Managing interfaces for dataflow graphs composed of sub-graphs

Specifications of dataflow graphs are generated and/or combined. A sub-graph interface (123) of a dataflow graph includes one or more flow junctions. A flow junction (204D) representing a connection between: a flow of data outside the sub-graph interface, and a flow of data inside the sub-graph interface. In some embodiments, information is processed to generate a combined dataflow graph specification (300), including: identifying an association between the sub-graph interface and the first dataflow graph specification, for at least a first flow junction, determining a direction associated with transferring a value of a descriptor, and transferring a value of a descriptor according to the determined direction. In some embodiments, a link (229) is rendered between the first flow junction and a second flow junction based on user input indicating a relationship between a first descriptor and a second descriptor.