OPEN-27
An interface entry may be unbound; its own declared schema is the contract.
What was open
An author can declare a workflow's interface before building what is behind it, so that another workflow can already call it as a sub-workflow. The rules assumed every manifest entry was bound to a node and a port: the contract was derived from the bound port, an entry with no binding was a client-side draft and was dropped on save, and an unbound entry was malformed at launch. An editor that offered "leave it unbound" lost the entry without a word.
Decision
An interface entry carries a name, and may carry a binding, a node and a port together. An entry with no binding is a real, stored part of the contract. An entry may declare its own schema, and its lane through that schema's x-data-type; where it does, the declared schema is the contract and a binding added later only says where the value goes. A bound entry that declares no schema is built from its port, as before. An unbound input is accepted, checked against its contract, still required when marked so, and delivered to no node. An unbound output is absent from a run result, as an output whose node produced nothing is (OPEN-26), not null. A bound entry whose port's lane differs from its declared lane is a warning, not a refusal, because the interface may have been declared before the wiring caught up. Only a half binding (one of node and port) is malformed. The checks that need a node or a port (R4.c, R4.d, R10) apply to bound entries only.