses a schema-driven parser that type-checks attribute values, constructs events according to those schema, and recovers from message errors using a conservative algorithm that discards only one token per mismatch; and simplifies debugging, exposing the tws api protocol languages by echoing binary and text data to various output channels.